Tuning a 944 Lux - ECU done what next?

[barks944]

For those of you who know about the 944 Lux, one of the big problems with tuning it has always been its engine management. A restrictive AFM and difficult to tune ECU means that it has always been difficult and costly to extract decent power gains from the 944's 2.5 8v NA engine. Well I have solved that problem and have built myself a new ECU board that replaces the original CPU in the 944's DME with a modern controller. This means I have a fully mappable system in my 944. It has many improvements over the original system one of the key being real time mapping and datalogging. I have programmed an entire engine management system in C from the ground up. Designed specifically for the 944's injection system so it utilises the standard triggering system and has an advanced batch injection algorithm that maximes the throttle reponse by removing the delay introduced by fixed injection stages. It also allows for compensation of ignition and fuelling by both coolant and air temperature vs the manifold pressure (3D maps like ignition/fuelling). The ignition is adjustable in 0.17 degree increments and the fuelling in 0.04 ms increments.

I have the system setup on my 944 lux, its fitted with a VAG coil pack which I will be replacing with a coil near plug system. It also incorporates a 1Bar map sensor and open element type air intake temperature sensor. Due to the fact that the lux's injectors are run at 100% duty with the standard system there is not much overhead for tuning so I have installed 944 turbo injectors and moved to a fixed fuel rail pressure for improved throttle response.

I would like to incrementally change components and record the benefit so I am wondering where the main restrictions lie in order to approach it in the right order. I have a good engine with new rings seeing ~200psi on all four cylinders now that is bedded in. I think 200hp should be achievable?! Any suggestions? I have a feeling that a supercharger might be the best way to go but its not an easy modification.....

 

[944 man]

The cam profiles are more steady than a steady thing.

 

[barks944]

Yeah, my dad always said they much have got the profile from a landrover engine..... The question is how to get a better profile, can we re-grind the 944's cam or get blanks. Apparently you can get a cam made from scratch from someone like piper. Can't imagine that would be cheap work however.

 

[PSH]

With a target of 200bhp you'll certainly have to do some form of forced induction, however for N/A gains the traditional way is camshaft,exhaust and intake which may give a further 20+ BHP. You could try John at Vitesse Racing for the camshaft , I believe he will make a profile to match your requirements if none of his existing profiles match your needs.

regards

Pete

 

[944 man]

I think that over 200bhp normally aspirated is easily achievable. After all, thats only 80bhp per litre.

 

[barks944]

How high can the 944 engine rev safely? I've tested the ECU to 9000 rpm. Not sure how high the engine will go however... I guess you would need solid lifters and stronger valve springs to get to say 8000 rpm?

 

[944 man]

If youre running up to 8k, then Id expect a good deal more than 200bhp with free cams and fully programmable management. At 9k Id expect to be seeing 100bhp per litre.

Five minutes speaking to Alex Eacock at EMC will probably answer any questions that you have about safe speeds. Id expect it to be pretty secure and well balanced enough from the factory for about 7,200rpm, but over that Id need my confidence buffering.

 

[PSH]

hmmm , I have to disagree with you Simon in regards to being able to easily acheive 200+bhp from a n/a 2.5l 944 engine. From my experience in modifying n/a engines( yes there was a time when I did such things) you need to spend vast amounts of money for little gain. Yes you can put high lift cams, head work, big exhaust, air intake etc etc but I'll bet you that once you reach the engines limits, ( from what I've just read 180bhp+ for full blown 944 n/a race engines) you'll have a car so lumpy on tick over that it will only be of use on a race track. As far as how high can you increase revs for the n/a engine 1'd say you wouldn't want to go above 8k although the 944 does has an advantage obtaining high revs , that being it's internal balance due to the balance shaft system, as stated you'd still need solid lifters and uprated double springs on top of all the other parts mentioned.
I've never heard of a 944 n/a getting even close to 200bhp although stand to be corrected if someone knows better..

Pete

 

[OLD_ian]

I'm curious. How much power have you gained at this point with the new ECU?

 

[barks944]

You wouldnt get such a mean torque curve as with a supercharger either..... Which is what the 944 engine is about really. I am rather tempted by a roots blower, perhaps an eaton m90 perhaps coupled to a charge cooler?

 

[944 man]

ORIGINAL: PSH

hmmm , I have to disagree with you Simon in regards to being able to easily acheive 200+bhp from a n/a 2.5l 944 engine. From my experience in modifying n/a engines( yes there was a time when I did such things) you need to spend vast amounts of money for little gain. Yes you can put high lift cams, head work, big exhaust, air intake etc etc but I'll bet you that once you reach the engines limits, ( from what I've just read 180bhp+ for full blown 944 n/a race engines) you'll have a car so lumpy on tick over that it will only be of use on a race track. As far as how high can you increase revs for the n/a engine 1'd say you wouldn't want to go above 8k although the 944 does has an advantage obtaining high revs , that being it's internal balance due to the balance shaft system, as stated you'd still need solid lifters and uprated double springs on top of all the other parts mentioned.
I've never heard of a 944 n/a getting even close to 200bhp although stand to be corrected if someone knows better..

Pete

I dont disagree with you in principle Pete, but I feel that youre overlooking a number of fundamental points. The 944 race engines were using standard camshafts with tweeked fuel/ignition. Hobbled by the standard DME and with the ultra conservative camshaft profile/timing they still made 180-odd bhp.

Im not suggesting a super lumpy cam nor sewing machine-like revs, because I think that with the already brilliant head and with the DMW restriction removed, even a modest 285 cam will get you there.

I dont think that 80bhp per litre is byond the realms of possibility with a good cam, or even a lotus profile re-grind. What you ultimately achieve depends on the bottom ends ability to rev, of course, unless you want it to get really involved (and expensive), but I think that this first level wont require revs beyond the standard bottom ends ability.

 

[944 man]

Thered certainly be a massive difference in the engines torque characteristics! It was all about tractibility and a fat torque curve from the factory, but what Im suggesting will move peak torque up by a hefty degree, but this is the only way to find normally aspirated power.

 

[TTM]

ORIGINAL: 944 man
Thered certainly be a massive difference in the engines torque characteristics! It was all about tractibility and a fat torque curve from the factory, but what Im suggesting will move peak torque up by a hefty degree, but this is the only way to find normally aspirated power.

Completely agree, and it also applies on turbo engines.
The intake manifold needs a serious rethink (shorter runners and larger plenum) to move the torque band higher, consequently allowing for a higher peak power.
Some days I wonder why P didn't make offer alternative intake manifold for these cars, as it was clearly designed for the exact opposite of a high peak power and lively engine in upper revs.
P did a great job designing a 4 cyl engine that felt like a 6, but this is not the type of performance a 4 cyl will shine best.

 

[Catamax944]

Many have tried over the years to get power out of the n/a engine and most have failed ,it's not a tunable engine . It will also get very expensive real soon. From what i've seen over the years you won't get past 180 from the 2.5 and if you go 3.0 you will see a little over 200 .
Only cheap and easy way to get more power is an engine transplant ,S2,968 etc.

 

[333pg333]

Not that this is an easily achievable outcome without lashings of Money, but have a look at this thread from Rennlist to see what can be achieved with an n/a motor.

http://forums.rennlist.com/rennforums/924-931-944-951-968-forum/628347-how-to-get-more-power-out-of-na-looking-for-400hp.html

 

[944 man]

ORIGINAL: Catamax944

Many have tried over the years to get power out of the n/a engine and most have failed ,it's not a tunable engine . It will also get very expensive real soon. From what i've seen over the years you won't get past 180 from the 2.5 and if you go 3.0 you will see a little over 200 .
Only cheap and easy way to get more power is an engine transplant ,S2,968 etc.

Errmmm.... I think that youve missed the point. With a restrictive inlet tract and ultra steady camshaft profiles, along with with a difficult to alter DME, people arent going to be able to achieve a great deal.

With a fully configurable DME and an owner who is happy to alter the inlet tract and change the camshaft, the obstacles to making more power have been removed. There is now no reason at all why this engine shouldnt make a great deal more power, in fact.

 

[Catamax944]

I was referring to a more off the shelf approach ,with already available performance parts . Performance camshaft ,reworked heads and tunable dme's are available , inlet manifold not so much.
The cost for custom parts is going to be very high . I love the 8v engine ,i wish someone could come up with some good but cost effective solutions but for now i think all that is just day dreaming .

 

[TTM]

Making a good intake manifold should not be too difficult for someone who can weld aluminium.
There are many offerings in the BMW world, and even if our engines are a bit crude in comparison to the average BMW 6, there is no reason why it shouldn't work.

Tom, care to show us some pictures of your complete ECU system?

 

[George Elliott]

Barks,
did you read that link Patrick put up? [] (thanks Patrick, incredible project.)

...so - to try and find your target of half that power, maybe run the question past Michael Mount?

as already mentioned, the cam, then the valve sizes, compression ratio, inlet manifold, exhaust manifold. I'd guess 6800rpm is safe for an 8v with a good cam belt[]

A 4 cylinder Renault Clio can put out around 200 horses with a 2.0L so I have confidence anyone who can make ECU's for a hobby can get there with a 2.5L.

but first, lets have the turbo version[8|]

George
944t

ps is inbox full?

 

[peanut]

I must be missing something ?

why are you not putting a 3.0lt S2 lump in ? that must be the cheapest and most reliable engine upgrade. You could then bore that to 3.2lt if you're still not satisfied