Nitrous dyno question

[RageAgainstTheMinivan]

A couple weeks ago I got my car on a dyno. It was just a club day so no tuning and no computer hooked up to the car. The tech said that he heard it rattle during the pull and it was too lean and to stay off the bottle. I want other opinions.

I was talking to a couple car guys I know and they were thinking if it was pinging the timing should have pulled way back and it would show on the power curve. I researched ls1.com and ls1tech.com for a while and found a/f ratios around 12.5, is that right? If so, thats about what I pulled so why would he say lean?

I think my problem was the gas. I run mid grade and didnt burn off as much gas as I thought I would before the dyno. I did fill up with some premo before the dyno but I dont think it helped much. But still, if it was pinging because of too low octane, wouldnt the curve show timing being pulled back?

The car: stock driveline, stock motor with 90k mi. bolt ons include 28# injectors, nos 100 dry shot, rpm window switch (3k-6k), fuel pres switch, polished maf/tb, headers, no cats, slp loud mouth, whisper lid with k&n, and 160* tstat (no fan tune, eng temp around 190). Bottle was heated and at about 750 psi.



Thanks for the input!

Oh and Im not hatin DRM so please dont turn this into a bashing thread.

[LS2Tuner]

That reading could be off. Plus if the tech could hear it pinging than it could just be too much timing.

How much timing is in it?
What plugs are you running?

[RageAgainstTheMinivan]

No idea. I bought the car as is in april from a board member. He said it was dyno tuned with the juice and I wanted to make sure. I did buy new plugs ngk tr6 but I havent checked to see whats in it. Too much to do, so little time.