up pipes

[off2harrys]

just bought a rage up pipe 2 1/2" can i put that on my zorst manifold since thats 3" or will that mess up the flow?cheers

[Stoffa]

that seems rather large for an up pipe, are you sure you dont mean down pipe?

uppipe goes between exhaust manifold and turbo, downpipe connects the back of the turbo to the rest of the exhaust.

I run 2 1/2 inch down pipe into a 3 inch exhaust with no issues

[off2harrys]

nah the up pipe but yea sorry actually i think its 2" (whats standard size for a ej20t it might be that havent actually measured yet)got a twisted up pipe from rage thought id get the smaller size my other up pipe was 3" into 2.5" thought that might be contributing to my lag

[Stoffa]

sorry, I didn't know they made them that big, just measured up a factory V7 sti one, 42mm or 1.65 inches OD.

Is the outlet on your manifold 3 inches? seems rather large

but to answer your original question, if the uppipe outlet is smaller than the inlet, its only going to speed up the exhaust as it enters your turbo.

[Nakiboy79]

Got a stainless up pipe installed yesterday, now that there's no heat shield there's a hose close to the pipe (looks like an oil return line from turbo) thats melting and creating a bit of smoke. Also, for some reason it sounds like my turbo is whining on boost. I suspect some wire weave has come loose and got into the turbine blades? Frikkkkken Frikk...No-one tells you bout this stuff!

[Nakiboy79]

Should I have heat wrapped this? Anyone had the same prob? I've never heard of this happening before

[Stoffa]

bugger, I'm sure theres at least enough people around that say don't buy cheap knock off parts.

I spent $221 on a trust up pipe and it didn't have wire mesh inside it, the wire doesn't come loose, it melts off from the high exhaust heat in a subaru.

Yes you probably should have wrapped it

[Nakiboy79]

I didn't install it, I got Pit Stop to do it coz I couldn't be bothered, thought they would've advised re: heat wrap/shields.. Anyways I took it all apart last night, heat wrapped the up pipe and inspected the turbine blades. Nothing wrong with turbo, must've been leaking exhaust from the dump gasket on boost. Found that some of the dump pipe bolts were only finger tight when I was disconnecting, plus they left the old gasket in and just threw the new one on top of it... got a refund from Pit Stop.

[Nakiboy79]

Its all a steep learning curve for me! :-[

[Guest]

 Nakiboy79 said:

I didn't install it, I got Pit Stop to do it coz I couldn't be bothered, thought they would've advised re: heat wrap/shields.. Anyways I took it all apart last night, heat wrapped the up pipe and inspected the turbine blades. Nothing wrong with turbo, must've been leaking exhaust from the dump gasket on boost. Found that some of the dump pipe bolts were only finger tight when I was disconnecting, plus they left the old gasket in and just threw the new one on top of it... got a refund from Pit Stop.

spose they blamed it on the apprentice? no excuse for shitty workmanship there .

[Nakiboy79]

Actually it was the owner of that particular shop who did the work! Another couple of things, the turbo oil return/drain hose wasn't hooked up properly (fixed that) and found a stray nut in the engine bay also. Just shabby work that you don't expect from a workshop. Won't be going back there thats for sure

[lunchie]

Doing the turbo "up pipe" on most subies is actually a great idea as almost all of the non sti models (and even some of the sti models) came with a cat converter inside that pipe so some decent hp gains can be had with replacing it.

However when replacing it make sure you dont just bolt on a straight piece of pipe as the original up pipe on subies comes with a flexy bend in the middle to allow for heat expansion and the constant shifting of the engine due to torque flex.

There is actually a great video on MRT's website if anyone wants to learn about them.

Ben

[WRXONP]

A lot of people run up pipes without flexis - as the manifold is bolted to the engine - and the turbo is braced back to ye engine as well - so when torque rolls the engine over - the turbo / up pipe mOve all as one unit - as does the down pipe

I have personally never seen these up pipes with cats in them - and I've pulled apart Stis - wrxs - legacys - forries and what not and have never ever seen a cat in ye up pipe - have never even seen a pic of one on a single turbo motor

The factory up pipe is good for upto 250 kw and probably more - its not a limiting factor - going to a larger diameter up pipe will only decrease eg velocity

[vorigan]

making the up pipe better great idea, ,making it bigger bad idea

subs already have headers that are too long thus why the factory up pipe isn't that big not much you can do about the header length but controlling the up pipe yes, going any bigger than the turbine inlet size slows flow reduces response even with a bigger exhaust.

[Guest]

arent cats in the up pipe a v7- non sti thing? i bought all my old mitzi parts back off the guy that bought my car and found a stainless dual walled up pipe in it heavy as f*ck bit of a score me thinks.

[Stoffa]

cats in the up pipes is just a USDM thing AFAIK

[reaperblitz]

^^ its mainly a USDM thing. Hence exhaust manufacturors from the States will all say they have them.

In Nz we arent so strict with the regulations so its not so bad.

[Stoffa]

JDM dont have them either. Im only talking about factory subaru up pipes.

[Nakiboy79]

I found a kind of steelo pad wrapped around a cylinder inside my standard up pipe. My car is non-sti GF8. I've noticed faster spool up and more low down torque since the install of the new up pipe. My heat wrap seems to be working well to protect the oil return hose and no more 'sqealing' noises on boost. Stoked. ;D

The rest of my exhaust from turbo back is wide mouth dump into 3 inch stainless straight thru with no cats, sounds sub-lime.

[Pappu1]

yep USDM and AUDM sold new had cats ..

the NZDM sold wrx v7/8 had cat but not sti

and i think from memory v9 onwards all had cats

all jap imports have no cats as JDM models didnt have them

if u got GC8 import then stock wrx/sti should not have cat

[lunchie]

 pappu said:

yep USDM and AUDM sold new had cats ..

the NZDM sold wrx v7/8 had cat but not sti

and i think from memory v9 onwards all had cats

all jap imports have no cats as JDM models didnt have them

if u got GC8 import then stock wrx/sti should not have cat

So in conclusion, YES some NZ wrx's did have cats in the up pipe