More results from my 3500Z!

[Superdave]

Thats one weird dyno graph... I dont know if I would trust those numbers.

Is there something you know of that would be causing those peeks and valleys? because thats nuts... Its like a instant gain of 50hp right before you hit your peak... That would feel like a nitrous hit.

Can't argue the slip though... I musterd a 13.818 at 100mph, so with you hitting 103 I'm sure you'll be mid 13's when you get a better day.

we ran into some strange stuff..


The engine likes high 11 to low 12.x AFR's.. the leaner we took it the less power it made. Dropping the spark advance from 36 to 34 lost me about 2 HP in the top end as well.

I got 0 knock counts during the session! (and yes the sensor works, LOL)



thanks for all the comments guys!


As for the track times, i hope to drop those down ALOT here in the next few weeks. I'll be pulling out my W41 tranny and swapping the good 4th over to the stock V6 tranny with my LSD.. the 3.94 diff is a little too much and i think it's hurting my times..

[3400-95-Modified]

Yes too much gear will hurt your times. Remember your time is really made before the 1/8 marker... Anything after that it just takes way too much power to make a difference.

Spark advance of 36 sounds nuts!!! I'm hitting 24 at WOT right now and I hear about boosted 3800's being in the low teens for timing... I wonder why you can get away with that high of a number.

[Superdave]

Long duration cams love higher spark advance... i was running around 38 on my T/A at WOT as well and it's a 270 advertised .510 lift cam with crappy heads.

[3400-95-Modified]

I guess that makes sense... The race car is 230 234 @.050 and we run 39* yeah its a dist setup and V8 but timing is timing really.

Where I'm at 209.4/213.1 duration

[sharkey]

im running 38 degrees, i have had it as high as 42 without knock on premium. old open chamber heads love lots of timing.

on the flip side of things, my buddys ecotec only runs 22 degrees max, and i knock it down to 15 at 5psi. they have an extremly efficient combustion chamber, so lots of timing isnt needed.

[3400-95-Modified]

I was unaware that the efficency of the combustion chamber will affect timing as well.

[IsaacHayes]

Yes fast burn style heads require less. The aluminum heads with the heart chambers have less timing than the old iron heads.

[ForcedFirebird]

Yes fast burn style heads require less. The aluminum heads with the heart chambers have less timing than the old iron heads.

Good to know .


Dave that cam is sick! It must idle like a 4x4 driving on railrod ties, no? I'm thinking of using a modified 260 advertised duration modified a little for boost.

[blackbombshell95]

What octane fuel are you running? Stock fuel pump right?

[Superdave]

It idles around 1200 RPM cold and 1150 warm.. and still is pretty choppy.


91 octaine and a 350 TPI fuel pump @ 55 PSI


I'll post dyno vids and track vids as soon as Moonwell gets them uploaded to his server.

[Superdave]

Here is a good pic..



Must have been right after it hit the rev limiter.. the WBo2 was reading a little lean there at fuel cutoff..

[SappySE107]

Id like to know why the graph is so extreme for high and low spots. I know what tuning does in regards to the jittery lines, but that is borderline absurd. How much KR do you have?

How big are the videos? We have 200 gig free. I gotta hear what that sounds like on a dyno.

[1988GTU]

we ran into some strange stuff..


The engine likes high 11 to low 12.x AFR's.. the leaner we took it the less power it made. Dropping the spark advance from 36 to 34 lost me about 2 HP in the top end as well.

I got 0 knock counts during the session! (and yes the sensor works, LOL)

....

[SappySE107]

I remember the af part but I guess I completely skipped the part about 0 kr. ok, well I can't think of any other reason for the line to be like that.

[Superdave]

I'll dig up the AFR VS RPM breakdown and post it up tonight.. It got drawn on but i think it's still readable.