since my cross over pipe on my 88 turbo a/t wagon is warpped , could i have made a larger pipe ? and would it improve anything, mpg, power, etc... i have a spare pipe ,

see if you can still get one of these

http://www.ultimatesubaru.org/forum/showthread.php?t=12054&highlight=tech+works+headers

I haven't seen one of these warp by the heads... yet. Usual problem is gaskets... or the very common crack at the turbo mount flange, which is difficult to see due to the heat shielding.

 

Anyways, to answer your original question, I wouldn't go much larger than the original, and certainly not larger than the port diameter. A better blend of left to right sides would help. The orignal pipe has a major restriction about the point where it bends upwards towards the turbo. About a year ago, someone

(IIRC, Rallyruss) did a thread about this and showed the restriction and his pipe that he had built.

ok, thanks will try oem gasket first , also look for crank in pipe

I haven't seen one of these warp by the heads... yet. Usual problem is gaskets... or the very common crack at the turbo mount flange, which is difficult to see due to the heat shielding.

 

Anyways, to answer your original question, I wouldn't go much larger than the original, and certainly not larger than the port diameter. A better blend of left to right sides would help. The orignal pipe has a major restriction about the point where it bends upwards towards the turbo. About a year ago, someone

(IIRC, Rallyruss) did a thread about this and showed the restriction and his pipe that he had built.

yup that was me.

 

I chopped out the old up bend and installed a slightly larger section for the angle up to the turbo(TD04).

 

its had a ton of miles put on it and its one of the few things that has not broken recently.

over all it has worked well.

 

If I were to do it again I would fabricate a 4 bolt flange to help keep gaskets from blowing out

decided to take a look at it again, gaskets is blown out again , in fact i can easily slide a new gasket in , right past the helicoil , also noticed the back side of the timing cover begaining to melt mpg down , + power

What kind of gasket are you using? It should have a metal ring on it to prevent blow outs. Also, you state there is a helicoil in the head, is this tight enough for you to get a good seal?

helicoil is not tight enough , because i can slide a gasket right past it, the gaskets i have been using are napa, or carquest, i had a few with the metal rings, + back side of the timing belt is starting to melt

ordered both sides turbo exhaust gaskets , going to take it my mechanic , he also asked if there was a coolant leak ? is he thinking there might be a a crack in the heads ? what would the exhaust gaskets have to do with the heads ?

Better to ask the mechanic about his question. Too many reasons why he might have asked, and most of them are unrelated to the exhaust gasket area.

if the pipe is warped what would the easy way to fix it ?

if the pipe is warped what would the easy way to fix it ?

Replace it. Should be easy to find a replacement, and the way these are constructed there is no easy fix unless you like cutting and welding... alot. It takes a while just to cut off the heat shielding to get at the tubing.

if the pipe is warped what would the easy way to fix it ?

 

I had a pipe that was warped at the head. The gasket would always leak between the studs. I stripped out the head trying to tighten it, thinking it was still loose. Fixed the threads and just lived with it. When the pipe was down for some other reason I pounded on the ends of the flange where the holes are with a hammer to flatten it out. Seems to work fine.

ok, will find out thursday, update, mechanic can not get to it until monday , sooooooooo may take it to the dealer , heck with it