Clio 172 MK2 + BMW M3 E36 Throttle Bodies

[griffonu]

Hello,

bought a Clio 172 MK2 2nd hand a couple of years ago and about 3 months ago we decided to do a rather strange project on it, namely add the throttle bodies from a BMW M3 E36

After a bit of work and redoing the positioning of various elements like the power steering pump, doing a custom flange between the TB and the block etc. we ended up with the throttle bodies + M3 E36 injectors + stand alone ECU + etc. all up and running. Hurray! (I don't have pictures at hand right now, unfortunately, will post some).

All nice and dandy, except the power is not there. Despite our efforts of tuning on the dyno, we didn't manage to go past 175 bhp @7500 rpm so we're definitely screwed up something.

So here I am, looking for advice on what we could've done wrong. I should mention the car is running Catcams 428 and has been running them for ~1.5 years without any problem with a custom tune done by Paul from RS tuning, via email/logs as I'm from Romania, so a bit far

--------------

What cold be wrong?
- Could the not perfect matching between the throttle bodies/flange and flange/block be causing so much turbulence in the air flow that we're losing 25 bhp? We were looking at maybe 200 bhp.
- Maybe the angle of the injectors is not ok? Is it super important for them to shoot directly at the intake valve?
- Are trumpets for the throttle bodies super important? We're now running on 4 individual motorcycle intake filters (truncated cones)
- Any other ideas?

It's a bit like a quest at this point

Thanks a bunch in advance! *gives a Guinness pint to everyone*

-VaVaVoum

 

[Cr33do]

Interesting project.

Without seeing any pictures of what you have done its hard to tell what could be improved. I cannot remember what size M3 bodies are (I think 3.0 and 3.2 evo were different) but they should be ok.

What manifold are you using?

Are you using velocity stacks/trumpets?

What is the approximate length of your total inlet? Measure from cylinder head flange to the tip of the trumpet(if used) or entrance of throttle body. Don't include the airfilter.

Finally, what power did the car make before you fitted the throttle bodies?

 

[griffonu]

Hi Cr33do,

just before going to work I snapped a couple of pictures of the thingie. Here they are:

Some answers to your questions:
- I'm not using trumpets, but I could machine those up quite easily. Didn't figure they are so important. I mean, are they? Speaking of which, should I remove the slam panel (seen some threads about this at some point)?
- the size for the TB is 50mm (so it's 4 x 50 total)
- the approx. length from the block to the base of the cone filters is ~15 cm (1 cm is the flange)
- the car was doing ~190 bhp

Sorry, I don't understand the question about the manifold :-/

Thanks a ton!

-Throttled

 

[Chip-mk1]

Lack of trumpets and lack of length are the most obvious problems just by looking at it, cant really comment on interntal turbulence etc as you havent put any pics of it from the inside.

Shame its not working well as it actually looks a nice install.

What AFR are you running? You want high 12s as a ballpark, but obviously you can then finetune on the dyno, how much ignition advance are you running? These engines tend to want quite a lot of ignition, obviously its specification specific but I'd expect to see well over 30 degrees.

The question above about the manifold you have answered with your pictures, as basically there isnt one, just a flange.

 

[griffonu]

Lack of trumpets and lack of length are the most obvious problems just by looking at it, cant really comment on interntal turbulence etc as you havent put any pics of it from the inside.

I can machine up some trumpets. From what I gather I'm targeting as much length as the space allows me, right? Of course, allowing a one piece filter on top of all the trumpets

What AFR are you running? You want high 12s as a ballpark, but obviously you can then finetune on the dyno, how much ignition advance are you running? These engines tend to want quite a lot of ignition, obviously its specification specific but I'd expect to see well over 30 degrees.

The AFR is about 13.0 at high rpm, as for the advance we're at 27 degrees. We tried going further (28, 29) but the power was not increasing and we were also a bit afraid of knocking. What do you mean by well over 30?

Thanks!

 

[Chip-mk1]

I can machine up some trumpets. From what I gather I'm targeting as much length as the space allows me, right? Of course, allowing a one piece filter on top of all the trumpets

Yes as much length as possible is generally what an F4R wants, but at high rpm it will have less effect than on the midrange so I would expect to see big gains to the peak figure, just to the torque curve if you go longer.

The AFR is about 13.0 at high rpm

That sounds fine then, I assume you have tried making it a little richer or leaner and found that to be optimum? Can be anywhere from about 12.5 - 13.2 I find.

as for the advance we're at 27 degrees. We tried going further (28, 29) but the power was not increasing and we were also a bit afraid of knocking. What do you mean by well over 30?

I meant as in its not unusual for one to want 32-34 degrees at high rpm, but if you rollers are telling you 27 is optimum for you, then that is obviously the correct value for this specific application (like I said there isnt a one value fits all cars answer)


From what you are saying about how you have tuned it, it would appear to be a mechanical issue in some manner, wether that be cam timing not optimum for your application (seems unlikely tobe just this if it was working well before but obviously different inlets do alter the amount of advance you require), or a problem with the airflow into the engine, as a combination of lack of length, lack of trumpet, and possible turbulence caused by the incorrect mathcing of head ports to intake shape (im making assumptions till you provide pictures) which seems most likely.

 

[Dan519]

how is the VVT being activated and when? Similar issus I've seen in the past like this have almost always been traced to the VVT not operating

 

[mr.pink87]

Is your aftermarket ECU controlling the solenoid for the inlet cam phaseshifter?

 

[griffonu]

Yes as much length as possible is generally what an F4R wants, but at high rpm it will have less effect than on the midrange so I would expect to see big gains to the peak figure, just to the torque curve if you go longer.

You mean you would NOT expect big gains to the peak figure?

That sounds fine then, I assume you have tried making it a little richer or leaner and found that to be optimum? Can be anywhere from about 12.5 - 13.2 I find.

Yes, tried going up and down.

From what you are saying about how you have tuned it, it would appear to be a mechanical issue in some manner, wether that be cam timing not optimum for your application (seems unlikely tobe just this if it was working well before but obviously different inlets do alter the amount of advance you require), or a problem with the airflow into the engine, as a combination of lack of length, lack of trumpet, and possible turbulence caused by the incorrect mathcing of head ports to intake shape (im making assumptions till you provide pictures) which seems most likely.

Indeed, the matching is not very smooth. As in I'm pretty sure there are differences of up to 2mm around there. But overall could trumpets + length + correct matching make up for ~25 bhp?

Is it possible to have the injectors not angled correctly in relation to the block/intake valve or this is not important since we're talking of a mixture of air/fuel anyway and the direction is not important?

Thanks!

 

[griffonu]

how is the VVT being activated and when? Similar issus I've seen in the past like this have almost always been traced to the VVT not operating

We did a run with the VVT unplugged and it was 20 bhp lower. The VVT is activated between 1800 - 7300 rpm. The stan alone ECU is controlling the solenoid, indeed.

 

[Dan519]

it's got to be related to the inlet length and those filters then. Trumpets are very important, and those filters are not good for airflow at all. Have you got a power graph?

 

[Chip-mk1]

You mean you would NOT expect big gains to the peak figure?

Yes, correct. I meant NOT

Yes, tried going up and down.

It sounds unlikely its your tune losing you the power.

Indeed, the matching is not very smooth. As in I'm pretty sure there are differences of up to 2mm around there. But overall could trumpets + length + correct matching make up for ~25 bhp?

I would be surprised at that figure personally, but the power that is missing has gone somewhere and im sure SOME of it is here, and SOME of it is probably cam timing, but as to the percentage causing each I could only guess, given the cam timing was working ok before, I guess its mainly due to the trumpets and intake length (or rather the lack of each)

Is it possible to have the injectors not angled correctly in relation to the block/intake valve or this is not important since we're talking of a mixture of air/fuel anyway and the direction is not important?

Unlikely to make a big difference to peak power where airflow is at its greatest, such things effect idle and low throttle economy far more than they effect peak power.
Couple of bhp maybe, but not 25.

 

[Silent_Scone]

I can imagine how that'd feel to drive with those cones on regardless! Bogged down to buggery through the midrange. Looks like a great install though

 

[Dan519]

for reference, this is what I run length-wise

Small variances from this wouldn't really matter, but I'd estmate you've got about 150mm less inlet length which makes a lot of difference

 

[Chip-mk1]

The ATP Power bodies on Porkies car (which are of course too short IMHO) are this sort of length:

The trumpets which go onto them are only very short.

But while I personally hate this AT Power layout due to its lack of length, the reality still is that this made 212bhp


So although I do think that more length would help you, I dont think that the lack of it alone should be causing you to lose anything like the amount of power that you are, intake length is far more important to midrange power than to out and out power.

 

[griffonu]

Thanks a lot guys for the useful info! Will go back to the drawing board and keep you posted

/bow

 

[Cr33do]

Dan,

What is the length of the manifold+bodies+trumpets in your setup. I have been trying to work out an optimum length and would be interested to see if the figure I have is close to you.

Cheers, Nick

Op. You definately want to get trumpets to start with. Smoother air and longer length in one hit

 

[mr.pink87]

The ATP Power bodies on Porkies car (which are of course too short IMHO) are this sort of length:

The trumpets which go onto them are only very short.

But while I personally hate this AT Power layout due to its lack of length, the reality still is that this made 212bhp


So although I do think that more length would help you, I dont think that the lack of it alone should be causing you to lose anything like the amount of power that you are, intake length is far more important to midrange power than to out and out power.

Are these the shortest AT-power runners as mine look slightly longer?

 

[Chip-mk1]

Are these the shortest AT-power runners as mine look slightly longer?

80mm IIRC

 

[mr.pink87]

Phew! Why that short? 100mm ones fit perfectly!?

 

[Chip-mk1]

Phew! Why that short? 100mm ones fit perfectly!?

It might even be 100mm mate, TBH I cant really remember now as it was a while ago, it is what were on it when it was originally converted to ITBs, its not what I would have specified, I suggested going to the longest ones but he didnt want to go to bonnet pins.

TBH since we have altered the camshaft timing its actually quite good now, the original graph for it looked like it had no midrange (well it did have no midrange at the time, lol) but now its far far better, should have got an updated graph really.

 

[Silent_Scone]

the longer runners on the AT kit mean you have to lose the slam panel and fit catches. The fact the off the shelf AT kit doesn't is the only reason I'd rate them over the Jenvey kit tbh

 

[Chip-mk1]

the longer runners on the AT kit mean you have to lose the slam panel and fit catches. The fact the off the shelf AT kit doesn't is the only reason I'd rate them over the Jenvey kit tbh

Jenveys are just far better quality bodies IMHO.

Also the AT Power linkages are all buried away inside them and difficult to service etc.

On Porkies one of them needs to come off and be sent back cause the plate on cylinder 2 (well 3 as renault name IIRC) is rattling around slightly for example.

Jenveys are just a fair better made product.

Shame cause I love the packaging of the AT stuff.

 

[Silent_Scone]

Shame cause I love the packaging of the AT stuff.

Must be where all the money goes lol

 

[Chip-mk1]

Must be where all the money goes lol

Yep it must be, just a shame the core product isnt quite as good in the first place!

That said, I bet in the "go faster roadcar" market they have taken a huge chunk of Jenveys market share recently as a lot of the people modifying their car are very influenced in choice by what looks cool and is easy DIY fit etc, and less likely to know or care about long term reliability etc.

 

[Silent_Scone]

I know Jamsport are very good at sending the Fiesta boys to the cash point for them, especially when you need the Dash2 to run them lol.

 

[Dan519]

I ported a Saxo head and matched it to the AT bodies the owner suppled recently. They're absolute s**t, worse than the F4R ones. He's using am emerald ECU too. I despair of people

 

[neil a]

Looks a nice install and could be a cheap conversion if it does make power.
Stupid question but have you ran the car up with the filters removed to see if there causing a restriction?