BMEP-Or why you only need 1 camshaft

[VICTORY RED 1SS]

..Here and I thought Engineers drove Choo Choos....

[MerF]

Originally Posted by VICTORY RED 1SS

..Here and I thought Engineers drove Choo Choos....

/facepalm

[CamaroSpike23]

[swifttal]

Originally Posted by CamaroSpike23

That is the funniest picture I have seen in a long while... BRILLIANT!!!

[Mr. Wyndham]

So...it's an alternative efficiency gauge?

I'm still confused where the 150.8 came from... But this BMEP...or the cylinder pressures during combustion...can tell us which engine is really the 'best'...hmm..

LLT:

BMEP = 150.8 x TORQUE (lb-ft) / DISPLACEMENT
BMEP = 150.8 x 273 / 219.6
BMEP = 187.5psi


LS3 (Camaro):

BMEP = 150.8 x TORQUE (lb-ft) / DISPLACEMENT
BMEP = 150.8 x 408 / 378.3
BMEP = 162.6psi


So...according to all this, the LLT is notably more efficient at making power than the LS3...

[DGthe3]

its an alternative to hp/L . . .

[Mr. Wyndham]

Originally Posted by DGthe3

its an alternative to hp/L . . .

So...I'm not wrong for thinking this is just painting the car a different color (bad metaphor)?

[DGthe3]

Nope, you're not wrong. While useful in determining what is the better engine, in the end it comes down to what the final output numbers are, just like with hp/L or hp/lb of engine. 240 psi BMEP is great, but 300 hp beats 100 hp in the same car, regardless of how efficient the engine is at producing power.

Also, colour is important. Red cars go faster! Proof? Ferrari.

[CWI]

Originally Posted by DGthe3

Also, colour is important. Red cars go faster! Proof? Ferrari.

Damn it!! Why then won't my red Colorado go past 100mph?

[rayhawk]

Originally Posted by Dragoneye

So...it's an alternative efficiency gauge?

I'm still confused where the 150.8 came from... But this BMEP...or the cylinder pressures during combustion...can tell us which engine is really the 'best'...hmm..

LLT:

BMEP = 150.8 x TORQUE (lb-ft) / DISPLACEMENT
BMEP = 150.8 x 273 / 219.6
BMEP = 187.5psi


LS3 (Camaro):

BMEP = 150.8 x TORQUE (lb-ft) / DISPLACEMENT
BMEP = 150.8 x 408 / 378.3
BMEP = 162.6psi


So...according to all this, the LLT is notably more efficient at making power than the LS3...

The 150.8 is a conversion factor. Once you input all the various factors, that is what the equation reduces to, so it is just a scale factor. The calculation you did shows what you might guess, that a 3.6L motor with 273 ftlbs of torque is more efficient than a 6.2l motor with 408 ftlbs of torque. Also remember that the peak torque on the LLT is at 5200rpm whereas on the LS3 it is at 4500 rpm, so the LS3 gives you a more user-friendly power band.

My post was really to show that 2v pushrod technology is just as capable as all the fancy tecnology they use for Indy cars. In other words, the LS3 is running at a relatively low state of tune compared to the LLT. Given a similar state of tune for the LS3-the BMEP will easily reach those numbers shown for the LLT-or about 470 ft lbs of torque at 187psi. Interestingly enough, the GM hot cam motor makes 475 ftlbs of torque at 4500 rpm...

LS3 for the MFW

But no disrespect to the LLT either, it is a nice setup.

[Vash]

More is not always better. I have a lot of solid kills in my classic RX7 and it's only 100 hp. No cam, valves etc either haha anyway point being bigger is not better just by default. Most time yes but not every road is a straight line.

[swifttal]

Originally Posted by Vash

More is not always better. I have a lot of solid kills in my classic RX7 and it's only 100 hp. No cam, valves etc either haha anyway point being bigger is not better just by default. Most time yes but not every road is a straight line.

A ported RX-7 is better than stock...

...which would be bigger... in the same sense