a friend of mine works at a service shop.......he said they have a mandrel bender ....I was going to by a turbo back exhaust and a new up pipe.....but I have been doing fabrication work for years and I have enough knowledge that I am going to build my own system.....what I was contemplating is this.....I think I am going to do a full 3" turbo back with 1 highflow cat, what I was wondering is if I should make a 3" up-pipe or go with a 2 1/2".....what does everyone think, 3" or 2 1/2"
I actually think you should go w/ a 2.5" uppipe because you want back pressure before the turbo I think. Do a search on this because I believe there was a discussion about the diameter or an aftermarket uppipe. The turboback should be 3" though. Just my .02
I did a search and not much came up whether or not to go with 3" up-pipe or not.....but I think I will probably go with 2 1/2" up-pipe because a little back pressure is needed to help with turbo spool I think...if I go with to big of up-pipe there will be to much turbo lag for my taste, but 3" may not be to big, anybody else have some input, thanks guys
I completely understand that cats do not give you any horsepower, and I know they are restrictive....the reason for putting on a highflow is to keep it somewhat legal
You do not want a 3" uppipe, nor do you want a 2.5" uppipe. A 3 inch pipe would probably swallow the flange on the manifold. TurboXS uppipe's ID is 45mm, and they claim to have the same ID as the stock turbo. 45mm is roughly 1.75", for those who aren't metric-literate.
Originally posted by T WREX You do not want a 3" uppipe, nor do you want a 2.5" uppipe. A 3 inch pipe would probably swallow the flange on the manifold. TurboXS uppipe's ID is 45mm, and they claim to have the same ID as the stock turbo. 45mm is roughly 1.75", for those who aren't metric-literate.
Yeah and that 1.75'' has been designed to create the optimum flow characteristics. You don't want to change that size over or under stock. Making a bigger/better Turboback is awesome, but don't touch the size of your uppipe.
Are there any uppipes w/ a flex section that are the same diameter (45 mm or 1.75") as stock. I was thinking about the Helix which was 2.25" but now that you guys say I shouldn't change the diameter of the uppipe, I need recommendations. Anybody have any?
EDIT: Actually flex doesn't matter as long as there is a really good chance I won't have a leak. So far the best I have seen are the TXS, Perrin and PDE. Any suggestions on which of those to get or is there something I am missing? And does anybody have the diameter specs of the Perrin and PDE uppipes?
Last edited by IBAUCLAPla : 06-28-2004 at 04:53 PM.
Originally posted by IBAUCLAPla From what I hear yes. About 1/2" too small in diameter
??? That post made my brain hurt.
Having a bigger uppipe will decrease gas velocity, translating to increased lag. The 45mm is designed to be optimal with the stock turbo. Having a bigger ID uppipe would be of benefit with a larger turbo, because it would allow the gas to flow across the larger exhaust wheel evenly, though lag would be increased. If you read the product description on Gruppe-S. com for the helix uppipe, you'll see "2.25" piping diameter - optimal for upgraded turbos".
If I do just a complete 3" turbo back on my 02 wrx, would it be safe to up my boost to 15psi.....right now I would be able to do the turbo back right away and I have in my posession a boost gauge and a MBC....just wondering if I would be safing turning up the boos a little with just the turbo back
The turboback will increase the boost about 1-1.5 psi by itself. You won't need the MBC. But you should hook up a boost gauge if its accurate and you could install the MBC, but if I were you, I would just sell it.
AutoForums.com is the premier network of enthusiast-owned
enthusiast-operated automotive communities.
We operate more than 100 automotive forums where our users consult peers for shopping information and advice, and share
experiences and opinions as a community.
....I was going to by a turbo back exhaust and a new up pipe.....but I have been doing fabrication work for years and I have enough knowledge that I am going to build my own system.....what I was contemplating is this.....I think I am going to do a full 3" turbo back with 1 highflow cat, what I was wondering is if I should make a 3" up-pipe or go with a 2 1/2".....what does everyone think, 3" or 2 1/2" 
Linear Mode
