P,
have you considered A28s? I believe that the power comes on very early with those but not sure if the topend is suitable for your needs. Lots of these on 996s but haven't seen any on 997s.

 

Yes of course Asher, but my hesitation is between 3071/76s, about A28s I'm sure the power band will be a bit too low.
Very good turbos indeed, probably the best for 996TT street use.

 

What I/C are you going to use with the 3071's? the 5"? why don't you test the I/C 1st with your set up?

 

The 5inch are not as good as gen2 I/C's!!!! Bigger is not always better bro! They soak a lot of heat.

 

can you use the .2 I/C with 3071's?

I believe you need aluminum I/C with welded BOV's

 

I will probably bolt the 5" with welded Bovs as I don't want "mushrooms" on my Ypipe, not so discreet!

I have now datalogs from an euro customer showing that 5" are very good at 300kph by 25°c AT. (same IAT as me by 15°c at same speed, both runnning vtgs)
With big turbos, even with equal cooling as 997.2s, better flowing is needed.
So perhap's 997.2's for sale soon!

 

P--If you are still working with TK, I know he has dynos for 996t 3071 vs 3076. 3071 come on about 600 rpm sooner but about 75 hp lower at top end. Not sure for 997t but I would go with 3076 (to add to your confusion).

 

One thing here...you don't mention anything about improvements between BMC and turbo inlets. OEM pipes are rather retrictive in your power level. Thus the compressor can't rotate freely but act as a vacuum pump which also affects the turbine side. There are few solutions for this -not even overly expensive- but unfortunately they -most likely- require engine drop. EvoMS' silicone ones -being flexible- may be installed eithout dropping the whole engine, but you should ask this from them.

 

So ,if i understand well and from what you said , with a bigger ex housing and with 49mm inducer you can go higher and take some more gain..and you can add extruded hoses for better response and a water/meth kit from aquamist ,all this sound very nice..with the alpha/ you will need injectors,boost controller,maybe another y-pipe etc etc...

 

Bump. Any other opinions on 3071 vs 3076? I am now in the same boat, and would like to hear from others. Has anyone gone with one, and switched to the other later?

What is the difference in spool vs power with .63 vs .82 on the 3076?

 

I bought from Sam 3076 with 0,63A/R...

The 0,82 will be more laggy for my opinion...

You have two ways, A28 or A3076.

A3071 gives you the lag of the 30 and not the same power up top.

 

Ok, my choice is done and parts are ordered: AlphaHTA3071R.
Anyway, A3071 can be upgraded by Tial to 76s if needed, but I don't drag nor race (not a lot of challengers here!) and early powerband is really appreciable when road driving. (like A28s in 996TTs)

A3071s and 76s share the same exhaust turbine/housing, only the compressor changes (71 to 76...).
I believe the size of the exhaust side is closer to the GT3076s than to the GT3071s, so I guess the A3071s will spool a bit later than the GT3071s but offer less backpressure, my ennemy for now!
My goal is an efficient powerband from 3500 to 7000, with at least 950Nm/750crankHp, will see soon!
My engine will be rebuilt next winter with Pauters or Carillos and studs for safety, after what perhap's going with an Aquamist to run 1.5/6bar boost and 800hp...

 

Nice
What else have you ordered? I/C? Fender well intake? Injectors?

 

For now I keep my 997.2Ics.
I will run fenderwell while I don't like the idea it sucks Ics' air, but Todd tells me it works very well...
I was prefering Emre's carbon pipes to the stock airbox but it needs to mod the car between the rear wheels and engine bay.
Proto Ypipe is on too.
Todd told me the oem injectors are Ok up to 1.5/6bar (not with E85) and before rebuilding I won't push the boost upper than 1,25bar I guess, anyway logs will tell me...

 

congrats P!

Can't wait to hear what you think about the Alphas. Hopefully you can get some pump gas performance numbers before going all out with meth etc....

How can you use the .2tt i/cs with alphas? I thought you had to weld on the mushrooms (bovs) to the i/cs?