The turbo setup on the 996 and 997 seems pretty similar with many components interchangeable (intercoolers, headers).

On the 996, to put Tial alpha turnos (GT28s or GT30s), it seems that all that is required is different headers, and the BOVs dump to atmosphere. The setups are pretty cheap.

However, for the 997, all the kits I have seen (switzer, protomotive, vivid 800) require much more extensive changes including relocated intakes, custom Y pipes that the BOVs vent to, etc.

What is different about the 997 setup that prevents the 996 kits from working to the intakes and Y pipes and BOV routing would not have to be all changed?

I'm building a track and autocross car and like the spool up and torque curves of the GT28s compared to all the dynos I have seen for modified VTGs (63.5mm and 65mm) but all the extra complexity and price for the 997 kits make them much more than modded VTGs. But the kits to run Tial alphas on a 996 are actually cheaper than modifed VTGs on a 997.

 

who says you do not need the intake piping and coolers, injectors etc? you wouldnt run high boost without these supporting mods.

 

you don't need different headers for the Alpha turbos

 

Doing it correctly the first time requires investing in proper supporting modifications.

 

So you can't just slap a few components together and call it a day, lol?!?

 

I am afraid not Bob, see the example below:

 

I wasn't aware of that. I guess you just need different headers for generic GT28s, not the Tial ones that have a different housing.

I already have a lot of the supporting mods that can run high boost:
1. Carbon fibre works Y-pipe that champion uses on there 68mm VTGs
2. Bigger throttle body
3. IPD plenum
4. EVOMS intercoolers

The question was specifically, if I bought the headers that match the Tail alphas, could they hook up to the stock intake (which can flow enough air for the 68mm VTGs) and do they have to be vented back into a custom Y-pipe or could they be vented to atmosphere?

I'm not looking for peak hp, I am looking for the widest torque curve possible as this is for a track/autocross car.

 

The stock intake plumbing does not flow enough for our P800 package, we tried it, does not work whatsoever, that is why we run fenderwell intakes.

See this:

http://jalopnik.com/5477510/switzer-...ses-no-bucking

 

Alphas are made to be bolt in units, the stock air intakes will work but you will be limiting a lot of flow - I would highly suggest going with aftermarket intake tubes for the turbos

 

OK, thanks. Although I am not looking to make anywhere near the hp of your P800, I'm just looking for a better area under the curve to get lower low-end torque.

I'd be fine with the peak power level equivalent to a VTG 63.6mm or 65mm turbo but with the torque coming on earlier. Based on the "Area under the curve thread" it seems like the GT28s are the best turbo for what I want to achieve on a track/autocross car.

I also dont like the heavy Y-pipes with the wastegates attached to them. I am spending big dollars to move weight from the back end of the car. Car is down to 3080 lbs. I could get it to under 3000, but then I have to start taking weight off the front and I am trying to shift the weight balance to the front.

 

Im thinking of switching over to the Tial GT3071s for my Tiptronic. I just finished the EVOMS775 kit with my fab-speed cold air intake- and the car flows really well on the VTGs now that these inlet pipes are connected to a big Fabspeed dual cone intake. The car is an animal and went through a trans, and even busted seals on my new built trans! I just think that these gt3071 tials will blow away the VTG in every aspect. I will eventually be doing rods/internals because ~700whp should be pushing internal limits...

 

its not so much the HP thats the killer but also the torque numbers

gt3071 will give out some monster #'s

 

Neil,why you are running the stock intake on the P800 996?is it better than 997tt?does it flow enough?