Sr20 Turbo Options

[Nissinja]

I've got a GT25/30 which needs reconditioning. I'm dicing up whether to recondition or spend a little more on a GT2872R. I love the performance I've gotten from the GT25/30; the response is great. Is the GT2872R any less responsive and is it a great deal better?

Also, I've been quoted around $800 for the reconditioning on the GT25/30. Is that reasonable? And what should one pay for a GT2872R? I've seen some older adverts offering new ones for around $1,500 which seems quite good value to me.

Response is probably the most important thing for me. I was making a bit over 200rwkw on the GT25/30 which was more than my wheels could handle already. I won't say no to more power though

[GTScotT]

If the 2530 is working well for you then stick with it. HKS put a lot of engineering into those turbos to begin with.

The 2871 will result in a fair amount more lag and pull UP TO 250kw, but no guarantees.

Friends have had 2871 (GTRS) powered SR20s and they honestly werent faster than the 200kw cars running regular T28s or Disco's (2860RS) around the streets. Sure enough from say 5500 and up it made a fair amount more, yet the down low where the SR usually shines was suffering.

SR's make good torque and rip through the rev range, I would want to stick with a turbo that accentuates that character. Your 2530 is probably quite on the mark.

GL

[DVS JEZ]

2872s are the devil. Very badly mismatched turbo. U should get a 3071 .63 t28 flange. Mine made 268kw on 20psi with this turbo on lowmount manifold and nearly everything from stock setup bolts onto it

[wolverine]

2872?

if you are talking GT2876 aka 2540 then perhaps so.

[discopotato03]

If anything SR20's are easy if you want a range of mild turbo upgrades based on the std T25/T28 mounting flange and GT28 turbines .

The GT25/GT28 family works with one of three turbines and the highest performance one is the way to go . Your 2530 has it as does the GT2860RS and the three GT2871R's .

Also that GT2860RS is virtually the same as a 2530 but is compressor wheel is a slightly more modern design .

If you were to follow the GT28 family (having that good turbine) what effectively changes is the compressor wheels - they go up in diameter then trim size so the pumping capacity goes up in steps .

Now the problem with GT2871R's is that in the past everyone bought the largest compressor trim option and real world its a bit of a dog . The compressor options are 48/52/56 trims and I'd avoid the 56T one like the plague .

Note HKS only used the 52T version in their GTRS turbos .

Off the top of my head the GT2860RS's pumping capacity is ~ 36 pounds of air by mass and the 48 trim GT2871R is ~ 39 pounds . The 52T I'd have to look up (search turbobygarrett site) and the 56T is a know problem - don't go there .

I don't have time to discuss turbine housing size right now but will get back in the "early hours" of tomorrow morning - joys of shift work .

Have a think about what sort of rev range you want this engine to work over power spread wise and know where its most usefull to have the torque from boost .

I had a GT2860RS on an FJ20ET in an old Series 1 TRX Bluebird and it was a great setup for me .

More later , cheers A .

[Nissinja]

Thanks guys. The car is a daily so power down lower is better. I also like the kick of quick spooling. My GT25/30 was running at 18psi and made 210rwkw with supporting mods (550s etc.). I was getting plenty of go from around 4k all the way up to the limitor which it hit with no sign of relenting.

There's plenty on the top end after the limitor I can't use which I'd like to trade for more down low if you get what I mean. Pretty happy with it as is though (but happiness is in its pursuit...).

[Harey]

Oh so you want more response they you have already? I think disco has been posting up bigger turbos as the first post didnt really say which way you wanted to go. If you want more response why would you choose a 2871 or bigger? My understanding is the GT2530 is closest to a GT2860RS.

[DVS JEZ]

Wats wrong with ur current turbo?

[Beer Baron]

my pick if you want a little more power and still excellent response? trust T518Z 8cm2. great turbo. on my S13 it makes around 230kw at the rear wheels on 16psi and gives great midrange. they are a well matched turbo to the SR20.

[N1racer]

t517z / t518z both got awsome mid range power. had t517z early last year pull max power all the way to red line

power n response best option would be 2871 with .64 rear.

I had t2 3071r with .64 made 265rwkw on my sr did 11.701 at eastern creek. so highly recomend 3071r.

[STATUS]

GT2871 or T518z + e85 = 270-280rwkw @ 21psi.... super responsive and torquey.... got one (gt2871 small trim) in ATM that rolled out 269rwkw @ 19psi and is real nice to drive and makes rb25 type torque.

[discopotato03]

HKS do a turbo called GTSS but its not the same one used for GTR twins , different wheels and housings both sides .

Its cartridge number from memory is 446179-53 , it uses the same turbine as your GT2530 combined with the compressor and housing found on OE SR20 GT28 turbos . 60.1mm 60T on the cold side .

A .

[Harey]

Surely all these turbo suggestions will be more laggy then his current GT2530 though??

[Nissinja]

Wats wrong with ur current turbo?

Needs a rebuild.

Just thought as it's off the road and I'm spending money anyway, might be a good time to upgrade if there's a better option. From the sound of things though, the GT25/30 sounds like it's pretty spot on though for the most response.

I'm starting to think more low end grunt might come from something like a different cam setup or something. There's definately a VTEC style change of character when the car goes from Dr Jenkyl to Mr Hyde somewhere between 4 and 5k. If only there was a VVTi kit for them or something

[discopotato03]

A lot of that is going to depend upon externals such as a good exhaust and filter/element . The other critical thing is how well its tuned to suit its mods . For example years ago when I changed out a std RB20 turbo for a GT2860RS , and a built T25/FJ manifold , the untuned difference wasn't what I thought it'd be . Once I wound some timing into the thing it made a hell of a difference because the restrictive turbo made the engine ping unless the timing was pulled out .

Specifically to the turbos no the SR20 spec GTSS uses a smaller trim (60 vs 63) compressor so I would expect it to spin up a little earlier than a GT2530 . Just note that a "GT2530" is really a GT2860R and the "25" comes from the fact that HKS was first out of the blocks with the GT25 ball bearing center section twenty odd years ago .

Also HKS appears to use the same T25 flanged GT28 0.64 A/R turbine housing on all SR/CA spec GT2510 GTSS GT2530 GT2540 GTRS turbos . It is their own housing and not supplied by Garrett . It is also different to the ones HKS supplies on RB26 spec GT2510 GTSS GT2530 GT2540 and if they do GTRSs they'd no doubt use this same one .

Often with HKS spec Garrett turbos the difference is a unique engine specific turbine housing and if required a port shrouded compressor housing though they are usually found on six cylinder specific single turbochargers .

Often they had Garrett supply a specific wheel trim or turbine/compressor combination to make their units a better match for a specific engine mostly for response reasons .

For Mr Woolaf yes the turbo Garrett call GT2876R is a super dog , its this same turbine with a 76mm OD 7/7 bladed I think 48T T04S compressor wheel . HKS had an only slightly better thing in their GT2540 with again the same turbine but with a slightly better 48T T04E compressor wheel . The GT2540R was superseded by the much better GT2871R 52T or as HKS calls it GTRS .

It took time for them to realise that too much compressor for a given turbine results in lots of initial lag and when it does get up to speed the marginal turbine and housing choke the top end performance . So the GT2540 became the GTRS and the GT2510 the GTSS , a bit less comp for the RS and more turbine and less comp for the SS .

I dare say HKS worked out that "power and response" meant making boost early to supercharge the engine before it runs out of port and valve area . By not choking the hot side the engines don't tend too fall over too much up high but still rev enough to make boastable Kw numbers .

For me personally torque is everything and if you can make it early you get more shove more often because its accessible in every day driving . To make a big Kw number you need the engine rpm multiplication factor to generate the big number .

A .

[greensa14]

Great post man....very interesting read.

I am running a 2871r 52t in my S14a. Usual bolt ons and making 210rwkw on 15psi. the difference between that and the std t28 was all in the top end obviously. Yes a bit more laggy but nothing too noticable imo.

Mind you i have never been in a 518z equipped car. These things have a great rep for sledge hammer torque in the mid range and top end.

I am one of those weird people that dont mind a bit of lag. I just love that slam you in the back of your seat feeling once boost comes in.

[STATUS]

HKS do a turbo called GTSS but its not the same one used for GTR twins , different wheels and housings both sides .

Its cartridge number from memory is 446179-53 , it uses the same turbine as your GT2530 combined with the compressor and housing found on OE SR20 GT28 turbos . 60.1mm 60T on the cold side .

A .

the gtss makes similar power to a off the shelf s15 t28 ive found give or take 5-8rwkw.

[discopotato03]

Yes they are supposed to be a mild upgrade . The major difference between an OE Nissan spec GT2560R and the SR20 spec GTSS is the turbine wheel , the one in the OE turbo is a 53mm 62T TB25 turbine where the GTSS uses a GT28 53.8mm 76T NS111 turbine . Less and more open blades and a slightly larger OD + 76 vs 62 trim .

At a guess the GTSS should be able to hold a few more degrees of timing but really the design of the engine and its externals have a big say in detonation thresholds - and of course the computers abilities and mapping .

I think for the OP if your GT2530 does everything you like then stay with it . Really in the GT2860R family all thats unique in a "GT2530's" cartridge is the compressor wheel , 63T T3 from memory .

Because the exclusive rights HKS has on Garrett cartridges would be long gone you may be able to order a cartridge through Garrett Japan if all else fails . I think its cartridge number is 446179-21 and will try to confirm tomorrow arvo .

The closest Garrett equivalent as I said is a GT2860RS and regardless of what anyone tells you the one time Garrett production engineer who spec-ed the thing intended it to have the 0.86 A/R turbine housing not the 0.64 A/R one .

SR people often question this but its what JC built for his Mazda Miata/MX5's BP 1800 club car .

As I said I had one on a late for them FJ20ET which has about the same CR as an SR20 but larger bore shorter stroke and longer rods . From memory the ports and valves are larger on FJ's and the OE cams reasonably warm 256 deg ones .

My 2860RS had the larger turbine housing and I didn't find it laggy especially with the timing set to pull up the bottom end and climb into boost . These turbos like a 2530 are responsive and make good torque but roll over up high , I just changed up when it stopped pulling hard and had no problem going faster than is healthy these days . It suited the FJ gearboxes ratios really well .

Anyway your choices are (in the Garret/HKS range) staying with what you have , trying the 0.86 turbine housing , maybe a small or medium comp trim GT2871R .

A .

[Nee-san]

Yes they are supposed to be a mild upgrade . The major difference between an OE Nissan spec GT2560R and the SR20 spec GTSS is the turbine wheel , the one in the OE turbo is a 53mm 62T TB25 turbine where the GTSS uses a GT28 53.8mm 76T NS111 turbine . Less and more open blades and a slightly larger OD + 76 vs 62 trim .

At a guess the GTSS should be able to hold a few more degrees of timing but really the design of the engine and its externals have a big say in detonation thresholds - and of course the computers abilities and mapping .

I think for the OP if your GT2530 does everything you like then stay with it . Really in the GT2860R family all thats unique in a "GT2530's" cartridge is the compressor wheel , 63T T3 from memory .

Because the exclusive rights HKS has on Garrett cartridges would be long gone you may be able to order a cartridge through Garrett Japan if all else fails . I think its cartridge number is 446179-21 and will try to confirm tomorrow arvo .

The closest Garrett equivalent as I said is a GT2860RS and regardless of what anyone tells you the one time Garrett production engineer who spec-ed the thing intended it to have the 0.86 A/R turbine housing not the 0.64 A/R one .

SR people often question this but its what JC built for his Mazda Miata/MX5's BP 1800 club car .

As I said I had one on a late for them FJ20ET which has about the same CR as an SR20 but larger bore shorter stroke and longer rods . From memory the ports and valves are larger on FJ's and the OE cams reasonably warm 256 deg ones .

My 2860RS had the larger turbine housing and I didn't find it laggy especially with the timing set to pull up the bottom end and climb into boost . These turbos like a 2530 are responsive and make good torque but roll over up high , I just changed up when it stopped pulling hard and had no problem going faster than is healthy these days . It suited the FJ gearboxes ratios really well .

Anyway your choices are (in the Garret/HKS range) staying with what you have , trying the 0.86 turbine housing , maybe a small or medium comp trim GT2871R .

A .

Seeing this,

How would you envisage GT2871R 48T in a parallel twins arrangement to perform on an RB26 ?

[hypergear]

The only turbo that I would build for a street driven SR20det would be using a 2871R CHRA or a equivalent ATR28G2 in .64 turbine. GT30 turbine is noticeably laggier unless greater torque is more important. You can machine little bit off the inducer from the comp wheel which would give you bit more power up top.

The GTRS wheel has 9 fins wile the S15 has 11 fins. The difference is larger in inducer and blade gapping. The GT2860RS would produces similar power as a normal T28 with more torque.