The Gt2835 Pro S R33 Drive Experience ?

[discopotato03]

Hi all , was going to tack this onto the real GT3071R results thread but sort of OT - sort of .

I mentioned recently that I'd like to look into these cropped turbine GT2835/GT3071R turbos but in a slightly different variation to those sold by Garrett or HKS .

Basically the gap between the GT25/28XX BB turbos and the GT30XX ones is a significant one and it tends to force people to accept limited top end or a trifle limp low end . I think HKS tried to bridge the gap between GT25 and GT30 with their

"GT2835" series which as we know uses a GT30 turbine cropped (clipped in US speak) to an in between diametre ie 56.6mm vs 53.85 and 59.9mm . They screwed it up with their version of this turbo using GT25/GT28 turbine housings because the over boring of these housings stuffs the nozzle section inside them . HKS also does T25/T28 (same) flanged GT30 housings profile machined for these cropped GT30 turbines and they seem to work because internally the housing is designed for the GT30 turbine family . The best news is that they also make the GT Pro (Pro S) turbine housing in T3 flange and IW to suit RB20/25 DET exhaust manifolds .

The general feeling is that these GT2835 Pro S turbos are good for ~ 280+ Kw probably in the larger of the two available A/R sizes - 0.87 A/R , the smaller one is 0.68 A/R .

I've said in the past that I think HKS went a little big on the comp trim size at 56 but thats the only way they sell the 2835 ProS . In other applications they did make the 2835 with both 52 and 48 trim compressor options so the cartridges do exist .

I think if I could find or get one made and locate a HKS 2835 Pro S IW turbine housing it could form the basis of a fairly responsive turbo that would bolt up easily to an R33 GTST . I don't think it would make mega high horsepower but for some its the overall result thats more important than a maximum figure .

I'd probably also think about using a T04B comp housing for the 52T compressor or even the std RB25 one with the 48T wheel because both are more compact than the T04E cover HKS and Garrett use with the 56T wheel .

If a few people with 2835 Pro S's in both 0.68 and 0.87 A/R could let me know how these turbos respond on internally std R33 RB25's I'd appreciate it . If there are any characteristics that people don't like about these turbos that would be good to know too .

Cheers A .

Edited December 7, 2007 by discopotato03

[NYTSKY]

Speak to Eug he has one.

[gtst25]

Hi there,

I've still got my 33 gtst with 2835 .68 housing. The only complaint I've got is the fact the boost drops off after about 5000 rpm. They are pretty responsive - not any need to drop back a gear to overtake unless you're in a hurry. I don't think mine has ever reached it's full potential because of tuning - I'll be playing with datalogit and wideband in a few weeks so that'll be interesting. As for kick it hits pretty hard - it's seen off a couple of gtr's with power fc's and has run a 12.7 with girly 3000rpm launch and wheelspin in 1st 2nd and third. I noticed no difference in power with the addition on pon cams and don't believe they are a great cost/smile factor upgrade. It's making 260kw at the tyres atm - dyno figures are hard to compare - if you set them up to sit on the front roller for a power run generally you'll get about a 15 rwkw+ figure. My runs were done strapped down on both rollers.

Cheers

[STATUS]

Basically the gap between the GT25/28XX BB turbos and the GT30XX ones is a significant one and it tends to force people to accept limited top end or a trifle limp low end . I think HKS tried to bridge the gap between GT25 and GT30 with their

"GT2835" series which as we know uses a GT30 turbine cropped (clipped in US speak) to an in between diametre ie 56.6mm vs 53.85 and 59.9mm . They screwed it up with their version of this turbo using GT25/GT28 turbine housings because the over boring of these housings stuffs the nozzle section inside them . HKS also does T25/T28 (same) flanged GT30 housings profile machined for these cropped GT30 turbines and they seem to work because internally the housing is designed for the GT30 turbine family . The best news is that they also make the GT Pro (Pro S) turbine housing in T3 flange and IW to suit RB20/25 DET exhaust manifolds .

The general feeling is that these GT2835 Pro S turbos are good for ~ 280+ Kw probably in the larger of the two available A/R sizes - 0.87 A/R , the smaller one is 0.68 A/R .

I've said in the past that I think HKS went a little big on the comp trim size at 56 but thats the only way they sell the 2835 ProS . In other applications they did make the 2835 with both 52 and 48 trim compressor options so the cartridges do exist .

I think if I could find or get one made and locate a HKS 2835 Pro S IW turbine housing it could form the basis of a fairly responsive turbo that would bolt up easily to an R33 GTST . I don't think it would make mega high horsepower but for some its the overall result thats more important than a maximum figure .

I'd probably also think about using a T04B comp housing for the 52T compressor or even the std RB25 one with the 48T wheel because both are more compact than the T04E cover HKS and Garrett use with the 56T wheel .

If a few people with 2835 Pro S's in both 0.68 and 0.87 A/R could let me know how these turbos respond on internally std R33 RB25's I'd appreciate it . If there are any characteristics that people don't like about these turbos that would be good to know too .

Cheers A .

i have a comparo on SR20 when i literally did over 2 days back to back testing of a few HKS2835 variants and 2530 and 2540... i will post it up tonight it will give some insight into the way the behave. the best combo was a HKS 2538 56trim .61 on a sr20... too small for a 25 but i reckon a .68 would offer similar sort of RPM vs reponse relationship we were getting good numbers from it at low boost levels.

[Kaido_RR]

i've got gt2835 pros with .68 rim on an rb25det engine is stock unopen. makes 350hp @ 16psi full boost by 3200rpm. the turbo is awesome, lag isn't noticeable on the track, and once its going it just pulls all the way to redline (7300rpm on mine)

i hoping to push close 400rwhp with a retune and 18-20psi

[STATUS]

here is the graph.

[Paul GTS]

Dont know whether you want to know any thing else about my turbo as its pretty close to the GT2835 just a little bit bigger.

It feels insanly quick at 1.2 bar and havent really driven it round much at that setting as its a bit slippery so Ive been using just 0.6 of a bar quite a bit.

It hits this really early around 3,000 and still gives just as much pull as the hybrid did at 1bar. 1.2 bar on this turbo is up by 3700 and really really pulls all the way to 6k, I havent gone any higher yet as I could only do a 4th gear run!

I also love the whistle is makes, sounds like a jet engine spooling up to 1.2 bar!

Would love to try it @ 1.5bar one day!

[STATUS]

^^^ yeah the hybrid turbos are crap used a few one originaly on cats sr20 then another on a r34 gtt... laggy and very doughy and needed a fair bit of boost to make power.