What "bolt ons" bring an s52 to 300hp and what's the cost?

[BimmerTim]

VAC Motorsports Stage 3 head.

Steve is supposed to be getting me flow numbers, but he hasn't gotten back to me quite yet.

[whiltebeitel]

What's the magical head? I'm on a run on Excel. Nothing better to do at the moment.

[BimmerTim]

I found a magical head, but I think the bottom-end will be the limiting factor.

[whiltebeitel]

That math is based on infinite con-rod ratio, btw. Easier to make comparisons witout getting into specific crank specs. Actual maximum acceleration (and thus, forces) will be significantly higer.

But that all assumes the head doesn't limit the power. That's where the magics must be!

[BimmerTim]

The max piston speed of a '04 R6, for example, is 79.98 MPH, at 14,000 RPM. 9,500 RPM in a US S50 is 95.47 MPH. A one-race CART engine in (Honda v-12, c. 1992) spins up to 14,400 RPMs with a 47.9mm stroke, making 80.79 MPH max piston speed.

What you are suggesting is possible, and has been rumored to be exceeded by a few current race teams, no one is doing it for less than 6 figures, just for the development expenses.

Oh, and FYI, 8k in a US S50 is 80.4 MPH, max piston speed. At that speed, the piston should see about 1,953 G's. 400 grams of piston puts ~1,720 lbs of force on the connecting rod. 350 grams would bring that down to ~1,500 lbs of force.

Yes, I have done all the math, but thank you for posting for others to see.

I'm pretty much going to be limited to 8k at the very max.

[whiltebeitel]

7200rpm is 20.59m/s

Standard F1 engine at redline(18,000rpm) is 23.86m/s

The max piston speed of a '04 R6, for example, is 79.98 MPH, at 14,000 RPM. 9,500 RPM in a US S50 is 95.47 MPH. A one-race CART engine in (Honda v-12, c. 1992) spins up to 14,400 RPMs with a 47.9mm stroke, making 80.79 MPH max piston speed.

What you are suggesting is possible, and has been rumored to be exceeded by a few current race teams, no one is doing it for less than 6 figures, just for the development expenses.

Oh, and FYI, 8k in a US S50 is 80.4 MPH, max piston speed. At that speed, the piston should see about 1,953 G's. 400 grams of piston puts ~1,720 lbs of force on the connecting rod. 350 grams would bring that down to ~1,500 lbs of force.

[FredK]

um, the S54 just has a dual pickup wet sump oil pump. Are there other details that I'm missing?

[BimmerTim]

I do plan to dry sump, not that it would change the internal dynamics of the oiling system.

8k is totally doable, but not more.

[nando]

True.

Mostly cuz I have an S50, not an S52.

Yeah, so the head really only plays a very small part in VE. I found a head that flows way more than enough air, but now looking at the piston speed, I really would be pushing it at 8k, as that would put me at 22.88m/s.

I think BMW should make their engines more detuned so that we can make more power easier.

while that might be more fun, the ceiling of what an N/A motor of a certain displacement can produce wouldn't change :p

8k is doable, the S54 does 7900 with the same stroke as the S52. Of course it also has a far more advanced oiling system and BMW ended up lowering the redline because of bearing issues..

[lifeiskaos]

I think BMW should make their engines more detuned so that we can make more power easier.

that's silly

[BimmerTim]

True.

Mostly cuz I have an S50, not an S52.

Yeah, so the head really only plays a very small part in VE. I found a head that flows way more than enough air, but now looking at the piston speed, I really would be pushing it at 8k, as that would put me at 22.88m/s.

I think BMW should make their engines more detuned so that we can make more power easier.

[nando]

It's actually only 27.17m/s, but I digress.

I was using the S52 stroke, you probably used the S50

[BimmerTim]

7200rpm is 20.59m/s

Standard F1 engine at redline(18,000rpm) is 23.86m/s

[BimmerTim]

It's actually only 27.17m/s, but I digress.

[nando]

but hey, that's only 28.4m/s mean piston speed. a mere 3.4ms/s higher than even F1 engines go to. :p