after a few good drives now on my finished kat i am noticing that it is backfiring a little and it is pretty loud. im wondering what would cause this? before when i had hs header it would backfire a little but i had a scilencer in my exhaust so it wasnt very loud. now im running all 3'' exhaust w/ no cat and no silencer. its just when im deccelerating it will backfire a few times.
also how much timing should i retard/lb of boost? ive heard .5deg. and ive heard 1deg. i have a btm and you can adjust it from 0-3deg. right now i have it at .5.
Backfiring?
youre prob just running a lil too rich. i wouldnt worry about it too much. get it on a wideband and tune that thing. or do whatever tunning you can cause i believe your running a hacked maf right? and for the btm if it was my car i would have it a lil more than .5 degrees. i would have it around .75-.8 degrees. so how does it drive now that you can get on it?
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tony/ka24de
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Structure240sx
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mine does the exact same thing. i remember before the turbot he car would do it just a lil after i got exhuast. i think its mostly from having a more open exhuast so u can hear the backfires that were already there. it has gotten louder tho now that im turbo im sure but i always figured it was cuz i have a fmu and it jsut added the fuel the i let off the gas and there not enough air for that fuel for a split second. of course u have hacked mafs so maybe its jsut the same thing. i say dont even worry about it running rich is better than lean
yea im not worried about that anymore, but i know its running rich when i rev it up and let off the gas because it is still dieing on me and then its very hard to start. im guessing the reason its so hard to start is because there is too much fuel in there. my bov is recirculated. i still havent bumped the idle up yet, i will try that next. it only dies when its really reved up and i put it in neutral or push in the clutch and let off the gas.
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Structure240sx
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yea mine does that too. i forget who it was that had the same problem figured it was the lightweight flywheel he had. i think u haveone but im not sure. but basically the revs come down too fast. but i guess this wasnt happening to u before turbo? btw i have a fidanza flywheel and enjuku 11lb driveshaft
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im two techno
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Structure240sx
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maybe since we have less backpressure? if we do have less than NA guys with 3" exhuast. maybe as the turbine is spinning it actually sucks air jsut a lil to make it flow faster thus less back pressure? i jsut kinda try not to put it in neutral when revving
im two techno- were has technoman been" i havent seen him on nico in forever
im two techno- were has technoman been" i havent seen him on nico in forever
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sil80drifter
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When I ran straight 2.5" pipe from the header down, on my NA, it backfired like a machine gun on decel from 4k down to 2.5k. It's natural when you free up the exhaust and remove the silencing, for the engines' sounds to become much louder and apparent.The turbo actually acts as a "muffler" and makes them less apparent. Of course in a rich condition, the turbo car can be very loud.
sil80
sil80
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Structure240sx
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C-Kwik
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Well, anything that makes the car run too rich will create both. Currently, my coolant temp sensor curcuit is messed up. It's making my car run way rich. It dies at lights if I don't stabalize the revs slightly with the gas pedal as I let it settle into idle. It also backfires here and there. Not a little pop, but a moderate one. I'm sure a few have been accompanied by a fireball.
My car does the same thing... if I rev it to 3k (either standing still or coming to a stop) push the clutch in and let it come down... well it doesn't come up. I have to control the rpms with the throttle until it settles at 750.
We checked for leaks and found 3 "big" ones. That's taken care of and the car spools up even faster, but it keeps dying. I'm pretty sure it ain't that I'm running rich since I have the stock fuel system. My temp sensor caused me to run rich the other day so I kept stalling, maybe it's busted but I cleaned up the terminals and it worked fine.
Hmmm... maybe it's the welded alum pipe after the MAF before the compressor that I have. Need to test that but haven't had the time.
Any other reasons, apart from running rich or leaks that could cause it?
We checked for leaks and found 3 "big" ones. That's taken care of and the car spools up even faster, but it keeps dying. I'm pretty sure it ain't that I'm running rich since I have the stock fuel system. My temp sensor caused me to run rich the other day so I kept stalling, maybe it's busted but I cleaned up the terminals and it worked fine.
Hmmm... maybe it's the welded alum pipe after the MAF before the compressor that I have. Need to test that but haven't had the time.
Any other reasons, apart from running rich or leaks that could cause it?
well ive asked all around and ive heard 2 things. one, the mafs need to be at least 18'' from the turbo(recommended by jwt) which mine is like 3'' and i have no room to move it. and your bov should be recirculated and angled towards the turbo and away from the mafs. i already tried that but it still dies. im going to bump my idle up to around 900 and see if that helps if not then i guess ill have to figure out a way to extend my intake pipe and get my mafs away from the turbo inlet.
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MikeMurphy
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daniel240 wrote:well ive asked all around and ive heard 2 things. one, the mafs need to be at least 18'' from the turbo(recommended by jwt) which mine is like 3'' and i have no room to move it. and your bov should be recirculated and angled towards the turbo and away from the mafs. i already tried that but it still dies. im going to bump my idle up to around 900 and see if that helps if not then i guess ill have to figure out a way to extend my intake pipe and get my mafs away from the turbo inlet.
Nah. My MAF is at almost 12" and my BOV recirc port is angled toward the compressor.
And I've set my idle at 1k and that didn't help much. I'm now thinking that the two ports I had welded above to the alum tube are leaking and that could be my problem.
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Structure240sx
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huguetpj wrote:Nah. My MAF is at almost 12" and my BOV recirc port is angled toward the compressor.
And I've set my idle at 1k and that didn't help much. I'm now thinking that the two ports I had welded above to the alum tube are leaking and that could be my problem.
i dont know. what is that smaller red hose from that is on the bottom side of the intake? if you think its leaking around the welds just put some jb-weld around it. thats what i did on a few of my welded IC pipes that i wasnt sure about.
Mine does the same thing--it backfires, and pretty loud at that. i didn't notice it as much with the catalytic converter in place, but w just a straight pipe, it's pretty loud.
I have the same problem with stalling if I brake on it really hard and then depress the clutch, or if I'm at say 3k rpm and depress the clutch to go to a stop sign; it usually stalls. And I definitely don't have any boost leaks. Also--my MAFS is about where huguetpj's is, and my bypass valve is recirculated and puts the air back in the intake past the MAFS, about midway in between the turbo inlet and the MAFS... I just have to watch the tach and get ready to give it a blip if it feels like it's going to stall. Kind of annoying, but I accept that it's not a regular street car--hopefully my JWT ecu/sr 370's will help out with some of these issues. We'll see.
I have the same problem with stalling if I brake on it really hard and then depress the clutch, or if I'm at say 3k rpm and depress the clutch to go to a stop sign; it usually stalls. And I definitely don't have any boost leaks. Also--my MAFS is about where huguetpj's is, and my bypass valve is recirculated and puts the air back in the intake past the MAFS, about midway in between the turbo inlet and the MAFS... I just have to watch the tach and get ready to give it a blip if it feels like it's going to stall. Kind of annoying, but I accept that it's not a regular street car--hopefully my JWT ecu/sr 370's will help out with some of these issues. We'll see.
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Structure240sx
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http://www.cardomain.com/memberpage/293867
the last 2 pics show how far my maf is from the turbo and bov recirculation.
the last 2 pics show how far my maf is from the turbo and bov recirculation.
daniel240 wrote:i dont know. what is that smaller red hose from that is on the bottom side of the intake? if you think its leaking around the welds just put some jb-weld around it. thats what i did on a few of my welded IC pipes that i wasnt sure about.
That would be the EGR line... but it's been blocked off since the EGR is disconnected. I'm gonna be replacing that pipe with just a straight through kinda deal (leaving the BOV open vented) just to see if it makes it better. If it does then I'll know its leaking and I'll have it checked and the EGR line removed.