I have a bone stock FD. I was thinking of taking a slightly different route on the mods.

Downpipe AND Midpipe (hear me out here..)
Stock Catback
ECU

I think the car will breathe better, but not too much. It will dissipate heat very nicely. The ECU will keep the fuel happy.

Am I asking for trouble or should I leave the stock cat on there? (I've read all the faqs, stickies etc etc). Just wanted to know if anyone has 'freed' up the exhaust with an ECU only.

 

By ECU, do you mean a piggy back fuel computer or a stand alone? I hope youre not thinking the stock ecu with a midpipe...Not only would the dp/mp/stock catback be really loud and stinky, it might flow too much. If I were you, Id go ahead with the dp, catback and leave the cat alone...Keep it safe while making a little power and noise stays within reason. Maybe even get a set of filters and ditch the air box! I drove like that for a while before i got rid of the stock ecu.

 

or if you do, get an ebc and port the wastegate, as long as you do that you should be fine with a midpipe. Or put restriction somewhere in the exhaust.

 

when you go catless, you'll most likely to spike or overboost.

since you are asking this question, I don't think you want to take your turbos off and such to port your wastegate. I would stick to DP and aftermarket catback. But stock Catback should be fine.

I also don't understand what you mean by ECU?? stock, chipped, piggy back, or stand alone??

 

the stock muffler would keep some restriction...still i would play it safe and port the wg and everything. for a midpipe i would also run a standalone.

i want a wg port but im too lazy to pull the turbos!! if you do just keep the main cat, its a lot easier. and u wont be disappointed with the power or anything either. wait on a midpipe i say. just a dp will greatly help with getting the heat out. i think its more than enough.
if you do just a dp intake cb ecu, maybe even ic for now, i promise you will be happy with the results.

 

I changed my mind, FD's aren't the place to 'reinvent the wheel'.

 

Good call.

 

The stock cat-back is almost certainly restrictive enough to prevent boost creep, but it is safer to stick with the stock main cat or a hi-flow cat until your ecu and fuel system is upgraded.

 

I think one of the main reasons I wanted to drop both cats at once is because it would be very easy to do and you save a TON of weight. Plus all that free flowing goodness. Oh well

I really want to drop both of them but be as safe as possible.

PS By ECU I meant something like Petit's.

 

Apexi w/ basemap = Pettit and after you have room to play FYI

 

Yeah. Might not be a bad idea. Risky to be on the cutting edge though. Youll be happier in the end if you take it one mod at a time. Takes longer. Breaks less.

you can biy a pfc and just go buckwild!!1!(with tuning!)
or
you can resist the buckwildness and build up to the pfc.

But thats just if youre going buckwild. If youre only going mild, or regular wild you can go get a pettit and have a ball and save at least $400.

 

I am using a stock cat back with down and mid pipe.
I have no boost creep or fuel issues.
IMO if you use the stock cat back there is enough restriction to
allow the boost control circuit to work properly.

I have the stock ECU, unmodified and the boost is set for a 12-10-12 pattern.

BTW the car runs great.

Joe Geiman
Gasoline Alley Fuel Injection
Speedway, In

 

Hey Joe,

Just wondering, how do you know you don't have fuel issues? What are you monitoring to make that statement? Also, how long have your been running your car this way. I'm just curious.

 

i ran my car with dp, mp, stock cb, ad apexi airfilters for about 3 months. it didnt overboost or creep or anything.

it completely blew the muffler apart on the top part of it. but it never creeped or anything.
i was on a stock ecu as well

 

I don't know except that I've run it this way for 2 years and there has been no detonation or lean misfire indications. The plug color is beautiful. 12 psi on stock twins is close to 300 HP. The fuel system w.o. mods is good for 350 HP.

I'd make sure your cat back is in good shape. I saw the other post about the exploded muffler. Mine looks fine.

Joe Geiman
Gasoline Alley Fuel Injection
Speedway, IN

 

Encouraging to hear! I will keep the stock (cheap bastard intake?) because I'm 100% sure that those non-CAI intakes are bad bad news.

Do you guys have upgraded intercoolers? Its the other thing that worries me on our FD's. (The cats, and intercooler hold too much heat in).

 

My mods for about a year:
Mild Streetport
M2 CAI
PFS SMIC
DP
MP
STOCK ECU
Profec B spec II EBC set at 10 psi <---extremely important that boost NEVER exceeds 10 psi
Stock catback, then for about 1 month I ran a magnaflow exhaust before I purchased an PFC.

Always WOT. Never any problems