RealQuick

If you did have spark blowout... you would think there would be a fluctuation in the A/F, but you said it was constant. Maybe it is tranny/converter related. Do you have another converter you can try?

1982z28with18s

I wish I did, but I don't have another converter to try.

I don't think it's blowing out the spark necessarly, I think it is just too weak of a spark or its just dropping it and the fuel(like the pcm isn't sending out a fire signal). My buddy had a similiar problem at random with his delteq doing this a few years ago.

Projectz28

a different converter might help but its not necessary. The problem is in the way the converter and rpm changed speed and power output. not exact but this may help explain it.

First off you have to know how a dyno works. They have a fixed wheel that has a known weight. The only thing the dyno then needs is an rpm input which is picked up off #1 plug wire.

The dyno can calculate HP by measuring how much time and how fast the drum turns at a given rpm. As rpm increases and wheel speed increases the dyno can then perform complicated matmatic calculations to get a specific HP reading. This is why HP and TQ always cross at 5250 rpm.

Your problem is in the way the converter transfers power to the wheels. The reason your graph goes funny is partly because of converter flash. It starts to put the higher portion of HP thru the converter in that area of 5250 rpm. The math can get screwed up causing goofy lines. Tire size and gear ratio also have an affect on the dyno. Slick tires will cause the ratio to change as speed increases and cause goofy graphs and incorrect numbers. The dyno does not know the ratio is changing as rpm and wheel speed increase.

Dont sweat the graph so much. Sit back a foot or 2 and generalize the graph from beginning to end and its probably fairly close.

Your best way to correct the problem is to install a lock up switch to lock the converter before you hit the gas pedal. You can also program it in but I know its not always possible. I can not lock my converter with programming. The motor will over power the lock up clutch and slip it causing goofy graphs again.

1982z28with18s

The converter is a NON lockup, so I can't lock it.

Datalogs and tach also show the RPM DROP, that is what I'm trying to figure out. What is causing my car to be down about 150-200rwhp, have a weird graph, and LOSE rpm at wot.

Click on the link in the first post to the other thread, you can see everything I've tried so far and am to the end of ideas of how to fix this problem.

IrocSS85

well how does this car drive? had it to the track yet? Id feel it out there and see how it performs and FEELS.

Stl94LT1

I'm still betting that it's the converter causing the rpm drop.

kylersaulsbury

Read the link. He's ran it several different weekends at the track, and just lays over at 5000+. and FEELS like its down on 150-200 like it should be.

IrocSS85

actually just did that. my guess is also convertor goin out. or out already. think you said somewhere on here the fluid is good still? droped the pan yet to see if there was anything in the bottom of the pan?