Stroker Crank, Rod and Pistons

We are nearly finished with the costing of the above option, but I would appreciate input from some of the more experienced tuners and members regarding the specification of a possible stroker crank, rods and pistons.

A bit of a wish list in terms of the whole package, capacity in cc's, max power, comp ratio, piston diameter etc.

There are a number of factors we need to keep in mind when we develop a stroker crank.

We need to find out how much stroke we can do and still have enough cross-section between the rod journals and main journals to keep the crank strong, light, easy to balance, and affordable.

(You can imagine this concept by looking down the center of a crank and looking where the rod journals are in relation to the mains)

I will post more info up on the Group Buy section once we have a ball park figure in terms of costng, but we should be able to do it with 5 buyers.

Capacity 2.4-2.8l
piston diameter no bigger than 83mm

compression - choice, between 8:1 and 9:1

Power - we can get 400bhp safely from a 2 litre block now, so anyone that's going for a stroker kit will be looking at 500+bhp and possibly a lot higher - JohnS saw over 600 from his 2.4

There is so much to consider when designing an engine, which is what you are proposing as you are getting a custom crank, rod and piston which is essentially the complete package minus the cylinder head. In fact it scares me how much you need to know and it will go way over everyone’s head on this forum including myself and most other experienced engineers. The Stilo stroker crank is not as bad as you are using an existing base designed by Fiat so you know to an extent that you only have to make the rod and piston work together by changing the pin diameter and rod/stroke ratio plus a few other things (not that I agree this has been done correctly as I have never seen the design but it works). With the introduction of a custom crankshaft you need to consider many more factors.

Below is a small list of things to consider off the top of my head but this is by far just scratching the surface:

Con road ratio
Piston to vale clearance
Pin diameter
Pin locking
Pin offset
ring placement
compression ratio
ring width
ring choice
bore size
lateral gas port size
skirt length
crank radii
groove clearance
piston or crank lead
cross drilling oil

If you think you can just slap a few measurements together and the piston/rod/crank manufacture decide for you whilst getting 5 people onboard for production discount then you are very much mistaken. How are you going to test this setup or are you just going to sell it and say at the owners’ risk? You cannot rely on the manufactures to make the decisions for you, sure they will advise on what they think is best but without working out the complicated maths and I really mean complicated maths of engine design and simulation as a foundation for justification you are asking for trouble. Below is a snippet of 7pages from and 800 page book just on this topic alone. If you don’t understand this then you will NEVER understand how much work is involved as this snippet is the easy part in fact it’s the introduction .


I am not trying to say you cannot do this but to get people from this forum onboard without explaining the high risks they are taking is bad. If you develop this for yourself and test it then that’s great but to use other people’s money as guinea pig money to keep your production costs down for an untested product is a very bad idea. I have done it once in the past but I have learned never to do it again, luckily what I did paid off but never the les it could have gone the other way. Barbz tested and developed his 2.4 conversion on his own/JohnS engine before releasing it to the public for sale. What you are proposing is NOT this. Legally people can hold you responsible as you are the reseller/brains behind the product. Lets say you do this and people engines blow up because of a mistake was made YOU can be taken to court.
In fact it’s been four years since you last posted your spec on here so what ever happened to?

The Technical Specification

You can use a stock 2.4L motor from a Stilo, but you will have to “space out the motor”, but more on that later.

Sub Assembly
Bore – 84.50mm (Re-bore standard 83.50mm)
Stroke – 91.40mm (standard 90.4mm) You can re-grind the crank with an off set to fit the new rods and to increase the stroke. Increased stroke means more power and less stress on the piston and rod due to reduced lateral pressure on the sleeve side walls.
Deck height – 178.30mm (center of crank to top of the block)

Conrods – Eagle rated to 750 BHP
Big end – 52.09mm
Small end – 20.00mm
Width – 21.00mm. We under cut the rod width to allow for improved oil dissipation at the big end and less friction. We centre the conrod on the piston and not on the crankshaft

Pistons – Wiseco including rings and high comp wrist pin, slipper piston design
Compression height – 30.87mm
Dish: - 25cc
Bore – 84.50mm

Cost
Pistons – GBP575.00 (we offer a cheaper version that does not have a thermal barrier coating)
Rods – GBP425.00 (we offer a cheaper version that excludes our modifications)

The rods are standard off the shelf units that we re-work and the pistons are custom made.

The EVO RSE 575

Specifications:

Sub Assembly
EVO RSE Plasma Nitrated Engine sub assembly
EVO RSE Proprietary Crank shaft (Plasma Nitrated)
EVO RSE Proprietary Pistons with anti friction coating and thermal barrier treatment manufactured by Wiseco Pistons
EVO RSE Proprietary Billet Rods (rated to 750bhp manufactured by Eagle)
Performance wrist pin and rings by Wiseco
Toga performance bearing set

Head assembly
EVO RSE Big Valve head (FIAT Stilo) 3 angle cut valve seats
EVO RSE Rev Kit and head modification (8500rpm)
Match ported and flowed

Transmission
QM V Drive Clutch kit good for 500NM +
QM Flywheel
QM Hydraulic Race Release bearing
EVO RSE Stainless Steel Hydraulic hose for clutch

Lubrication and Cooling
EVO RSE Dry Sump System
EVO RSE 19 Oil cooler (19 rows)
EVO RSE electrical water pump conversion
EVO RSE Alloy radiator upgrade

Engine Management
KMS Programmable engine management unit and mapped to 575BHP on 98RON
KMS Linear lambda controller
KMS Map sensor
EVO RSE Wiring Loom and all fittings
5 X Marren Fuel injectors 575cc
5 X Bosch Injectors 390cc
EVO RSE Twin Fuel Rail Assembly
EVO RSE modified intake manifold
EVO RSE twin fuel pump assembly including hose and fittings
EVO RSE fuel filters with reusable elements

Forced Induction
EVO RSE Exhaust manifold with external wastegate
EVO RSE Blow off valve (50mm)
Turbo smart external wastegate (50mm)
EVO RSE FMIC (600 x 300mm x 76mm)
Garrett GT3582R ball bearing turbo (600bhp)
EVO RSE boost pipes
Eaton M45 Supercharger
EVO RSE bypass valve

Suspension
EVO RSE Chrome Alloy Front A – Arms with PU bushings and spherical bearings (in development)
EVO Engineering Chrome Alloy sub frame (in development)
EVO RSE Front Upside down Coil-over kit with Hyperco springs
EVO RSE Rear Adjustable Coil – overs
EVO RSE Adjustable camber plates
EVO RSE Strut Bar

Brakes – No more ABS
EVO RSE 6 pot radial mount front brake conversion (Wilwood calipers)
EVO RSE 335mm X 32mm brake disks
EVO RSE 4 pot rear brake conversion (Wilwood)
EVO RSE 305mm X 28mm brake disks
Wilwood BP – 15 Pads
Tilton Twin pedal brake conversion and Tilton Series 75 master cylinders
EVO RSE Braided Stainless Steel Brake lines

Lighting
EVO RSE XENON HID Kit (Front)
EVO RSE LED Kit (Rear)
EVO RSE LED Indicators
EVO RSE XENON HID Fog Light Conversion

Interior
EVO RSE Racing seats
M&R 6 point racing harness
EVO RSE 10 point Roll cage (in development)
EVO RSE MC Performance gauge

Body Styling
EVO RSE GRP Bonnet
EVO RSE GRP Front spoiler
EVO RSE Rear spoiler
EVO RSE GRP boot lid
EVO RSE GRP Front spoiler inserts
EVO RSE Lexan window set (5 pieces)
18” Dimag Magnesium Alloy wheels
Dunlop R 225/40/18 rubber

Yes, sacrificed the aircon for the supercharger.



Didn’t think it would be 27 November 2010

have you looked at the configuration from the 2.4l stilo crank that has been used in the 2.4 conversion before?

I dont want to put a downer on your development work, but you may well struggle to get 5 buyers depending on the cost. I would love to see some more 2.4l coupes though!

I8AV8 (Matt?), I remember way back when, the various 'discussions' you had/posted including a 200mph project. You even tried an Eaton M45 which apparently didn't work. From the impression I got, you are a very knowledgeable man who should have a tried and TESTED kit ready for sale, not one where nobody will have a clue if it will work or not.

I'm aware you know ALL about the Stilo block, Rods/Pistons etc. so maybe it is a version of this you are/should be selling.

Whatever did happen to your coupe pjoect?!!! Surely 5 years is more than enough time?!

Thanks for the brain dump,

One of the hottest discussion points on this forum has been the 2.4l conversion and the issue of forged pistons and conrods as an upgrade on the 20VT.

During the past couple of weeks I have been trying to highlight the fact that you don’t have to go for the most expensive components to achieve the same results as you would with custom components primarily sourced in the EU.

You have been on my case since I started with this initiative and to be fair I would appreciate it if you would be as thorough as you were in taking my post/ topic apart in discussing the following.

To build the bottom end of the 2.4l stroked motor a Stilo 2.4l crank, custom rods and pistons were used by JohnS and Brabz. So tell me, how much complicated math went into the 2.4l Stilo conversion?

Was the Stilo crank developed for a forced induction application or a NA application?

So would it be safe to say that a custom billet crank made to the same specification as the 20VT crank with the exception of the stroke that is increased to 90.40mm (same as the Stilo crank) would be the same as fitting a Stilo crank?

Let me get this one for you, maybe I can post a couple of snippets to enlighten you. The custom billet crank will be better since it is stronger, lighter and more cost effective because it requires less engineering to install and you can use the standard 20VT flywheel and clutch and it would be far more accessible and less risky that hunting around for second hand Stilo cranks.

Further more the crank, pistons and rods that will go with the stroker kit is made by the same company which ensures 100% compatibility.

How is the above approach untested (does the Stilo crank work or not??) and of higher risk than installing a 2.4l Stilo crank with pistons from one manufacturer and rods from another?

How does all of the above boil down to using other people’s money as guinea pig money?

And lastly please enlighten us to the difference in risks associated with the 2.4l Stilo crank and the 2.4l custom billet crank? Be so kind and explain them.


This brings me to the custom forged rods and pistons. When you are upgrading the standard 20VT motor or building a 2.4l motor the traditional route would be go for custom rods and pistons and to be honest I would agree with the custom pistons, but there are other options in respect of forged rods other than the made to order units you are promoting on the FCCUK forum.

I have a feeling that you are now going to go into a long winded discussion about the inferiority of forged rods made in the Far East and finished in the USA, but they work and they have been doing so for years. K1 and Eagle are reputable products (minimum 150bhp per rod) and with minimal engineering work they will work in the 20VT.

K1 will manufacture a custom rod for the 20VT motor for under USD450 provided you order 8 sets.

How am I using other people’s money as guinea pig money? The only product on offer in any of the Group buys that will not fit the standard 20VT is the Eagle rod and that only requires a big end diameter increase on a honing machine of 0.15mm which could be beneficial since it would give you the opportunity to hone the rod big end to exactly the size you require to match up with your crank.

Secondly, I am not making 1 cent on any of these deals and you are welcome to try and buy any of the components that I listed in any of the proposed group buys at a lower price. I am offering the product at whole sale cost. You are welcome to contact Race Engineering directly and check for yourself on the pricing.

I have asked Begbie to open a topic for me in the Project area so that I can post the final build of my car, but unfortunately I have had no response to date.

I have had one group buy on this forum for HID kits and to date I have had no negative feedback form any of the members that supported me on that group buy.

I am not even convinced that 2.4l is optimal for the stroker kit and it might be that 2.2 or even 2.6 might be better solutions hence the reason for this post, to discuss and to explore, but as always everything has to be a bloody secret.

Please send the information of any company that sell custom rods, pistons and cranks with a guarantee as to the reliability of the product.
It is my opinion that your attack on this topic is based on financial considerations and nothing else.

Ok let me start of by saying that you may have got the wrong end of the stick. I am only pointing out facts that seem to go by unnoticed so I will comment on each paragraph you have written:


Very true


Also very true

Probably not a lot. But I’m not saying what was done here is neither right nor wrong.

N/A but yet as I said earlier “not that I agree this has been done correctly as I have never seen the design but it works”

Yes, but you are not suggesting this changing the stroke changes everything.

That may be true but can/have you proved this.

Really and how many 5 cylinder fiat engines have they designed and tested? Just because it’s made by the same company doesn’t mean it going to be right.

So you have built and done this already then?

Because you have this idea on paper and haven’t made it work. Unless you have a running engine with dyno results you are risking peoples money.

There is no difference the risks are the same expect the stilo crank has been tested yours hasen't.

I’m not promoting them I don’t care if people buy them or not I don’t make a penny. But what I will say is the piston & rods in my GB are proven.

Not at all I expressed my opinion on this to you via PM and you answered back with a fair comment I have no problem using these componets as long as they meet the spefication stated. If they were totally wrong then I would have made my comments public. Good luck with the sale of these I see no problem with the connecting rods from K1.

That is a fantasict price lets hope quality isn’t the compromise.

I would suggest you remove the Eagle rod completely from the listing and stick with rods that fit properly. i.e K1 you suggested.

I don’t make any money of my GB’s either and I have no reason to question you about price validity but that doesn't neglect the fact that if it is wrong YOU are 100% liable.

That has nothing to do with me

I never suggested that you have negative feedback

I totally agree 2.4 is prorably wrong, but you cannot explore on other peoples money.


Why would they YOU are the engine designer not them they produce the product. If it is wrong it is your falt or to prove otherwise.

Why don't you front the money to test this kit yourself by buying a one off prototype design and building it making sure it works first before asking five other members to trust your knowledge? Because it will be cheaper for 5 people on board won't it? So who is the one benefiting from financial consideration? Not me as it doesn’t affect my life one bit.

My “attack” if that’s what you want to call it. Is based on the fact that you are offering a product that you have not tested. If you said I have prototyped a 2.2-2.8 engine and the results are promising or I am planning to build a new type of stroker kit that I have not actually tested then fair enough but to ask people for group money for a design (if you can even call it that) that is totally unproven and based around the fact that because Barbz has done it and that works so mine should is ludicrous. I am protecting the people on the forum and yourself by letting them know that it is not just a matter of slapping parts together. If they want to take you up on your offer then fair enough but I cannot sit back and let people decide without explaining the risks.

I have no personal problem with you but I totally disagree in what you are suggesting. It may work out fine but if it dosn't what happens then?

As someone who has done just what your talking about for the 16v engine I can tell you the potential for error is enormous. I found it very hard and had to scour the world for help. What would worry me in your case is the nature of torsional harmonics in a 5cyl, it was something I agonised over for the 4cyl and they are much more simple in as much as they are static whereas the 5cyl isn't.

I don't see a lot of reason for increased capacity/stroke, I'd focus on getting it to rev hard, this is the nature of high power small cube engines (which a 2.4 still is)but each to their own, crack on IMO but do it and test it for yourself or you just might end up being hauled over the coals.

One thing I can tell as fact is to compromise on quality/manufacture/materials is foolish, so many stories of poor tolerances, counterfeit bolts, forging consistancy etc to even consider anything but quality manufacturers, they aren't much more expensive.

1NRO you have explained my point exactly.

I want more power but as a numpty, as far as engine building goes,think I will wait until there is a general opinion by the whole forum of the way to go forward on this one.
Paul

I don't have anything to add to what TurboJ or 1NRO have said as my own views echos there's

But there is so much to discuss on this subject it's difficult even on a forum. It would be easier if you raised individual points that you want to discuss

But I have breezed over the aspects of upping the capacity in the coupe block and no matter what you do there seems to be massive compromises in the design, as 1NRO said if your after ultimate performance the best option seems to be to keep the capacity about where it is as this offers the best compromise and work on effiency and eaking more RPM out of it to gain the desired performance


But answer me one question what are you trying to gain buy increasing the capacity? Give me a figure or a specific charicter you are seeking?

Another point is the deck height on the stilo block is taller. This makes it easier to keep a higher CC without putting the pin so far into the piston keeping a nice rod to stroke ratio and plenty of space for ring placement. Using the coupe block seriously compromises this ratio and as mentioned above many other factors.

I think I worked out a few years back that using the coupe block with a custom crank a 2.2L was a cc that seemed to be the best compromise in terms of ring placement, pin size, rod to stroke ratio, bore to stroke ratio etc...but this was only running some basic numbers on paper. Actually going ahead with the development is far more complex.

Thanks for responding,

The concept behind this post was to invite people to comment on the feasibility of developing a truely custom value for money stroker kit for the Fiat Coupe 20VT.

Why a stroker kit?, because it is continously being raised on the tuning section and a lot of members has been asking the question.

It is my opinion that the 2.4l route is not optimal in the 20VT bottom end and that a smaller capacity motor (maybe 2.2l) would be more reliable in the long run. There is a reason why Fiat increased the deck height fo the bottom end.

Ultimately your money would be better spend developing a quality exhaust manifold for the 20VT that is efficient/ strong and can accommodate a number of turbo options.



I will

I think if you could present people with a package of rods, pistons, crank etc which would would be a plug and play kit (i know it's not quite that simple but you get the general picture) a lot of people would be interested.

But only and this is the main point, if you have the kit on a car which is up and running.

A further development of the idea would be to provide people with the entire bottom end built up with the new parts once it's proved it works.

Roger Clark Motorsports do 2.5l subaru bottoms ends, if you did something similar like this for the fiat i am sure folk would be very interested.

Eh?

I'll accept that its a bit restrictive on the range of suitable turbos, but the stock manifold has proven itself to be better than any tubular manifold produced thus far. The stock manifold (admittedly port-matched) has been used on just about all of the big power Coupes in this country - the only reason I can see for going tubular is if you want an external wastegate (which I realise will release power in its own right, due to the better turbine housing)

Hi there Nigel,

I don't exactly understand you comment since you agree with the fact taht teher could be benefits.

What I am trying to say is that if you want to develop an upgrade for the 20VT the tubular manifold would be a better option than the stroker kit.

Doug20vt, thanks for the comments, I agree, but I first want to get the costing done of this project and then we could look at other options.

Nigel, even though this has nothing to do with a stoker kit (we are going off topic). I completely agree with Matt here. If I was given a serious budget to develop an item on the coupe it would be the manifold. A turbo manifold is extremely critical to turbo efficiency and engine output, I have always felt that getting the manifold correct is key. The problem here is not only the fact that it has five cylinders but other aspects such as space, bend radii, pipe diameter, pipe length, material, costing etc. The Fiat cast manifold may address some of these issues and may appear to “proven itself to be better than any tubular manifold produced thus far” but I feel there is a lot to be gained in this area if done properly especially when you try and pulse tune it.

I'd agree but unless a special engine is being developed I'd consider the exhaust to have more influence, every psi of back pressure that can be reduced in the downpipe transfers into a psi less in the manifold. My honest feeling is the area to concentrate on is the inlet side of the engine, to my eyes this usually is a mess.

The thing with exhaust manifolds is that to do a proper one means scrapping the oe turbo location and providing a location that allows the length and routing to start thinking about harnessing pulse tuning, there are very few engine build that change the turbo location much.

Nik

2 things
- why develop a custom-made manifold, if there are good solutions on market? I use a special Cufaro tubular manifold in combination with a 2,4l engine and a GT3082R - result is full boost at 3200rpm! Try this with a standard manifold - you won't be successful, because tubes do not have the same length etc.(no kinetic energy of the exhaust etc.)
Moreover the 4th tube is too short - the other cylinders will press their exhaust into the 4th port...
therfore in almost all cases 4th cylinder is first cylinder which will start pinking.
In my opinion the original manifold is good for maybe 450HP... after this you will definitely get big problems to get the heat out of cylinder No.4.
Other very good solution sells TIGART. They produce very good manifolds as well.
- to 2,4l crank from stilo: why develop a new crank?! This crank is proven to do >600HP, much more than the gear box will do over a longer time???
Hartmut in German forum ground the crank for more stroke and used shorter rods from an Audi RS x? (I do not know the model any more). I think regarding torque in lower revs this real 2,5l engine is the strongest Coupe engine available so far. Full boost with a big GT2871R at a little bit more than 2000rpm and original manifold.
Let's imagine what the engine would do with tubular manifold...
Juergen

Juergen, I think they used the Audi RS2 rod which is 144mm CTC which is 1m shorter than the 20VT rod. Scat makes them

The RS2 rod needs minor work on the big end to make it fit the Stilo crank, you mentioned that they ground the Stilo crank, it would interesting to find out if they re-hardenend the crank afterwards.

My main concern on the Stilo crank in the 20VT turbo is the increased side lateral force on the piston skirt and on the cylinder sleeve.

I don't want top go off topic in my own thread, but why is it so important to have a tubular manifold made from stainless steel? Won't shot peened steam pipe with a ceramic coating do the job? I guess your road conditions are far more abrasive with salt added on the roads for icing etc.

My experience from the plasma nitriting process is that you have to balance the crank afterwards and

Hello Nik,

as far as I know the crank has been rehardened by use of nitrite.
If done well, it won't need balancing any more?!
To your other problem - increased lateral force on the piston skirt - this problem you will have with every long-stroke engine and short pistons?! I do not see any problem here. I did some invetigations regarding the piston / rod design. It is ok.
Only problem I could find is that the opening width of almost all forged pistons is wider than the opening width of original piston. Therefore you won't lose the piston guided design of the rods - means the rod is not guided any more and it can slide along the crank. A solution would be to use special high-tensile aluminium washers, free of clearance - else they will saw through the pisto pin.
This solution is proven in race engines - thus there should be no problem.
The additional lateral force regarding the piston lead -design is absolutely negligible, no problem for the short pistons.
Fiat chose best solution for a sport engine - piston lead design. Thus Aston Martin claimed that the new engine of One-77 reduced friction levels by using piston guided design instead of crank guided. This resulted in 1,2% power gain (from magazine engine technology).
Fiat knew this 15 years before :-)
Juergen

theres no need to change the turbo location like people have said before "we have had 500+bhp with equal length tubular manifolds that keep the turbo in the same position" also sorting the exhaust pulses out is easy with a good manifold and ported turbo set up.

To be optimum you do need to move it, there's no way in the world you could get the required lengths of runners in that space, suprisingly long when you look further into it.

Juergen,

I think your reply was meant for I8AV8 whose name I don't know? Interesting though, have you retained a piston guided setup or are you using floating pin pistons now?

Nik

100% agreeded.

disagree due to the fact ive seen 4 balanced tubular manifolds so far which retain the turbos position and like i said before if johns made that power without moving it then why move it?

I'm with Juergen and Knight here, why is there a need to develop a brand new manifold when there are two proven manifolds which will support big power? Both of these have produced 550bhp+ so it is more than enough for 99% of coupes.

There is also the arguably the best designed manifold of the lot with the TigArt version which has also supports big power. So although in theory it might be better to move it, it is absolutely unnecessary in my opinion especially with the manifolds available.

Just depends how much you want to leave on the table? Optimum takes doing.

Exactly, compromises have to be made tuning the 20VT without going into uncharted terroritory and potentially spending huge sums of money. For example nobody has a rev limiter past 8000rpm, no aftermarket LSD and the only custom gearset costs 5k+.

If the manifold is unneccesary then so is the 2.4 conversion, at the end of the day you set a target and develop the best yo can to that point, if you wanted there is no reason why 900 bhp would not be possible with the right amount of development to the 2.0 litre setup, tue argument here is what's going to be best or cheapest


This is a pointless discussion if we don't have a target to aim for and discuss the best options to get there

I agree with Trickymex - if F1 turbo cars can get well over 1000 bhp from 1.5 litres, then a 2 litre Coupe must be capable of roughly the same

However, it would require massive investment and huge development resource - for example, the gearbox would be custom, the chassis would need to be re-engineered, the block would be strengthened, the crank would be a one-off, as would the rods and pistons. The head would have to be a complete work of art, with lots of hyper-expensive materials used for valves, guides, cams etc

And after a easy 30-50 grand, you'd be left with what? A stupendously fast Fiat Coupe that would probably be close to undriveable on the road

Personally, I reckon a 500bhp Coupe is the limit of what is achievable for remotely sensible money (ie sub £10k). After that, its telephone numbers on the invoices

That is not the point I am making I know JohnS makes the power. But is it optimum? no. To optimise the pulses the tubes will need to be modified and turbo location will likely have to be moved to achieve true optimization. I am talking on the fact of proper development with a decent budget and nothing else. Plus you cannot compare a four cylinder engine setup to a five it’s a complete different ball game. That extra cylinder causes a major issue for manifold design. The point I said and I will say it again “If I was given a serious budget to develop an item on the coupe it would be the manifold.”

one mans optimum is anothers so obviously not

It's not that expensive really, if your buying a custom manifold like Begbie did your mostly there. All that needs to be done first is to forget about the oe location and come up with one that assists in allowing much straighter pipes the length that would put you in a tuned length ballpark area and to them manufacture the bracketry that will hold the turbo in its new location before lashing the cash with a suitable craftsman.

To nail down an exact length is impossible, application dependant and to dail it in on a desired rpm would require two manifolds with different length to test and evalutae before further manifold lengths could be made to get closer still. Not really a concern unless your competing at a high level, somewhere in the relevent region would do just great.

Now I have to ask:
What do you want???
You want to have a reliable Fiat Coupe doing 500HP...

My thoughts
1. Existing manifolds do this without any problems. I read a lot of book about manifolds. Every specialist tells another story:

For example MacInnes suggests that turbo exhaust manifolds should use small diameter runners with about the same internal area as the ports and that in turbo engines, the use of "smooth flowing exhaust headers with beautiful swerving bends.... is more aesthetic than power-increasing"

Allard (from 1982) suggests the use of a log-type manifold pipe of not more than
2.5 times, and not less that double, the area of one exhaust port. The log is joined to the individual exhaust ports with stubs with the same inside diameter as the exhaust ports, each as short as possible and of equal length. The stubs can enter the log at right-angles or be angled towards the turbo.

Book "Supercharging und Turbocharging"

In a pulse-type manifold, Humphries suggests that the pipe runners should have a "cross-sectional area....not significantly greater than

the geometric valve area at full lift [and] these connections should be kept short and free of sharp bends".

He says the reflection of pulses within the system will be determined by pipe length, exhaust temperature and the status (ie open, closed or partially open) of the exhaust valves.

In order to take advantage of this pulse flow, "narrow pipes from several cylinders can be connected through a single branched manifold to one turbine....a four stroke engine which can have its cylinders grouped into threes is particularly attractive." This is because "the opening periods of the exhaust valves follow successively every 240 degrees with very little overlap between them.... thus a sequence of pressure pulses arrives at the turbine..."

Humphries suggests that the use of twin turbos on a six cylinder engine allows for efficient pulse operation, and where cylinder multiples are not in threes, a single turbo entry can be linked to multiple cylinders through "pulse converters". Pulse converters are suitably shaped junctions which prevent reverse pulse flow. Humphries shows a four cylinder exhaust manifold with cylinders 1 and 2, and cylinders 3 and 4, paired and then coming together through a pulse converter junction.

My conclusion:
You will get the best manifold by try and error. To claim that it will need longer tubes is no proven experience.
With existing manifolds you will get much more than 500HP - this with a very good power band...
Why should I design a complete new manifold and play guinea pig...
You will invest a lot of money for perhaps 100rpm earlier boost (or later, if wrong designed?)
Another topic: It is proven that the gear box is the weakest part in 500HP region?!
Nobody talks about this?!
There is no solution on market (for 6gear box)...
Thus - to develop a new manifold is useless in my opinion...
If your engine (because of your special designed manifold) would do 600NM in 3000rpm your gearbox will get killed after a short time...

Juergen

I personally think that to rework/ increase the strenght of the 20VT gearbox will be far more expensive than developing a stroker kit or a reliable efficient exhaust manifold.

How much benefit in terms of horsepower gain will be achieved with any project is relative depending on the total package and specifically what turbo is used in the build.

Maybe we must ask the question as to which upgrade will make more power on the 20VT more affordable.

Unfortunately it is a case of not being able to satisfy everybody in respoect of what they expect from a specific component. FE Some are very pro equal length and others want more pulse etc, you will never satisfy everybody.

I have also noticed that stainless steel is almost always a pre requisite for an after market exhaust manifold, but most writers on the matter recommend using Buttweld Fittings as mentioned here http://autospeed.com/cms/title_Making-Turbo-Manifolds-Part-1/A_2604/article.html

The above artcale and part two get quoted quite often on this forum and it makes for interesting reading.

Juergen,

This is a thread about optimum effort engine not what is possible with standard parts. It's wandered all over with different areas under discussion, such things as squeezing more capacity, what a proper exhaust manifold consists of and now gearboxes. The level we are discussing is only the best possible, not to dismiss excellent effort by people to date but rather what is possible.

With regard to capcity I stand in the camp that says it's really not an area worth changing. Much could be written about it but an example if you like from the real world. Titan Mototsport in the US compete in a class that includes some big V8 stuff like the Americans love, capacities over 600ci. Titan lead the way currently with a miserable 190 ci. http://www.youtube.com/watch?v=sTaPp9vLYe0&feature=channel

Quite simply a high spec exhaust manifold that is going to make an attempt on harnessing wave/pulse action won't be a log manifold, they work as you say but not to the full potential possible. Another extreme example maybe, look at the manifolds used by the F1 teams from back in the turbo era, no short runners seen there, pretty picture of an italian attempt http://i3.photobucket.com/albums/y85/1NRO/f1turbo3nh6.jpg
This trait is seen over and over in high end turbo engines used to this day, not by accident I'm sure.

Ah yes, the bloody transmission. Hard to discuss properly on here with some guys FWD and some like yourself AWD, I'd be of the opinion that there's always a solution. You yourself have seen the gearbox do fine at strong power, by the time you've fitted the spectacle plates my hunch is you'll do well to kill the gearbox. The FWD guys face the prospect of re engineering the transmission, wait maybe for someone to offer better internals or take the matter into their own hands? thats up to the individual but I'll bet anyone wh gets to that stage would be better of getting stuck in, they might wait some time before someone else wipes their backside. How might it be pursued? Hand a wedge over to a gearbox company of good reputation and get them to make a bespoke set of gears and engineer them into the oe caseing, do the work required to mate a gearbox from another car which has the potential to cater for requirments (some excellent products out there to fit Honda and Mitsubishi FWD gearboxes) or if they are taking their search of optimal seriously turn the engine and mate one of the many gearboxes available for RWD. One thing for sure is there is always a solution.

Nik

Here's a good example of a car with an optimal exhaust manifold.
http://i3.photobucket.com/albums/y85/1NRO/manifoldlength.jpg

For sure this is no good solution from my view.
It's a very bad solution!
You will need the exhaust impulses from your engine to get the turbine wheel spinning (means kinetic energy)
You will loose this energy, because the volume from outlet to turbine is too big!
Moreover the turbo lives from exhaust temperature - you will loose a lot of it because of such a length.
A formula one has installation place problems – therefore I am sure they would have chosen another solution, if they would have more space!
Juergen

I think the fact he gets his heavy nearly complete road car into the 8's is testament to the fact it does work. There are a ton of examples I could give you but sometimes the horse just won't drink. I could go on and examine all your points with evidence to back up my claims and try my best to show you the reality but I don't think it's worth my effort. Carry on as you are, makes no odds to me.

ditto

Personaly I'd leave flea and the other big boys to it, in 5 years time we'l have the knowlege or at lest a man that does! to build 500bhp coupes, but I really think you lot should stop and think where the hell can you find a cheap, not so common, turbo charged out the factory monster and modifiy with the complete help of this site and the members come and gone to produce power upto 350-400bhp without striping the engine down and forging and lightening and balancing fly wheels, cranks ect.

Other then a Audi s4 and the alroad I don't know of any other cars where you can get 350bhp just like that! Granted you need a decent turbo but if your a good spanner monkey you can do it

with regards to the gearbox issue, a lot of the internals of the alfa, lancia gearboxes can be swapped to give different ratio's,

i currently have a mix of alfa, fiat and lancia internals in my gearbox to give me the ratios i want

whether they would stand up to the big power that is being discussed here is a different issue

from a personal point of view going back to the idea of a stroker kit for the 20vt, i am sure if you offered a complete package that wasn't that much more than the known forged pistons and rods that are currently available for the 20vt i am sure lots would be interested

if you were aiming for 400bhp say with the aid of a gt2871r for instance, rather than going forged and having the power come in at 3700rpm if you could fit this kit and have power come in at around 2500rpm it would make the car massively more driveable with the power available at far more useable speeds

rob40's 2.4/5 is just that, no lag.

that must be a fantastic car to drive with that set up, massively quick at everyday speeds without having the rev the nuts off it

"You will loose this energy, because the volume from outlet to turbine is too big!"

This statment is nonsense, these primarys are full of gas flowing all the time even at idle. Soon as the throttle is touched the flow volumes become huge.
A turbine does'nt care for temprature, it works by way of a pressure differential accross the turbine wheel. High temprature is what kills a turbo not to mention exhaust valves when the pressure backs up and can't get away at the higher rpm. By virtue of having a turbo placed in the exhaust stream LOOSES bhp and there is not much that can be done about it.

This shows me, what knowledge you have from thermodynamics…
For you as information: I am a engineer and studied these topics amongst other things on an university in Germany. Up to now I am test / quality engineer in a big automotive company. From October I will go back to university and I will teach students regarding measurement technology and combustion engines – for this I will be the officer for the 3 engine test benches in this university.
Therefore: please do not talk about nonsense – I am no idiot! I also programmed the ECU of my Fiat Coupe myself.
Back to topic:
My problem is to tell this topic in English, but I will try. Also I will try to do this not in a scientific way - The turbo lives from two main factors:
- Pressure charging by accumulation (in German “Stauaufladung”): This is the topic, you mentioned. The pressure, coming from the cylinders, fills the collector and this pressurized air then flows through the turbine and get’s it to rotate. This is the simpliest method to get a manifold. Advantage of a manifold, constructed in this way: lots of maximum power.
now consider: when do you have most difference in pressure?! – YES – if the exhaust temperature is really hot – now he have reached the carnot cycle of a heat engine – means very hot exhaust temperature brings most pressure, which can be used for the turbocharger.
The turbo engine with best efficiency in my now older books (from ~2000) was the Opel Calibra Turbo – why – he has a very very short manifold (it’s part of the turbo itself) – therefore you won’t lose any energy regarding temperature. Porsche does another way with their turbo engines: they use ceramic inlines, to avoid temperature drops of the air before turbo.
Try to take a turbocharger and build it to your exhaust. You still have the same amount of pressure… or NOT??? In your theory you should have. But you won’t – you won’t get a good running turbo engine – no efficiency any more, because you exhaust temperature is much too low meanwhile!
Therefore: hotter is better – only problem is the material of the charger – it won’t do much more than 1050°C for a longer time. If you want a better response in low revs, it theoretically helps to insulate your manifold…
- Now to the second (much more effective) method in lower revs: using Kinetic energy, resulting from opening valves – an impulse is coming from the cylinder which has a lot of energy. In Germany this is called “Stoßaufladung” – in English translated impulse charging. To use this energy, all primaries have to be the same length to avoid a backflow of exhaust in other cylinders. You get separate impulses coming from each single cylinder – each cylinder does a impulse which get’s the turbine to rotation. Now you have to secure that you summarize cylinders which do their impulse to the same time. If you don’t do this then one cylinder pushes, the other pulls – no efficiency any more. To avoid this you take the cylinders with same working cycle and collect them. This is simple at four cyclinders, not so simple at 5 cylinders. For this also new chargers have been developed with divided turbine housings. At a 4cylinder you use your common pulses coming from cylinder 1 and 3 and lead it to first part of the divided housing. The same can be done with cylinder 2 and 4. You collect their common impulses and lead it to part 2 of the divided housing. -> result is much better response in lower revs because of this kinetic energy. But now back to our theory very very long primaries to get a wonderful manifold (which is trash – this may be good for very big engines with >5000cc, but not for our Fiat Coupe!).
Try to blow into a little wind turbine from a short distance. You will do an impulse if you empty your lungs – like a cylinder. Now - Take this wind turbine, take a tube, blow into this tube and beyond this tube you place your little wind turbine. Your wind turbine will be much slower – why??? You will lose your impulse during the way through your tube…
- Little (or bigger) Problem of impulse charged manifolds – to let the impulse alive, the diameter of the tubes is restricted – it may not get too big. This will be bad for maximum power in high revs.
- Therefore best is to develop a good combination from German “Stoßaufladung” for low revs and “Stauaufladung” for high revs…
- And now it is enough – believe me or don’t believe me. I know for myself who tells the truth.

I’m not getting into an argument as to who is right or wrong because I will be performing all sorts of tests involving turbocharged engines with exhaust manifold pulse tuning later this year. So I will be commenting on actual world testing rather that spewing stuff out of books I have read.

What I will ask is when the primary pulse wave from cylinder one leaves at the speed of sound ie 350m/s the gasses leave at a somewhat slower i.e 50/ms. What happens to the pulse wave when it hits the turbine blade?

Also consider the earlier you open the exhaust valve the greater the cylinder pressure. (Bit of a broad statement but still cam timing is all important to manifold design)

Sorry, but I myself stop this discussion now regarding manifold etc.
You will not have the possibility to build all sorts of manifolds with different diameters, different lengths and so on. But some people who wrote books did it. Therefore I believe them.
Johns and Barbz, two persons, who I value very much, did some test regarding manifold. Their result was, that the best power output they gained with 34mm ID, not really much - but it helps the impulse to survive till the blade of the charger which is constructed to do this implulse without defect.
TurboJ - I do not "attack" you - it is ok to do tests - they often show that theory and reality is not the same.
Thus I was the guinea pig in Germany for a GT28R, 2004!
After this I was the first (I think also in England there was no car with it), who had installed a GT2871R and original internals! Nobody knew at this moment, if the engine would keep this power without damage.
Now I am the first and only in Germany with GT3082R and 4x4.

I attack other people in this forum who do claims without any knowledge...
Unfortunately a lot of good members have left this forum, because the Coupe is not interesting any more... (too old, a cheap car for people, who buy this car, invest little money for a big charger only and later on wonder, why they got a engine failure).
Good tuning topics are rare meanwhile.
Before investing in a new manifold - it is better (from my opinion), to do some research regarding:
- prepare the valve train for higher revs - thus I am doing some research regarding this - this would be interesting for 2l engines - reving up to 9000rpm would be good for the power band...else you could reduce torque and save the gearbox
- block guard: important for engines >500HP
- strengthening the gear box (old topic)

But let's stop it now...

Juergen,

Obviously we've a translation issue and I much admire how you write in English but in your writing there is an ever increasing aggression, such writings as "I attack other people in this forum who do claims without any knowledge..." will do nothing for proper discussion, please keep your cool. Number one rule in discussion (argument if thats how you feel) is to keep your temper.

I've read through what you have written and forsure I'm not an expert but I know enough on some of these areas to know you are still someway from understanding the mass volumes a combustion engine exhausts and the way that pulses work in an manifold before the turbo. I'm not about to start writing again what I've covered enough in another thread (look through my previous posts if interested , it's not far back) but I will say that the pulses from my point of view (and you can be 100% sure I've had good advice and readings on this) don't have any influence when they hit the turbine. Pulses function off changes in area. If you write of pulses but are refering to a single exhaust charge I would see more truth in what you write.
Volume of gases in the exhaust are huge, even from a 2 litre engine at little more than idle. The exhaust volume is different to intake volume I understand but for simplicity think in the same terms for a moment. At 2000 rpm (no boost)with 100% Ve a 2 litre engine intakes (or exhausts but for some differences I am aware of) 2000 litres per minute which is equal to 33.3 litres per second. All if it is moving constantly looking for that pressure differential (which Tricky is correct on) but imagine if you can a snapshot where this volume had to be in a pipe at atmospheric pressure. Lets use a 1 3/4 i/d pipe as an example. 33.3 litres of air will fill a pipe 2144 cm long, so thats over 20 meters of pipe which in a 4 cyl (like I prefer) thats 5 meters of pipe for each runner. Nobody in their right mind is going to use runners 5 meters long (though I'll show you later something not far off) so it would be fair to asume some nutter that doesn't know what he's talking about who builds a manifold with 1 meter (no I don't mean we need 1 meter runner, it's an example) long runners would in fact have gases in the runners under pressure which as I understand it will be trying to get out into atmo, through the turbo in our case. I'll leave the example at that and let you calculate/imagine/see for yourself what actually is the case in those runners at higher rpm or even when it all gets exciting with improved mass/pressure as boost climbs.

Forgive my liking for examples of other people work but here's another good one for you, real world and not unusual and certainly not talking rubbish.

This is mounted in the back of a truck. http://i3.photobucket.com/albums/y85/1NRO/truckrearmount.jpg
Can you see the length the exhaust gases travel?
http://i3.photobucket.com/albums/y85/1NRO/truckrearmount3.jpg
Goes on forever wouldn't you say?
http://i3.photobucket.com/albums/y85/1NRO/truckrearmount2.jpg
Now don't go telling me he's using a big cube engine because thats a hell of a turbo he's spooling no matter the engine size.
http://i3.photobucket.com/albums/y85/1NRO/truckrearmount4.jpg
So it's bound to be a slug off the line, no secret assistance you'll notice but again here's someone telling us that you don't just know everything you think.
http://www.youtube.com/watch?v=pYVqtCWPUbk&feature=related
He's brave though don't you think, wouldn't fancy that intake backfireing and bursting that intake pipe right next to him! and yeah, that is an aluminium exhaust which is another of those talking rubbish won't ever work kind of topics.

For your students sake my advice is to open up to what IS done and not be stuck in past theory, open minded is how to learn, nothing is ever final.

Nik (not looking to argue but only share opinion, it's hard to write anything of persuasion without sounding harsh, I honestly don't want it to sound like that)

Is it possible to manipulate the flow of exhaust gas as it enters the exhaust housing and it hits exhaust wheel.

We are attempting to build a pulse based manifold that will allow exhaust gasses to enter the exhaust housing from the collector in their respective firing orders in a configuration that will ensure a anti clockwise flow of exhaust gas into the exhaust wheel since the spent exhaust gasses exiting the exhaust housing of the turbo is expelled in a anti clockwise fashion.

The exhaust wheel needs to turn anti clockwise to generate boost on the compressor side and if the exhaust gasses hit the exhaust wheel in a clockwise fashion you get inefficiency.

This is pure theory and comments are welcome, I have my burn suit on

Like a natural pre-swirl ? I can see the theory in there, but I beleive that because the gas is approaching the side of the wheel the effects will be minimal. Still, every little helps.

My idea was to build a housing that changes it's area ratio using an actuator (not in the same way as VNT). It would be extremely difficult to make though and I am yet to put pen to paper.

Costing info on stroker kit posted under Group buys.