Small (0.64 a/r) GT2860 dynos or boost datalogs
#4
Former Vendor
iTrader: (31)
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,103
I'd never recommend a .64 2860RS to anyone. Hell, I don't even recommend the .86 2860RS - the 2871R's compressor is so much more versatile and the response difference is negligible.
2560R for <250whp or stock motor
2871R for >250whp or built motor
#5
It's the turbine. You can't flow anything past ~275-280whp through a .64 T25 turbine housing. Look at BEGi's early attempts with the .64a/r 2860RS on the S4 (?) manifold - the power numbers were pathetic.
I'd never recommend a .64 2860RS to anyone. Hell, I don't even recommend the .86 2860RS - the 2871R's compressor is so much more versatile and the response difference is negligible.
2560R for <250whp or stock motor
2871R for >250whp or built motor
I'd never recommend a .64 2860RS to anyone. Hell, I don't even recommend the .86 2860RS - the 2871R's compressor is so much more versatile and the response difference is negligible.
2560R for <250whp or stock motor
2871R for >250whp or built motor
--Ian
#8
Former Vendor
iTrader: (31)
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,103
2876R is an oddball. Massive compressor wheel so it will respond a little slower, but you can't flow 500whp through a T25 turbine so it's not really a good match. Garrett themselves admit this, and it's not a common turbo.
3071R is basically the same turbo as a 2871R, just not as good IMO. The compressor wheels are nearly identical (they ARE identical if you have a 56-trim 2871R), and the turbine uses a slightly larger wheel with the smaller A/R. The larger wheel means less response (high wheel inertia) and you won't make more power than a 2871R since you have a smaller turbine.
The original 3071R had a 60mm turbine with a .63a/r turbine housing, which is basically identical to the 2871R (except with a much larger turbine wheel, which doesn't help transient response).
The 2871R .86a/r is a pretty bitchin' turbo.
Info below for reference:
2871R 52-trim:
Comp: 51.2ind,71.0exd
Turb: 53.9mm, 76trim, .86a/r, 21lb/min peak turbine flow
2876R:
comp: 52.8ind, 76.1exd
turb: 53.9mm, 76trim, .86a/r 21lb/min PTB
3071R 56-trim (T25 turbine)
comp: 53.1ind,71.0exd
turb: 56.5mm, 84trim, .64a/r, 19lb/min ptb
3071R 56-trim (T3 turbine)
comp: 53.1ind, 71.0exd
turb: 60.0mm, 84trim, .63a/r, 20.5lb/min ptb
3076R:
comp: 57.0ind, 76.2exd
turb: 60mm, 84trim, .63a/r, 20.5lb/min ptb
3071R is basically the same turbo as a 2871R, just not as good IMO. The compressor wheels are nearly identical (they ARE identical if you have a 56-trim 2871R), and the turbine uses a slightly larger wheel with the smaller A/R. The larger wheel means less response (high wheel inertia) and you won't make more power than a 2871R since you have a smaller turbine.
The original 3071R had a 60mm turbine with a .63a/r turbine housing, which is basically identical to the 2871R (except with a much larger turbine wheel, which doesn't help transient response).
The 2871R .86a/r is a pretty bitchin' turbo.
Info below for reference:
2871R 52-trim:
Comp: 51.2ind,71.0exd
Turb: 53.9mm, 76trim, .86a/r, 21lb/min peak turbine flow
2876R:
comp: 52.8ind, 76.1exd
turb: 53.9mm, 76trim, .86a/r 21lb/min PTB
3071R 56-trim (T25 turbine)
comp: 53.1ind,71.0exd
turb: 56.5mm, 84trim, .64a/r, 19lb/min ptb
3071R 56-trim (T3 turbine)
comp: 53.1ind, 71.0exd
turb: 60.0mm, 84trim, .63a/r, 20.5lb/min ptb
3076R:
comp: 57.0ind, 76.2exd
turb: 60mm, 84trim, .63a/r, 20.5lb/min ptb
#11
Savington,
You have an absurdflow setup and VVT.
What about us folks with a log manifold and a 95 head?
What if the ultimate goal is never over 250~280whp?
I am in the process of choosing a turbo now for my track only car and had the 2560, 2860, and 2871 in mind. I am leaning towards the 2860 because the 2560 would be working harder, and the 2871 seemed like overkill for my goals.
You have an absurdflow setup and VVT.
What about us folks with a log manifold and a 95 head?
What if the ultimate goal is never over 250~280whp?
I am in the process of choosing a turbo now for my track only car and had the 2560, 2860, and 2871 in mind. I am leaning towards the 2860 because the 2560 would be working harder, and the 2871 seemed like overkill for my goals.
#12
Tour de Franzia
iTrader: (6)
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,085
Total Cats: 375
Savington,
You have an absurdflow setup and VVT.
What about us folks with a log manifold and a 95 head?
What if the ultimate goal is never over 250~280whp?
I am in the process of choosing a turbo now for my track only car and had the 2560, 2860, and 2871 in mind. I am leaning towards the 2860 because the 2560 would be working harder, and the 2871 seemed like overkill for my goals.
You have an absurdflow setup and VVT.
What about us folks with a log manifold and a 95 head?
What if the ultimate goal is never over 250~280whp?
I am in the process of choosing a turbo now for my track only car and had the 2560, 2860, and 2871 in mind. I am leaning towards the 2860 because the 2560 would be working harder, and the 2871 seemed like overkill for my goals.
It surprises me to see how close the 2860rs and 2871 are. I think my turbo on a proper dyno would show a more favorable low rpm output, but not by much. I also have no desire to run more than 280whp at all and these days I'm perfectly happy with 240whp on a Mustang.
#14
mkturbo.com
iTrader: (24)
Join Date: May 2006
Location: Charleston SC
Posts: 15,189
Total Cats: 1,685
Savington,
You have an absurdflow setup and VVT.
What about us folks with a log manifold and a 95 head?
What if the ultimate goal is never over 250~280whp?
I am in the process of choosing a turbo now for my track only car and had the 2560, 2860, and 2871 in mind. I am leaning towards the 2860 because the 2560 would be working harder, and the 2871 seemed like overkill for my goals.
You have an absurdflow setup and VVT.
What about us folks with a log manifold and a 95 head?
What if the ultimate goal is never over 250~280whp?
I am in the process of choosing a turbo now for my track only car and had the 2560, 2860, and 2871 in mind. I am leaning towards the 2860 because the 2560 would be working harder, and the 2871 seemed like overkill for my goals.
I believe Hustler disliked his 2860 on his old Begi log manifold. I do know his spool was a shitton faster when he upgraded to the absurdflow manifold.
#16
Tour de Franzia
iTrader: (6)
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,085
Total Cats: 375
I was pretty happy with what I had. However after going to the tubular manifold, it will be a cold day in hell (which doesn't exist) before I ever own another cast-iron, log manifold for a track car.
#17
Former Vendor
iTrader: (31)
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,103
Savington,
You have an absurdflow setup and VVT.
What about us folks with a log manifold and a 95 head?
What if the ultimate goal is never over 250~280whp?
I am in the process of choosing a turbo now for my track only car and had the 2560, 2860, and 2871 in mind. I am leaning towards the 2860 because the 2560 would be working harder, and the 2871 seemed like overkill for my goals.
You have an absurdflow setup and VVT.
What about us folks with a log manifold and a 95 head?
What if the ultimate goal is never over 250~280whp?
I am in the process of choosing a turbo now for my track only car and had the 2560, 2860, and 2871 in mind. I am leaning towards the 2860 because the 2560 would be working harder, and the 2871 seemed like overkill for my goals.
In the end, you're going to be disappointed with the spool no matter what, because you have a log manifold and a '95 head. I think Trey said he ****** his torque curve back 800rpm switching from a BEGi cast manifold (which is already better than a log manifold) to an AF shortram.
Turbo cars running hot on track is normal for everyone who doesn't own a Trackspeed radiator. :P I struggled with CLT issues until we started developing ours, and now I can do a 20 minute session at 350whp at Willow in 100*F heat without any temp issues, pull into the pits at the end, and then realize that I accidentally left the cooling fan off for the entire session, lol.
#18
Maybe a 2560 is the answer then with my setup if I can reach the 250whp goal with my current manifold/DP. My problem in searching was finding a middle of the road number, most threads I found quoted upper limits like you did above, which I'm not particularly interested in.
To get more on track with the OP and stop totally threadjacking.
I have read several post about the .64 a/r on the 2860 limiting ultimate HP but what about this at a modest power goal?
To get more on track with the OP and stop totally threadjacking.
I have read several post about the .64 a/r on the 2860 limiting ultimate HP but what about this at a modest power goal?
#19
'2560 , tops out at 14.5 lb/min:
Small a/r potato (lower line), tops out at 17 lb/min:
#20
VitaminD, *if* your goal is 250 hp, you will be happy with the '2560 on the street and tight mountain roads. Don't understimate the value of response. My buddy with a 3071 chased me through some tight twisties with me and my 2560. On tight corner exits he said my car would leap ahead and he wouldn't be able to catch up because the straights were short. We both have 6 speeds and 3.9 rears, and were both using 3rd gear. 2nd gear would have been too short for him and the upshift would cost him time.
The 2560 is the perfect match for the stock motor because the latter can't take advantage of the higher boost the bigger turbos shine at. For an all-street car I would argue the 2554 is even better, giving up about 15-20 hp up top (maybe even less than that on an NA head) but generates oodles more torque and response at the bottom which is nice on a street car.
The 2560 is the perfect match for the stock motor because the latter can't take advantage of the higher boost the bigger turbos shine at. For an all-street car I would argue the 2554 is even better, giving up about 15-20 hp up top (maybe even less than that on an NA head) but generates oodles more torque and response at the bottom which is nice on a street car.