~400bhp CSLs?

[alexk]

Mr Gorilla
Once more, I can't agree more with you.

The P54 is the absolute benchmark and when I am reading people claiming 385-395PS with a remap and exhaust, I consider it as at least naive (not to say stupid).

Sometime ago I dyno-ed my CSL on the famous Swiss tuner Sportec.
We did multiple runs and the best figure was 369PS and 390Nm.
All the engineers said that the car is excellent and I shouldn't touch anything (all M3 E46s they have dyno-ed were maxing out at 320PS).

[NZ_M3]

Whilst I agree in NA form the S54 peaks around ~420hp the restriction isn't so much in the undersquare nature of the motor (in terms of bore/stroke) - How high a motor can rev also isn't so much in the 'squareness' of the motor - but rather the rod/stroke ratio.

The so called perfect rod/stroke ratio for a high revving motor is said to be 1.75:1, the s54b32 has a rod/stroke ratio of 1.59:1 which is on the lazy side, but in no way what you would call inefficient for high revving (heck Honda vtec engines rev to 9500rpm with lower rod/stroke ratios than the s54b32).

Being able to rev of course doesn't always equate to making more power. Heck any motor that can rev beyond 6500rpm is a feat in itself (I won't go into the dynamics of this, google if you don't know).

Having said that, the iron block of the s54 means that it does take internal resonance pretty well (that and being 6 cylinder) - hence why it responds quite well to forced induction.

The limit is really in the head and the ability to flow much more in NA form. Hence the reason that high lift cams does bugger all when compared to a longer duration.

One way to increase power without adding extra stress to the s54 is to actually go longer stroke thus increasing rod/stroke ratio - 3.4 ~ 3.6l is doable I believe, and reliable/durable 450hp+ isn't unheard of.

Dyno figures are easily faked to the untrained - what gear you do the run in, what correction factor you use, what final drive ratio number you use can all determine whether you see gains or nothing at all in a dyno run. It means nothing as a comparison from motor to motor, only useful as a tuning tool on mapping gains or losses during a certain time and day for one particular machine.

[flow_csl]

My CSL has/had Shrick cams and headers , race cats , mid pipe and race back box . ALL from supersprint .

After a remap the car had 381bhp and 410NM torque .
With these mods you wont have 400BHP . The numbers are the same as my stock 996 GT3 . But the GT3 was still faster .

[cantfind1]

Whilst I agree in NA form the S54 peaks around ~420hp the restriction isn't so much in the undersquare nature of the motor (in terms of bore/stroke) - How high a motor can rev also isn't so much in the 'squareness' of the motor - but rather the rod/stroke ratio.

The so called perfect rod/stroke ratio for a high revving motor is said to be 1.75:1, the s54b32 has a rod/stroke ratio of 1.59:1 which is on the lazy side, but in no way what you would call inefficient for high revving (heck Honda vtec engines rev to 9500rpm with lower rod/stroke ratios than the s54b32).

Being able to rev of course doesn't always equate to making more power. Heck any motor that can rev beyond 6500rpm is a feat in itself (I won't go into the dynamics of this, google if you don't know).

Having said that, the iron block of the s54 means that it does take internal resonance pretty well (that and being 6 cylinder) - hence why it responds quite well to forced induction.

The limit is really in the head and the ability to flow much more in NA form. Hence the reason that high lift cams does bugger all when compared to a longer duration.

One way to increase power without adding extra stress to the s54 is to actually go longer stroke thus increasing rod/stroke ratio - 3.4 ~ 3.6l is doable I believe, and reliable/durable 450hp+ isn't unheard of.

Dyno figures are easily faked to the untrained - what gear you do the run in, what correction factor you use, what final drive ratio number you use can all determine whether you see gains or nothing at all in a dyno run. It means nothing as a comparison from motor to motor, only useful as a tuning tool on mapping gains or losses during a certain time and day for one particular machine.

+1

[breeze]

Some great info on this thread - really interesting reading.

It does seem to start to challenge the value in spending on the motor, particularly when so many of us have a BMW warranty.

Part of the thinking came from conversations I've had with a friend with a 997.1 GT3. Something along the lines of, how comparable a 400bhp CSL would be to his car (which is definitely quicker in standard trim).

I should say, the 400bhp figure didn't come from JT...

[breeze]

Hey Dunc,

Yep that's what I thought, I don't really give too much of a toss what its made tbh, I didn't have them changed to go trying to get massive increases in power, one cam was worn out, my fault I guess. But the shrick cams were a nice alternative to standard ones.

Does the car feel quicker with them in and the claimed increases?

Well its hard to tell when driving it, it feels like it wants to spin up more in second than it did before, or was that the cups not up to temp?

On the ring the car feels better, pulls more up the hill or so the speedo tells me and I'm having to let off in places I was flat, and also getting in to higher gears in places I wasn't before and also changing up gears earlier than before.

Can't give you a time as (i'll upload the videos from the last trip) loads of crashes all weekend and lots of traffic so didn't really get any quick full laps in only sections really.

So overall pleased with the apparent gains,

Was it worth the money??
Not on your nelly, if the old cams hadn't wore out I wouldn't have touched it.

As an aside, how many of you guys really only use your car on track compared to road driving, as my cams went because I didn;t do the clearances often enough, or so I was told by a specialist, they need to be checked every year.

cheers

Ando

Ando - did you get a 'before' figure? Guessing not if your factory cams are worn, but it would be interesting to know what a factory CSL makes on the same rollers.

[ando]

Ando - did you get a 'before' figure? Guessing not if your factory cams are worn, but it would be interesting to know what a factory CSL makes on the same rollers.

Long story about the cams in my car, briefly 3 garages, 2 sets of cams and some dodgy workmanship, before finally, With Dunc's help, getting it in with someone who knows his stuff, and now a bit of a legal battle on my hands with one of the earlier garages.

There wasn't a 'before' run as the cams needed changing anyway, and they were done by another guy before Schirmers finished it off.

Schirmer reckons he has never seen a stock CSL make stock claimed outputs.

Like I said earlier, I'm not that fussed about power figures just want a good strong motor that preforms well on track and I can have some fun with it.

I know all about Dyno's, Gears and how to fudge figures, but if you've got a reputation and you build cars that win a lot of races, then maybe they do not bullshit?

Cheers

Ando.

[alexk]

Schirmer reckons he has never seen a stock CSL make stock claimed outputs.

How to interpret this ?
As they are making more or less than stock figures ?

[ando]

How to interpret this ?
As they are making more or less than stock figures ?

Less apprently, than stock.

Ando

[_Nathan_]

Anyone who thinks they have more than the claimed 355bhp on a stock CSL is deluded, especially now they are 9 years old, I couldn't care less what any dyno says, it just isn't going to happen.

Mine made 349 at 40k miles, that car never got left by the "I got told I had the most powerful stock CSL ever seen at 370bhp" lot either, if anything it felt stronger that others I drove?

[alexk]

Anyone who thinks they have more than the claimed 355bhp on a stock CSL is deluded, especially now they are 9 years old, I couldn't care less what any dyno says, it just isn't going to happen.

Mine made 349 at 40k miles, that car never got left by the "I got told I had the most powerful stock CSL ever seen at 370bhp" lot either, if anything it felt stronger that others I drove?

I think relative dyno figures (on the same dyno) is something we can use to compare.
Standard M3 E46s had at best 320PS on the same dyno that I dyno-ed my car.
Additionally, telemetry tests can also give an indication on how an engine performs and I know for a fact my car is quick.
Maybe in another dyno it will show 340PS, but I reckon other CSLs will show 330PS and M3 E46s 290PS.
I was never left behind too from other CSLs that claim 380+ figures with exhausts, maps etc.

It might be the Swiss Shell V-Power :wink:

[alexk]

Nathan

Do you have any acceleration tests that you can share ?
And what is the spec of the car in these tests ?

[breeze]

Anyone who thinks they have more than the claimed 355bhp on a stock CSL is deluded, especially now they are 9 years old, I couldn't care less what any dyno says, it just isn't going to happen.

Mine made 349 at 40k miles, that car never got left by the "I got told I had the most powerful stock CSL ever seen at 370bhp" lot either, if anything it felt stronger that others I drove?

I've had quite a few people say that S50 engines make more power as they get older and I would have assumed that the S54 would be similar - whether they ever make 355 bhp standard is another story...

[breeze]

The limit is really in the head and the ability to flow much more in NA form. Hence the reason that high lift cams does bugger all when compared to a longer duration.

Does the engine respond to head work? If that is where the limit is, is there anything that can be done to the factor head to enable it to flow better?

[shane@mbtech]

Does the engine respond to head work? If that is where the limit is, is there anything that can be done to the factor head to enable it to flow better?

This is my next task. I have a CSL head here, I am going to get it flow tested and see if any improvements. Different thickness headgasket is another avenue I am contemplating.