I am a newbie, my brother and I just picked up a '93 FD in North Carolina. I had a few questions regarding some modifications, and their ramifications. The car has high-flow pipes replacing the pre-cat (downpipe?!), the cat, and a petit racing cat back exhaust (I personaly think it is a little ricey). Anyway, when my brother goes to shift, the car seems to backfire, or make a loud POP! We also have a brand new A'Pexi intake on it. I guess my question is, what do I need to consider with this set up. I hear about using a bost controller to keep boost around 10psi, but what does it al really mean? Are we in danger of engine trouble without a controller etc.? Any help would be GREATLY appreciated!

Thanks,

Karl

 

Check out the post at the top of the page

https://www.rx7club.com/forum/showth...threadid=68640

I don't own an FD yet, but I think the backfires are common, but don't take my word for it. Do some research, and do the reliability mods. The links in the thread above should help you out.

Welcome to the forum

 

backfires are very normal....if you are running a unrestricted exhaust system


dont be scared if you see a 6 foot flame in the rear of your car everytime you shift.......leave that to the little honda following you

 

Backfires are common in fd's. If you have a downpipe, catback and intake you need an ecu has soon as possible. A boost controller will help keep the boost at 10 psi, but if you ever wanted to turn it up then you will need an ecu to correct the air/fuel ratio. Try finding a used pettit or m2 chip. You can prob find one around $500. As far as reliability mods go, make sure you replace the ast, get a boost guage and A/F guage, and replace the fuel filter. But right now you need to get a chip or you'll find yourself def buying a new motor. nick

 

If you do not have any type of an upgraded ECU, or Boost and Fuel computers you are sitting on a time bomb here. Do you have a boost guage? I guarantee you with a complete straight through exhaust and intake you are getting some serious boost spikes!

 

Thanks for the info guys, and any more from anybody else will be greatly appreciated. Looks like I have a lot of fun and $$$ spending to look forward to. But I think it wil be worth it when we can eat my dad's new C5 for breakfast. BTW we aren't young knuckleheads, and look forward to meeting several of you guys at local events; or on the street...

 

If your description is correct, you are running a downpipe, midpipe, cat-back,and intake on the stock ecu. This is BAD and you are heading for an engine failure (unless there's something controlling boost such as a leak or home depot controller or something similar). You need to get an ecu or control the boost to 10 psi immediately.

If you are not experience any fuel-cut at WOT, then it is possible you already have an upgraded ECU (Pettit, M2) in the car. If that is the case, you might be fine as you are, although I would upgrade the intercooler as you are likely running 14 psi or so.

 

karl , where are you in NC?

 

I'm in Raleigh for the summer (parents), but med school at Chapel Hill. You in Winston Salem Silver 93? Thats actually the year/color of ours. Silver/Red.

 

Back fire is a norm when you own one of these... with my mods, it's loud. If you want to get rid of the rice sound go with the Apexi GT Spec, and the 3 inch DP, with my mods I was hitting 12 psi at one time. I suggest to upgrade the ecu," I didn't but wish I did, rpm varries now at idle" just spend the money and buy the PFC.

 

yeah, i'm here in winston. congrats on the new car...
if you're around these parts, let me know -
actually, i am currently borrowing a wideband for tuning, i can ask the owner about using it if you are interested in getting readings to know what your car is really doing instead of guessing! (with the backfiring, you're running rich- couldn;'t tell if you have a cat installed or not)