need the help of a turbo "edu-ma-cated" person
 

Knowing that my little disco potatoes will not make my power goals for this car I was sitting down looking over the forced performance upgrade order form and I thought to myself " theres got to be a more cost effective idea than this. 1500$ to upgrade two turbos is pretty steep,(not that I wont pay it if I have too because im not for cutting corners.) so I was doing a little "googling" to find out a couple of things 1. a GT2860rs and a GT2871 are the same turbo and 2 from what I can tell a GT2871 and a GT3071 are the same cartridge just larger compressor and wheel so I guess to get to the point here;

can anyone EDUCATEDLY CONFIRM that it is possible to convert my 2860 to a 3071?

you just need to get the same style housings, so if it has a t04e comp cover and t25 5 bolt turbine housing then make sure to match that.

I didn't figure I would have to change the turbine side just the compressor side of things. That's all forced performance would be doing with the HTA upgrade to my understanding.

well a gt 28 and a gt 30 have two different sized turbines I believe usually the GT XX YY where the XX is the turbine series and YY is the compressor size.

actually a gt2871 is a gt2860 with an 11mm larger compressor, a gt3071 is a larger turbine with the 71mm compressor. so for you to go from gt2860 to gt3071 you would need completely new turbos but if you order them with the correct style housings they will fit.

God I had this alllll messed up. Smfh. Well I guess back to the drawing boards. If I have to buy two new turbos I might as well do the upgrade

Upgrading your GT2860 RS turbo will be cheaper and more cost effective than buy two new turbos. You will end up paying over $1000 easy just for one turbo. Upgrading to the HTA 2868 Billet Wheel with your turbo will pretty much give you the performance of the GT3071 just more efficient because of the billet turbo wheel. The Hp rating for both turbo are pretty much the same ball park 475 each.

Also I don't think you can upgrade your 2860 to a 3071.

the hta turbos require a different compressor cover machined for them so you will get to guess if it fits or not, with the 3071 you can still get the compact gt28 3" housing

Like these here ATP 5bolt 3071

Edit: again make sure to check the box that says "3.00" inlet (Alternate compact housing used on 2871R/28RS) "

I called and personally spoke with HTA and they can indeed machine the housing on the turbo I currently have to ensure fitment. So the GT28RS can be machined to fit the 68mm wheel apparently. At least from what information I received on the phone as I expressed tight fitment concerns.

Well than that is an option for you. What a/r are your turbine housings btw.

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Cliff- I wasn't necessarily looking to buy two new turbos more so looking to see if it was possible to change wheels and compressor covers to increase the HP output of the disco potato. I read Garret's break down backwards the T25 5 bolt turbine housings are interchangeable from the 2871 3071 and 2860RS but it doesn't appear "according to the blueprints" that it's possible for the other side. I will just send the turbos to HTA and leave it at that. Once again I'm not looking to cut corners just seeing if I had other options besides 2: being either buy new turbos for 3000$ OR sent them to FP for 700$ a piece rebuild and 100$ shipping.

.86 slo

I guess my next question is; is it possible on e85 @ 9:1 comp to push these turbos into the 700whp bracket? Or will I flatline at high 600s? I see face glide boast about the turbos being good for 700whp but I don't personally think they'll make it. Difference between myself and you guys is I haven't spent a lot of time assessing compressor maps to see if its possible

Sorry have to edit this I was on my phone and miss read your post E85 and 2860 RS turbos 9:1 compression. I think its going to be hard to hit 700 WHP with the GTM kit. Those turbos will run out of steam at around 17 plus PSI and start blowing hot air. I think it will be hard to hit that number and you should upgrade the turbos while the are out the car.

Well I'm thinking for now I can be happy with 700 wheel though honestly then have the turbos rebuilt with the HTA's this winter and another tune first thing next spring. Then I can go ahead and take care of a few other performance aspect issues ie too small fuel system small turbos and hopefully by then Charles can design his dang intake manifold! I'm hot on him about that thing because I love his work! I'm afraid how much boost can really be forced through these plastic intake manifolds before it will have had too much and begin to separate at the seams. 700 will be a good mid point to get used to rather than going straight from 450 to 800+. I text with tt370z on the regular about his build so I know once my wheels get upgraded ill be good for my goals this thread just pretty much started foolishly as a bang for a buck thread but got me quite a bit more knowledge! Thank you to both you(squeeze) and slow!