2.25" turbo exhuast?

[JustinP10]

Hey guys, I have a question (DUH! ). I'm about ready to build a custom exhuast, 2.25" madrel bent w/ the largest resonator and muffler I can fit. I'm also eventually wanting to go turbo (who isn't! :hehe. Anyways, my question is, how much would a 2.25" exhaust hurt, in comparison to a 3" exhuast? Both being mandrel bent, and assuming muffler and resonator selection stays the same (bigger I.D. of course) and guesstimates? I'm wanting to go with a larger turbo setup, something like an F-max stage 2. But, say i run the 2.25" exhaust on the street, as apposed to the ideal 3"+ exhuast, is there going to be a huge differnce in power, or spool up time due to the increased backpressure? Thanks. Oh yeah, turbo is probably a year or more away (saving that much $$$ takes a while on a student's budget)

[Nismoboy1]

sounds like something geo could answer lol

but if it were me i'd wait to get the turbo first then build a custom exhaust at the same time, because if i decide to throw on a 3" exhaust now w/o turbo, i'd probably lose a hella hp on the low end but maybe gain very little on the top, i remember in my old sentra i had a 2.5 in crush bent exhaust (yeah, i know) but it help a lot when i was spraying lol but just cuising around town kinda sucked cause i had no kick off the line, their was probably zero back pressure, so i'd just wait and see if you really end up turboing, which i don't have a doubt, and then decide from their, so anyways good luck :alien:

[jprimera]

Hi you shoud go with the 3 ,remember that the turbo cars like no back presure.

[primera man]

I put a 3" system right through mine from the flex hose.
All up cost with end muffler and one other about half way to keep it quite was $500NZD($210 USD)
Depends a lot on where you go and what you want as to how much it well cost.

Have a good look around first and tell them what you want to do.

[JustinP10]

well, i'm planning to eventually go 3" or larger, as that is the best, but i'm wanting to get more power for the next year or so (maybe longer) while i'm waiting to get my turbo stuff all purchased, put together and fitted, etc... but I don't want to run a 3" until then, as it will be WAY to loud, and probalby hurt power, but i'm wondering how much a 2.25" exhuast will "hurt" a turbo car vs a 3" exhaust.

[P10DET]

Originally posted by JustinP10
well, i'm planning to eventually go 3" or larger, as that is the best, but i'm wanting to get more power for the next year or so (maybe longer) while i'm waiting to get my turbo stuff all purchased, put together and fitted, etc... but I don't want to run a 3" until then, as it will be WAY to loud, and probalby hurt power, but i'm wondering how much a 2.25" exhuast will "hurt" a turbo car vs a 3" exhaust.

I don't know if I can tell you how many hp you are going to lose, but if you plan to go with 3" when you get the turbo, I'd say wait before doing any exhaust work unless it's rusting (yours had better no want to be in AZ)

If you want to add some performance to your car, there are several things you money would be better spent on. Or, but it towards your turbo fund. You'll be able to get your turbo that much faster.

[JustinP10]

Well, it's not rusting, but there is a pretty nasty (loud) leak, that I'm wanting to repair. And it's truthfully probably another year at the soonest, i'd guess probably a year and a half before I have a turbo. Also, the other thing i was thinking, is that i could always just sell the 2.25" exhuast, if and or when I go turbo. Who knows, in a year and a half a lot can change too.
As far as other mods i don't have too many bolt on power mods left. I should be getting a Primera cam this weekend. other than that and the exhaust all i'd have left is the ECU, which I'm going to wait to get last, once i know for sure what i'm going to do.

Oh yeah, forgot to mention, i'm going in with another G20 owner on parts and stuff, so i'll be able to get a killer deal on the exhuast right now.

[AZP10]

There is a large difference between 2.25 inch exhaust and 3 inch. Remeber that for diameter you must use 2PI, In other words, the 3 inch exhaust is going to have just under double the flow as the 2.25; check my work on a calc

[JustinP10]

Yeah, i actually did kinda go through some of that in my head... and did remember from old math classes the flow rate goes up by a lot, when the i.d. is incresed just a little bit (in this case 3/4"). I've decided to wait and just go with a 3" down the road. I'm not sure what i was really thinking when i was thinking about going with a 2.25" exhuast and then turboing the car a year or year and a half down the road. While it would be nice right now, it'd be extra money later, that could do towards something else.