Thoughts on backfire?

[XfireZ51]

Originally Posted by KILLSHOTS

Hey Hog,

I talked to Marc and he says he can remove some fuel on decel, which will hopefully help. I'm going to try to get it up to Bill's next weekend; hopefully he can take a ride in it and datalog it for me so I'll have some fuel ratio info to send back to Marc with the PROM. If that doesn't work, I'm definitely going with your idea of installing some remotely-operated spark plugs in the tailpipes!

On your SOTP question, I honestly don't feel it. In fact, my experience with this car seems very strange to me overall, as for some reason, I'm having a hard time actually "feeling" any of the mods. I have added at least 35HP, plus new injectors/coils/plugs, switched to 4.10 gears, and switched to tires that DO NOT slip at all. Yet, for some reason, it doesn't "feel" any faster to me than it did the first time I drove it back in February, when it was 100% stock and had faulty injectors. It's not because it's running poorly; this thing pulls hard and revs to 7000 so fast that I HAVE to keep an eye on the tach or risk hitting the limiter. I've never become jaded to the power of any car so quickly. My butt-dyno must be faulty!

Smooth cars are fast cars.

[mike100]

roam the streets and find a stock zr-1 or even a C5-Z06 and you'll see what you got.

[Hog]

I had some time, so I pulled the mufflers off of one of my rigs, leaving the LT headers and about 3" of pipe after each collector.

I flash the PC with a calibration with the stock 4 seconds of DFCO engage timing. While driving I would release the throttle and count 4 seconds then "CRACK" a severe snap as the DFCO shut the injectors off.

Then I reflashed with the DFCO timer set to 0.250ms(1/4 of a second) and it was almost comical, lift throttle "CRACK" on throttle, off throttle "CRACK".

that lean snap as the fuel shuts off sure is loud.

KS: I went from a stock 3.08 gear to a 4.10 gear and added a locker at the same time. After a short break in, I went out and romped on it and I was disappointed. I thought even with the 325/50/15 BFG drag radials I would have some traction issue, but no.
Wit the 3.08's and 28" tire, trans in OD with the cruise control engaged, at 70mph climbing a mild grade on the highway would cause the throttle to open, torque converter to unlock, and sometimes a down shift to drive. After gear swap, same hill, speed etc. the cruise control would barely open the throttle while climping TC stayed locked, and trans stayed in OD. My trans OD is 0.70:1 vs the ZF's 0.75:1. I noticed the gears more during light driving than I did during performance street driving.
The dragstrip is where I noticed both my gear swap, and subsequently my calibration/header/exhaust mods. The ET drop was substantial.
My "butt-dyno" was also miscalibrated.

I'm sure Marc will set you up. Goodluck.

[KILLSHOTS]

Originally Posted by Hog

I had some time, so I pulled the mufflers off of one of my rigs, leaving the LT headers and about 3" of pipe after each collector.

I flash the PC with a calibration with the stock 4 seconds of DFCO engage timing. While driving I would release the throttle and count 4 seconds then "CRACK" a severe snap as the DFCO shut the injectors off.

Then I reflashed with the DFCO timer set to 0.250ms(1/4 of a second) and it was almost comical, lift throttle "CRACK" on throttle, off throttle "CRACK".

that lean snap as the fuel shuts off sure is loud.

KS: I went from a stock 3.08 gear to a 4.10 gear and added a locker at the same time. After a short break in, I went out and romped on it and I was disappointed. I thought even with the 325/50/15 BFG drag radials I would have some traction issue, but no.
Wit the 3.08's and 28" tire, trans in OD with the cruise control engaged, at 70mph climbing a mild grade on the highway would cause the throttle to open, torque converter to unlock, and sometimes a down shift to drive. After gear swap, same hill, speed etc. the cruise control would barely open the throttle while climping TC stayed locked, and trans stayed in OD. My trans OD is 0.70:1 vs the ZF's 0.75:1. I noticed the gears more during light driving than I did during performance street driving.
The dragstrip is where I noticed both my gear swap, and subsequently my calibration/header/exhaust mods. The ET drop was substantial.
My "butt-dyno" was also miscalibrated.

I'm sure Marc will set you up. Goodluck.

Hey Hog,

That's what I figured, too. I know the car is quicker, just can't "feel" it for some reason. Marc is great and I know we'll get this figured out sooner or later.