mattmontalvo

I have a 2003 WRX Sedan. Currently have 84k miles on the car and engine. Stock tranny with coctail, stock clutch and stock flywheel. I have a COBB Lightweight pulley, Grimm AOS, COBB Up pipe, COBB XLE BPV (recirc always), large off-road knobby tires on stock rims (43lbs each), K&N drop-in panel filter with modified stock air box (silencer elbow delete). I am running the COBB catted 3" dp to a stock STi cb exhaust. I have a COBB OTS Stage 2 91ACN v3.1 map.

My questions:
1) is it really necessary to perform a custom tune for an up pipe to avoid complications later, or is a custom up pipe tune just there to milk the hp for what it's got?

2) how do you feel about running the stock STi exhaust with a stage 2 tune? Would a 3" really make THAT big of a difference power and gas mileage wise? I've heard it all at this point.

3) does running larger size tires mess up the tune at all? The odometer reads about 8.5% off from stock (60mph odo= ~65mph actual).

4) I kind of already know the answer but am still curious: Would there be any advantage of running the COBB SF intake system over the K&N panel filter?

5) COBB MAF hose: Worth it on stage 2?

KrAzYkld

iTrader: (30)

This is just my personal opinion, but
1) I say get a protune if you plan on staying with the listed mods for a decent amount of time. Stick with the OTS map if you plan on adding additional mods later.

2) Will not make a difference at all at these power levels. 2.5in is more than sufficient.

3) I have no idea.

4) Not really. You get the hear cool sounds with the SF Intake though.

5) Nope.

foosh

iTrader: (2)

1. Stick with the OTS, a custom tune will run around $500 bucks and won't make much of a differene on a 2002/2003

2. No difference, get it if you want to reduce noise

3. No

4. Not enough to buy the intake

5. Stock hose leaks over time, get a Perrin, not cobb.

Heedz

iTrader: (51)

I'd get rid of that lightweight pulley, I know a few local shops advise against them. \

Removing the cat in the uppipe won't need a tune. While headers will usually.

mattmontalvo

thx!

thx!

Any particular reason for NOT using a lightweight pulley? I haven't noticed any downside do far?

KrAzYkld

iTrader: (30)

I thought lightweight pulleys were okay and underdriven pulleys caused problems?

DabiDa

iTrader: (6)

I looked up your exhaust question when i was running my 02 stock exhaust on stage 2 found out i have a newer 05/06 exhaust it has just one tip not two like on the 02/03 model from what i gathered it is just fine to run.What i noticed from stock,srs straight 3 inch pipe & tanabe CBE.
Stock feels like it had more torque
Srs with a straight 3 inch pipe feels like i had more top end
Tanabe feels like a little of both
Also it depends on the sound your are looking for just like the Cobb intake you will get a psssshhh and swoosh aswell.Im running a JDMV7 Sti up pipe,HKS Downpipe,Cobb intake,Tanabe CBE,Cobb AP Stage 2 OTS v3.10 map aswell and you can def hear the turbo spool.

mattmontalvo

I've noticed a pretty big difference performance and sound wise from the K&N drop in filter. I have the sound box resonator out of there and have the air box pretty much open to the air in the fender as well as the intake ram over the engine to the hood. I closed the hole 3/4 way in the fender so that it won't draw in extra moisture or dirt when I go play. It's noticeably whiney now compared to before esp with the xle bpv - that thing is loud even on recirc! With the exhaust I actually have the stock 2.5" STi catback and to be honest, I feel like I have better performance in the higher altitudes than I did with the full 3" can exhaust I had... I don't notice any real difference on the lower end really at all but it might be more torque-y now that I think of it - it just felt faster when it was loud it actually felt a little better with the cobb catted dp over the catless helix I had months ago... weird?

downsti

iTrader: (10)

so let me get this straight, going from stock STi catback exhaust to a aftermarket full 3 inches catback doesn't make a difference?????

please explain, and show proof of this

mattmontalvo

Update:

I just got a COBB Tuning ss 3" catback to mate up with my COBB DP. Power is VERY noticeably smoother. I was starting to get some back pressure flutter with my STi exhaust and decided to give the 3" another shot. I'm VERY impressed with the overall quality of this piece. I can't say that I've noticed much of a raw power gain (I'm no dyno) but the spool up and over all drivability is much much smoother.

Heedz

iTrader: (51)

I'm gonna take what I said back about the pulley. I have an 03 now. It's different. Now both with a LW flywheel probably not too much free spin. The car I picked up has the GFB pulley kit on it.