I want to make a 2 1/2" down pipe for a K14 turbo in a mk2.
A couple of questions;
Can I make this out of 16g mandrel bends, SS or mild steel? Tig welded.
Where can I find a ready made flange or do I need to make/have made one?
Yeah, it's a bit confusing... but the T2, T3, and K24 flanges are all the same square 4-bolt pattern... so if you find one you've found them all. I got mine off eBay the last time actually.
The K03 found on early AAZ engines is the only weirdo flange.. sort or a rectangle with room for the wastegate to vent.
I would recommend using 3" for the down pipe, I felt like it has faster spool-up and lower EGT's than the 2.5".
Just my 2 cents.
-JB
Well, it does not add much to the cost of materiels to go 3".
1.57" extra weld per joint
I would assume SS to be the better materiel, unless someone has another opinion?
Would not the total length from the downpipe to the end of the pipe out the rear be shorter on the vanagon because the engine's in the back in comparison to a front engine car?
although, I can't argue with your comparison of no exhaust to exhaust. I just felt that the larger exhaust allowed less back pressure and lowered my EGT's at both cruzing and full throttle.
It is harder to fabricate 3" but in my case I felt it was worth it. (Or maybe I have some miss-guided fixation that bigger is better, lol)
Cheers,
-JB
Biggest is usually not always the best.. bigger yes, but not biggest possible. 2.5 inch is plenty less back pressure then what was there stock. Too big and it will loose velocity going through the tail pipe, and actually be counterproductive. Like a 3inch on a 1.6L engine. little unnecessary, when cummins boys are running 3.5-4.5inch exhausts, and then the motehr of all.. 5inch mandrel bent SS.
2.5inch is more than adequate.