I have just installed GM 1.6 RR with lt4 springs and the other parts that needs to be upgraded in the valvetrain and my question is, can i rev higher than before without hurting the engine? I still have the stock rev limiter at 5800 or whatever it is at, and I can feel how it pulls harder in higher rpmīs then before. Do you guys think I should set the rev limiter a couple of 100īs rpm higher? Right now I never rev higher than maybe 5400, how much am I available to rev with this setup (check sign.)

Thanks

 

I'd stay around 6 grand. There is no point in going any higher without a cam. Besides your power peaks before 6 grand anyway. Should be able to get some of that top end with your springs. JMHO

 

Yes good point. I just wanna get out the most power I can from this setup, and Iīm just afraid of that Iīm shifting to early and miss the point where the power peaks and if maybe that point is a little bit higher in the rpms then before the RR install. Just some thinking Where do you guys think the power peaks with this setup?

Thank you

 

probably around 55-5600. Just a wag.

 

Absolutely. The main problem with higher revs on a bone stock engine is the springs.

Doesn't matter what anybody thinks. Calculate your optimal shift points based on your gearing and a stock+1.6RR LT1 dyno chart and see if they are higher than the stock redline.

 

i have the same setup and would like some more info... what would be the best rev limit and shift points with 3:42's...

how do you calculate optimal shift points?

krillformula: what preload are you running and are you running stock lifters?

thank you

 

So how much reving is the LT4 springs good for? Didnīt the LT4 have a little higher rev limit stock then the LT1?
I also have 3.42 and Iīm gonna search for dyno charts with the same mods and see ~ where the power peaks.
Iīm running stock lifters and 1/4 past zero lash.

 

good luck, can you let me know what you find out...
the lt4 red-lines at 6300 rpm... but it peaks out at 330hp @ 5800 rpm...

 

I think BUBBA is pretty close. Most will tell you to shift 200 to 400 rpm after peak hp is reached. My small cam peaks at 6k and my 1-2 shift is set at 6400, and the 2-3 shift is at 6300.

 

The optimal shift point is where the torque at the rear wheels is the same before and after the shift.

If you do a google search there are a number of pages that tell you how to calculate it. There are even a couple of online calculators that will let you input your torque curve and gearing and will do the work for you.

 

i will have the same setup after this weekend,i'd would also say 6 grand

 

OK looks like a good idea to set the rev limiter a little higher and maybe shift at 5800 or something, and I will start the search of dyno charts and post here if I find anything useful :P So is there any program I can download or buy to my laptop and change the rev limit by myself? I have everything needed cable etc.

 

Why don't you have PCMforless do it for you----since you already had him perform an initial tune?JMHO

 

Yeah, just saw that I have unlimited re-burns in 6 months so I will contact Bryan again. But it is still fun to learn and do things by yourself =)