Need A Solid Opinion: Hks Gtrs Vs 3037 Vs 2835?

[gtst25]

Hi there,

There's a couple more differences Dale and my cars had that day. i was moving house and had a bloody heavy filing cabinet full of paperwork and books - I had a sore back lifting it into the car, 20 litre drum of methanol, toolbox, hydraulic jack, rb30 parts ie crank girdle and crank and other parts - the car was full of stuff. When I unloaded it that afternoon it felt zippier that's for sure!

The other thing is rolling resistance and tyre diameter - dad worked it out and the difference is equivlent to me running 3.9:1 diff ratio compared to the standard skyine 4.11's. It's very noticable - driving out of Dale's driveway to the corner you can shift to third in his car, mine it's a second gear affair. His car feels so much better at light loads - my car feels like it's got flat tyres... It goes to show that big wheels aren't that great when all you want is acceleration and traction. Going around corners is a different matter with low profiles though!

Seat of the pants the cars didn't feel that different - I haven't driven Dale's machine with a higher than 6700 rev limit though and that comes up real quick. I don't think you'd want anything bigger on a rb25 though - if you want more I reckon more cubes is the go if you want a bigger turbo. Side by side my car pulls away in third but hit forth and Dale's would overtake. The 3037 certainly has more top end!

My tune isn't the finest - I don't think my water nozzle's big enough on my water meth - best I can do is 18 degrees at full load - afr's in the 11's - if I lean it out I've got to compensate by pulling a degree or two at full load. It's bloody hard to road tune if you're looking for 10 rwkw - I certainly can't tell the difference!

I really like the way the 2835 hits hard around 4000rpm - if I dial in 22psi boost it wheel spins into third. Second is a bit of a waste of rubber - it's a bit silly I spose but lots of fun!

Cheers

Edited May 1, 2008 by gtst25

[sl33py]

Well I got my GTRS in last week and just tracked it at Wakefield, had a ball. I wouldn't want the turbo to come on any later or harder. As it is, it's nice and smooth and (call me a woose) but I'm happy with the 256rwkw I ended up with (stock airbox too) and don't want/need any more GTRS's have made more power for others, but I asked my mechanic for an insanely safe tune and to set things to I don't have to worry about killing the engine AT ALL. Revs are limited to 7.5k. My low boost is set to 12.5PSI giving 240rwkw, high is 16.5 and gives 256rwkw. You're easily doing 110kph before you realise it. It holds traction very well and doesn't wheelspin at all as has been suggested earlier in this thread unless you drop a gear and stomp it on purpose (but I've sorted the suspension and my tyres aren't junk so that helps).

Absolutely lovin' it. Oh, and I just hit 3/4 full on the tank and have done 132kms!

[lcy]

So whats the verdict my friends?

GT-RS or gt28 pro S or gt30?

[discopotato03]

Dale we will have to agree to differ on the turbine housing A/R with GT2835 Pro S's on RB25DET's .

I also once thought that the smaller 0.68 housing was what was needed to get a reasonable boost threshold on an RB25 but from talking to people who started out with the 68 and exchanged it for an 87 I think the 87 is the go .

I think its all about decreasing the restriction on the exhaust side and screwing more ignition advance into it so that the engine can use its heat energy more effectively .

My thinking is more along the lines of making the engine stand on it's own two feet as in not be totally useless off boost , to do this it needs to be able to run advanced timing and clean mixtures . The challenge is to be able to do it with the least exhaust system restriction while having the turbine windmilling fast enough to accelerate quickly when boost is required .

Now Nissan already gives you a decent static CR in RB25DET's so if you can uncork the hot side and screw up the ign advance you should find the light throttle light load torque increase most useful . I think there's a good chance that you could use the water methanol injection (like Mafia does) to keep the timing fairly advanced as the engine climbs into boost (initially) and the torque from advance could blend in with the torque from boost as the revs climb .

As per which turbo , that's going to depend on how much effort and money you wish to put into your car and how much power potential you want it to have .

There's a lot to be said for the GT-RS kits simplicity and ease of fitting , against that the GT Pro turbine housing and dump pipe I think has the most potential of any GT30 integral waste gate system out there .

If I could have anything it would be very likely the 3037 Pro S 68 or 87 turbine housing on a real GT3071R - with the 2835 PS's port shrouded comp cover . Anyone want to sell me a 3037 Pro S turbine housing/dump/2835 PS comp cover ?

My opinions only and I'm not looking for an argument .

Your calls cheers A .

Edited May 1, 2008 by discopotato03

[sl33py]

Yeah mine was chosen for ease of installation, the fact it is 99% street driven in the city and I hate lag, and combined with what the bottom end can handle safely (without any doubt, because I have no intentions of paying for opening it up). Having said that, I'm sure there are people with Garret (/HKS hybrid custom) setups that ended up cheaper than mine. Mine is on boost a bit faster than stock and is only JUST starting to tail off in power when I hit 7k. If you think about the machines Nismo make, ie not the most powerful, but thoroughly designed and relatively easy to drive when compared with some of the big power 'monsters' that are out there, that's the kind of result I went for with my car.

[Dale FZ1]

Dale we will have to agree to differ on the turbine housing A/R with GT2835 Pro S's on RB25DET's .

There's a lot to be said for the GT-RS kits simplicity and ease of fitting , against that the GT Pro turbine housing and dump pipe I think has the most potential of any GT30 integral waste gate system out there .

If I could have anything it would be very likely the 3037 Pro S 68 or 87 turbine housing on a real GT3071R - with the 2835 PS's port shrouded comp cover . Anyone want to sell me a 3037 Pro S turbine housing/dump/2835 PS comp cover ?

The odd thing is that the only recent (relatively speaking) SAU experience with a GT2835 + 0.87 Pro S was from Grepin (where is he these days?). He made the horsepower, but evidently due to slower acceleration rate of the turbine suffered a loss of low-mid range grunt. Result: go back to the 0.68 housing. But that was with a unit that runs the smaller 56.5mm turbine rotor. Not directly comparable to the 60mm unit.

If there is evidence of the “corking” effect of a smaller turbine, it is in Glen’s comment that he can’t run more full load timing than 18 degrees on the map, vs 19 on mine. Remember, I have stock cams, and no WI. The only airflow development comes via external bolt ons, and knock is controlled only via fuel and ignition strategies. Smaller turbine provided extra psi on the gauge, but cams only allowed better cylinder fill and scavenging until the point that the turbine inlet pressure starts to rise. Therein brings the limit of ignition timing.

Compressor wise, it’s been bandied about that a well set up (read: housing specs, pipe work, tuning, and perhaps porting + cams) 2835 or 3071 will produce the same sort of max power level as the 3076 but with a more urgent progression into boost and associated bottom end grunt. From the comments by myself and Glen it’s clear that if tested from 2000rpm, trailing throttle and then 100% throttle, there will be a slight advantage to the 2835 that is soon enough knocked on the head as the rpm rises. Real world stuff along flowing switchbacks where there is a lot less than 100% throttle, there was no apparent advantage. In fact for some reason it felt as though the 3076 was producing slightly more useable torque – ignore the boost gauge, just what the chassis was doing and how the speedo needle moved. But refer back to my experiential view that neither is stand out superior @ 270kW.

For the generally uneconomic process in acquiring a GT30 Pro S housing, it would be difficult to prove or disprove whether the 3071 cartridge would outperform the 3076 if both used the 0.87 housing and 60mm rotor. However I would be happy to try one out if offered the chance. Meanwhile the best approximation we have is the Garrett IW efforts of BHDave and his 0.63 housing with upsized wastegate, and skylinecouple with his 0.82 housing which also has the larger wastegate. Dave has had issues with getting good boost control, while Gary loved his but wanted to upgrade to the 3076 cartridge. The compressor maps tell the story, and basically the GT35 (71mm) requires about 10 -12000rpm extra to provide the same mass flow as the GT37 (76mm). So for overall performance, it’s all about shaft speed, gas speed, and rising turbine inlet pressures.

I have proof in the metal (and mapping) that larger freer breathing turbines allow quite a bit more aggressive ignition timing and result in far better than just “adequate” low – mid rpm performance. My experience suggests that provided boost can be controlled properly, none of those four units (five if you include the HKS 2835 0.68) will be laggy or lacking progressive delivery if tuned properly. But I’ll still back it in that the smaller compressor would be better served by the smaller turbine housing.

Do I take it that we will be seeing / hearing results of the Discopotato03 R33 running with a 3071 with a 0.82 Garrett housing, in the absence of an available HKS Pro S unit? Getting that comp cover surge slotted is not difficult or expensive. We have had discussions going on for 18+ months about what you would like to fit, so when do we get the satisfaction of seeing just what can be achieved from this unit? I’m prepared to help out where possible, and have a dump/front pipe assembly that will sort out the exhaust plumbing at a modest cost. Then you’d only have to be concerned with fabricating the inlet trunking as the major impediment to a bolt in fitment.

Keep us posted.

[BHDave]

hmm, anti surge mod on the 3071 compressor housing now? don't tell me that will be the next issue i encounter......

Out of interest though, if experience shows it doesn't surge, whats the point of the mod. I only ask becasue my stupid thing stuffs a lot of boost in below 3k and i haven't had an issue (yet).

[discopotato03]

No , Dale if I was running a GT30 anything it would use a Pro s housing - meaning if I couldn't find one I wouldn't bother now .

Also if I needed the 280 odd Kw then I'd run the 3037 Pro S too .

It makes me wonder how a GT-RS (HKS housings on a Garrett GT2871R 52T) would go with the cropped GT30 turbine and a GT Pro turbine housing .

It's also interesting that someone got 256 Kw from a GT-RS on an R33 . I'm stuffed if I know how you get 256 Kw's worth of exhaust flow through a 2871R but obviously its possible . I wonder what happens if you also port the head and use Poncams .

I'd like to see the dyno graph of that GT-RS car mainly to see what its torque delivery is like . I know conditions on the day and other variances make a difference but just assuming for a tick that this car and one with a GT Pro turbo were tuned and the numbers come out at 256 and 280 - thats a whole 8.5% .

Dale my goals have changed in the past couple of years since I've owned my R33 , it is the most modern and capable car I've had so far but it is big is heavy and not as agile or economic to run as smaller lighter cars . I am reluctant to sink serious money into a nearly 1400 Kg car because they need serious Hp to have serious squirt . Serious Hp costs money to develop and to feed with garbage grade fuel costing up to $1.50 a liter . If you use 98 oct juice and buy it at the right time with a shopper docket it may cost this or a little more . When its $2+ L and costing $120+ to drive 400-450 K's it's going to start to hurt .

Cheers A .

Edited May 5, 2008 by discopotato03

[Lithium]

I am reluctant to sink serious money into a nearly 1400 Kg car because they need serious Hp to have serious squirt . Serious Hp costs money to develop and to feed with garbage grade fuel costing up to $1.50 a liter . If you use 98 oct juice and buy it at the right time with a shopper docket it may cost this or a little more . When its $2+ L and costing $120+ to drive 400-450 K's it's going to start to hurt .

Most cars are around 1400kg these days, all the EVOs etc have porked up to that kind of weight. There isn't much you can get modern which is much under 1300kg. And in terms of fuel, you just described the state in NZ - 98oct is $2.04 a litre at the moment

[sl33py]

I'd like to see the dyno graph of that GT-RS

Your wish is my command:

My dyno printout

The max power figure shows when he had a hacked up airbox on the engine, but the line just below (much quieter and only 3rwkw less) is how it stands today.

From page 11 of the Rb25 turbo upgrade thread.

There's no torque readout, but it plants me hard in the seat. There's a few other dyno's around here, next time there's a dyno day I might go and ask for a torque readout.

My tuner said he used 'setting 6' on a Dyno Dynamics, and didn't mess with the correction/adjustment figures to make power look big, like some others do. Also said if I go on any other realistic dyno, used properly, I should get the same result +/- 5rwkw depending on the weather and all that. Of course if I get on something happy, he said I'll get way more.

I love the way the power is delivered, very smooth and predictable and it just ramps on the speed. Just out of curiousity, the same mechanic said he could have easily given me 280rwkw, I just asked for safe and easy. He's also tuned a GTRS equipped engine to over 300rwkw (but doesn't recommend it).

Edited May 5, 2008 by sl33py

[Dale FZ1]

I’ve gone through the exercise of running a 2871 hybrid and then moved up to the 3037 Pro S. If you want early torque, and a reasonable spread thereof, the GT-RS will do it in spades. I wouldn’t think it likely that one would reliably (emphasis there) screw much more than 250kW with the GT-RS from an internally standard RB25, though there is evidence that people are getting more. Simply running more boost and tuning it to suit is not the answer if you want 280+kW. The amount of area under the curve for those running well tuned GT-RS, and the number of satisfied owners tells the story – they are a good unit that makes for a quick road car. Ben should feel happy with what his car is delivering.

I’m left scratching my head on a couple of assertions though, given what has been raised over an extended time about what opinions were regarding the optimal unit to actually spend money on. Yes, it means taking the punt that everything adds up, and being confident that you can expect the car to produce its power in a specifically defined manner – and to produce within a reasonably well defined maximum number. For me it’s about the faith in your own research and that you’re not emptying the bank account to try for an unknown result.

Why push the GT3071 as offering the holy grail of RB engine performance – strong power from the bottom end without choking high rpm flow, super fast response, and power potential virtually equal that of a 3076, and then step back from that choice? It may well be the case that the 3071 is the duck’s guts, and I’d just like for another punter other than BHDave and skylinecouple to back themselves and demonstrate what this unit is all about.

Fuel consumption? I’ve kept meticulous fuel records of my own car over 35000+km. Every litre put in the tank has been recorded, and I have actually slightly improved the rate of consumption when running with a stock turbo @ 170kW, to the 3037 @ 270kW. It’s definitely not being driven any slower, though the fuel costs are definitely a real issue if the weekly commuting trip is anything substantial. My arithmetic average is 12.0l/100km and that is not bad by any measure when the performance on tap is considered. FWIW, it does about 450km/week.

The ECR33 is not a race car – fact. That’s what a GTR is all about. Chassis response is not as quick as a lighter weight / shorter wheelbase S13, so not as well suited to many tests of agility. And it doesn’t have the sheer mechanical grip of an Evo, so not a competitor there. But the R33 is a great mid sized Grand Tourer. A damn quick, stable, good handling all-rounder. It will do most things very well and need not cost exorbitant sums to up-spec into something far more potent than the factory provided.

It seems that Garrett have now pretty much got the wastegate capacity sorted with the GT30 housing, and even if it looks a tad agricultural compared to the Pro S, that 0.82 housing seems to work very well indeed. It would be great to be shown the way a streetable RB25 should be uprated by the intelligent selection of parts. Come on…. please consider giving it a run

[Lithium]

Why push the GT3071 as offering the holy grail of RB engine performance – strong power from the bottom end without choking high rpm flow, super fast response, and power potential virtually equal that of a 3076, and then step back from that choice? It may well be the case that the 3071 is the duck’s guts, and I’d just like for another punter other than BHDave and skylinecouple to back themselves and demonstrate what this unit is all about.

This is interesting to me - GT3071R and GT3076R being capable of similar power, cases I have seen at least the GT3071R (at least on our hub dynos) start falling over just above 300kw where the GT3076Rs can start pushing higher than that. You probably need cams to really utilise the higher flow of the 76mm compressor wheel though. I know people have got well into the 350wkw area on hub dynos with them on pump gas, or over 370kw on race gas with the right setup.

[mattysaidso]

Massive grave dig. 

I am currently running a 2835 pro S kit (IW) on my RB25. Looking at upgrading to a 3037 (IW) as it would be a fairly easy swap over and I have enough fuel system to support a bit more HP. 

Can anyone confirm if the HKS 3037 IW shares the same  HKS  5 bolt dump pipe as the 2835? Or is it a different size/shape?

Thanks

Matty

[Dale FZ1]

Is a 3037 Pro S housing actually available these days?

[mattysaidso]

I dont think so, I am looking at a second hand one thats in great nic. 

[Dale FZ1]

59 minutes ago, mattysaidso said:

I am looking at a second hand one thats in great nic. 

If it's all in good order (free rotation, no grinding or end float, no flange warp) and is cheap, you could give it a try.  But I wouldn't bother if it's running a 0.68 A/R turbine.  The bigger 0.87 is what you'd want with that turbo on a RB25.

Definitely nothing inherently wrong with a 3037/3076.