Rb20det With Garett Gt2871r To Laggy?

[Interloper]

Yeah tottally agree with you mate, and not forgetting this is a GTS4 so more losses in the drive train compared to a GTS-T and from what I understand The gtrs is still fairly efficent over 18psi.

I want one!!!

not sure how much drivetrain loss there is as it was run in rwd...i read somewhere that drivetrain loss is about 17% so that would make it 252kw at the flywheel?

the cheapest prices on GTRS kits are on ns.com and nengun.com...

[Interloper]

I had my car tuned at Dr Drifts as well about a fortnight ago. Full 3" zorst, FMIC, fuel pump, GT2871r @ 16psi it made 183rwkw, no cams. This was all through a bit shift kitted VLT auto though...with a manual I would expect it to be slightly higher

Mines a 400hp spec GT2871r

have you got a dyno sheet? be interesting to see the midrange power....is yours the .64 or .86 exhaust housing?

[yogi000]

who cares how much power it makes, how does it drive???? how much boost is used to make that power with the gt-rs

[Roy]

Cool. so lookign forward to swapping keys at DECA. Forget dyno figures see how they drive back to back...plsu Dr Drifts dyno seems pretty lazy. Roll on DECA

[Interloper]

Cool. so lookign forward to swapping keys at DECA. Forget dyno figures see how they drive back to back...plsu Dr Drifts dyno seems pretty lazy. Roll on DECA

would be interesting to see how your set up goes on this dyno...there should be a dyno day at DrDrifts in a few months time......time for a few myths to be busted

[salad]

yeah, i was talkin to sam when he was in adelaide and he used a sorta low reading dyno here and i asked him about it and he said his dyno reads even lower.

and drive trains dont lose a percentage of your total power, they lose a static amount of power (but different amounts in different gears and depends on rim size(weight) etc)

Edited July 27, 2006 by salad

[RNS11Z]

i fitted the 56t version, but slightly bigger front wheel spec (compared to gtrs) gt2871r to my s15. Hoping to get it tuned in the next couple of days. I know its not a rb20 but its still 2l capacity. Im on full boost @ 4000rpm if not earlier. Car keeps pulling all the way. Im hoping for 220rwkw @ 1.2bar

[Interloper]

ok people, here it is a HKS GTRS on a RB20 - 215rwkw using 18psi.

i have put the dyno graph in the Rb20 dyno results thread with all my mods...but here it is anyway:

The blue line is my old R34 GTT highflow turbo, was pretty laggy in comparison...now the difference in response is huge, i now have a 50% increase in power at 110kmh

All comments are welcome!

[Dale FZ1]

A clear demonstration of the benefits of increasing area under the curve, even if the max figure is not greatly changed in percentage terms.

The thing that is prominent to me is the shape of curve difference between 90-120km/h. Gone from concave (ski jump) section, to convex (hump) section. It looks like a big indicator of response, possibly related to the size of the turbine housing (R34 vs HKS)?

The full load dyno curve might show the difference in power, but I get the impression that power is only a small portion of the story. Transient response is where it's at for me!! Proof is in the driving no doubt.

Looks like it was money well spent.

cheers

Dale

[Rolls]

Just out of curiousity what causes the power to drop off after 5700 ish rpm, I thought being a bigger a/r then stock it would allow better flow up top. Or is this just more a characteristic of the head/cams etc?

Either way looks like a very nice upgrade over stock.

[Interloper]

A clear demonstration of the benefits of increasing area under the curve, even if the max figure is not greatly changed in percentage terms.

The thing that is prominent to me is the shape of curve difference between 90-120km/h. Gone from concave (ski jump) section, to convex (hump) section. It looks like a big indicator of response, possibly related to the size of the turbine housing (R34 vs HKS)?

The full load dyno curve might show the difference in power, but I get the impression that power is only a small portion of the story. Transient response is where it's at for me!! Proof is in the driving no doubt.

Looks like it was money well spent.

cheers

Dale

Hey Dale,

your right, the difference is even more noticable when driving, I think full boost is reached about 4100rpm in 4th gear

the R34 housing is visibly bigger than the HKS exhaust housing. If the HKS exhaust housing is .64 then what is the R34 one?

In summary: Definitely money well spent

Rolls Posted Today, 08:54 PM

Just out of curiousity what causes the power to drop off after 5700 ish rpm, I thought being a bigger a/r then stock it would allow better flow up top. Or is this just more a characteristic of the head/cams etc?

Either way looks like a very nice upgrade over stock.

Hey dude, the rpm on the graph was not calibrated so don't go by that, the KM/h are accurate though. So power drops off more like 6400rpm, and i think thats because of the stock cams....maybe someone else can add to this....?

[Cubes]

Just out of curiousity what causes the power to drop off after 5700 ish rpm, I thought being a bigger a/r then stock it would allow better flow up top. Or is this just more a characteristic of the head/cams etc?

Either way looks like a very nice upgrade over stock.

Could be a few things... I would measure manifold pressure before throwing cams etc at it.

Its not only the a/r but also the turbine wheel size that determines exhaust flow ability.

An example of this is the GT30r 1.06 and GT35r .82, the turbine maps both flow roughly the same.

Also.. regarding the power run.... Can I ask why the difference in correction between the two runs. 1.13 vs 2.71. None the less power is roughly the same down low so the different correction values clearly make bugger all difference.

[Cubes]

the R34 housing is visibly bigger than the HKS exhaust housing. If the HKS exhaust housing is .64 then what is the R34 one?

The local turbo dude down here in Adelaide said he's checked a few out and they appear to be a .7 something.

He also mentioned there's no listing of them anywhere so unless he cuts one up its difficult to get an exact measurement. But he was certian they are a .7 something.

The R34 turbine housing is the same as the late model VG30 turbine housing.

[Interloper]

Also.. regarding the power run.... Can I ask why the difference in correction between the two runs. 1.13 vs 2.71. None the less power is roughly the same down low so the different correction values clearly make bugger all difference.

hey cubes,

i have no idea about the correction values on this dyno, maybe because the ambient temperatures between the 2 runs were quite different it compensates for it? as you can see on the chart, that the old turbo run was done on the 3rd Feb so it was a while back...

[Cubes]

Yer either way the off boost power reading is basically the same so nothing to worry about.. Thought I'd ask anyway incase you had some interesting info to share on the correction values.

But yes very nice... Now settle it in for a while then ....... 22 maybe squeeze 24psi in to her.

[salad]

the guy from horsepower in a box told me the stock vg30 (R34) housing is around 0.70, so that would most likely explain the comin onto boost heaps later etc

[Interloper]

the guy from horsepower in a box told me the stock vg30 (R34) housing is around 0.70, so that would most likely explain the comin onto boost heaps later etc

yeah, that would confirm what cubes said, so that explains where most of the lag came from

[Roy]

ok people, here it is a HKS GTRS on a RB20 - 215rwkw using 18psi.

We have a winner. Thw GT-RS . Based on the fact that ppl typically say his dyno reads low, and a quick comparison is...

At 90km/h i have 72rwkws you have 65rwkws.

At 110km/h I have 150rwkws, you have 150rwkws

At 130km/h i have 210rwkws, you have 190rwkws.

At 150km/h i have 234rwkws you have 217rwkws.

At 170km/h i have 235rwkws you have 200rwkws.

So allowing for the fact that his dyno reads low, its looks like the GT-RS tracks about the same as 20G but with more down low....and about the same top end (we are running the same boost)

To me its making the same numbers as my setup without all the agro of manifold and gate...so its a bolt on winner

The only thing that seems to fly in the face of my results is the way the power falls away. Do you run cam gears? I will look at what mine are set to in the morning...lol oh, thats about now. Time to put down the scotch glass and go to bed

[kwazza11]

Yep definately looks like this turbo is a winner, i've got half a power run on 18psi with my 56T GT2871/vg30 due to a blown headgasket and a dodgy dyno operator, but my power readings are very similar up to 130kph with the 2.4l and much bigger exhaust housing.

90kph i have 75rwkw

110kph i have 140rwkw

and 130kph where it was shut down i have 212rwkw

doesnt really look like its slowing down at all on my graph and with 15psi and a rb25 turbine housing before the HG went it made 230rwkw.

it will be interesting to see just how much the vg30 turbine housing and 56t comp wheel opens up the top end.

Edited July 29, 2006 by kwazza11

[Dale FZ1]

Yep definately looks like this turbo is a winner, i've got half a power run on 18psi with my 56T GT2871/vg30

it will be interesting to see just how much the vg30 turbine housing and 56t comp wheel opens up the top end.

I think you have got the difference in characteristics nailed:

top end flow, at the expense of low end/mid range. Depending on what you actually want the car to do, that ski jump mid range can make it tiresome, if exciting to drive.

I agree, it will be interesting to see the extent of the differences. Bear in mind the first upgrade Interloper was running shared the same spec VG30/R34 housing you want to use.

FWIW, I suspect the 56T cartridge is just a little too large for a responsive match to RB25, let alone an RB20. While the RB20/25 spec turbine housing would keep the results biased towards mid range, the larger A/R R34 unit wouldn't allow the assembly to respond quickly. Keen to see your results though.

cheers

Edited July 29, 2006 by Dale FZ1