Hey dude you seem to know ur $hit pretty good so I'll hit you with the question. When I had my car Dynoed my trend looked pretty $hitty after 5K or so there was 10-15 hp/tq spikes and drops. My a/f ration dropped to abt 12.5 on the start and hung tight through the whole run so I don't see a fuel issue. Also I don't see a misfire issue either useing (autotap). Do you have any idea what else could cause this ? The guy told me it was from vibration (high speed) 2.73 gear topped out @ 177mph. But the only reason I don't beleive that is because I had a previous run before my header install that was smooth..all other mods were the same. Could it be false knock retarding timing ? I logged a run down the strip and showed a max knock 12deg but I was already off the throttle then.. I asked this question once before and also got on a thread with another guy with the same prob and nothing. Also that other guy had his done at the same place as me, could it possibly be their dyno ?

 

It's likely an ignition problem. I had a similar one:

http://www.jonaadland.com/NewPics3/Dyno2.JPG

I replaced the coil, ICM & PCM:

http://www.jonaadland.com/NewPics3/Baseline.JPG

So for me, one of those three fixed it. Next on the chopping block would have been the Opti.

For you, since you just put on headers, plugs & wires should definately be triple checked.

 

No dyno experience. Did you log your run and see any spark retard?

 

Showed 12* knock (max) retard but timing advance was up to 33*. I was told the advance was normal so I assume the computer isn't pulling any timing due to that knock retard.. besides that the plugs and wires look good. There is only one thing I still question when the car is @ idle in gear or not I get counts on random cylinders showing misfire and there will be a random misfire code in the "history" everytime I start the car. I was thinking it was from the cam lobe at idle cause when under acceleration or cruising there is none. I know something is wrong here this this should be laying down better #'s please help guys

 

If you are logging knock retard and the knock counts are incrementing simultaneously, timing is being pulled.

 

Yeah I don't know if 33* is good advance then it can't be pulling that much huh? or enough to hurt hp or performance can it. Like i said timing advance + not retard - . I don't know Whats the max timing advance you have seen?

 

The spark advance for a given MAP/RPM is going to be whatever is in the tables. It varies over all operating circumstances. It can go as high as 44°, but not in WOT situations for a stock tune. More like in the mid 30s at WOT (or close) from about 2800-6000 rpms.

Still, if the log says knock retard, it is retarding the spark from whatever it would normally be without knock.

 

Some other guy told me my car sounded like it had stock tuning and from what ur saying I agree. Do you think its possible they screwed me on a dyno tune? Is there anyway to tell if its stock besides a couple of simular characteristics? The tuning has been questionable to me ever since it was done. It was dyno tuned and the guy is suppose to be top notch 330 on these mods aren't showin that