So it seems that my car is a bit flame-crazy when you shift at redline (I did my first full-throttle pull about a week ago) since it has a sizeable backfire (racecar-like), at least through first and second (the only gears I pulled in since I ran out of...well, I was doing 70 in a 50).

I wonder if that should be normal even with a high-flow cat? (unless it was already gutted... I haven't checked). Otherwise my exhaust is pretty mundane (downpipe, high-flow, Magnaflow mufflers), so I hope it's not something wrong with the air-fuel system.

For the record, my port air solenoid is throwing a code.

 

You're going to run rich because it's an rx7, flames are even more predominant in modified exhausts and more so with a high flow cat. Just get a friend to drive behind you, film it and enjoy.

 

backfires are half the reason we buy rx7's lol

 

True... hehe

 

Do all 2nd gen run rich? or is it only certain engines or years? I've read that you could get a little more hp just from leaning out a bit on the fuel curve is this true?

 

yes that is true...i have an apexi safcII and it works wonders...for a beginner tuning device anyways

 

N/A's run alot richer than stock TII's

 

Especially with the boost turned up... N/A's are gas hogs by comparison.

 

I wouldn't go that far. N/As run richer, but still use less fuel, especially once you start bumping up the boost.
And yes, all NAs run rich at high revs.

 

Well, per molecule of air sucked into the engine, of course.

 

throughout the powerband, N/A's run rich...

 

Now shooting flames with a hi-flow cat shouln't hurt the cat much should it? It's not like a huge flame is passing through the cats honeycomb, it's just fuel going by, then when it hits the outside air it explodes and thus a flame.

 

what's the diameter of the piping?

 

So can anyone answer my question about shooting flames with a cat?

 

Doesnt seem like it would as its just fuel going through it.

 

N/A's run rich to prevent knocking. One good knock will blow a seal... i.e., if you run too lean it'll be fine for a while and then <bam>, time for a new engine. Leaning it out improves power and fuel economy, though.

I heard Mazda made N/A's rich enough for the worst case scenario intake temperature (high temps), while an SAFC can have a different setting for each intake temp (i.e., for high temps you'd use the stock setting). Dunno if this is true, though. I'm thinking of getting an SAFC some day; I don't have one.

Regardless I've read multiple times that the N/A's are extra rich to be conservative. FDs, OTOH, can knock if you even upgrade the exhaust a little bit without retuning them to run richer.

 

BTW, would you guys say it's normal for an FC to backfire EVERY time you shift at over 7K?

Because it seems to do it like clockwork... I mean, it doesn't bother be, but not even race cars backfire every time they shift (I think), although they almost always do when they downshift.

Then again, I might not be getting big flames, it may just be a little pop. I DO need to film it though

 

I want hugh flames.....well....maybe a foot or so instead of poping flames : /

 

I love getting two nice 1foot flames out the rear of my car.... its fun to time it, and make them pop right as you pass by somebodies window...scares the crap outa my friends.

 

my na shot huge flames through all gears above 4k. actually better around 4k than at redline. i could just sit in a parking lot and stroke the gas at 4k and pop em for hours. some were just pops but some were a few feet long. my exhaust was 2.5 all the way back with a header resonator and ebay special muffler. the resonator burned out pretty fast so dont buy one. it was loud and nasty and i got pulled over when i shifted and a cop was tailing me. no ticket but he "suggested that i get it fixed".

 

Well my S5 n/a would shoot flames easily, just by reving it up to 7k or so and letting off, that was with RB 2.5" manifold-back exhaust.

That same exhaust is now on my S4 n/a and it never shoots flames (no exhaust or vacuum leaks that i know of)
so i dont know if S5's run richer or if something is just different on my S4

 

S4's do too. Probably just a difference in tuning or something.

 

Haha! So true!