yes.. searched for it.. but most people backfire at high rpm or backfires with no boost or crappy revving engine..

here is my story.
yesterday I have installed the apex'i twin chamber bov.. and I had to make a hose to the bac with two pieces of hose I had left..
and the problem with my car is as follows.. it backfires a lot when I'm light on the throttle at circa 2500 to 3000 rpm, the engine speed decreases. And for about a second or 10 I hear loud bangs and so.. It appears most in second and third gear.
The engine has a solid idle at 750 rpm when hot.. the engine runs smooth in all rpm.. the boost is good (almost at top of std boostmeter.. not a good point to rely on but before I mounted the bov it was at the same level)
the car is fast.. so no problem accept the backfiring at low speeds in low gears (thus mostly in residental area's.. )

my car is a eurospec S5 TurboII with the corksport catback 3" all the way no cats. K'n airfilter and the rest is stock..

I guessing that I should adjust the spring of the BOV but.. should I tighten it or loosen it? at idle the bov is closed so that is good..

should I be worried?

 

post a pic of ur BOV setup

are u re-circulating? or venting to atmosphere?

venting to atmoshper will cause the cars to run crazy rich between shifts...

 

The apexi unit vent to the atmosphere. So basically ur car is just shooting flames like the rest of our cars. The only way u can fix it is to either vent the bov into the intake tract again. Or put a catalitic converter on ur car. Thats all i can think of right now.

 

ditto both the above, i don't think the apexi's are designed to be allowable to recirculate. you can live with it or get one that can recirculate or you can simply put on the stock BOV and sell the Apexi.

 

Well it is not backfiring between shifts..

its too dark now to take pictures.. mayb tomorrow

 

i have the same bov...... that is very common.... they all stated above that its an atmospheric bov.... so, we just have to deal w/ the side effects!! you'll also notice it stalls every once in a while when decelerating to a stop... common too!!

 

if it is backfiring all of the time then it is likely leaking, unless the spring is all the way loose it shouldn't be bypassing at all. try disassembling it and cleaning it, it may be sticking partially open.

 

yes it is temporarily.. still searching for a tube/hose in the correct shape for the bac..
I have a avi of me cruising and popping.. but It's too big to place it at homestead.. can someone host it? it is about 10Meg..

 

that's really..... wierd... looking

the hose from the bac to the ic pipe is mostly strait with a tiny bend in it... you just need to turn the pipe you put in so the medal outlet thing is going towards the bac. sometimes it helps to take the bov off the pipe when trying to get stuff in the right place cause it'll hit the strut tower dealy.

-Myk

 

I can't.. the ABS unit is in the way... or do you have a picture of someone with abs and the apexí BOV?

I be making a mp3 of the avi.. so you can hear it.

 

Click here for mp3

Okay be gentle with it.. I have a very tight bandwidth limit so it may only be downloadble for a couple of times..

what is happening in it then.. the car is first at idle (+/- 750 rpm), going very slow chage up to second.. almost no boost.. and when I hit the gas.. it's only like 1/2 throttle and 3/4 boost.. the popping is between 3000 rpm and 2000 rpm..
I Hope it can be solved because I don;t think this is normal.. even for a catback and air vented bov equiped car like mine

 

^^bump^^
things to do to solve it
1. get a good hose for th BAC (But I don't think that is causing the backfiring)
2. adjust the spring of the BOV (it may be leaking at little throttle and a tiny bit of boost although it is closed at idle)
3. Reset the ECU (why not.. A S13 here passed emissions after the ecu was reset)

or is something else causing the backfiring?

 

I have the same exact setup as you except I have a Greddy type s bov.

Thats just the way it is my friend. The car runs rich as hell on Deceleration. (runs rich as hell anyway.)

Solution: techedge wideband or EGT + S-afc or boost controller.

 

kay thanks... so I will safe money for a ECU.. + boostcontroller..

does it ever stop

 

And after a while your car will smell look rotten eggs.
Catalitic converters don't like backfires.

 

I think its more catalitic converters dont like rotaries.

 

when you adjusted the spring did you tighten or loosen?