SupraKiller

I was cruising the freeway last night and my buddy was behined me and he noticed that I was blowing out blue flames out of the exhaust!!!! could it be possible? I am running octane 94, what do you guys think?

Talek

Yeah, if you've got a straight thru exhaust you'll get some flames. Just be careful when there's a cop behind you.

2 hott

iTrader: (4)

what other mods do you have?

7-sins

Stock ECU and midpipe... that doesnt sound too safe to me. One of those flames might have been a Apex seal flying out.

94RXMAGEE

iTrader: (3)

Yeah mine does the same thing, I run 93 and the af reads rich all the time, with a down pipe and midpipe and stock cat and ecu it shoots flames.

cash money

ianewk

It's one or the other man...either you have a midpipe, or a cat, but not both.

SupraKiller

Stock ecu and midpipe and downpipe if fine as long as the wastegate opens at 10psi, if you spike for more than 2 seconds two higher boost, thats where you can risk engine damage. My Catback isn't a really good one its only 2.5 inches but I have been told that I have Borla free flowing muffler.

7sweetie

yeah with a midpipe its easy to shoot flames, because youve got a straight line and its dumping all the exhaust to your midpipe. which i may say thats dangerous cause its not keeping any residual exhuast in the engine. MHO is i think midpipes are dangerous and should be kept off.

SupraKiller

No Rx7 sweetie, a midpipe is actually better than a converter. You see with a midpipe the motor wont have any back pressure, with that back pressure the temps of the motor are forced back into the engine bay area, and you know what happens if the already scorching rotary temps exceeds a certain limit, reduced engine life. Midpipe I put there so there would be less stress on the motor, and the turbos. I just installed rebuilt turbos and I want them to last for a long time, so I dont want to ruin them for I have paid alot of money. Anyway I do have a downpipe, but I wanted to place the main cat back in, but was told that my catalytic converter if looked inside had a hole in the netting inside. But if the catalytic converter was damaged, how come the car passed air care every time from the previous owners history? any answers? would it matter if the catalytic converter was a little damaged, for I dont see it being a problem, as long as I have a downpipe there, I cant get the back pressure to back into the engine bay right? or the heat generated from the catalytic converter, or no?

7sweetie

well i cant tell you first hand that i've had problems with a midpipe, because i dont own an fd. talk to goodfellafd3s about midpipes and what happend to his car. his motor blew, dave at kdr says because he was running a midpipe and running really lean. i've just heard too many people say midpipes are a fast way to blow a motor, but you very well may be right.

potatobbq

Actually, I don't see how the exhaust gases leaving the motor would be any hotter than gases in the motor... If you don't have any backpressure, it will be harder to regulate boost and you risk running lean.

7sweetie

thats exactly what i was trying to say, lol

gzon

That sounds nice. I hope I get some good ones when my MP comes on to.

3rdGen7

Actually, That's exactly what happens. The exhaust gas leaving the motor can cause excessive heat because of the backpressure, it prolongs it's escape causing it to heat the surrounding more before it's exit. That is why if you do a streetport and run a stock exhaust the entire manifold glows red hot.. when you change out the mid pipe, and cat back the glow goes away.. even with the dp still in place. If you swap out the DP and run a stock MP and CB .. the glow also goes away.. The stock exhaust (whole or partially) gives that much more backpressure to cause things to get bright red.

..speaking from personal experience.

AJC13B

I would say you have a small airleak somewhere in the exhaust.