hi !


quite interesting thread....

so the oem grale inlet manifold flows 125 cfm at guy crofts flowbench.

but how are the differences between the cylinders ? any facts from guy croft ?

does every cylinder get the same flow or are one or more worse in flow ?


macki

no one ?

begbie, do you know the particular cfm´s of each runner of the grale inlet manifold ?
in guy´s forum thread only the overall cfm of the grale inlet manifold is mentioned....

the inlet manifold might be also a reason for the known heat problem of our 2l 16vt engine at cylinder 3 and 4 ?


thanks.


macki

I don't know each runner, and at a guess it would be a very close value as stated on Guy's forum.

Inlet manifold has nothing to do with the heat problem on cylinder 3 & 4, it will be down to the log manifold and turbo sitting by cylinder 4

Also note the cfm quoted is not a maximum figure in anyway it is the flow measured at a certain vacuum, to allow comparisons at the same vacuum to be made (i.e. against inlet port flow).

1NRO i just sent you a PM. I want one of those intake manifolds!!!

"The Kappa manifold flows good enough for a ambitious engine build BUT it tunes at the wrong rpm for that kind of engine. You are afterall asking a lot of the 2 litre engine so rpm comes into play. It also has a less than satisfactory plenum volume and without modification won't accept a suitable throttle"

Nik, you're a bit off the mark here. There are NO pulse-tuning effects/benefits in a turbo unit due to inlet runners (such as one sees on an atmo unit and which they depend on) when on boost (of any level) because the cylinder sees +ve pressure upstream of the valve as soon as it opens. And because the charge is being rammed in under pressure well above atmos they don't need any either.

The ONLY problem with the Kappa is that the runners are still a bit on the small size. It is however markedly better than the Integrale 16v and is on a par when modified to the (yellow) 16v Coupe one above. I don't think you're right about recovery rate in the plenum either. The plenum size is only an issue on change of state from closed to open throttle. Judging from test results I have of atmo engines the Kappa item is plenty big enough to satisfy the change-of-state on any liter and being pressurised in this application it will be better still.

GC

this is what I found to be different between standard 16vt manifold and grale one :

Runners are quite a lot shorter wich should be good for higher rpm power ( and loss for down torque )

after TB the original one have first bottleneck, it has much smaller hole, than grale one..

cant remember the measurements anymore but overall it was something like 20% smaller hole on standard 16vt. its because of the manifold shape.

On a turbocharged unit the runner length is only relevant in terms of the viscous loss!

G

but what about the size of the hole ...

??

that should matter... ( size does matter )

JTM you idea of a bottle neck is probably capable of flowing more air then the engine is likely to need for road use even tuned.

Hey Guy, in one of your threads you mentioned chord/diameter ratio. What does that mean?

This might help, Clicky

Hello Guy,

Good to see you here, a place that can benefit.

With regard to there not being pulses within a forced engine inlet I can't agree. Am I right in understanding you are refering to the higher density of the medium (air) causes the pulses to cease to be?

Will a very efficent NA engine pull + pressure at IVO? Is this not the same but less prominent?

I'm trying to get the density influence clear in my mind. Casting thought to a natural example is the wave/pulse, whatever is best to call it, created by a tsunamis not passing with force across whole oceans through a far denser mass?

I can't for the life of me see how they would stop when above atmo.


Nik

i took some measurements on that bottle neck...

hole after TB is 63mm x 63mm ( 2,5" )

but in 16vt it goes right after that to size of

63mm x 46mm ( 2,15" 54,5mm )

so its a little smaller, than our standard TB is

Cheers

Nik, a negative wave from the cylinder (at depression) is reflected as a pos wave where it sees high pressure, which in this case is immediately at the non-firing side of the inlet valve not the plenum - as would happen on an atmo engine.

G

chord rule:

http://guy-croft.com/viewtopic.php?f=6&t=2110&p=11022&hilit=chord#p11022

Guy,

My understanding is that the pulses/waves created by flow accelerating/decelerating due to the PD are not influenced by changes in pressure like you say. If this was the case there would be a massive jumble of waves even in a NA engine from every small change in pressure within the port (non-firing side). The pressures as you'll know vary within different areas around the port/intake runners.

My opinion is that waves reflect at abrupt changes in area (when it hits the plenum for instance). As you say their origin is initiated by the PD and then the IVC creates no area which would see the wave traveling in the same state as it arrived, no matter the pressure, until is next meets a change in area. The density change in the air influences the speed of the waves IMO so there is a difference but they don't reflect off the PD.

I know it's not something you care for but forgive the link, I find it excellent on this subject. http://www.sengpielaudio.com/calculator-speedsound.htm

If I might mention the size of plenum and the influence on this subject, a bigger than usual plenum, from my research, allows a steadier flow without too harsh a change in pressure.

Nik

Should be getting car back at weekend... Inlet manifold has been ported to max gasket port size but thats it! I'm hoping to see 350 plus bhp but am a little worried by this thread as it seems the coupe manifold is so poor? Nick

Good thing you have brought this back up, i've read something where someone has taken a coupe inlet manifold and an integrale inlet manifold and stuck it on the flow bench, the results? Both flow the same, so there is no difference in swapping the manifolds

yes there is a difference ..

at least the grale manifold is 2.5kg lighter

and injectors are better to be seeing ( for chancing etc )

does someone have flow results ?

my next manifold is going be the wrc double style plenum, thats for sure .

Ok There is that (lighter and easier to change the injectors), but there isn't any flow results, but would guess it was similar to the tipo inlet manifold i have

Any links - Vas, if I recall correctly had before and after dyno results for the grale manifold but it could be the difference (10-15bhp) was within the margin or error for the dyno and the difference in the days - ie could have been cooler more humid etc

:-D Fantastic news beggars.... I'm a lot more confident now of reaching where i want to get to.... Should have some dyno figures within the next 14 days! Nick!

But didn't Vas do some minor mapping tweaks as well?

Link is http://deltaparts1.blogspot.com/

That's a deluded patter writen by someone who doesn't know what he's talking about, when you tell so many lies you start to believe yourself.
One minute talking about 28" and then quoting numbers related to 10" with a thinly veiled theft of numbers from elsewhere and some stupid wild claims in amongst a script designed to reel in those that know no better.
If there was even the slightest understanding of the potential performance from given numbers there would be no mention of silly big valves, a standard sized valve with correct port dimensions is capable of supplying enough air to take the rpm's to crazy levels. The reason for equal length manifolds is nothing to do with flow levels, just sounds fancy though doesn't it?
If it was about cfm we'd be hacking heads as big as we could, this is not the case in a correct job.
Don't be lured in by the patter, you can be sure it's misguiding.

The problem with any of the manifolds (the two coupe ones, kappa and integrale) is that the minimum cross section of the runners is some way off suiting the head. This is the case even with a standard head but start working the cylinder head and the restrictive part that is the inlet manifold just gets steadily worse. They can be eased and improved to a point but the likes of the plenum part and the integrale one have areas that just can't be accessed with the grinder so the fundamental restriction still remains. The coupe one having the rubber jointed sections allows better working and the bit that joins onto the head can be ported to some very suitable dimensions. Takes a bit of doing though http://i3.photobucket.com/albums/y85/1NRO/inletmanifolds033.jpg

well my inlet has been ported where it joins the head but no work has been carried out on the parts shown in the pics..... seems there would be a massive gain there, looking at the 2 ports next to each other......
well one thing i know now is that my inlet will flow in excess of 360 bhp as i know vas was running around 350-360 with the grale manifold... and i don't think he even ported it!?
(Thats if the flow testing on that link is accurate.... LOL)

NICK

I needed a turbo race engine and for reasons of cost I originally started with an 8 valve 2 litre Lancia turbo engine. For a plenum/inlet manifold I selected the one designed for the Thema but for a number of reasons it doesn't work too well. The torque curve is heavily influenced by inlet tuning and the Thema plenum/manifold gives peak torque at around 3000-3200 rpm and then works quite well up to about 6000 rpm after which it becomes seriously restrictive. This is largely due to the relatively small cross sectional area of the runners.

Having decided to build a 16 valve engine rather than chuck more money at the 8 valve engine to get the power I needed, I was concerned that I didn't end up in the same place - with a stock manifold that was too restrictive. This 16 valve engine will need to rev to make the power it is designed for and the wrong manifold will strangle it.

The Kappa manifold seems to be the one most commonly chosen by the Lancia drag racers on the continent but rarer than hens teeth in the UK. In any event it was bound to be a compromise in some area of it's design - either runner area, runner length, injector location or installation was likely to bring some problems - so I decided to design and have built a custom plenum.

With the aid of Engine Analyzer Pro I was able to simulate the whole engine, exhaust and turbo and ran multiple itterations of the inlet runner diameters and lengths until I found the 'best match' for our cams and timing.

I would like to confirm at this point that inlet pressure wave tuning is as fundamental to the correct design of runners on a turbo engine as it is on a normally aspirated engine; anyone who says otherwise has either not done their homework or has no personal experience in this area.

The inlet manifold design I settled on gives a 5.4 psi boost immediately behind the inlet valves at 5000 rpm - that is either on top of atmospheric pressure if running N/A or off boost - or on top of boost pressure when running flat out.

This 5.4 psi of boost costs nothing - it brings no additional need for intercooling with it, for example.

My design brings no increase in inlet pressure below 4000 rpm, but that is more down to our cams than anything else. At 4000 rpm is gives 4 psi, peaks with 5.4 psi @ 5000 rpm, gives 4.9 psi @ 6000 rpm, 3.3 psi @ 7000 rpm and 1.8 psi @ 8000 rpm.

The cross sectional area of the runners is 1590mm^2 - the equivalent of a tube with an ID of 45mm. The runner length (head face to plenum) is 200mm. Shortening the runner length from 200mm to 175mm reduces peak torque and pushes peak torque up 500 rpm to 5500. It also extends the rev range to 8500 rpm. None of these effects was desirable in my application, so I stuck with 200mm.

If someone could tell me how I could post a picture of the design and if anybody would like one for themselves I can put you in touch with the company that made mine.

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