Backfire problem
Thread Starter
Instructor
Joined: Apr 2013
Posts: 114
Likes: 4
From: Lititz Pa
Backfire problem
I have a C6 LS2 with American racing headers, Large straight X pipe to Corsa sports.Engine upgraded with Edelbrock E-Force Supercharger
Typical cold air intake. After Dyno I ended up with 750/Crank 690/wheels.It has been able to turn high 10's (10.922/10.950) at the track. Charger has been on for 3 years now. Went with smaller 3.25 " pulley to achieve about 12 lbs boost.
Have not had this problem till now.Rolling start in a race. About 3500 launch. If I am being challenged I use third otherwise with "hopeful" cars I stay in 4th. I can't peg it to the floor in either case or my back end becomes my front end so I increase as quickly as possible without breaking loose. Obviously not like you'd do it at the track....I just don't want to wrap it around anything just playing around. ANYWAY.....My problem is I get one Backfire when the pull is at max. It seems to be performing OK other than that. I don't want to break anything since the backfire happens around 4500-5000 in 3rd or 4th.
Any quick opinions????
Fuel pump is a top end high capacity. Injectors are as big a possible.
Thanks
Rick Spalding
Typical cold air intake. After Dyno I ended up with 750/Crank 690/wheels.It has been able to turn high 10's (10.922/10.950) at the track. Charger has been on for 3 years now. Went with smaller 3.25 " pulley to achieve about 12 lbs boost.
Have not had this problem till now.Rolling start in a race. About 3500 launch. If I am being challenged I use third otherwise with "hopeful" cars I stay in 4th. I can't peg it to the floor in either case or my back end becomes my front end so I increase as quickly as possible without breaking loose. Obviously not like you'd do it at the track....I just don't want to wrap it around anything just playing around. ANYWAY.....My problem is I get one Backfire when the pull is at max. It seems to be performing OK other than that. I don't want to break anything since the backfire happens around 4500-5000 in 3rd or 4th.
Any quick opinions????
Fuel pump is a top end high capacity. Injectors are as big a possible.
Thanks
Rick Spalding
Last edited by phylrick; Nov 29, 2017 at 08:06 PM. Reason: mis-spellings
Melting Slicks
Joined: Jun 2006
Posts: 2,482
Likes: 261
From: Miami Florida
Hey Rick you got a real beast there, sounds like a forged engine, what fuel are you using?
also what tires/wheel combo.
The power you have does call for some hard rear control arm bushings if you want to keep her straight, there’s a couple of options Delring or spherical type.
I opted to pin mine's just as long as bushings can't compress (to eliminate lateral excursions) when combined with high traction tires minimum of 35 aspect ratio drag radials you'll be able to pull some incredible traction on the streets, you will have to work on your suspention though.
Going back to the back fire prob try a new set of spark plug wires.
You may try this, at night in the garage engine in idle turn all lights off look under the hood for sparks jumping around the spark plugs boots, Dave.
also what tires/wheel combo.
The power you have does call for some hard rear control arm bushings if you want to keep her straight, there’s a couple of options Delring or spherical type.
I opted to pin mine's just as long as bushings can't compress (to eliminate lateral excursions) when combined with high traction tires minimum of 35 aspect ratio drag radials you'll be able to pull some incredible traction on the streets, you will have to work on your suspention though.
Going back to the back fire prob try a new set of spark plug wires.
You may try this, at night in the garage engine in idle turn all lights off look under the hood for sparks jumping around the spark plugs boots, Dave.
Instructor
Joined: Mar 2017
Posts: 239
Likes: 30
From: Columbus, GA
To add onto what boost said if you change plugs get AC Delco plugs. Other brand plugs emit radio frequencies that mess with the ECM and you get a false “service charging system” warning. Also, what he said about look for sparks jumping pull each boot one by one and put a crosstip at the very end of the boot where it would connect to the plug and have someone try to start the vehicle and you’ll be able to see sparks and how weak/strong the sparks are. Best of luck brother ����
P.S Mickey Thompson ET Street R’s are awesome tired for hooking. Don’t waste your money on Nitto NT05Rs they’re garbage
P.S Mickey Thompson ET Street R’s are awesome tired for hooking. Don’t waste your money on Nitto NT05Rs they’re garbage
Melting Slicks
Joined: Jun 2006
Posts: 2,482
Likes: 261
From: Miami Florida
All in with the AC Delco for competition top LS plug still the ls9 OEM AC Delco 41-104
My favorite plug wire still the Magnecor kv85
For 2005-2013 C6 Corvettes with the LS2 or LS3 motor, order part number: 85229
For 2006-2013 Z06 Corvettes with the LS7 motor, order part number: 85283
My favorite plug wire still the Magnecor kv85
For 2005-2013 C6 Corvettes with the LS2 or LS3 motor, order part number: 85229
For 2006-2013 Z06 Corvettes with the LS7 motor, order part number: 85283
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
I've experienced WOT backfires that apparently were the result of an iridium tip breaking off the spark plug, which increased the gap from .040 to about .080. Since the car will still run fine in normal driving without any unusual issues, it's easy to disregard the backfire as an anomaly.
It sure showed up on the timeslips at the drags. I couldn't seem to get one clean pass, nor immediately diagnose the problem. Later, I found 7 of 8 plugs had missing tips.
It sure showed up on the timeslips at the drags. I couldn't seem to get one clean pass, nor immediately diagnose the problem. Later, I found 7 of 8 plugs had missing tips.
