Hks Gt3037 Pro S Or Gt2835 Pro S 0.86 Or 0.87 Rear?

[SLYDA]

Hey guys,

Ive read a few posts and seen that a 3037 with a 0.68 will pretty much just light up the tyres comming onto boost, just wondering if this is the same with a GT2835? they still come in a full bolt on kit from hks but are only listed on nengun and rhdjapan as a 0.68. It may be a while before i can afford the engine mods, and when that happens ill probably get a 700HP+ turbo anyway. GTRS from what i have read will seem to run out of puff before i really want it too.. 3037 comes onto boost too late so it seems like the 2835 is the best compomise? anyone got any ideas when a 0.68 rear will come onto boost? i just find it strange HKS would supply this turbo in a kit with this rear if it wasnt the best choice for the car, however i have seen it listed elsewhere (cant remember where with both rears)... ALSO if this does turn into a bit screw up is it possible to change the compressor wheel later? and what could u expect one to cost to change out? thanks in advance

[Devils_Advocate21]

ive got the 3037 pro s in 0.87 format and still fry the tyres 1st 2nd and 3rd

[discopotato03]

Slyda I'm not so sure that the smaller 0.68 A/R version is a "screw up" , don't forget that these turbos can bolt onto an RB20DET as well .

The Garrett/HKS GT3037/GT3076R cartridge is not exactly small and to get it going early requires reasonably small (small side of medium actually) A/R turbine housings . Its interesting that HKS chose this 0.68 A/R size for the smaller of the two integral gate or Pro S type turbine housings . In external gate type HKS chose 0.61 and 0.73 as the lower end of five optional GT30 turbine housing sizes ie 61/73/87/1.01 and 1.12 A/R's . I think its a pity that the smaller Pro S housing wasn't 0.73 A/R because its a size that works well on 2L fours . It probably comes down to the fact that engines with small pots like RB20's take a few more revs (greater exhaust gas velocity) to get a turbo going with med to large turbine housings so the RB20 would have been a bit short changed . I also suspect that in the R32 era lots of petrol heads dreamed of GTR's but the money only stretched to GTST's so the aftermarket had to cater for what people drove .

Anyhow a 0.73 size would have been better IMO on RB25's , users could have got a bit more from 2835's and 3037's before needing a larger rear housing .

HKS should have also offered smaller compressor trims which they do sell with non integral gate turbos . Both the 2835 and 3037 are made with 48/52/56 trim compressors but only sold in 56 comp trim form for Pro S turbos .

Generally the smaller trim compressors work better with the smaller A/R turbine housings IMO , its the way to balance compressor speed against airflow and turbine power requirement and exhaust manifold pressure .

The thing is not everyone wants 440 Hp from a 2835 or 540 from a 3037 so the aftermarket has to make what they think people will be happy with and minimise their own inventory .

To alter (lower) compressor trim size you need the compressor wheel itself and a compressor housing because it will naturally be smaller to suit the wheels smaller inducer size . Garrett don't supply spare wheels - they want to bite you for a complete cartridge if you use yours up or force you towards HKS for their unique sizes . However these wheels have been used in some other Garrett turbos say with other turbines and it can be easier to change the turbine and get what you want that way . An example may be that you want a Garrett GT3071R in 52 comp trim but can't buy it in that form . No prob , you buy a GT2871R in 52 trim and fit a GT30 turbine to it . Can get the 48T comp this way as well .

Some dealers will mix and match new parts to get you what you want straight up . You would have to expect to go through someone that moves lots of turbos and regularly goes inside them for rebuilds and customization . You would not expect a small dealer to make you a bitzer turbo from two and only charge for one - they gotta eat too .

I would also not expect to pay rock bottom prices for one offs and if it cost RRP so be it . Still probably cheaper than a complete HKS unit . Where the buck stops is should you go ahead and do this and it doesn't meet with expectation don't expect anyone to take the fall because its your non std combination .

I think by the sounds of things most are fairly happy with a 2835 Pro S 0.87 A/R on an R33 RB25 , I'm told they pull from a tad higher than std and run out at around 280+ Kw . Different people think differently but I think thats pretty good from a bolt on kit (+ fuel/ECU/IC/exhaust) and more than enough for a road registered R33 realistically . With a bit of headwork and cams a bit over 300 Kw would not be unreasonable .

Cheers A .

[pommey barstard]

Slyda I'm not so sure that the smaller 0.68 A/R version is a "screw up" , don't forget that these turbos can bolt onto an RB20DET as well .

The Garrett/HKS GT3037/GT3076R cartridge is not exactly small and to get it going early requires reasonably small (small side of medium actually) A/R turbine housings . Its interesting that HKS chose this 0.68 A/R size for the smaller of the two integral gate or Pro S type turbine housings . In external gate type HKS chose 0.61 and 0.73 as the lower end of five optional GT30 turbine housing sizes ie 61/73/87/1.01 and 1.12 A/R's . I think its a pity that the smaller Pro S housing wasn't 0.73 A/R because its a size that works well on 2L fours . It probably comes down to the fact that engines with small pots like RB20's take a few more revs (greater exhaust gas velocity) to get a turbo going with med to large turbine housings so the RB20 would have been a bit short changed . I also suspect that in the R32 era lots of petrol heads dreamed of GTR's but the money only stretched to GTST's so the aftermarket had to cater for what people drove .

Anyhow a 0.73 size would have been better IMO on RB25's , users could have got a bit more from 2835's and 3037's before needing a larger rear housing .

HKS should have also offered smaller compressor trims which they do sell with non integral gate turbos . Both the 2835 and 3037 are made with 48/52/56 trim compressors but only sold in 56 comp trim form for Pro S turbos .

Generally the smaller trim compressors work better with the smaller A/R turbine housings IMO , its the way to balance compressor speed against airflow and turbine power requirement and exhaust manifold pressure .

The thing is not everyone wants 440 Hp from a 2835 or 540 from a 3037 so the aftermarket has to make what they think people will be happy with and minimise their own inventory .

To alter (lower) compressor trim size you need the compressor wheel itself and a compressor housing because it will naturally be smaller to suit the wheels smaller inducer size . Garrett don't supply spare wheels - they want to bite you for a complete cartridge if you use yours up or force you towards HKS for their unique sizes . However these wheels have been used in some other Garrett turbos say with other turbines and it can be easier to change the turbine and get what you want that way . An example may be that you want a Garrett GT3071R in 52 comp trim but can't buy it in that form . No prob , you buy a GT2871R in 52 trim and fit a GT30 turbine to it . Can get the 48T comp this way as well .

Some dealers will mix and match new parts to get you what you want straight up . You would have to expect to go through someone that moves lots of turbos and regularly goes inside them for rebuilds and customization . You would not expect a small dealer to make you a bitzer turbo from two and only charge for one - they gotta eat too .

I would also not expect to pay rock bottom prices for one offs and if it cost RRP so be it . Still probably cheaper than a complete HKS unit . Where the buck stops is should you go ahead and do this and it doesn't meet with expectation don't expect anyone to take the fall because its your non std combination .

I think by the sounds of things most are fairly happy with a 2835 Pro S 0.87 A/R on an R33 RB25 , I'm told they pull from a tad higher than std and run out at around 280+ Kw . Different people think differently but I think thats pretty good from a bolt on kit (+ fuel/ECU/IC/exhaust) and more than enough for a road registered R33 realistically . With a bit of headwork and cams a bit over 300 Kw would not be unreasonable .

Cheers A .

i'm running a 2835pro s from nengun with tomie pon cams,q45,700cc injecctors and a pfc running 1bar of boost and i'm getting 346bhp at the wheels the turbo comes on boost at between 2000 and 2500 rpm it's a good setup for fast road driving and does'nt run out of puff plus at 1bar the engine is'nt goint to get stressed so will remain reliable