LSA Question

Garrett Ellison said

Yeah, I kinda figured this thread would be fairly polarizing once bringing up the 128 rule.

Click to expand...

His formula suits his design philosophy. Here's an engine Mike Jones built for himself, look at the duration, split and LSA its a HR from memory.

There are very few pump gas 355" SBC engines that will out-pull my boat engine
It's 10:1 with ported 492 heads, Performer RPM, and Holley 600.

RPM---TQ--BHP
3200--436--266
3400--443--287
3600--445--305
3800--444--321
4000--443--337
4200--440--352
4400--440--368
4600--441--386
4800--441--403
5000--432--411
5200--422--418
5400--412--423
5600--400--426

The cam is 216/220, on a 112 LSA, and 108 ICL

Some generalizations from Mike:

If you took an engine, with a head/manifold that's all done at 6,000rpm, and you are going to look at the power from 3,000-6,000, you could use different durations to get the results you want.

If you want the results to show that the tighter the LSA, the higher the low-end power, and the lower the top end power, you go with the proper cam duration for 6,000rpm.

If you want the tighter LSA to make more power everywhere, you take out compression, and add a bunch of duration.

If you want the wider LSA to make more power everywhere, you add compression, and take out a bunch of duration.