gutted vs. aftermarket UP

[ColoWRXer]

i'm currently cobb stg.2 and am looking at going with an FP 18g. i will of course be getting a big TMIC, modding the stock injectors, fuel pump, one step colder plugs. then i'm getting a tune for both 91oct and E85!

i already gutted my stock UP and took out the EGT sensor and plugged the hole up with a bolt. i'm wondering if there are any gains to be had or advantages with getting an aftermarket UP. i remember hearing that they are, atleast some of them, larger in diameter than the stocker.

thanks

[seanwrxwagon]

Alot of people will say that there is no real advantage to switching at this point. You have already went through the trouble of modding your stock up. I am of the opinion that there are some advantages to an aftermarket up pipe. The stock one is not the same diameter all the way up for one. During my research, before I bought my up, I read that if you increase the diameter of the up pipe you will lose exhaust velocity. This will increase lag. I choose to replace the up pipe with a stock diameter pipe.

[nagyhead]

i had both. the gutted stocker was good for the stock turbo, but when i went to a vf-39 the stock up was causing some problems, and my tuner Dom couldn't tune it, very agressivley, so i switched to a cobb uppipe, which is close to the stock diameter, and have had zero problems after my re-tune

[Black05WRX]

I went with a megan up pipe, works fine and I have no increase in lag, even tho its the stock size.

[seanwrxwagon]

If you can swing the price, Cobb is a great unit. It's cast which will hold in heat better. More heat=more exhaust velocity=quicker spool up
I went for a thin walled up with a flex section because i could not swing the price at the time. I think I will swap them when I get my TD05 18G 7cm^2.

[VD5505]

i bought a turboxs up pipe and im very happy with it, stay away from the up pipes with that flex hose part in there that is a joke and will come apart like it did to mine and took out my VF22 now i have a evo3 big 16g

[WRXtreme]

I went with a Helix uppipe with a flex section so that I wouldn't run into issues with the uppipe leaking in the future. 3 years and no problems thus far. The Helix uppipe was also larger then stock because I anticipated upgrading the turbo, which I havn't done yet, but I haven't noticed any disadvantages with the larger diameter.

[seanwrxwagon]

Any increase in lag from the larger diameter was more than made up for by removing the cat. Going to a larger turbo will exasperate the issue though. i would imagine the increased volume might make up for the decreased velocity in the higher RPM's.

[ColoWRXer]

thanks for the replies. sounds like there would be some advantage to an aftermarket because of an even diameter all the way through and a cast one would keep some heat and increase spool up. i'm all about that. nagy, was it only when dom tried to go aggressive that he had problems?

i really would rather not spend $235 on the cobb pipe. i know i have seen some that are more like $100. can anyone point me to a good UP that is cast, same diameter as stock and relatvely cheap?

also, i'm looking into getting some heat wrap. i was thinking of wrapping the UP, hotside of the turbo and first part of the DP. would this help out with heat retention and spool? i also no longer have a heat shield, would this help with heat soak or is a shield absolutely necessary?

sorry about so many questions.

thanks.

[nagyhead]

He could tune it but it wasn't that aggressive, and it was at the point that he was unsatisfied with it. After I got the Cobb he had no problems at all. I would spend the money on a good quality uppipe like the cobb.

[ColoWRXer]

i may just have to do that....if i'm already spending 2 grand on a pnp 18g, supporting mods and a tune hey, whats another 250 bucks.

[newtothegame]

Thats a good mentality. Dont skimp on something that might come back to haunt you later.