GT2871R Maps

jebsleo · 02-21-2005, 11:37 PM

Are these maps available? I just purchased a GT2871R .64 a/r.

JayHass · 02-22-2005, 08:43 PM

Quote:

Originally Posted by jebsleo

Are these maps available? I just purchased a GT2871R .64 a/r.

.64 A/R on the exhaust? Um, I wouldn't run that if I were you. The REAL GT2871R uses the NS111 exhaust wheel in the .86 A/R exhaust housing with the 71mm compressor wheel you can find at turbobygarrett.com in the PDF catalog. Look at the GT3071R compressor map. We use a T04E compressor cover with our GT2871R

jebsleo · 02-24-2005, 12:09 PM

Why not? Looks like it would suit my goals just fine. Should hit 200ft/tq @3300 RPM and make upwards of 300rwhp and pull hard to redline. Not like its cousin, the GT28RS.

JayHass · 02-24-2005, 10:10 PM

Quote:

Originally Posted by jebsleo

Why not? Looks like it would suit my goals just fine. Should hit 200ft/tq @3300 RPM and make upwards of 300rwhp and pull hard to redline. Not like its cousin, the GT28RS.

Basically what you just told me is you have a GT28R with a larger compressor wheel. The compressor is not the bottleneck on the GT28R, it's the turbine side. If you have the .64 housing you do not have the NS111 exhaust wheel.

Look at the compressor maps of the 28R and the 28RS...not much more total flow between them but the turbine maps show a LARGE increase on the exhaust side. That is where most of the power gain comes from. The VE of the motor is increased via the exhaust side which translates into HP.

The 2871R with the NS111 wheels is on the edge of being a mismatch between compressor and turbine, putting the smaller exhaust housing and wheel pushes it over that edge. The tip speed are off even more along with other factors. The 28RS is pretty much a perfect match between turbine and compressor which is why it's such a lethal street turbo.

The turbo kit developement we have done with the 28RS have shown full boost by 3000rpm (Full boost being roughly one bar) and hp in the 275-300whp range on 1.8-2.0 liter engines at that one bar boost level. You can push it further and easily get 325whp or a little more if the motor can take the boost. The added flow of the 71mm compressor wheel in the 2871 pushes the envelope a bit further to roughly 375whp and closer to 400whp if pushed as the larger exhaust side can support that without totally choking.

Run what you like, I was just trying to offer some advice as we work with all three turbos on a daily basis and have more data logging and dyno time than I can remember for all of them.

Good luck, feel free to write or call if you have any other questions or we can help you out in some way.

krikra · 02-25-2005, 04:17 PM

Not to hi jack this thread - but Im trying to choose between the GT2871R (0,86A/R) and the GT3071R-WG (0,64A/R) - both will let me keep the stock location and T25 internal WG setup - but finding it hard choose and need a little advice...
Want to hit 400bhp on my pulsar GTIR
Standard manifold (ported/flowed), 3" exhaust, PowerFC PRO, Z32 MAF blow thru, 600cc injectors, standard CR (8.3?)

Dont want silly high boost -Would like to make the 400bhp close to 1bar

Jayhas (or other with much experince in turbos) please advice!!

Enthalpy · 02-25-2005, 05:02 PM

Jay,

once again you and I are in a major disagreement.

which housing you choose on your GT2871R has no bearing on which turbine wheel it comes with. Both versions of the GT2871R have the same CHRA pt. #. thus they both have the NS111 turbine wheel.

Furhter more I disagree with you on the followign points:

1) the .64 housing is able to maintain good flow up to the 360whp mark provided the rest of the engine is set up to properly maintain good high RPM volumetric efficiency.

2) thus the Compressor wheel on the GT28RS is the restriction. only maintaining efficiency to the 33 lb/min region it is a very limited compressor wheel. especially when mated to a .86 turbine side which i have proven to be capable of over 380whp without losses of V.E.

3) good luck seeing 14 psi on a 2.0L engine by 3000 on any .86 housing. most of the time (even on the GTi-R turbo) they dont see full boost until at least 4000 rpm. This is the same debate we had about the GT30R. i dotn know how you guys are measutrign this...but it disagrees with EVERY car i have ever seen in practical application.

with the .64 GT2871R on a SR20 the user should expect 18 psi around 3800-3900 in a street driven vehicle. I have dyno charts to back this up. on several cars both tuned by me and by others.

Jay, as usual i would like to see some of your dyno charts.

JayHass · 02-26-2005, 03:07 AM

Quote:

Originally Posted by Enthalpy

Jay,

once again you and I are in a major disagreement.

which housing you choose on your GT2871R has no bearing on which turbine wheel it comes with. Both versions of the GT2871R have the same CHRA pt. #. thus they both have the NS111 turbine wheel.

Furhter more I disagree with you on the followign points:

1) the .64 housing is able to maintain good flow up to the 360whp mark provided the rest of the engine is set up to properly maintain good high RPM volumetric efficiency.

2) thus the Compressor wheel on the GT28RS is the restriction. only maintaining efficiency to the 33 lb/min region it is a very limited compressor wheel. especially when mated to a .86 turbine side which i have proven to be capable of over 380whp without losses of V.E.

3) good luck seeing 14 psi on a 2.0L engine by 3000 on any .86 housing. most of the time (even on the GTi-R turbo) they dont see full boost until at least 4000 rpm. This is the same debate we had about the GT30R. i dotn know how you guys are measutrign this...but it disagrees with EVERY car i have ever seen in practical application.

with the .64 GT2871R on a SR20 the user should expect 18 psi around 3800-3900 in a street driven vehicle. I have dyno charts to back this up. on several cars both tuned by me and by others.

Jay, as usual i would like to see some of your dyno charts.

It's 3am, I have to catch a flight at 6am...I dont' know where you get your info as it doesn't line up with the rest of the world...well at least the world I play in. Honest.

We never had a debate about the 30R...I posted a video of the car making 10psi by 3200rpm which you said "can't be done".

What it seems to break down to is you seem to build lag monsters and I don't. That's about the sum of it.

I'll reply in more detail when I'm not on a plane to Europe to tune a customers car.

Take care,

Enthalpy · 02-26-2005, 10:04 AM

well i guess we can have ths debate when you get back from europe. but i would really like to see some dyno charts form some of your cars.

and for the record...your video didnt prove anythign to me. that car looked like it made 18 psi around 4600 rpm right where i said it would. you told me you were goign to post a video of a car making 18 psi before 4000 rpm. i told you no way. you posted a video in which the boost gauge needle stopped moving at 4600.

jebsleo · 02-26-2005, 12:28 PM

I've never seen so much inconsistancy in my life between 2 reputable members. Should I have just purchased a GT3071R .64 ? Please let me know asap so I can cancel my order.

Thanks!

discopotato03 · 04-11-2005, 01:15 AM

I'll stand with JHass , the reliable road to turbo power is minimum exhaust restriction . I don't give a rats arse what dyno figures are shown , its extreme exhaust manifold pressure and heat that kills engines far more than warm air out of over reved compressors . You may get 80-100 deg centigrade out of the compressor but how hot are the exhaust temp gasses going to be ?Given the choise I will always run the compressor to the limit rather than the turbine and housing . I see it this way , high turbine inlet pressures lead to reversion on the valve overlap period . If hot exhaust gasses backflow into the chambers all the intercooling in the world wont control charge temperature and detonation . Dyno charts should show ignition timing , AFR and exhaust manifold pressure AS WELL as boost pressure . If the exhaust manifold pressure is going through the roof the turbo is a dog . Turbos like the GT28RS , GT3071R , GT40R were developed for a reason - keep the pressures as close as possible . All we need now is a GT3576R and a GT4082R plus a turbine in between the NS111 and the GT30 . By that I don't mean the 84 and 90 trims of the cut down GT30 at 56.6mm . Enthalpy we've been down this road before , I think you'll find the laws of physics agree with me . Have a sniff around the Grp A GTR's , Nissan went to a lot of trouble to balance exhaust and boost pressures and the GTR blitzed all oposition . I wonder how............................................... .........................................

jp · 04-12-2005, 03:31 PM

Bump...very interesting thread ,and informative.

chimmike · 04-12-2005, 03:39 PM

no need to bump it...it was dead for a reason.