2 1/2 or 2 1/4 inch exhuast piping??
 

what should i redo my exhaust piping with 2.5" or 2.25". i heard that 2.25 inch is probably the best because it is not too free flowing but thats for a non turbocharged car. Since mine is turbocharged i want the most free flowing exhaust i can get so the turbine can spin more freely since there is less back pressure right??? also should i just get rid of my cat and resonator?? i dunno..help me out.

For a guy with turbo you're asking us :dunno:


If you want the best "free flow power" then just straight pipe it for best results.

2.5"

I'm NA with a 2.5" cat-back and have no loss of torque with just an intake and bored tb up front. I can't see why it'd cause a problem for you or anyone. I used to think 2.5" was too big for NA...honestly it hasn't had the slightest negative affect.

Yea, definitely go at least 2.5"...a lotta ppl I know like to go 3" w/ turbo...

yeah.......dont go any lower than 2.5" ....... and yeah many ppl go w/ 3" piping on their turbos....but thats mostly on bigger engine cars.....i dunno if that will be TOO big for ours......do they make 2 3/4" piping?? if they do i'd get that.......fi not get the 2.5" ....thats my advice

I disagree with Hobie on this... I have 2.25", and I noticed a significant loss in off the line torque until I installed the Injen to even things out... but, with a turbo... whole different story. Just thought I'd throw my two in on the NA set up... I got a small performance shop in my area running an OZ with a 2.75", and they had to change mufflers to accomodate a tunable so that they could get ANY off the line. It might just be this region's weather and height, but, I don't know enough to say. But, around here, I was having definite backpressure problems until I upgraded the intake. Hobie, didn't you have your intake first?

Yeah...I wasn't trying to imply that you need an intake for 2.5. I'm just saying I didn't feel any loss and that's prolly a big part of the reason. Anyway, I stand by 2.5" no matter what the application. If you're tuning, it's the way to go.

K... you know, we're both right... I think I remembered an article or a letter in SCC saying that for a 2.0L, 2-2.5" is the way to go NA... I put mine smack in the middle.

I retract my disagreement on those grounds.

By talking about the intake, I was just saying that was probably the reason you didn't notice any decrease in power. With the restrictive stock, there was a BIG difference in the back pressure needed to get off the line.

Seeing as how RRM's catback hasn't been released yet, I obviously don't know it's size, but isn't the RRM exhaust 2.25"?

I would imagine that they'd recommend their own exhaust for their own turbo kit, so what does that mean?

Will RRM release an even larger exhaust/catback or will they simply recommend 2.25" for their turbo kit?

Boni, if you're reading this, what size exhaust/catback did RRM install on your Lancer?

EDIT: Just checked the registry. Looks like RRM installed 2.5" on Boni's car.

Hrmm...correct me if I'm wrong but I was always told that w/ turbo there is not really a backpressure issue so you should try to get the biggest piping you can get without worrying about scraping on the concrete all the time...like if you had a true turbo race car (off road use only ie drag) then you wouldnt even need the exhaust and everything would come straight out of the headers...i've seen a lot of turbo drag cars that have no exhaust...so w/ no exhaust being the ultimate free-flo, I'm assuming that having 3" would give you more flow than 2.25" or 2.5"...but yea, correct my logic if im wrong

z-lancer, with a turbo you definitely want to put the largest piping that will fit under your car. Because you want the least amount of back pressure after the turbo to speed up spooling. Also I would suggest that you keep the cat on so you don't pull a check engine code and cause the ecu to go into a limp mode. And keep the resonator also, unless you like setting off car alarms in a two block radius.:D

u said taking the cat off may cause a check engine code, would this also occur if i was to purchase a high flow cat??

also can someone a little more car knowledge than me explain what a ECU and resonator are, and what they do????

LoL, kinda funny to see what everyone had to say about this.

Z: 2.25-2.5, don't go no bigger than 2.5 or you will lose power. 3" exhaust is for 300 HP + cars. You will LOSE power by getting an exhaust that big.

Mine is 2.5" mandrel bent and its from the cat-back. I still need to get the downpipe built. The one with the flex crap and the squished metal, you know which one i mean :P

Resonator: big "chamber" style object that sits in the exhaust to baffle noise, and sucks a marginal amount of power.

ECU: Engine Control Unit - Take info from various sources (like the Mass Air Sensor (read THIS thread about my rant on it) and tells the fuel injectors how much fuel and air to mix, spark duration etc. It's the brain of the car. Mitsu ECU's are not easily hacked hence why you don't see "chips" for most Mitsu cars.