Pimpium57

iTrader: (104)

If I were to upgrade my pushrods, valvesprings, etc, how high could I spin my stock cam LS1 before it starts losing power, while still keeping on the safe side to leave room for error?

I'll go the cam route in the future, but right now I'm concerned with making the most power with the stocker...

Thanks!

TheBlurLS1

iTrader: (8)

i'm in the exact same boat, i want to put a whole new valvetrain in it (have a bad lifter and might as well go bonkers ). i want to run the patriot gold duals and hardened pushrods w/ maby comp r lifters. i also want to get my rev limiter bumped up a few hundred so i can stay in 4th through the traps w/ my 4.11's.

ArKay99

iTrader: (1)

I have a 99 C5. On the dyno it started wheeze ~5600rpm. I had my rev limiter set to 6400rpm on stock springs. It was done by then.

MNR-0

With decent valve springs you can spin the otherwise stock valvetrain to 6600RPM but I wouldn't do i too often. I spin to 6500 with just valve springs all the time in 1st and 6300 in 2nd. In any other gear apart from 1st the stock cam runs out of puff at 6300RPM with a good tune. Peak power is at 5600RPM so Im holding on to it as long as possible.

PREDATOR-Z

Anything beyond 6100 on a stock cam is a waste of time.

MNR-0

For a manual you are 100% correct. For a stock stall auto that is incorrect. The 1-2 upshift results in such a crappy shift extension you still make more torque in 1st at 6400RPM than in 2nd at 4000RPM.

A converter will change things somewhat as you want to keep the shift extension and shift RPM balanced around the peak power output, depending on the fall-off after peak power.

I gained 0.4 seconds by revising my shift points from 6000RPM in 1st to 6500RPM in 1st, even though I aint making any more power past 5600RPM. Peak power doesnt determine your shift points rather average power.

PREDATOR-Z

Yes, to a certain degree, but 900rpm shift drop at 6500 will bring you at 5600 rpm and smack into the downslide of your trq curve. Also reving the stock springs at this level 6500 is a welcome invitation for valve float, as we all know stock LS1 springs are not rated for those rpm levels.
I have experimented widely with my car at different rpms and found the most consistent being 6100. (in the days it was stock).
Also if you're in Aussie, are we talking about a F-Body? or a Monaro/Holden, because that car is 500lbs heavier and i believe have 3.08 in stock form.

MNR-0

Yuppers. I own a Monaro which is 500lbs heavier in stock form - which is how I run it. The diff gears are 3.08 stock but I upgraded to 3.73 from 3.46. Will be stalling it up with a custom 3000/2.0STR in a few weeks. That will mean a complete revision to the shift points to maintain max. average power.

I agree about the valve float - my stockers floated at 5200RPM . I upgraded to duals and can spin to 6500 easy without float, but there's no point in an otherwise bolt-on only heavy car as the cam runs out of puff and flutters from 6300RPM. It does a venerable job of holding onto it with the 117LSA and 2* retard, but thats its stock limit.

I think we both agree here. You want the shift extension from the shift point RPM to be evenly balanced around peak power. So it also depends on your shift RPM lag for the upshift.

Im hoping that my 3000/2.0STR stally will generate a reasonable shift extension so I don't have to rev as high. In 1st, I shift at 6400 to return to 3900 - thats 2500RPM drop - . If I gain 500RPM shift extension thats still not enough to change my WOT points, but if I gained 1000RPM then I would shift lower.