my 70Z dyno tune
 

for those of you who remember, i was having an issue with exhaust popping when backing off on my 70 Z28. We threw it on the dyno, and clamped the smog hoses. Cured it so we installled freeze plugs. We then decided to do a pull. Much to my chagrin, we discovered spark degredation at about 4850 rpm. Car would quit accelerating.
Now we have to hunt that down. We are going to start with the date coded wires. Any suggestions?

In the meantime the aborted pull to 4850....
300 rwhp 375 lbs

John

Re: my 70Z dyno tune
 

Nice numbers! Is that a stock set up?

Re: my 70Z dyno tune
 

Some pics


John

[image]http://http://i197.photobucket.com/albums/a...John_G_002.jpg[/image] [image]http://i197.photobucket.com/albums/a...John_G_014.jpg[/image] [image]http://http://i197.photobucket.com/albums/a...John_G_016.jpg[/image]

Re: my 70Z dyno tune
 

It is stock, however they may be inflated because our weight was a guess. I don't even remember how much we plugged in.

It is running stock compression, 100 oct race gas, and pertronix ignition.

Next time i pull, i will grab the weight off of nasty z28

John

Re: my 70Z dyno tune
 

I guess we were not that far off and in talking to my engine guru he said it really does not affect those numbers, just acceleration times.?.

Re: my 70Z dyno tune
 

Possible Coil failure at higher revs or distrib shaft bushings...plugs?.

~ Pete
https://www.yenko.net/ubbthreads/imag...lins/beers.gif

Re: my 70Z dyno tune
 

[ QUOTE ]
Possible Coil failure at higher revs or distrib shaft bushings...plugs?.

~ Pete
https://www.yenko.net/ubbthreads/imag...lins/beers.gif

[/ QUOTE ]

Thanks Pete, Plugs and coil were on the list. I'll add dist shaft bushings.

John

Re: my 70Z dyno tune
 

cool car

Re: my 70Z dyno tune
 

Gotta love the 70 Z's! Hard to find one with the original engine. Nice car https://www.yenko.net/ubbthreads/imag...lins/beers.gif

Re: my 70Z dyno tune
 

Make sure your coil isn't wired backwards...the car will still run, but won't rev...