boosted4life

iTrader: (4)

I was just wondering if anyone had an example of what valve float sounds like on an ls1? I think I am getting valve float but not sure because it feels pretty bad and I thought valve float would be more minor.. seems kinda like a bad misfire but only at about 4500 rpms and up.

It is a 98 ss camaro with a 99 firehawk ls1 engine, vortech g-trim on 7psi. Mild cam.. I feel stupid because I didn't even remember to change the valve springs when I put my cam in my new motor..

G Engines

It may have too much fuel at the uper rpms ?

MrDavid

iTrader: (11)

Doesn't sound any different on my car which currently is floating valves at 5800. Just feels sorta like hitting a wall, so to speak, in the powerband. Loses 80rwhp within the next 500rpms, but never sounds any different.

Sluggish

iTrader: (10)

I think I have a valve float issue also, but my sympton is boosting falling off fast above 6000. When the car is super fat it will cut out like your saying.

boosted4life

iTrader: (4)

Ok so maybe it fell out of the tune somehow? Because the car does have a tune for the larger injectors but the gm dealer reset my pcm when I was having problems with it.. I figured the tune was hard flashed..

98Z28CobraKiller

iTrader: (17)

You could be dropping a cylinder or blowing out your spark.

MrDavid

iTrader: (11)

You aren't making that much boost so its hard to believe that you're blowing out the spark. What heat range plugs are you using?

boosted4life

iTrader: (4)

tr6 plug with no change in the gap from what they come at.

Black_98Z

iTrader: (13)

Might want to close up the gap on the plugs. I had TR6's gapped around .035 and it was blowing out the spark at 10-12 psi over 5k. Switched to NGK br7ef plugs. On heat range colder and gapped to .027. Fixed the spark blowout issue.

MrDavid

iTrader: (11)

I ran TR6's with stock gap when I was making 7lbs and had no issues with blowout.

boosted4life

iTrader: (4)

Yea im running 7psi.. I just want to know what valve float sounds like because that is the most likely situation right now with boost + cam + stock springs.

MrDavid

iTrader: (11)

If you really think you're floating valves, put your car on a dyno with a wideband and watch the air fuel when you get into the upper RPM band. It will probably dip down into the 10's and you will see a drop in power when you hit that certain RPM and the drop will be pretty substantial.

boosted4life

iTrader: (4)

Well it just feels like it cuts out at upper rpm's.. it is not smooth at all. It definately seems like a misfire or fuel problem.

MrDavid

iTrader: (11)

Then you NEED to have your car hooked up to a wideband to accurately address the issue instead of doing all the guess work.

boosted4life

iTrader: (4)

Ok ill do that.

RS_SS69

iTrader: (31)

What are the specs on the mild cam? If this was DanDans motor the springs have almost no miles on them, If the cam is small grab a set of yellow valve springs from a z06 or get some Duals. Are you hearing a rattling sound at higher rpms? If so thats detonation not valve float.

hellbents10

iTrader: (10)

There is the problem.

boosted4life

iTrader: (4)

Yep its dandan's motor.. but I don't know what springs he had put in it, im just assuming stock.. I have the springs out of my old motor I can use, I think they are the z06 springs. The cam is .520 lift.

MrDavid

iTrader: (11)

Cam lift won't be as important as cylinder pressure pushing the valves open when you get into the upper rpm band where you make the most boost. You need some springs that are rated at or above 130lbs of open seat pressure.

Bob@BruteSpeed

iTrader: (16)

I'd get the car retuned before you ruin the engine. You should never have a dealer touch the pcm after the car has been tuned. Bob