Dougs951S

Since my Xover is coming off to have a crack welded, I decided I'm going to go T3. What is the diameter of the pipe so I can find a flange with the correct size hole? Also just for the record, the KKK outlet flange is the same as T3, correct, and does anyone know where to source a 3" bolt circle flange that matches the stock triangle style flange on the downpipe outlet? I'm trying to find two, one for the end of the downpipe and one for the cat pipe. Though I suppose If I'm fabbing two whole new pipes, I could use whatever 3" flange was convenient...

Dave W.

The stock K26 flange is almost identical to a T25 flange, the bolt holes just need to be filed out slightly. The crossover pipe diameter is 2". A T3 flange is an odd fit, it takes a little fabrication to make it fit since the edges of the rectangular opening are larger than the crossover pipe size. The 3 bolt downpipe flange is an odd size, too. I looked but didn't find any matching flanges, although Lindsey sells a copper gasket that matches the flange, so they might be able to make one, or just take the gasket to your local fabrication shop and see if they can make a set.

Dougs951S

Couple more questions, I think I'm about to buy a brand new T3 hotside, school me in V-band. I really like the idea of V band in and out flange. I've seen some 3" outlet T3 hotsides but they are labeled for GT turbos, so I'm a bit confused. I'm trying to get a hot side for a t350 (stage 5) wheel that fits a garrett T04 CHRA.

I'm looking at this : http://www.treadstoneperformance.com...rbine+Housings but I think the V bands are 2.5".

or this : http://www.atpturbo.com/mm5/merchant...egory_Code=GTH

Can I get a hotside with 3" v-band in and out? Will it even fit? I found this, but it still has a T3 4 bolt inlet. http://www.agpturbo.com/t3-inlet-3-v...rbine-housing/ Will a hotside for a precision turbo fit a garrett center?

Paulyy

The crossover is not actually 2" it's slightly larger than that. Because the car is german, the pipes are metric, not imperial.

If you notice on my build i posted in the other thread, the extended pipe is flared at the bottom to match the crossover. that pipe i used was 2" and was smaller than the crossover. obviously to get that size i needed to order a whole length of tube which was a waste for me.

Dougs951S

Paulyy, I can get some 16 gauge 2.125" OD tubing, that should have an ID of 2". I imagine that would alleviate me having to flare it? A 4 foot section of it is like 12 dollars. I can get mandrel bends for also around 12 dollars.

I assume your V bands are 2.5" as well?

Paulyy

the vband (tial) was 2" so it worked with my pipes. if it wasn't i would have opened it up with a lathe.

Dougs951S

With the 3" Vband outlet common to all GT turbos, yes?

Dougs951S

Reopening this thread, the build is still under way and the new motor is coming together. I will be starting on the exhaust hopefully in the next 2-3 weeks. The current plan is subject to change depending on clearance issues, but so far it follows thusly:

I will chop off ~9-10" from the turbo inlet flange end of a factory crossover. I will then weld on a slightly flared out 2" to 3" adapter. To that I will weld on a 3" Vband flange. I will bolt a T3 inlet to 3" pipe flange to the turbo, and to that weld on the other 3" Vband flange. All of that is necessary because my hotside has a standard T3 4 bolt inlet and the ~2" crossover pipe is too small to fit the T3 flange; and I want Vband.

For the downpipe, I have a 3" outlet flange (big steel plate with internal wastegate blockoff) matched to my turbo to which I will weld another 3" Vband. Another 3" Vband will join my downpipe to the rest of my 3" exhaust.

Lots of fab, but should be worth it to have Vband on the entire exhaust save for where the headers meet the crossover. If any of you guys have some better suggestions than this or any tips, please chime in. Cheers gents.

V2Rocket

First thought I had after reading that was...

"I wonder if carefully positioning the diameter change 2->3 would allow any sort of pulse tuning at a target RPM"...

Dougs951S

I had the same thoughts, and also concerns that the step change would would have negative consequences, being a closed system and all. The crossover pipe is already too small for an engine making real power, to drop the velocity just before the turbine wouldn't increase flow but could hurt spool up. I would have preferred to step up to 2.25" pipe and 2.25" Vbands; but Vbands only come in 2" or 2.5".

2" presents the aforementioned pipe sizing issues, and nobody makes a T3 4 bolt inlet to 2.5" pipe flange.

The endgame is still the HX35 with 12cm^2 housing. If it ends up being too big, all I do it swap to a smaller T3 hotside.

Pauerman

I would recommend that if you have already considered turbine housings from ATP, you should just pick up a .63 housing already machined to the KKK inlet / outlet bolt specs. I did this with installing a GT30R and it took a little "less" work with just modifying the piping instead of having to deal with fabbing flanges - been there, done that too.

I apologize if this turbine housing option only applies to GT based turbos. GT or GTX based turbos are the way to go anyway.

Black51

If you decide on a GT30, you can use a tial hotside with v-band in and out. The inlet od is 2.125", the outlet is 3". The big issue with the v-band is there are no gaskets. The flanges have to be bang on, or it will leak. Just something to think about.

Dougs951S

Running an HX35 guys in a 12cm^2 dual scroll hotside...similar in size to a .82.

anyone got a link though to those v band tial hotsides? they sound nice, i can make my HX35 fit in one designed for a gt35 turbine.

GJB928

When welding the crossover pipe, keep in mind that it is made of Inconel. Incalloy 800 in my recollection. My best results came from the shop using Inconel 625. I was lucky to find a local shop (40 miles) that does DoD contract work and was familiar with Incalloy fabrication and welding. Repair is holding up nicely.