Too good to be true?

[DinanM3_S2]

IAs far as I can tell, virtually nobody has experamented very much with turbo BMW 3.2l S54 engines (E46 M3 and 2002 M Coupe/Roadster). The 11.5:1 CR has been generally percieved as way too high for a turbocharger; until recently. A company named DA-Motorsports is about to release a turbo setup for the S54, at stock compression and 8-10psi. They estimate 550hp.

I am not too up to date on turbo technology, but I always thought that an 11.5:1 CR was way too high for most FI. Here is a link...
http://www.da-motorsport.com/projele...kits/index.htm

My first question is if these numbers are even feasable from the S54.

My second question is if this setup would reduce the reliability of the engine to the point of it breaking down too often for daily use.

[beef_bourito]

it's all about engineering the kit to work well. these people put alot of work into designing these kits so that they do work.

If you have the proper cooling you might be able to run that kind of boost, it seems kinda high to me but they might have done something good.

As for the numbers, it could be that high, with that compression ration on that boost it wouldn't surprise me.

Again, these people engineer their kits to work well with the car they're designed for. i doubt it would reduce the reliability of the car much, it's all about how you drive. if you redline it on a regular basis, the engine won't last as long, if you drive normally, it could last very long.

[Schister66]

all you have to have is good tuning....you can boost anything, but the tuner has to be dead on. I would assume that they're using a big turbo that flows a lot of air, but doesn't run high PSI. They used a fairly large intercooler as well, that'll help decrease the risk of detonation too. It'll be interesting to see what happens w/ it.....

[nissanfanatic]

Gonna take a lot of timing retard or higher octane fuel. Dynamic compression ratio will be high, but fuck, some people run 16-17psi on our stock 9.5:1 compression ratio KAs.... So 8-10psi is reasonable with good charge cooling. Maybe even more if you use water injection...

And it doesn't require "better" tuning... Saying that is basically saying that with lower compression ratio, you don't need to put effort into tuning car. Which is BS.

Biggest thing on this setup as opposed to other setups is how much timing retard is needed....

Reliability won't go down....but the engine will require more frequent/in depth matinence...just like any turbo car...

[Schister66]

Originally Posted by nissanfanatic

Gonna take a lot of timing retard or higher octane fuel. Dynamic compression ratio will be high, but fuck, some people run 16-17psi on our stock 9.5:1 compression ratio KAs.... So 8-10psi is reasonable with good charge cooling. Maybe even more if you use water injection...

And it doesn't require "better" tuning... Saying that is basically saying that with lower compression ratio, you don't need to put effort into tuning car. Which is BS.

Biggest thing on this setup as opposed to other setups is how much timing retard is needed....

Reliability won't go down....but the engine will require more frequent/in depth matinence...just like any turbo car...

Not necessarily a "better" tune per say, but a more conservative tune at very least....

[nissanfanatic]

Not really... Every tune has a point of knock for timing and a point of ping for Air/Fuel ratio on a given fuel and ambient air temp. If 8.5:1 CR on 15psi allows only 18* total timing on 93 octane pump, then 20* is going to knock. If 10.5:1 CR on 10psi only allows 18* total timing on 93, the 20* is still going to knock. Same with Air/Fuel ratio.

The only thing CR changes is how much boost you can run on a given octane fuel... If you can get 116 octane fuel cheap and abundant(yea right), then fuck it, go for 10.5:1 and enjoy the off boost driving.. But if you are limited to 93 octane, you should prolly aim lower for streetable power(8.5:1-9.5:1). Personally, whenever I finally do build an engine, I'm prolly going as low as I can find just so I can run 400whp on the street without having to run racing gas all the time...Since thats my goal...

[Schister66]

gotcha...

[fairladyz_gt-r]

I though the S54 engine is already at its edge...i heard people who remove their speed limiter often blow their engine up if constently travaling above 250km/h

[nissanfanatic]

Could be because when you operate in higher RPM ranges, it is highly recommended that you switch to one step colder spark plugs...