Backfire

[lightsource]

I'm getting a backfire from my engine, the only time it happens is when I go over 2K RPM, and let it coast down past 1500RPM, and it's only when I'm moving. So whenever I go passed 2K rpm as SOON as it gets to 1500RPM I get the backfire, it's not loud (full stock exhaust) but it's a problem that I would like to get diagnosed/fixed.

[jaco]

sr20det.....with a stock...2"exhaust that comes on a 240?

[lightsource]

Really?

So you would say the perpetrator is the stock exhaust?

[nzmoman]

I wouldn't say the stock exhaust is the perpetrator. But you can damage your turbo from back pressure especially if you are running a three inch dump or downpipe with stock exhaust. Basically you will collect tons of air into a larger space and try to force it into a smaller space. that will force the pressure backwards, but when it goes back the turbo is still blowing more air. This is a bad combination.

you need to go get a tune? Are you running an atmospheric BOV?

is it really back fire or is it unburnt fuel in the exhaust (backfires in the intake and will jack your motor up)

a backfire usually happens when you lean out which is bad for turbo motors.

if you are running rich you can get a loud popping noise when you come off the throttle when you have excess amounts of unburnt fuel going into your hot exhaust

[Tulsa_S-13]

First things that come to mind:

1. Are you running an atmospheric BOV? If so, because what was once metered air is now leaving the intake tract, the A/F go rather rich at deacceleration.

2. Are you still using the vehicles catalytic converter? Usually running a test pipe can cause unburnt fuel to ignite.

Be sure to check timing, as this can also be suspect to backfiring.

[IanS]

First things that come to mind:

1. Are you running an atmospheric BOV? If so, because what was once metered air is now leaving the intake tract, the A/F go rather rich at deacceleration.

2. Are you still using the vehicles catalytic converter? Usually running a test pipe can cause unburnt fuel to ignite.

Be sure to check timing, as this can also be suspect to backfiring.

Check the basics.

[shift_SRDETuser]

I read somewhere that the stock exhaust 2.25 inches is the same that came on the jdm silvia in japan. I am using a stock exhuast back from a greddy elbow and megan downpipe. I am also using a HKS BOV with is recirculated back to the charge pipe.

Should I currently not be running my car too hard in order to save the turbo. It boosts strong up I here a slight backfire when I rev the car on idle?

[nzmoman]

with that exhaust setup you are definitely fighting back pressure.

This is going to cause the noises even more if it is the fuel igniting in the exhaust. You dont have flow so your downpipe is just holding hot air and at a higher pressure. Throw another piston and keep it running and you will have a 5th cylinder.



that was a joke!

[shift_SRDETuser]

with that exhaust setup you are definitely fighting back pressure.

This is going to cause the noises even more if it is the fuel igniting in the exhaust. You dont have flow so your downpipe is just holding hot air and at a higher pressure. Throw another piston and keep it running and you will have a 5th cylinder.



that was a joke!

actually I have only heard it do this like once. I know I need another cat back system but I do not like loud. I am at stock boost levels right now so it should be good until I can afford a cat system -- are high flow cat coverters worth it or should you run a test pipe or stocker cat?

[nzmoman]

High flow cats are fine. the loss in power is so minimal if you get a good one that its worth it just to help with emissions a little (thought you still wont be universally smog compliant).

try to find a used catback. there are good ones out there with a good note and they will work fine. theres no need to wait for a really nice one.

My blitz NUR spec is got a good tone and is not that loud at all.