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I Had a cam installed with new 02 LS6 springs last year, car ran good after tune and dynoed ok considering my car only dynoed 311hp 333tq before cam.


I went to the track and the car was not pulling that good , was going flat around 5800, 6000rpm instead of the 6400rpm it was pulling before. So I knew something was wrong At the end of the day my car gained only 2 tenths and no mph , It was running 110mph with 273s and stock cam, that day with cam and 342 gears an extra 31hp and hooking good it would only run the same mph, and all my gain was in the 60ft, 1/8 mile and 1/4 mile times were the same. D/A were almost IDentical

So back to the dyno I went,(More Money)
So at the dyno this is what came up something is wrong and not sure where to start, Something happened after a while of driving it Only 400miles and cant see what, car doesnt feel that bad but the results of my track day prove that something is going on. Any help would be nice at this point before I go and spend more money. Car only has 21000 miles onit, was ataped and nothing showed up, no knock, no codes no misses, plugs are good.

good dyno graph

Bad dyno graph

 

What cam are you using?

 

Its in his sig. It looks like a comp grind.The only thing i can see different in the 2 graphs beside the lack of top end on the one, Is the good one has a A/F of 13.1 and the bad one looks like 12.5 or less. It shouldnt have made that big of a difference. My first thought was valve float but i dont see it in your dynos.

 

Looks like the computer learned itself.Looks like you were 14-1 on the first dyno graph and it went down to 13-1 at the end of the run.2nd graph was richer.I'm guessing the car was dyno tuned.If the car is not tuned on the street for L-terms it will learn them after the dyno tune and can cause a lost of power.

This is only my guess,don't know if you even had it dyno tuned.

 

Yes it was dyno tuned at Eastside performance by NOGO, Only thing that was changed after the good dynotune was some Idle adjustments to stop some surging. Is it possible that going alittle richer would cause that much power loss.

 

any knock retard?

 

COT turned off? hot lapping? trans slipping?

 

What is COT, doesnt feel like any slipping, but I wouldnt be able to tell if its slipping alittle. The dyno graph doent look to show valve float (bad springs) And there was only 2 pulls done that day within 5 to 10 minutes of each other.

 

Who did the install for you?Maybe the cam is off a tooth.Samething happened to me with mine.I lost power on the dyno after my cam swap.

 

The install is correct, did it myself , as i stated it dynoed 342hp and 400 miles later it dynoed 327hp, lose of power happening.

 

I've noted a change in AFR after making adjustments to the RAF and IAC tables. I don't think that would cause you to flatten out at 6000 RPM's.
with EFI you can log Trans input, Trans ouput and trans slippage.
I had a slipping problem and confirmed it with these logs. In 3rd input and output should be 1 to 1 less a small amount of slipping right before shift. If you have a stall it will show more slip up high. It's worth logging before you start tearing into things.

 

What did ESP say? You had it tuned there and brought it back to dyno again and the hp was down..Did they atleast offer to adjust the tune for you while you were there?Only takes minutes if you they had your last tune on file.

 

All they said was that all perimeters look good, from tps, to knock ,to plugs , to timing. Nothing changed in the tune, everything is ok. They said possible valvesprings, possible tranny, or tq converter, or loss of compression. Dont know where to start but i do not beleive its the springs according to the dyno graph.

 

Could be a slipping tranny.The dyno HP loss is the A/F difference and probly different days.

 

did you do a compression test?

 

Should I do leakdown test or compression test. Dont no where else to start.