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Forum nameTurbo/Nitrous Tech
Topic subject3 inch downpipe for t3/t4 turbo (Star Kit)
Topic URLhttp://forums.2gnt.com/dcboard.php?az=show_topic&forum=8&topic_id=109439
109439, 3 inch downpipe for t3/t4 turbo (Star Kit)
Posted by Sorry_i_Win, Dec-31-69 06:00 PM
I want to purchase or fabricate one but the only 5-bolt turbo flanges I can find are 2.5". Those that have made their own or bought something, please let me know your secret. I've searched the forum extensively and haven't found much. Should I just cut up the Star downpipe (2.75" I believe) and adapt it to 3"?
109442, RE: 3 inch downpipe for t3/t4 turbo (Star Kit)
Posted by 98gs--turbo, Dec-31-69 06:00 PM
Look on Ebay item number "380446256113", You will have to convert it to v band. Also for your tuning go to Greater Pittsburgh Auto Center. To tell you the truth 3" is a little over kill unless you are just running it at the drag. It you have done any internal engine mods your factory ECU wont be able to handle it. What all have you done i will help you in any way i can. Im from PA also i live in Beaver County. Hope this helps you.
109443, RE: 3 inch downpipe for t3/t4 turbo (Star Kit)
Posted by CODE4, Dec-31-69 06:00 PM
There is nothing valid about a factory ECU not "handling" a 3" down pipe.

If you look at his signature his mods are provided.
109444, RE: 3 inch downpipe for t3/t4 turbo (Star Kit)
Posted by 98gs--turbo, Dec-31-69 06:00 PM
My bad. Just trying to help Captain Obvious.
109445, RE: 3 inch downpipe for t3/t4 turbo (Star Kit)
Posted by Sorry_i_Win, Dec-31-69 06:00 PM
Originally posted by 98gs--turbo
Look on Ebay item number "380446256113", You will have to convert it to v band. Also for your tuning go to Greater Pittsburgh Auto Center. To tell you the truth 3" is a little over kill unless you are just running it at the drag. It you have done any internal engine mods your factory ECU wont be able to handle it. What all have you done i will help you in any way i can. Im from PA also i live in Beaver County. Hope this helps you.


Thanks for the ebay item and tuning suggestions. That looks like it should work out okay. I hadn't thought about using v bands though. Has anyone used them? Do they seal well and hold up okay over time? It's a little late to go to anything but 3" now. I already have the flex section, high flow cat, muffler, and electronic cutout in 3".

It looks like you are about 1.5 hours away from me. When I finally get this thing on the road again, maybe we can meet up in Pittsburgh or something (that's about halfway between us). Way back in the day, I went to a few local 2gnt DSM meets in Monroeville but I have no idea who's around us from 2gnt anymore.

I need to update my sig pic to reflect some of the changes that I've made but it's not too far off.
109447, RE: 3 inch downpipe for t3/t4 turbo (Star Kit)
Posted by CODE4, Dec-31-69 06:00 PM
V-band flanges are great performers if you can spare the coin. No gaskets needed and allows play in the angle to line things up.
109473, RE: 3 inch downpipe for t3/t4 turbo (Star Kit)
Posted by justins71, Dec-31-69 06:00 PM
I didn't have much room to use a V-band, but I kept PS & A/C. I kept the original elbow then flared it to 3" right after, when the pipe got vertical. Used a section of braided flex just at the rear of the oil pan, and wrapped the upper section with header wrap. I have a TIAL 38mm though, just with an open dump but there's still room to pipe it in.
109474, RE: 3 inch downpipe for t3/t4 turbo (Star Kit)
Posted by bullettdsm, Dec-31-69 06:00 PM
I did 3" V-band. V-band is considered a better seal/alternative to standard gasket connection.
109475, RE: 3 inch downpipe for t3/t4 turbo (Star Kit)
Posted by Star Turbo Talon, Dec-31-69 06:00 PM
I have made several 3" Star Downpipes. Best easiest way to do it is take a 2.5" 5 bolt flange and weld the 3" pipe to it. there is no value to having a custom 3" flange cut because it will warp very easily and the turbo outlet is still only 2.5".

You can buy a V-band adapter but in reality your still gonna hve to bolt and gasket it to the housing and you start getting very close tot he radiator hose and P/S pump with the 3" bend.

I do recommend a V band coupler right before the 90* that goes under the motor. Makes disassembly and maint that much easier.
109476, RE: 3 inch downpipe for t3/t4 turbo (Star Kit)
Posted by Sorry_i_Win, Dec-31-69 06:00 PM
I bought the 5-bolt flange to v band adapter but it's too tight to fit... hits the wastegate (turbonetics delta). Looks like I will have to cut off the vband flange and weld 3" pipe to it instead.
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