Forcfed93

iTrader: (10)

I've been chasing a high RPM miss recently and hope someone else has some insight. At about 6300rpm in pretty much every gear, the engine feels like it hits a rev limiter.

The rev limit on these stock is 6600rpm right?

I've replaced the fuel filter, plugs, wires, put a K&N intake on it, cleaned the MAF... I would also suspect valve float, except that it's stock internally with only 85k. I doubt that the springs would weaken to the point of floating the valves.

Anyone have any ideas?

vmapper

iTrader: (8)

Its very possible you are hitting 6600, but the needle is slow at responding.
I would start by scanning and verifying rpm.

07CTS-V

iTrader: (6)

I have the same thing when boiling through first gear. I've gotten it better by adjusting the max torque values.

FuzzyLog1c

iTrader: (4)

I think it's valve float. Forcefed, are you N/A? Even if you are, those stock springs are pretty weak (294 lbs open seat). I'm running Comp 26926 springs, which I bought and installed, thinking that I was going to be able to boost the stock motor. They're rated at 470 lbs of open seat pressure (a little much for this, I know)--was selected per the methodology that you always want extra spring pressure when going FI because the boost will tend to float the valves and it's okay to give up a couple of RWHP to ensure correct operation of the valvetrain.

Forcfed93

iTrader: (10)

N/A and pretty close to stock really. I haven't decided yet which type of power adder I'm going to do, so I haven't upgraded springs. Maybe I'll just swap out to some comp 918's for the time being in hopes that those can handle the massive factory LS6 cam.

07CTS-V

iTrader: (6)

Maybe you can just shift before it gets to 6300 until you do some valve train work or log some data and see what it is.


My issue is quite different than yours.

I've had two sets of valve springs, two sets of lifters and two separate motors do it. The current valve springs are Comp 26926's with Lunati lifters. Mine happens anywhere between 5000 & 6000 rpm in first gear while spinning tire and the rpms are climbing real fast.

I've logged data while doing it and it shows a definite reduction in spark timing but NO knock. If it were valve float there wouldn't be any reduction in timing without some knock. The only explanation is the computer reducing it due to some internal calculations. I haven't spent too much time trying to find it, I just lift the pedal off the floor about 1/2" when ripping first gear. Lol

69stangscj

iTrader: (3)

Do these cars have torque reduction?

FuzzyLog1c

iTrader: (4)

The first thing that Janetty Racing did to my car back in 2011 was disable torque management.

07CTS-V

iTrader: (6)

There is still torque management even though they "turned it off". There are acceleration based calculations and others.

kjr6306

iTrader: (1)

Sounds like the same problem I was having a few years back. I changed my TB to 90mm and then dropped it off at the local tuner for dyno tune. I was sure to mention the problem I was having with it cutting out around 5500 RPM. When I picked it up a few days later I asked what the issue was. I specifically remember him saying that the torque mgmt. was all screwed up. Problem fixed and none since. Sounds like you may need a tune.....

Forcfed93

iTrader: (10)

So just an update to this. I finally got my Comp 918's, titanium retainers, YT 1.7 RR's, hardened pushrods and my pacesetter LT's installed.

Took it out last night and wow what a difference. Spun through first like usual, then I hit second and bounced the rev limiter at 6600 so fast I thought I broke something... Until I noticed the back end was fish tailing.

Night and day difference and it definitely solved the issue. Still not sure why the stock springs would weaken so much though after only 88k.

NIKDSC5

iTrader: (10)

88k of high reving awesomeness!