[e.n335]

Hi,

I'm asking for your opinions and did not find a better place than posting here.

The N54 has an aluminium block with iron sleeves, a CR of 10.5:1 and is designed for FI.
The S65 has an alusil block without sleeves, a CR of 12.0:1 and is designed for NA.

Now, what is your opinion about boosting the M3 ( intercooled ) and how far would you go with boost pressure on the S65 ? Distance between cylinders is 6mm, rev limiter @ 8400. Pistons, rods and crank are forged.

Thanks,
Eugen

[Kelvin1000]

You just can't stop yourself, can you?

I think that moderate boost below 10 psi with under 7 psi would be fine. That M3 engine is rock solid. There are already a few people running this setup.

[benton0311]

The N54 has direct injection which allows for the relatively high (for FI) compression of 10.5:1, otherwise the compression ratio would probably be in the 8.5-9:1 range as in most other FI applications.

Low boost pressure ~6 psi probably wouldn't be too bad for the block or cylinders. The 12:1 compression ratio would be a huge issue as for not detonating on pump gas with even a low level of boost. 93 might work, wouldn't want to do it on 91. Might really need water/alky/meth injection to do it safely.

Individual throttles could be an issue depending on how well they seal. They're also designed for a vacuum environment so I don't know if there could potentially be a problem with even air distribution under pressure.

You'd need to find a tune that pulls a lot of timing under boost.

Should be doable, just need to keep to boost low to get along with the high CR. Apparently
there's already some supercharged M3's out there.

Edit: Just noticed the OP is from Switzerland. I was referring to 93 and 91 octane using R+M/2.

[Sniz]

boost it

plenty of people have already paved the way for you.

[Brey335i]

There are several Supercharged M3's out there... that is the setup I would go with personally

[e.n335]

Yes, there are supercharged applications out there and ESS seems to provide quite good solutions.

However, there is no long-term proof ( SC's for the S65 exist basicly since 6 to 8 months for the V8 M3 ). Boring and stroking the engine will not be cost-effective at all. Supercharging the M3 could be the way to go, but should I wait for longer-term experience and improved SC kit / tuning software versions or just go ahead right now ? I'm currently looking for only 4 psi ( ESS VT2-550 kit with a larger pulley to reduce boost by 1 psi ), providing a +~100 chp increase.

Eugen

[forza1976]

Do it man, that car is just simply insane boosted. Saw a bunch of them at Mfest in April and I was definitely jealous!

[Panoz]

A local ESS equipped M3 , pulled 8CLs to a Lambo SuperLeggera

[per]

I have the ESS VT-625 kit om my car, and so far i am very happy with it, the car is like a stock car under 4000rpm and i use it as a daily driver.
Since there been over 70 kits sold without any engine problem, i am confident that the motor could handle the power , as far as i have heard the only problem was that they had to change the clutch on there Norwegian race car after doing 0-402 meter pull with slicks

[GreenPlease]

Might really need water/alky/meth injection to do it safely.

+1. This is really just an insurance policy more than anything.The S65 seems pretty solid, you should be fine with moderate boost.