Highest rpm to shift stock ls1 at?
10-09-2013, 10:46 PM
#3
There are two questions here.
How high can you possibly shift?
When should you shift to be the quickest?
You "can" shift at 6400, but don't see why you want to. Generally most LS1 motors make most of their power in the mid 5000's. Here is a dynograph of a stock LS1 from a 99 T/A
The HP peaks out at around 5300 then starts to steadily decrease. There's no reason to keep on reving into the 6's if you're losing power. Now to shift to be the fastest you need to basically shift so as to use as much power under the curve as possible. Just because you make your peak power at 5300 doesn't mean you need to shift at 5300. Doing that will drop you down to the mid 4000's where you make significantly less power than if you were to rev to say, 5800 then shift to 5000.
There is a delicate balance that needs to be struck than just revving the ***** off your car until you smash the limiter.
How high can you possibly shift?
When should you shift to be the quickest?
You "can" shift at 6400, but don't see why you want to. Generally most LS1 motors make most of their power in the mid 5000's. Here is a dynograph of a stock LS1 from a 99 T/A
The HP peaks out at around 5300 then starts to steadily decrease. There's no reason to keep on reving into the 6's if you're losing power. Now to shift to be the fastest you need to basically shift so as to use as much power under the curve as possible. Just because you make your peak power at 5300 doesn't mean you need to shift at 5300. Doing that will drop you down to the mid 4000's where you make significantly less power than if you were to rev to say, 5800 then shift to 5000.
There is a delicate balance that needs to be struck than just revving the ***** off your car until you smash the limiter.
10-10-2013, 12:57 PM
#5
TECH Fanatic
I think everyone was assuming your car is a M6, but from what just posted I'm guessing you have a A4. If so your running faster because A4's have larger a rpm drop between gears. So even though your revving well past you peak HP your rpm's are dropping into a better part of your torque curve. Are you going to hurt your valvetrain? A set of LS6 springs would be cheap insurance.
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10-11-2013, 08:46 AM
#8
Staging Lane
Join Date: Sep 2012
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I don't know how many miles there are on your components, but I do know from 45+ years of experience of road racing, drag racing, and auto-x that components fail at the most inopportune time when subject to abuse beyond their designed RPM range.
Spring metal fatigue is difficult to detect prior to breakage unless you lucky enough to spot the "blued" metal effect of over heated valve springs. Like Fry_ recommended, an upgrade to a set of LS6 springs would be cheap insurance.
Also, M4N14C is right on about tuning your shift points to keep the engine in it's best power band based upon the RPM drop between gears. This was a secret to winning stock car drag races back in the '60's. The savvy driver knew when to shift to keep the engine pulling hard all the way down the 1/4 mile while the average driver shifted at redline (typically way outside the engine's power band) and lost the race. (If I can find it, I'll post an interesting article on to determine shifting points from Chevy Corvette engineer Jim Ingles.)
Hope this info helps and that you keep your LS1 together for the future cam change.
Then again I'm not very bright. 
