Backfiring. Talk to me about it.

[Marauder.45]

I have read a couple things on it, but wanted to get some more info.

I understand it isn't harmful, just loud. What exactly is causing it? I don't think I was backfiring until the FMIC install. Can it be tuned out? Would it be happening even if I had a cat'd dp instead of the TP?

 

[justanothermp5]

it'll backfire no matter what, my car backfires and its NA and has a cat.

it happens when u let off the gas and a little bit of unburnt fuel gets into the exhaust stream, hits the hot exhaust walls and detonates
makes a pop, not really anyway to get rid of it that i know of

 

[Mistersix]

i'd assume the combustion process is not complete enough, thus the car runs rich. i get a little pop here and there ever since i put the turbosmart dual port on.
less air accounted for so you get a lil wasted fuel.

though i would think a good tuner with the right tools could lessen if not eliminate the back fires with a well rounded tune.

 

[Marauder.45]

I guess a little poppin never killed anyone.

 

[BoostedSpd6]

yup i get them from time to time.. i had a loud one the other day everyone was lookin at me haha (lol2).. it can be tuned out using the cp-e standback but its not worth it IMHO

 

[Mistersix]

i hate it and find it annoying. so i'm goin fully recirc with the dual port.

 

[zinger002]

stock exhaust it sounds like a little fart here and there.

 

[coyfish]

I have read a couple things on it, but wanted to get some more info.

I understand it isn't harmful, just loud. What exactly is causing it? I don't think I was backfiring until the FMIC install. Can it be tuned out? Would it be happening even if I had a cat'd dp instead of the TP?

You already have a catted DP . . .

 

[Marauder.45]

You think recirc over VTA will keep backfires down?

 

[coyfish]

Yes thats the problem. Run recirc and i bet most of those pops will stop.

 

[tunersteve]

If you're running untuned, I'd be willing to bet not running 100% recirc is your problem. Try going back to a stock BPV or a full recirc setup and they should go away.

 

[bova80]

even with full recirc with the hks ssqv you'll get an occasional backfire every once and a while even being tuned. and when i say every once and a while i mean like maybe once a week if that.

 

[Marauder.45]

I have an AP FMIC tune on, and I'm probably getting a dozen backfires a day. I've been driving the car with the current setup for about 5 days. I do drive about a 100 miles a day, so I get a lot more use out of my ride than some.

Eventually I'm going to etune, but right now it's an OTS tune.

 

[bova80]

are you vta or recirc?

 

[Marauder.45]

vta

 

[tunersteve]

vta

There's your problem then.

 

[Evolved]

VTA definitely throws off the mixture resulting in more backfires. My old turbo'd 240sx was VTA and had fireballs being blown from the back of my car. It got hot enough back there that the paint cracked and melted above the exhaust lol

 

[Sp33dFr33k]

VTA is most definately the cause. If you had the cp-e standback u could run vta without issue, but I don't believe the AP has the option.

 

[tunersteve]

VTA is most definately the cause. If you had the cp-e standback u could run vta without issue, but I don't believe the AP has the option.

I think there is a way to do it with ATR, but I don't know exactly how.

 

[bova80]

nope. you can't tune for vta with ATR. I've asked christian and there just isn't a way. you can either use the standback i guess or run the maf as a blow thru which is more difficult cause then you have to move the maf to the cold pipe.