Twin 2871on A Rb26

[frankxinyu]

as topic states, is anyone using twin Garrett GT2871s on their GTRs? if so, how laggy are they? and what kind of power are they putting out?

cheers guys

[frankxinyu]

no one uses them???

they are rated at 400hp each....one size bigger than the 2860s....

[frankxinyu]

bump

anyone has any opinions on this matter?

[stuartr32]

i don't own a gtr but i have one on my s15. if you wan't lag this is your boy lots and lots of lag full boost at 4,000 but in saying that it pulls ll the way to the redline. any questions pm me

stuart

[frankxinyu]

it sounds like a bit laggy...

i might just stick with GT2860s.....

[gun32gtr]

yeh im going either the gtss or gt2860 both make good power,and good response ive heard

[phatsky32r]

yeh im going either the gtss or gt2860 both make good power,and good response ive heard

Im thinkin of doin the same there Gunner i was sweatin on the GT_RS's but from what ive heard the 2871's might be the same laggy but good power from 4grand onwards

[gtr jason]

Hi mate i have them on my gtr and it made 510hp at the wheels on 22psi and 345kw on 17psi at the wheels they come on boost around 3000rpm and make strong power all the way to 8000rpm they work great with the right set up i have all the dyno sheets if you need any more info drop me a line thanks Jason

[RACESPEC]

The 707160-10 Turbos from Garrett have the same specs as the 52 Trim GT2871R (commonly referred to as the GT-RS)

So Garrett have the -10 versions same specs but with housings to suit the GTR

Hope that helps

RACESPEC SALES TEAM

[frankxinyu]

Hi mate i have them on my gtr and it made 510hp at the wheels on 22psi and 345kw on 17psi at the wheels they come on boost around 3000rpm and make strong power all the way to 8000rpm they work great with the right set up i have all the dyno sheets if you need any more info drop me a line thanks Jason

what else have you got in your motor?? stand 2.6L? cams?? see 3000rpm is not too bad...care to share a bit more?? cheers

thanx guys, just i thought this thread was dead

[R31Nismoid]

coming on boost is what? = 1psi, 20psi?

Loaded up on a dyno on 4th or on the street?

There is no way your going to see anything decent before 4500rpm on a stock capacity RB26.

They are 400hp turbos, not 300hp GT-SS or that ballpark turbo

[gtr jason]

14 psi at 3500rpm and then 18psi at 4200 rpm 22psi at 5500 rpm there is no lag this is a race car only and yes there is head work and cams 87mm bore stand stroke

[R31Nismoid]

Again, is that loaded up in 4th on a dyno?

Or are you seeing this sorta thing with a roll-on in 3rd.

Its hard to gauge and compare the two as they are totally different to each other.

Not saying your results are false or whatever, just trying to get an accurate picture

frankxinyu - whats your use for the car?

[gtr jason]

them results are on the dyno in 4th gear on the track it feels even better fell like no lag the car revs very quick so hard to watch both gauges

[gtr jason]

i had 25/40s on it before and it had lag and made less power i have also changed one of the cams that made a big difference

[pnblight]

as topic states, is anyone using twin Garrett GT2871s on their GTRs? if so, how laggy are they? and what kind of power are they putting out?

cheers guys

frankxinyu the garret Gt2871 are basically the HKS GTRS turbo and are quiet common on the rb26 but they have had mixed results. They do make more power than the 707160-5 gt2860r but not by much and the turbo responce loss i believe doesnt out power gain. The best results gained fromt the HKS GTRS/GT2871 have been on stoked rb27/28 or rb30. You find it hard to beat the garret Gt2860R 707160-5 or HKS 2530 for alround twin low mount turbos.

Pete

[N I B]

This is the -5s at only 17psi with basic tune as the injectors are 100% duty so by the time we fit bigger injectors and run 24PSI with a full tune i really cant see the point in looking past these turbos for a dual use car and the price it right. RB26 std stroke and head,260Poncams and single throttle kit on stock intake so the engines not wild,shows how good the turbos are.

Boost controller is now sorted so boost is now earlyer and flatter.

[frankxinyu]

Again, is that loaded up in 4th on a dyno?

Or are you seeing this sorta thing with a roll-on in 3rd.

Its hard to gauge and compare the two as they are totally different to each other.

Not saying your results are false or whatever, just trying to get an accurate picture

frankxinyu - whats your use for the car?

i do wanna maintain the street drivability, but it will see some track days.

by talking to another owner who is running twin GTRS on his stock RB26, these turbos are way too laggy on the street....i think i am going to stick to GT2860s-5

[frankxinyu]

This is the -5s at only 17psi with basic tune as the injectors are 100% duty so by the time we fit bigger injectors and run 24PSI with a full tune i really cant see the point in looking past these turbos for a dual use car and the price it right. RB26 std stroke and head,260Poncams and single throttle kit on stock intake so the engines not wild,shows how good the turbos are.

Boost controller is now sorted so boost is now earlyer and flatter.

thats awesome figure....

the thing is these 2860s are so cheap nowadays.. they are cheaper than the GTSS ones, yet still make more power.....

[discopotato03]

To a large degree the jump from a 60mm to a 71mm compressor is going to affect the boost threshold because you have essentially the same sized turbine and housing with the same exhaust gas velocity trying to spin them up .

Lots of people ask me what is the next step up from the bigger trim 60mm compressors ie 2530's 63T or the high tip height 60mm 62 trim from the GT28RS/2860RS . So next up in Garretts GT range is the 71mm wheels (GT 35 comp series) which my list shows three sizes .

1) 71mm 48T , 49.25 inducer diameter , 4.75 mm tip height .

2) 71mm 52T , 51.20 inducer diametre , 5.00 mm tip height .

3) 71mm 56T , 53.10 inducer diametre , 5.00 mm tip height .

The larger trim and exducer tip height wheels have greater pumping capacity but it comes at a price , moving more air for the same wheel rpm means they need extra power to drive them . If the extra shaft power is not available then we need more engine revs giving more exhaust gas velocity to power the turbine/s . Basically the big trim/tip height wheels with the same turbine force a slip loss effect of the exhaust gasses round the turbine blades . Its a lose lose lose situation because boost threshold goes up , exhaust restriction goes up , detonation threshold comes down - backpressure if you like forces exhaust gas reversal back into the chambers in the overlap phase so charge dilution and preheating as well as pumping losses . All biggies .

Note in (1) above that the 48 trim 71mm wheel has obviously a smaller inducer diametre size AND lower exducer tip height . This is the next incremental step up from the 60mm GT compressors and will generate a bit more airflow (maybe 3-4 lbs) but have the least negative side affects of the three 71mm compressors . I don't think I'd go past this stage if at all on a standard capacity RB26 because its already starting to turn laggy and getting a bit hot and restrictive on the turbine side if really pushed . Probably more to be had from porting and cams with less trade off . 2860's and 2530's seem to be the sweet spot and after that really need larger turbines to compliment the larger compressors . This then really pushes the boost threshold up and increased capacity is the only way to help bring it back down .

Cheers A .

Edited November 10, 2006 by discopotato03