20v Turbo "Big MAF" conversion

This one is for the 350bhp - 600bhp brigade, especially if you want to run big boost

Why?
The role of the air flow meter is to measure the air mass being consumed by the engine at any given rpm/load point. This is sent to the ecu via a 0-5v signal. There is a limit to how much air flow that can be measured by the standard MAF, therefore it stands to reason that when increasing boost there will be a point where this limit is reached i.e. the MAF can only send 5v, anything above this it cannot measure. This doesn't mean we cannot fuel for the higher boost, but it does mean that there may be a "dead zone" where there is little to no resolution for mapping at lower boost points i.e. 1.3bar and 1.7bar both produce a 5v MAF signal. The fueling (and timing) can be very different between between such boost levels therefore in most instances we choose to fuel the higher boost as this is most critical and of course where more power is made.

The solution?
Well we need to broaden the resolution of the air flow meter. We can do this in two steps 1. Using a bigger MAF housing 2. Re-calibrating the ecu to accept the new air flow measurments. Step 1 cannot be done without Step 2 as this will create problems whereby the ecu is thinking the engine is consuming X mass air flow when in fact it is Y. Given that fueling and ignition timing are calculated according to mass air flow (amongst other sensors) we need to make sure that the our new measurments are calibrated correctly within the ecu.

Results...
Once the ecu has been calibrated with the new Big MAF, we can now utilise the greater air flow resolution. So if we run 2bar of boost, 1.5bar or 1bar, this can all be optimised for both fueling and timing making sure we can achieve maximum power and safety regardless of air flow. In fact, we still have headroom to run even more boost should it be required!

Big boost + Big horsepower = Big MAF

Nice work! It's about time someone used a larger MAF housing properly.

Flea you are really doing some serious developing. Keep up the good work!
So what MAF can we use? How much does it cost?

Leighton - you know I'm up for this - Seeing as I run 1.2 bar daily, I know the fuelling and ignition won't be optimal as you've mapped it to cope with 1.6 bar (or more)

it would be nice to have spot-on fuelling for day-to-day running as well as for berserk boost blasts

Sounding good but how does this affect lower down the rpm e.g. idle, light cruise? If you’re moving the scope up the rev rage do you still have enough points lower down? Is there a smooth transition between the points?

Really interesting

I'm going to follow this closely!

Like you know Leighton, my 20VT is going for 400+ hp soon... so i have to keep an eye on this

Nice Leighton.. another development on the Coupe

Was it only tested on your Coupe?

I'll keep an eye on this thread as well.. You have a PM

It doesn't have any affect on idle or light throttle. It also doesn't move the scope further up the rev range, quite the opposite, it allows a broader resolution at any rpm/load point depending on the air flow requirements of a specific engine setup. Of course it has to be calibrated within the ecu in order to take full advantage.



Yes, I have been running this for a few months although finding the time to tune my own car is becoming harder!

600cc injectors (peak & hold)
Big MAF
Boost: 0.8bar - 2bar
Idle & part throttle - stoich

O no Flea doesn't read my questions

Begging your pardon...

Cost, still finalising this but it will be a custom machined MAF

Leighton

depending on cost (and availability), I might be up for this in the second week in April - I have a week off, so we could spend a little time playing with my car if you're up for it.

why MAF? why std ECU?

does it really have that much potential to be used with larger amounts of power?

I mean, when going for some serious power levels (400+) why not use stand alone ecu? by that you throw out maf and replace it with map sensor..

Leighton, when / if you have a spare, please bung it my way ( cost will be covered ), on full chat, I now get the injector light, it's simply maxxing my AFM I'd imagine too much

If it needs machining, I have a man that will do that

you also throw out a couple of grand (by the time you've bought it and mapped it) - MUCH easier to map the existing ECU

I'm getting around 400bhp, AND it starts and runs properly AND I can get over 40mpg if I try hard enough

Why change?

I can't help but agree with Daeron. But in Flea's defence if people have the option then it is entily down to them.

Yes it does. If you read my first post it should hopefully shed some light on why

For me the Motronic is a stand alone ecu, I have not reached the limits at 450-500bhp which is fantastic. I drive my car almost every day, it's a road car but more than anyone on here I have abused it on the drag strip and track To be able to run 600cc injectors (I estimate 750cc being the limit), that would be over 900cc on a 4 pot! This is also with the ability to pass an MOT, and fuel big boost.

As Nigel says why change? He has run up 50,000 miles or more, competed at TOTB, 12.3 on the dragstrip, track days... that says it all

Its absolutely correct that IF I had gone for a Motec or Omex a couple of years ago, I would have spent less on mapping than I've done on getting my car right.

However, IF Leighton had been around when I first needed my car mapping, then I would have got the right map, with no learning issues and proper cold start and idling, and all for half the price of an unmapped OMEX.

I have no doubt that a standalone ECU is the BEST option, but if you include cost into the equation, there is no contest.

Forget the issues that I've had - they weren't the fault of the ECU - tell me, what would I gain by fitting a standalone ECU?

launch control? - don't need it - I don't have traction issues and I can launch my car well enough without it

Aquamist control? - don't need it - my chargetemps are fine and I have enough fuel getting in

Most owners simply don't need to squeeze the last ounce out of their setup - they just want to increase the performance without lashing out a fortune - there will always be people that spend more than they need to in order to get where they want to be - its called trailblazing and someone has to do it. I would imagine you have spent money on stuff that you later found could have been achieved more easily / cheaply. Its modders like me and people like Flea that end up allowing ordinary owners to reap the rewards from our efforts (and spending)

I would like to compare the bods @ BOSCH to say "Motec" etc......

I doubt they would compare, else they would be making OEM ECUs from day one off the factory line.

Quite simple really gents

Kidding me right?

launch control, traction control .. if you wish to use 400+ bhp FWD, this is must have!

aquamist - why not? you raise the power for more than 100% .. when running it properly why not use water/methanol?!

as for the prices.. I saw in TurboJs website he has Megasquirt.. ask him how much for the DIY kit. price is a laugh.
there are lots of tutorials online how to connect it, and "starter maps".. not to mention that Flea could tune it probably every better tuner.. and the car will run brutally, without a need to spend lots of money for Motec, Autronic, Vipec or some other more expensive SA..

Dunno.. That's just my two pennys.

edit: and btw, Flea respect for done. Research and development. It still stands in 20vt tuning workshop, that going beyond 440cc injector you need SA.. Well, guess what

Launch control ?

At every traffic light ? C'mon ? Are YOU serious mate ?



Most are rubbish spark inhibitors, they either use your ABS, or cut your spark, hardly hi-tech

I have looked into all of this a LOT.

To get a proper stand alone ECU, loom, and setup would cost in excess of 3K. The only reason people went for this option was that no one at the time was willing to spend the time learning how to map the stadnard ecu, Flea has learnt how to do this by putting in a lot of effort, and is able to do it very well.

So.....£3500 for a QUALITY ecu and map, or £500 or so for a live map and a bigger MAF - no brainer.

Aquamist is a matter of debate - my opinion is that you dont need it if the car is mapped well - but that is for another thread.

Launch and traction control spoils the fun IMO. I bloody hate it when I'm having some fun in a car and I feel like it's miss-firing....there have been some nightmare stories about race logic traction control on coupes going wrong.

£3.5K you been getting quotes from Harrods

Without getting involved in the whole Bosch vs Standalone debate because quite frankly it's been discussed many times on here. I just want to clarify that I don't run Megasquirt. I made if for somebody else. Megasquirt doesn’t support a 5 pot yet but their new ECU will and will be very very cheap, worth keeping an eye on for the future...

According to the garage tha tdid my car, he has managed to do launch control with the standard ecu, dunno how, dunno how good it is, just know what he told me...

There is already basic traction control on the std ecu. It is the first thing most people had removed - the 1st and 2nd gear base boost. That can be tuned though so that it cuts in only if the rise rate means you are spinning up in 1st lets say. So if you were wise enough to still use the ECU to control boost then you can probably take advantage of this

As for traction control in general bear in mind it is in the rain that it comes into its own. Booting it in 2nd and 3rd in the rain is not an option when you've got over 400lbs/ft torque

I went down the aftermarket ECU route because I had no choice. I think this is a good option and there are also compromises wih aftermarket ECUs - such as a lot of them are poor at cold start maps etc.

The only thing with this is that the load point table is getting spread across a massive range of power with the same granularity as it was originally (same number of load points) which means less precision compared to an aftermarket ECU.
Also on modern aftermarket ECUs you can do full wideband so the fuelling is always right under all loads.

btw I just thought I would add that I would trust Leighton to map my car for what it's worth.

sorry for OT but.

http://www.vems.hu/wiki/index.php?page=MembersPage%2FJimmieJ

in DIY vartiant this cost ~500£.
with assembled unit+loom+instaling+mapping ~1000-1300£

btw, check their home page.. VEMS powers Europe's fastest street legal car.

sorry fot OT once again..

I looked at an OMEX ecu - around 2-2.5K for the best one, and then around a grand for installation, custom loom, and mapping.

Speaking as someone who has been running well over 400bhp for the last 2-3 years, it's not I cannot emphasise how much my car has been put through its paces. It's very much a road car but if I can manage an 11.94 @ 121mph using just my right foot, this is this same time as a Motec coupe with anti-lag, launch control and traction control!



I use water/methanol injection, as Simon says it's not required but it does have some benefits.




Thank you I think! It's about time the tuning workshop was updated

You forgot to mention that you were both wearing some very slick tyres

That's very true John, I have ran my car like this with an uprated ebv and it does work. That said I find the Apexi AVC-R is a little better in this regard so have reverted to that for the time being.



I can't argue with wideband open loop fueling! In terms of the number of load points being the same, yes that is true (for now ), however, when calibrated correctly to the car I can create more resolution where needed i.e. on boost, and reduce the resolution where it is not needed i.e. off-boost.



I thank you kindly

Yes I was using his cast offs!!

Well that just show your knowledge! But aren't you the one who asks where are the high boost heroes... I mean why build a 400+ hp machine and then use it like a street car. It should be used properly to its limits on the track. Being that quartermille or even better on trackdays. Its obvious that you have the knowledge, why not use it for futher development into areas where std ECU cant go..
But I guess thats a discusion for an another topic.

Nice work with this!

I think you have misunderstood Daeron. I track my car regularly (it has the bruises to show!) and I have done the best part of a 100 drag runs, competed at TOTB the last three years and against other "supercars" over a 1 mile drag run (doing rather well I might add ). Of course, if someone chooses to run a 400bhp as a street car then why not? It is surely no different to owning a Porsche, Ferrari etc.

I have absolutely no good reason to use any other engine management system...

No no.. I havent misunderstood.. I wanted to say, that in your hands that Coop with Motec, LC, TC, antilag etc.. could go better

Well, as long as we can obtain the maximum from the standard ECU, why not use it.

For example, I'm abroad and intending to use the FC Performance chip and I hope it works fine with me (even if it is going to be trial and error). Motec and other standalone ECUs are familiar here but at this time (and simply), I can't afford them.

You can chack my intended setup in my signature. I'm expecting (and hoping) to see 400hp and I'm not intending to use the Coupe for drag and track only. I need it to be a street car as well (in fact for street racing )




Back to the MAF

Is it going to 4" size from both ends?

If it is 4", and I'm going to use the 3" TI SIP and 3" APEXi air filter, I think I'll need 2 transition hoses (4" X 3") between the MAF and the air filter and between the MAF and the SIP.

I don't like to use transition hoses but it seems to be the only valid solution.

Isn't it better to make a 4" SIP?

No it’s not, OMEX 710 ECU with standard loom is £805 all in. Pre-assembled kit for plug and play is an extra £50. It comes with a base map. Then full mapping is £300. So you looking at about £1200 fully mapped.


I have to disagree with you there, it’s not the ECU’s fault it’s poor it’s because the mapper is cutting corners. Car companies spend months developing OE maps under loads of conditions making sure everything is right. To get a proper polished map for an aftermarket ECU will take ages and cost a bomb so quite frankly they never bother to polish it up. If somebody put in a load of time to the cold start on aftermarket it will be just as good as OE.

Right, I have spoken to Leighton and he know's his stuff when it comes to re-programming the std ecu, I would also expect that given the same amount of time in the learning process that the same or slightly better results could be achieved using any number of aftermarket ECU's.
I work with motec nearly everyday, and I've seen alot of supposedly set-up bikes that don't start poor running etc and like leighton I know how to achieve good cold starting using motec.
Anyway enough, My point is it's not what you've got it's how you use it and how good the person is who set it up.
Oh and motec do make OEM ecu's, ok mainly for small manufactures. Ascari A10 anyone?

Leighton, Keep up the good work and if I keep the coupe I'll be seeing you shortly.

Cheers Tim

I think you may have missed the point here. Using a larger housing means that the same output voltage span from the MAF now represents a higher air flow. Since this voltage is quantised to a fixed number of bits by the ADC within the ECU, this means each step represents a larger change in airflow, so at low air flows your resolution is degraded.

I haven't missed the point at all, in absolute terms yes that is what happens, but TurboJ asked whether it affected idle or light cruise. The straight answer is no it doesn't. While 0-5v is covering a greater mass air flow range, in real terms there is no significant degradation in resolution at lower air flows if calibrated correctly.

and you have to consider that what we're getting now is higher resolution until about 4,000rpm (on my car), after which the MAF is giving 5v and we're onto pure maps to fuel the car - I'd much rather have correct fuelling at different boost levels, rather than perfect fuelling off-boost - I accept that the bigger MAF may have some tiny drawbacks because of less points, but as long as Leighton calibrates it correctly, I doubt if I'd ever notice

OK let me explain in more detail what I was trying to ask originally.

Ok, for example lets say the scalar of the standard AFM is 0-5V and for this range you have 10 points which are set at 0.5 intervals. If you change to a bigger MAF each point will now represent a "new" airflow which can simply be incorporated by adapting the maps. However my questions are:

Are the 10 points fixed at 0.5 intervals or can they be moved around?

Can more points be added if needed or is it fixed at 10?

If the 10 points can only be moved then will some parts of the range have fewer points than others?

If the scalar cannot be changed is there still a smooth transition between points as some parts of the rev/boost range may jump a significant amount of airflow?

It's ok Jason I knew what you meant. I'm sure you know that MAF conversions are not new, the VAG tuners use them a lot as do many other marques. The reality is at low loads fueling is relatively static so we don't need huge resolution, indeed many load points are rarely used but they are there regardless. The biggest problem for a boosted car is that it has a profound impact on air flow therefore it is at the top end we need this extra resolution.

Suffice to say, I'm not theorising here. While I welcome the questioning, it is the results that determine the litmus test. This has all been tested over the last couple of months on my own car, a useful platform for such developments! The reality is it complicates matters considerably, but the results speak for themselves.

The other point is, at lower revs and throttle openings, won't it doing the fueling of the lambda sensor a lot of the time anyway? Or have I lost the plot?

If you believe you can get all the features of an ECU in a form that a normal punter can program then you are sadly mistaken. Aftermarket ECUs are all constrained to a point because otherwise your average user could not use them. It is not just the time, it is the access to a full programming language that you need to make it perfect. How many people who buy and use aftermarket ECUs can do procedural programming let alone declarative programming which it is naturally more akin to.

This is true of my ECU as much as any other. The Motec has got better in some ways as you can now put a compensation map onto any number of ranges of parameters etc. in the v3 software, but in previous versions it was only what the manufacturer gave you access to.

John I’m not saying that at all. I am saying that the cold start maps etc... can be perfect if the time is put in on a standalone unit without having the need for any full programming language. If you need to have full programming language to get the cold start right then quite frankly you have the wrong ECU.

“The Motec has got better in some ways as you can now put a compensation map onto any number of ranges of parameters etc.”

I’m sorry but that’s hardly cutting edge technology in fact that’s well dated. If I was to show you what we play with you will be amazed.