I've had popping out the exhaust lately and am trying to figure it out.

Is popping out the exhaust cause by a rich condition or a lean condition?

My car is kinda baffling me because Friday at the track, I popped on my first pass. I then changed one of the fuel jets to richen it up and the next pass was perfect.

Now, with the same jets that ran perfect on that one pass, I'm getting some popping.

The only thing that is different is that I'm dumb and accidently put 89 octane in after racing where I had 93 when I raced it.

Could low octane cause a pop?

This pop out the exhaust, is it different than the backfire's people talk about blowing apart their intake; or just a similiar, but smaller backfire.


Thanks.

 

They are both backfires, but one is in the intake (thats the one that blows intakes aparts), and then there are backfires through the exhaust, which can be caused by rich or lean exhaust, you need to get it up to a dyno with a Wideband A/f to find out whats going on, I would also pull your plugs to make sure all the electrodes are still there.

 

If its a TNT kit I would check the fuel noid immediately. Sounds like a possible lean condition to me.....

 

im pretty sure running rich cant make you "backfire" only lean. and as was said, an intake backfire will blow your intake off. enough of those exhaust backfires will blow your motor up. the first run you were running lean so leave the second jet in. and FYI, octane is a measure of a fuels resistance to detonation, the higher the number the better. the 89 octane IS the reason you were backfiring the time you put it in.

 

you can also get a backfire if too rich but considering that this guy is spraying, more then likely he is getting a lean backfire. a rich back fire can occur when you are getting too much fuel in the exhuast and it ignites, or if you flood your intake and if ignites. both causes are more likely to happen on caurberated cars were it is easy to do that.