I went to the dyno this past weekend to check up on how my car's running, making sure everythings alright b/f i race a mustang. I was making about average hp on motor, a little lower than normal with a best of 277 rwhp, but i expected it b/c it was hot and humid. We then sprayed it, and turned out a best of 385rwhp and 440 torque, over 50 hp down and 60 lb/ft down from my best a few months ago. What the f***. I haven't changed anything except added a purge, did the throttle body coolant bypass, and the donkey **** delete.

Now to the wierd thing, i figured maybe it was a bad bottle or i have a clogged filter or nozzle, but the a/f ratio was a little LEAN. I went and checked my n20 filter, its fine, nozzle's fine, the purge fitting isn't intruding into the manifold. All this would cause it to run rich, but i checked it out anyway. We did have the laptop hooked up to the ecm during all the pulls, and very strangely the IAT was reading the same during motor and N20 pulls, my nozzle is located directly across from it in the 90degree bend. Remember that my car is speed density! I'm going to replace the IAT and get a fresh bottle b/f i go back. Anyone have any comments or other suggestions b/f i spend the money for the dyno!!!!

Thanks,
Kevin

 

I didn't see anything about bottle pressure. Do you have a gauge, or bottle warmer?

 

I will post here for z28ke, as I am familiar with his situation.
The bottle pressure was good, 950 or better during all pulls. Its a 175 shot BTW.

 

Double check your pill patern. Then check your plugs.

 

I checked out everything, got a fresh fill, and replaced the IAT sensor and went back yesterday........same damn thing. It was real consistent, just down on power. I'm going to track in 2 weeks to see if its runnin way slower or not. If it is i'm going to put in the smallest fuel jet i have and leave parts on the track! Any other ideas?

kevin

 

The first thing I would do is check the plugs. I found out checking the plugs was alot more involved than what I had thought and I can email you a great article I have. Let the plugs tell you if you need to take fuel out instead of just doing it and leaving parts on the track =)

 

Also check your micro switch.Make sure its not clicking off.

 

Well if you were burning lean, I think I'd check the fuel pressure with the nitrous and fuel solinoids open. Your fuel pump may not be strong enough to pump the fuel that you need.

Maybee not though. Won't hurt to check. Pump may be going bad or fuel pressure regulator may be weak.

D Moss

 

Are you running the stock fuel pump? Deffenently check the fuel pressure....Do you have a fuel pressure safety switch.?

 

Guys: he is running a Walbro 340 pump and adjustable regulator. AF ratio looked great on all pulls. Actually, it looked like it was running great, just down about 50 rwhp. Maybe a restriction somewhere in the solenoids??

 

I've got the Walbro in-tank pump and an Aeromotive Adj. fuel pressure regulater, all are within 9 months old. I'm going to order some new wires just to make sure that's not an issue, other than that all i can think to do is run it. If it runs off, maybe get the solenoids rebuilt. this sucks!!!

kevin

 

oh yeah, no fpss. Thanks for the replies everyone! And about the plugs, the other day i noticed a couple of my wires were getting crispy from the #2 primary, and the plugs in the #6 and #8 cylinders were looking a little darker than the others--I'm going with over the valve cover wires this week i think. Would the car still run fine on motor and off on spray if this is it?