GT2871r, .63 or .82 exhaust housing? (or gtx29/30)

[mhiscott]

I have a stock longblock fa20 with a map performance turbo kit. I'm looking to upgrade the Precision 4854 to a better ball bearing turbo.

I'm leaning towards the GT2871r turbo with a t3 4 bolt housing. The exhaust housing is available in .63 and .82. I want the turbo to pull hard to redline, but also spool quickly. I get the feeling even a .82 would spool well on the 2 litre with stock compression ratio, but I'm sort of unsure what would be best.

Looking to make ~ 330 whp max with this setup. I had originally had it in my head to get a GTX30, but it seems a bit large for my application on 91 octane with meth (aquamist hfs4). I was then checking out the new GTX29 but they all seem to have t28 exhaust housing flanges.

[FRS Justin]

Talk to Spencer Fab they has a vast amount of knowledge on this type of setup.


http://www.spencerfabrication.squarespace.com/

[mrk1]

^^^^ This dyno is a GT2860RS with a .86 housing

[mhiscott]

So I have a gt2860rs sitting in my basement from a previous ae86... I figured it would be too small for this application. I should take a look at it and see if it's still in good shape. Talk to me mk1

[SmsAlSuwaidi]

Go with a gtx30 ! I run that with my MAp kit and love it. I've also pushed it to the limit

[mhiscott]

The guy who tunes my car (James/HRI) is also a big fan of the gtx30, but I'm trying to not build the motor. I'd rather long term shoot for a smallblock v8. If I was looking for 400 wheel I'd definitely think about that turbo. I just think it'll be unnecessarily laggy with a goal of only 300 rwhp give or take.

I also run the car for 30 minute sessions at the track and don't want to push my luck on the stock longblock.

What's your current setup smsalsuwaidi? Your build is much more balls to the wall and you have much better fuel available than me IIRC. I'm stuck with 91 and meth.

[mrk1]

Originally Posted by mhiscott

So I have a gt2860rs sitting in my basement from a previous ae86... I figured it would be too small for this application. I should take a look at it and see if it's still in good shape. Talk to me mk1

Yeah its not a big turbo but I love it, the dyno posted was about 12psi on 93 octane. If your not looking to build a motor and stuck with pump gas then its a great choice!

Large AR turbine helps to offset the small turbo.

[mhiscott]

I'm running 11.5-12 now on 91 with the 4854. Looks like I could get same numbers as you on meth easily enough and get the same 300 rwhp. What kind of dyno was that? When do you get full spool? Does it hold peak boost to redline?

I need to go check out my compressor housing and chra to make sure they're good to go. I can get a turnbine housing in t3 4 bolt for 250 bucks. Much cheaper than a new turbo for the time being....

[mhiscott]

And just to be clear yours is a 2860rs not a 2871?

Any videos?

[mrk1]

Originally Posted by mhiscott

I'm running 11.5-12 now on 91 with the 4854. Looks like I could get same numbers as you on meth easily enough and get the same 300 rwhp. What kind of dyno was that? When do you get full spool? Does it hold peak boost to redline?

I need to go check out my compressor housing and chra to make sure they're good to go. I can get a turnbine housing in t3 4 bolt for 250 bucks. Much cheaper than a new turbo for the time being....

That was a Land and Sea Dyno, convert that to Dyno Jet readings would be 335whp.

Peak torque is 4500, full spool is a flawed question as it varies by starting gear, rpm, and speed. I can tell you driving the car if your cruising along and punch it boost is immediate. 12psi is held all the way to redline, all though that is a result of the brilliant eBoost2 boost controller.

Boost is as much a function of the entire setup not just turbo alone. If I ran my car on the dyno with just a 12psi waste gate spring and no electronic control the resulting torque curve would not be as appealing.

[mrk1]

Originally Posted by mhiscott

And just to be clear yours is a 2860rs not a 2871?

Any videos?

GT2860RS also known as the Disco Potato, no videos

[Yoda]

Originally Posted by mrk1

GT2860RS also known as the Disco Potato, no videos

Love that turbo so much.

[mrk1]

Does this count as a video,

https://www.instagram.com/p/-m03IKCX...-by=spencerfab

[mhiscott]

Nice! Yes that's the exact turbo I have. I seem to remember there was some compressor fin damage or something. It's been years since I've looked a the turbo. Will grab some pics of it tomorrow, it's at my parents place.

The video sounds great. I loved the noise that turbo made on my ae86.

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

The above turbine housing would allow me to drop in the gt2860 in the spot where the 4854 is now with little to no changes. A strange note on the atpturbo page though...

T31 (T3) turbine housing with 4 bolt outlet. Fits turbine wheel found on GT28RS, GT2876R (GT25/40R) and all GT2871R turbos. Turbine housing A/R is Garrett T3 .63, or .82 A/R. Turbine flow rating of .63 A/R T31 is comparable to T25 flanged .86 AR.

The turbo currently has a t28 .63 ar housing. Seems they are suggesting the housing size difference between the t3 and t25 is significant even without the AR change.... I suppose I'd still get the .86 AR four bolt t3 housing to achieve similar performance to the v band tial housing you're running? Very nice housing btw. I wish I had went with a vband mani...

Lastly, as far as spool, in third gear from an off throttle roll, would you have full boost by mid 3k rpm?