Gt3071r On Rb20

[R31Nismoid]

noone cares about lag when you have a good power range....

this is a rb20, they love to rev so he will be able to rev from 4500-8500

thats like having a rb25 that comes on at 3500-7500

If it makes anywhere near its peak power by 4500rpm i'll be very surprised.

More into the 5000rpm's which is cutting back useable power.

Late RPM does matter in a street car, and plenty of people care about it.

In a track car it doesnt matter. Who wants to have to launch a car @ silly rpm's just to get the thing moving because if you launch sanely you'll wait for power forever.

Good luck Grim32, waiting to see the results as its something no-one has done at this stage it seems

[grim32]

im curious as to why you've chosen such a laggy combination

you don't mind that power will come on so late in the rpm range ?

Because responsive turbos wont make the power i want :confused:

[grim32]

Have the exhaust and wastegate pipes done now, so its time to start putting it all together after a real good clean of the pipes. Got the heat wrap for the manifold and im having a bit of trouble with it but im sure ill work it out. Still a few small things need to be done but im confident ill have it to turn key stage by the weekend.

[grim32]

Well worked on it all weekend and just went for the first drive. It feels great off boost, i didnt drive it to hard but gave it a quick stab here and there, it pulls pretty hard at 4000rpm so im pretty happy with the response but i only reved it to about 5000rpm and cant see why it wont keep pulling right through the rev range. Battery is stuffed in the car so its time for a new one, then off to the dyno this saturday coming at 10am for a tune.

[legend01]

Who's doing the tune ???

[grim32]

Who's doing the tune ???

I have it booked in at Rotamotive for a quick touch up and to make sure everything is right. Then ill take it to a guy that SK told me about that tunes racecars.

[legend01]

Daves good no's his stuff turned mine when i first got it going

[grim32]

Daves good no's his stuff turned mine when i first got it going

Yeah but still want someone else to have a go that knows RB motors just to try for that little bit more.

[grim32]

Ok just had the tune done, the only thing i was a bit disapointed with was the paper saying 203kw, but im not to worried after driving the car. The dyno is known to read quite low. Boost starts at 3000rpm, 15psi by 3500rpm and full boost at 4000rpm, it pulls hard all the way to 7000rpm where the power just starts to drop off. This is running 22psi, at 23 it made 210kw but the GTR injectors were at 98% duty cycle so we backed it off a touch, this shows the turbo isnt at its limits yet.

It gets a bit of wheelspin halfway through first gear and into second, blink and its time for third where it has full traction. Im so happy with how it drives and with the power delivery, it doesnt lag then come on like a switch. I think this is a great turbo for the RB20.

I will take it to the next dyno day to see what power readings it will get but at the end of the day if it still says 203kw ill be happy with it. My tuner said with traction and a ok driver it should run 12.3, 12.4 down the quarter.

[discopotato03]

Congrats on a fine result , many would probably agree that the RB20DET is difficult to get good responsive power from particularly from under ~ 4000 rpm to over 7 .

That GT3071R happens to be a very good match ie 71mm GT35 comp with 60mm GT30 turbine . In theory both the turbine and compressor run out of puff in the 450-480 Hp range (assumes 1.06 exhaust housing) . The turbine would go a little further than the comnpressor which is as it should be . I imagine you are running the .63AR Garrett T3 flanged housing on yours ?

These would be an interesting turbo for RB20's with the 52 trim comp as well (56T is std) , it would be sort of similar to some versions of the HKS GT2835 but with the unmolested GT30 turbine . My orphan opinion is that this is the propper way to go rather than bigger compressor with GT28 turbine ie GT2871R 52T/GT-RS or 56T . A GT3071R would not be difficult to build from a GT2871R in any of the three trims . If a GT30 turbine was exchanged with 2871's GT28 turbine (identical GT25 centre section bearing/housing/shaft dimensions) you end up with the same thing except your choise of compressor . The same thing could be done to a GT3071R WG to fix its woes .

The tune should have made the car feel much better down low than std , the extra timing these can use when un corked should make a marked difference to the low speed torque . Im wondering if it could use the next taller 4.1 final drive to take advantage of the extra torque and give the turbo a little more load to push against .

Before I go the cartridge no. on that turbo should be 700177-23 , if so its a rare bird in Australia - for the moment ....

Cheers Adrian .

[SXC180]

hmm strange you shuld have got more power than that ...

i had a similar setup on my rb20 and got 254rwkw at 19psi with all standard internals etc

[grim32]

Congrats on a fine result , many would probably agree that the RB20DET is difficult to get good responsive power from particularly from under ~ 4000 rpm to over 7 .

That GT3071R happens to be a very good match ie 71mm GT35 comp with 60mm GT30 turbine . In theory both the turbine and compressor run out of puff in the 450-480 Hp range (assumes 1.06 exhaust housing) . The turbine would go a little further than the comnpressor which is as it should be . I imagine you are running the .63AR Garrett T3 flanged housing on yours ?

These would be an interesting turbo for RB20's with the 52 trim comp as well (56T is std) , it would be sort of similar to some versions of the HKS GT2835 but with the unmolested GT30 turbine . My orphan opinion is that this is the propper way to go rather than bigger compressor with GT28 turbine ie GT2871R 52T/GT-RS or 56T . A GT3071R would not be difficult to build from a GT2871R in any of the three trims . If a GT30 turbine was exchanged with 2871's GT28 turbine (identical GT25 centre section bearing/housing/shaft dimensions) you end up with the same thing except your choise of compressor . The same thing could be done to a GT3071R WG to fix its woes .

The tune should have made the car feel much better down low than std , the extra timing these can use when un corked should make a marked difference to the low speed torque . Im wondering if it could use the next taller 4.1 final drive to take advantage of the extra torque and give the turbo a little more load to push against .

Before I go the cartridge no. on that turbo should be 700177-23 , if so its a rare bird in Australia - for the moment ....

Cheers Adrian .

Thanks mate, yeah the cartridge no. is 700177-5023. It would be interesting to change the diff gears to see how it goes but im stoked with how the car runs and responds at the moment so ill leave it alone for now. And yep its a .63ar rear.

[grim32]

hmm strange you shuld have got more power than that ...

i had a similar setup on my rb20 and got 254rwkw at 19psi with all standard internals etc

I did expect to see a bit more power out of it, but at the end of the day its only a piece of paper with a number on it. My tuner said another car that made the same power as mine went to a dyno day and rolled off with 247kw, thats 44kw difference between dynos.

[FATGTS-R]

Do you plan on running down the quarter anytime soon?

Did you look at your new graph compared to your old with T3/T4? They are pretty much identical including the shape of curve which amazed me.

Both your posted results are non shootout mode which is all I can suggest as to why you havent made "dyno" power as expected. You made 190 with a T3/T4 which although there are a million variables the mean average for even the worst dogs of versions is a lot more than 190 when using 22psi. My dyno figure is over 280rwkw with a version of a t3/t4 with 22psi.

So to match the responce with a larger turbo says a lot to me as I have always had my eyes open for a more modern turbo than my 1987 piece of junk but honestly havent seen anything that could possibly match the power of my current one but have an earlier boost threshold. Even Roys trust unit, there is nothing I have seen in ballbearing that buries it in the darkages like is assumed.

I will have a keen eye as to your outcomes grim. Well done for going out on a limb.

[grim32]

I actually just put both graphs side by side, at a quick glance they look the same, but you can see the new one has more torque and power everywhere. Ive got a small clutch fluid leak to fix and then its off to the track.

[Butler]

nice setup, would have expected more power too but i suppose its only a dyno. What sort of manifold and wastegate did u use? Also did you think about running a gt35r with a small exh housing?

[grim32]

nice setup, would have expected more power too but i suppose its only a dyno. What sort of manifold and wastegate did u use? Also did you think about running a gt35r with a small exh housing?

Hi, its just a cheap ebay manifold and a 35mm xspower wastegate, it holds boost well but. I didnt even think about the gt35r when picking the turbo, someone suggested a 30/40 but after 3 months of research and talking to people, and looking through catalogs i just went with the 3071.

[grim32]

Ok i didnt sleep well last night thinking about the car, how could i be maxing out gtr injectors at 203kw when using a good pump 2;1 reg with heaps of pressure unless the afr are all over the place. Just went for a power run on a local dyno that is said to be quite accurate and here are the results.

please comment on afr, would you leave the tune alone and be happy or have it looked at by someone else. The car drives great, little hard to start when hot and uses heaps of fuel.

Thanks guys.

[Roy]

Im no tuner...but i would think the tune could be a bit nicer then that. Im running the same injectors as you, making a bit more power, and im nowhere near the duty cycle your running and i dont have an aftermarket fuel reg.

I know my tune is leaner and still very safe, as i have driven the wheels off the thing on the track and it never pings and is still a healthy engine.

HArder look at the tune me thinks...and also can you give a detailed list of all the mods...What boost is the above plot

[grim32]

walbro pump, malpassi 2:1 reg, gtr injectors

600-300-76 hybrid cooler, k&n pod

high mount manifold, 35mm wastegate, gt3071r turbo

3" turbo back exhaust, no cat, cannon on rear no silencer, 2" wastegate pipe plumbed in just before cat

wolf 3d with ebc

splitfire coils

7 heatrange plugs gapped to .6

when tuned boost was set at 22psi, today it was showing 25psi by the dyno, i havent looked at the gauge when driving for abvious reasons