When I shift above 4000 or so, I get a backfire sound. I really didn't notice it until after I put the 10:1s in. I have the JWT ECU w/ S3 program, but the cams are not in yet. Timing is at 15deg, and I have the Courtesy cat back, with the neck down removed. Any thoughts?

I have a gurgle pop pop sound. This only started after I installed the HS header and magnaflo. And you removed the neck down? Is that when you first started noticeing it?

Originally posted by eric96ser
When I shift above 4000 or so, I get a backfire sound. I really didn't notice it until after I put the 10:1s in. I have the JWT ECU w/ S3 program, but the cams are not in yet. Timing is at 15deg, and I have the Courtesy cat back, with the neck down removed. Any thoughts?

Mine does that also. When I rev to 4k and get off the throttle fast it goes pop-pop out the exhaust every once in a while. I don't know if you saw this in another post I did today but in the old days they call this afterfire and not backfire. Afterfire comes out the exhaust and backfire was through the Carburetor (I told you it was the old days). Afterfire is caused by un-burnt gas hitting the hot exhaust and combusting. The stock restrictive exhaust has enough packing to absorb these minor explosion. As soon as I put my 2.5 with no resonator on it did it all the time. Put a resonator on and now it only happens in special situations. This has been my experience in all the switching of exhaust I have done over the last 4 weeks. I love it. It sounds like my old dual 40 DCOE L16 510. I miss that car. I know you hate your exhaust. Have you put a bigger resonator on yet? Your Muffler/Resonator's packing material may be breaking down.

my exhaust started doing this too, only after I put the header on. Its a cool little sound, but I'd rather not have it there.

I hope that when I put on my Thrush glasspack in a few days that the raspy blatty note goes away and the afterfiring is reduced.

I only noticed it after the new pistons and engine rebuild. Maybe removing the neckdown caused this to become audible. I had the messed up S3s when I hacked the exhaust up. I haven't replaced the resonator yet. I'm still not sure if I want to cut this one all up, or just sell it, and go the custom route. I just drove my wife's '97 SE-R for a quick Dairy Queen trip, and her car feels faster. I'm thinking its because her car still has the stock cat back. The POP just sounds so nice at WOT.

True, recently i just installed my hotshot header and now i get popping as well. It doesnt really bother me at all though. Ill take some popping noises over any noise under the hood. :)

My car has always pops when shifting. It only happens when I shift above 4,000 RPM like Eric said. My car shoots out this blue flame everytime I shift!:cool: You can see it at night. This all started happening when I put my test pipe in.

Originally posted by SE-Rican
My car has always pops when shifting. It only happens when I shift above 4,000 RPM like Eric said. My car shoots out this blue flame everytime I shift!:cool: You can see it at night. This all started happening when I put my test pipe in.

The cat was igniting/burning the excess fuel before it went thru the exhaust.

Here is a stupid thought...

If you put a MSD ignition on that has a rev limiter you could set the rev limiter right before the JWT fuel cut off. Then the msd will cut spark. When you hit the revlimiter it will cut spark not fuel. Keeping the throttle floored while you shift it will keep bouncing off the rev limiter and dump more fuel. When you get back on the throttle you will have a temporary rich condition in the exhaust and you will shoot big flames out the exhaust on every shift. This is probably a good way to blow your engine up also. Then you can get a DET and start all over again. HAHAHA :rolleyes:

yeah eric, my courtesy pops pretty bad too at high RPM, in addition to being INCREDIBLY loud, i am gonna throw on the stock axle back for road trips