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-   -   Repeat question - Max RPM 6.0 .030 over (https://www.performancetrucks.net/forums/gm-engine-exhaust-performance-21/repeat-question-max-rpm-6-0-030-over-515097/)

aldrichg9 03-05-2013 12:57 PM

Repeat question - Max RPM 6.0 .030 over
 
I know this question has been asked thousands of times but I want to make sure I get it correct with all the mods on this engine. (mods below)
Where should I set the fuel cutoff, and where should I shift with this engine.
Right now for tuning I have it cutoff set at 5500 and shifting no later than 5500but I shift it earlier by speed.
Where would you all shift this thing
I would like to go a bit higher with hit and I think the LS3 max is around 6500??? correct me if I'm wrong.
Should I base the max RPM on the bottom end? or be more conservative since its all in a older block?
Dyno is not an option for me right now but might be some day.

Mods are in my sig but I thought I'd list everything engine related here.

02 cast iron LQ4 bored .030 to 6.2l
2010 Camaro LS3 crank, rods, and pistons
Isky cam 218/218 110lsa have the cam card if you want to see it
317 heads milled 0.020
Z06 Valves, LS7 lifters, trickflow springs and pushrods
TBSS Intake, Edelbrock 90mm Throttle Body, 85 mm MAF



One more question.
My oil pressure is not as high as I think it should be.
45 cold idle - 40-45 hot WOT
I have read numerous threads on what it could be (pickup, or insert in oil passage)
I am deciding right now how to troubleshoot the issue, but should I be afraid to take RPMs very high without have more oil pressure?
I know this is a particularly subjective question that I have already gotten a range of answers.
Most have told me this engine doesn't need 80 psi to survive
But when I have been driving around tuning and spending time at higher rpms getting the oil hotter and such, when I come to a stop and idle the oil psi dips down to 5-10 psi at 650 rpm

AgFormula02 03-05-2013 03:00 PM

Rpm limiting factor is valve train stability, not bottom end.
The only way to know where to shift is either dyno or track.
It all depends on the cam and where you stop making power

AgFormula02 03-05-2013 03:01 PM

Ps: you have oil issues. Either pump or bearings.

aldrichg9 03-05-2013 03:02 PM

I wondered about that.
Thank you for the reply.
Since dyno is not an option right now I guess butt dyno is probably how most guys do it.

dirt track racer 81 03-05-2013 03:02 PM

In my opinion shift 200 rpm passed peak hp..

BigDaddy0381 03-05-2013 03:07 PM

02 cast iron LQ4 bored .030 to 6.2l

I thought it had to be .065 over (4.065) to be a 6.2L and the .030 was a 370?

I'm building a .030 over 6.0 now so just curious for info.

dirt track racer 81 03-05-2013 03:13 PM


Originally Posted by BigDaddy0381 (Post 5075234)
02 cast iron LQ4 bored .030 to 6.2l

I thought it had to be .065 over (4.065) to be a 6.2L and the .030 was a 370?

I'm building a .030 over 6.0 now so just curious for info.

You are correct on that

old motorhead 03-05-2013 04:47 PM

I'd bet the cam you've chosen will have the hp peak well under 5500 rpm. Torque should be stupid high though. The safe peak rpm, as stated earlier, has more to do with the valve train vs the bottom end. The bottom end is good for 7K+ if set up properly. As yours is set up, there's little if any value running the engine past 5500 rpm.

I'd confirm the oil pressure with a mechanical gauge, that's of known accuracy, before jumping to any expensive conclusions.

aldrichg9 03-05-2013 08:33 PM

Hmm.
I bought it this way so i may have just dreamed those numbers up...
I was told ls3 bottom end and i may have came up with the .030......

I am thinking of looking into some of the dyn cyl air calcs in hptuners and use that to help get close to the peak.
Anyone done it that way?

TXsilverado 03-06-2013 01:42 PM

i would be setting the shift points to 2,500 until you fix some oiling issues. what does your hot idle psi show?


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