how much back pressure does an 86 na have?

at idle my car would make some popping sounds but really low... kinda like: pop... ... pop... pop pop... ... pop... and so on.

and when i run my car hard on "touge", during my downshift and high rpms (5000-6500), i hear a really loud popping sound... kinda like: EEERRRRrrrrrrr *POP* ERRRRRrrrrrr

it happens when i downshift from 4th-3rd and 3rd-2nd... i mostly stay in 2nd and 3rd most of the time.

 

back fire

maybe bad timing

 

The popping at idle is called afterburn. It is no big deal, most FCs will have this after removing the emissions equipment.



As for the popping at high rpm that is backfiring, I assume that you have full exhaust on your car, and no emissions. Have a friend follow behind you to see if you're shooting flames.

 

my car is stock... all i have is an hks filter.

 

Depending on how loud it is, you should probably also check your ignition system to see if your car is firing properly(could be missing, just a guess) when was the last time you set your TPS and how rich does it run?

 

well it's pretty loud... and it only happens when i drive it hard, daily driving i hear nothing... and i don't think i'm misfiring, because i have a lot of power... no lagging anywhere.. and my tps i messed up i think.. .i can't seem to adjust it properly, i think it's just broke, so i'm replacing it... as for richness: it's stock as far as i know, unless there's a way to adjust it... my pd used to leak, but i replaced it with an s5 fuel rail.. i still smell fuel very faintly, but not as bad as i did when my s4 pd was leaking...

 

oh yea, and as far as i know, nothing has been removed like emissions stuff...

only thing gone is the power steering and a/c

 

once again.... timing check??