Normally I don’t cross post but no one in the 997 TT forum was responding.
I've had my 996TT for about 8 years now and I love it. It is my 2nd 911 (1st was an '03 C2). My current car is set up exactly how I want it and I did all the work to get it there myself. I do my own maintenance also so over the years I've gained intimate knowledge of my car and how to take proper care of it. As much as I love it, it's hard not to appreciate the beauty of the 997 body and interior.
My plan is to pick up a clean example of a Mezger engined 997TT and use as some of the parts from my 996TT (specifically the turbos, IC's and meth kit) I know the methanol injection system is compatible as well as the GT2 RS IC's but I do not know if the Alpha 28s I have will fit in place of the stock VGTs on the 997. They are not the Xona models, but the most recent Tial A28s before Xona internals were available and they have very low miles on them so I want to put the k16's and stock injectors/tune back on my 996 before selling it. I'm shooting for 600awhp which is what I have now (rwd).
Anyone who has made a similar upgrade, please share any tips or advice on how to accomplish my goal or whether I should even attempt to replace the stock 997 turbos or just get a tune/exhaust and leave it alone.
I appreciate any advice from the community. Thanks

 

If 600awhp is your goal, you don't even need to upgrade the Turbos on a 997TT. The VGT Turbos have A LOT more headroom than the K16/K24 Turbos on OEM 996TT cars. A good friend of mine has a 7TT that makes mid 600s to the wheels on stock turbos with intercoolers, exhaust, clutch, TB/plenum, and a MAFless E85 tune from Sam.

 

It seems like I've got a lot of research to do. I know the technology and theory behind what makes VGT's have some advantages over fixed geometry turbos but the two things that concern me about them (ok 3) are that they supposedly run very hot, they are physically packaged in the 997 in a way that makes maintenance - specifically changing plugs and coils a far more involved task. Finally, I believe they are simply more complex than necessary considering the advances in traditional turbo design that have taken place in the last decade alone. Let's face it...if there's more $h!t to break, more $h!t will break.
I guess ditching the cat's will help a lot with the heat problem when I replace the exhaust. The sensible thing to do is to leave the VGTs on the car and gain first hand experience with them before spending the time and money required to upgrade.
The 600whp I mentioned would be on 100octane so if I can do that with a tune, exhaust and injectors that would be great.

 

A28's will fit in a 997. You will need a tune for it plus a boost controller. Both turbo's use the same flanges, you may need to re clock the turbos tho.


Tim

 

Definitely decently complex, but they still seem to be reliable. Good move to work in slowly. You'll always have the A28s on standby if you want to toss them on.