I know this has always been a question here but someone told me yesterday that it was bad, well my car backfires in every gear after around 5.5k when I let it go or shift. Its a 90 gtu with no cat (Im pretty shure theres my problem).

 

Ohh and I knew I had another question, its Idleing like crap too, it idles at 300 and it goes up and down all the time.

 

Who told you it was a problem?? Someone who doesnt know anything about rotaries?

 

the guy drives an fb but I dont think he knows alot, my dad told me it was cool but sometimes I dont trust my dad too much cause he only works on fd's, but I guess is ok then right?

 

It's pretty normal for a little afterburn on aftermarket exhaust. I have a bonez cat and mine will do it when i get above 6k or so. The guys with no cat and headers, and fart can mufflers will actually pop flames, and apparently they dont mind this.

The idle problem may be that its just set to low. 750 is the normal idle speed, so if yours is around 300 you need to raise it up.

 

5.5k sounds kinda low actually. i have no cat and i dont backfire unless i take it up to 7.5

 

How hot does the exhaust have to be for it to shoot flames? As in, will it only work after/during hard driving?

 

my pops if i redline in first.... wondering if my cats have been gutted or not.
I'm fairly certain that my 13b may also have a streetport of some kind, and is a rebuild

 

yeah I have an hks ex. and no cat, so thats cool, yeah my dad told me about actually adjusting my idle too (sorry I ask u guys before doing anything even if I know), Is that Ive just been with rotarys for like a year 1/2, my dad's been with them forever but then again he's blown a bunch of engines so I guess thats why I havent trusted him alot with my car cause Ive seen those engines blow since I was little (sorry for telling u my life). well thanks

 

ohh and yeah it actually does it at around 6k I went out and checked.

 

is your A/C on or off when it's idling like this?

 

I dont even have it connected, it does go down when I move the stearing wheel (power stearing) and when I hit the break.

 

That's normal. The car runs momemtarily rich when the throttle snaps shut before the ECU catches up. It becomes more apparent with an open exhaust and if the car is out of tune.

That's a problem. Most likely a bad or dirty BAC valve, vacuum leak, or a combination of the two.

 

I have no emmissions anything, header, straight resonator and straight single 3" exhaust. I pop as low as 3500 some times and I can blow flames at 5500

 

thanks Ill check

 

Not only do i not mind it, I actually enjoy it quite a bit. hmmmmmmm pop, hmmmmmmmmmmm pop POP pop POP

 

it scares people on the sidewalk LOL

 

Hello. I just connected my air pump and my car pops every time I shift at somewhat high RPM, is the only way to get rid of this pop to disconnect the air pump again? I dont like the pop at all, to me it sounds like the car is broken. I like a nice smooth ride myself.

 

Oh the backfire is great you gotta love spitting a flame out the back. I don't really get it anymore with my new exhaust that only collects right before the muffler. I did get a really loud one the other night though. I used to be able to spit pretty good flames out the rear with a cat replacement pipe and stock exhaust.

EDIT: Here is a vid. http://videos.streetfire.net/search/...01F7A72C90.htm

 

bbrrraaaAAAAAAAA POP..
you doesnt like it!!

 

no I think it sounds VERY VERY cheap. If someone knows how I Can fix the poping let me know. I really dont want to have to take off the air pump, it really mellows out my exaust. (instead of so ricey) and seemed to have fixed my idle issue.

 

I think you missed this part that Aaron mentioned, TweakGames. While you're on a stock ECU with no piggyback, there is almost no way around a rotary backfiring, it is the partial nature of the beast. Stock ecu maps are RICH. If you don't have a cat then you shouldn't have the airpump on anyway. You're just feeding oxygen to fire, in a manner of speaking, at that point. If you still have a cat, then you need the airpump else you'll just end up destroying it. My car used to pop pretty good when all of the stock equipment was still attached. I had found out, when I moved up to a header and high flow cat, that my precat had blown out and into my main cat. My main cat had a nice circular chunk of its innards partially displaced. So if you still have the stock cat, I would suggest you inspect your cat to make sure it is not damaged like mine was. With my high flow, my backfires are no longer pops, usually, but just a subdued gurgling.

 

I REPEAT!!! HOW COULD YOU NOT LIKE THIS!!

for the record...this is not my picture!

 

i have been able to tune out alot of the popping with adjusting the TPS and the screw by the AFM by turning it to leaner. a misadjusted TPS will make it pop alot more than necessary, and that screw by the AFM seems to have alot to do with it also (on my car at least). mine still shoots flames at high RPM's tho

 

every since i installed the rebuild I can't seem to shoot flames the way I use to

I'm still on a stock ecu with no obvious sound of back fire.