turbos turbos turbos.....

[Cazisk]

heheh thx heaps SydneyKid, u been a real help mate!

[dojobi]

Actually the main difference between the GTRS and the GT2835R's is the turbine . Both of these turbo's use varying trims (52T - 56T) of the GT35 series compressor which is 71.1mm OD .  

The GTRS uses a 76 trim version of the 53.85mm NS111 turbine in a .64 ARR GT28 turbine housing . The 2835's use a Garrett hybrid turbine that's actually a modified GT30 turbine . These start life as a 60mm UHP (ultra high pressure ratio) turbine which is factory cropped down to 56.6mm OD and is about the turbine size limit of the GT28 exhaust housing - without totally killing the nozzle section . They are made in 84 and 90 trim and have .64 and .86 housings to suit .  

All of this was a bit of a desperate by Garrett to fill the void between the 53.85 and 60mm turbines - in other words too much turbine inlet (back pressure) and not enough shaft torque for the larger trim GT35 compressor wheels . Note that HKS uses the smallest compressor trim (52) in the GTRS with the small turbine . The hybrid turbine is a bit of a dog because the hub section is a bit big (restrictive) and heavy for the length of the blades , GT28 housing really a bit small as well .  

For an engine needing a T3 exhaust flange there are few GT28 housing options ie the .64 from the HKS GT2530 or the expensive .68 and .87 from the 2835 Pro S .  

In my opinion the Garrett GT3071R is a better bet , it uses the non bastardised GT30 turbine with the same GT35 56 trim compressor as the 2835 . If you need an integral waste gate HKS do a T3 flanged .68 and .87 version for their GT3037 Pro S turbos which you can buy seperately . If you look at the Garrett Catalogue PDF it shows the 3071R CHRA and a couple of compressor housing options .  

Cheers  A .

Nice post disco. It'll take me a while to decode all that, but I'm sure it's worth it

Very very slightly off topic, but would you recommend the same setup for a VVTi 1JZ? They're very similar to the RB25 Neo, but just thought I'd confirm. If I did go for an aftermarket turbo, I'd be after a maximum of 250rwkw or so with the least amount of lag possible.

[discopotato03]

I dont know much about the 1JZ but would be interested to find out the bore , stroke and rod centres length .

To explain my preference of the GT3071R . I prefer the closer turbine diameter to compressor diameter match ie 60mm/71mm . Secondly Garrett do .63 , .82, and 1.06 ARR turbine housings for the GT30 turbine which gives you the ability to tailor the velocity of the exhaust gasses through the turbine to suit your boost threshold requiremnents . The larger turbine stands a better chance of developing more shaft torque and less restriction to flow . You can always put a smaller exhaust housing on a big turbine , putting a larger exhaust housing on a small turbine is not the same thing - less restriction , less shaft power to drive the compressor .

Cheers A .

[dojobi]

I couldn't find out the rod centre length, but the bore x stroke is 86.0×71.5.

Thanks for the info on the 3071. I'm a little worried that it would be too big a turbo for what I'd want, though. What's the next size down, but not mismatched?

[dojobi]

Here's a bit more info for you actually - http://babelfish.altavista.com/babelfish/t...r%2F1jz_gte.htm

[discopotato03]

The GT3071R is not really a "large" turbo for 2500cc's , if anything it may not pull a lot of boost at the top of the rev range on an RB25 . On a std engine (injectors , computer , AFM) it should do better than the standard turbo because you loose the very restrictive turbine and housing . The 71.1mm GT35 series compressors are not much if any bigger than the std Hitachi's but the turbine and housing are light years ahead from an aero and gas flow point of view .

Don't be afraid of the number 3071 , all it means is a GT30 series turbine with a 71mm or GT35 series compressor . A lot of confusion exists with the GT (Garrett Technology) Ball Bearing turbo descriptions . The first two numbers describe the turbine wheel by series eg GT28 , GT30 , GT35 , GT40 etc . The second two numbers describe the compressor wheel in either series ie 35 , 37 , 40 or outer (major) diametre ie 71.1mm , 76.2mm , 82mm . The fact that the Garrett re sellers use their own number system mucks it all up . Using the original system the GT3071R should have been called a GT3035R using the wheels series numbers instead of diametre numbers in mm . Garrett also are guilty , their GT30R is really a GT3037R . Off the top of my head I can think of eight different compressor wheels that can be had with the GT30 turbine so arguably they're all GT30 turbos but they don't all do the same thing . The GT3071R has the smallest (but not tiny) compressor option of the GT30 turbine based turbos . Also the "R" on the end stands for rolling element twin ball bearing cartridge or CHRA (Centre Housing Rotating Assembly) .

Whats the next size down from the GT3071R , probably one of the GT2835R series which goes down on turbine size - bad in my opinion . I think the smaller .63ARR exhaust housing on the GT3071R would work better . The power rating on them from memory is 430-450hp at the crank based on compressor flow , a lot of turbos are rated this way with total disregard for turbine flow - or the lack of it .

The big advantage of the GCG Highflow is that its externally identical to standard so one out one in and no expensive one off bits to make it fit . What it dosen't have is current technology wheels and housings though having said that some here have had good results with them . Those "STR" style ball bearing turbos use older type Garrett bush bearing wheels and the big sell was that they're re buildable ball bearing turbos . From what I can tell they use the large trim or Stage 3 TA34 turbine and a late evolution seven bladed T04B 71.1mm compressor wheel (299-4) .

My opinions only , cheers A .

[dojobi]

Thanks for that disco. You've cleared up heaps for me. I never knew there was any actual logic in the numbers. I always just thought they were model numbers.

The reason I asked for the next size down was, as you had guessed - because the number 30 scared me . I have always associated anything above 28 as a lag monster, but your post definitely has set me straight there. You certainly know your turbos inside and out, btw.

Cheers,

Michael

[discopotato03]

To give you some idea the GT30 turbine measures 60 by 55mm and the VLT's T3 turbine 59 by 47mm . HKS make exhaust housings for these (GT30) turbines down to .61ARR in T28 flage most likely for CA18DET's and in .73ARR for SR20DET's . It should be a walk in the park to excite this turbine on an RB2500cc with a Garrett T3 flanged .63 ARR turbine housing , provided the compressor wheel is not of too high a capacity requiring more shaft torque to drive than an adequate one requires . The perfectly sized turbo does not have extra capacity for a bit more urge later on without sizeable compromise - lag . Extra urge means extra gas flow needing less restriction , less restriction as well as less gas flow means lower gas velocity and no turbo or I should say turbine exitation when you want it .

Have to go , threatening looks from she who must be obeyed and me with no emergency chocolate , cheers A .

[Michael Goldspink]

Actually the main difference between the GTRS and the GT2835R's is the turbine . Both of these turbo's use varying trims (52T - 56T) of the GT35 series compressor which is 71.1mm OD .  

The GTRS uses a 76 trim version of the 53.85mm NS111 turbine in a .64 ARR GT28 turbine housing . The 2835's use a Garrett hybrid turbine that's actually a modified GT30 turbine . These start life as a 60mm UHP (ultra high pressure ratio) turbine which is factory cropped down to 56.6mm OD and is about the turbine size limit of the GT28 exhaust housing - without totally killing the nozzle section . They are made in 84 and 90 trim and have .64 and .86 housings to suit .  

All of this was a bit of a desperate by Garrett to fill the void between the 53.85 and 60mm turbines - in other words too much turbine inlet (back pressure) and not enough shaft torque for the larger trim GT35 compressor wheels . Note that HKS uses the smallest compressor trim (52) in the GTRS with the small turbine . The hybrid turbine is a bit of a dog because the hub section is a bit big (restrictive) and heavy for the length of the blades , GT28 housing really a bit small as well .  

For an engine needing a T3 exhaust flange there are few GT28 housing options ie the .64 from the HKS GT2530 or the expensive .68 and .87 from the 2835 Pro S .  

In my opinion the Garrett GT3071R is a better bet , it uses the non bastardised GT30 turbine with the same GT35 56 trim compressor as the 2835 . If you need an integral waste gate HKS do a T3 flanged .68 and .87 version for their GT3037 Pro S turbos which you can buy seperately . If you look at the Garrett Catalogue PDF it shows the 3071R CHRA and a couple of compressor housing options .  

Cheers  A .

Hi,

> Can you please tell me what Garrett turbos I can use to upgrade my 1993

> R32 Nissan skyline GTR Twin turbo that are a direct bolt on fit?. I

> think the car has T28 standard bushed turbos.

> I would prefer turbos with ballbearings flowing 300+ hp each and capable

> of handling 1.2-1.4 bar.

> I have been told from a local mechanic in A.C.T that a GT28r and the

> GT28rs (disco potato) will fit and bolt directly on.

> I have also been told from another mechanic that the GT28r and rs wont

> bolt directly on to a standard skyline and will need certain things

changed.

> Is there a t28 Ball bearing turbo direct fit made?

Can you please recommend what turbos will best suit the engine that come under my budget of $3000..

The engine has just been rebuilt and has forged pistons and the head has been ported flowed.

> I appreciate your time and help.

> Regards

> Michael

>

[discopotato03]

I can't speak from experience what works on an RB26 , I've never driven a GTR or RB26 anything . Garrett does make an RB26 specific GT28R which seems to be identical to the Garrett produced and HKS marketed GT2530 . The easiest way to tell a direct fit RB26 (GT28) based turbo is the two holes on the bottom of the compressor covers to mount the plumbing gadget for water and or oil supply . The compressor outlet from memory has a two bolt flange where most single turbo CA/SR/RB engines have a three bolt flange to connect the ducting . There could be a difference with the dump pipe mounting flange bolt pattern , I could be wrong but the exhaust manifold mounting flange is a little offset from the center line of the housing .

I do know that the GT28RS's as they come are not a direct fit turbo due to minor differences in the exhaust housing and the compressor cover/adapter ring is a size up (T04B instead of T3) . It can be done but not a cheap option .

Prices vary but three grand is tight to supply new and fit , its a lot of work to R/R turbos on a GTR in situ .

Cheers A

[Cazisk]

http://www.hksusa.com/products/?id=1672&rsku=0

GT-RS Turbo

HKS GT-RS - 400 PS Output

COMPRESSOR:

-Wheel- 52 Trim - 51.2 Inducer / 71.1 Major

-Housing- 60 Inlet / 50 Outlet - 0.60 A/R

TURBINE:

-Wheel- 76 Trim - 53.8 Major / 47.0 Exducer

-Housing- GT25 inlet / Internal GT25 outlet; 0.64 A/R

thats from the site above, that rating is atw? or at the flywheel?

[Dale FZ1]

Is there a link available to get the specs of a 3071 directly up against a GT-RS? Are there versions of the 3071 produced by both HKS and Garrett? Also is the 3071 a bolt-on proposition or is there work ($$) to get pipes and flanges to marry up?

Discopotato03 do you consider the 3071 a street or drag-type match to the RB25? For my money I would want any turbo upgrade to keep a low boost threshold and progressive transition to full boost. Achieving a target power output is one part of the equation; driveability/useability is another.

You've sparked my interest in them as a possible fitment, and the discussion to this point has opened questions that I would like to see progressed in this thread.

cheers

[Drkside]

http://www.hksusa.com/products/?id=1672&rsku=0

GT-RS Turbo

HKS GT-RS - 400 PS Output

COMPRESSOR:

-Wheel- 52 Trim - 51.2 Inducer / 71.1 Major

-Housing- 60 Inlet / 50 Outlet - 0.60 A/R

TURBINE:

-Wheel- 76 Trim - 53.8 Major / 47.0 Exducer

-Housing- GT25 inlet / Internal GT25 outlet; 0.64 A/R

thats from the site above, that rating is atw? or at the flywheel?

The 400PS rating is output from the engine (the amount the turbo will flow)

I would be more inclined to check out the Garrett range, GT2871R is identical to the GT-RS but much cheaper, Garrett make the GT-RS for HKS under contract.

Most RB25's running GT28R's and larger GT2871R's put down reliable 260 rwkw providing you have a good tune and all the other bits (cooler, zorst etc) I'm not sure whether you would need bigger injectors - don't know what the neo Rb25s flow

[Sydneykid]

http://www.hksusa.com/products/?id=1672&rsku=0

GT-RS Turbo

HKS GT-RS - 400 PS Output

COMPRESSOR:

-Wheel- 52 Trim - 51.2 Inducer / 71.1 Major

-Housing- 60 Inlet / 50 Outlet - 0.60 A/R

TURBINE:

-Wheel- 76 Trim - 53.8 Major / 47.0 Exducer

-Housing- GT25 inlet / Internal GT25 outlet; 0.64 A/R

thats from the site above, that rating is atw? or at the flywheel?

400 PS = 298 kw - 60 kw losses = 238 rwkw

HKS seem to rate their turbos around 10% conservative, so;

440 PS = 328 kw - 60 kw losses = 268 rwkw

[Abo Bob]

Stock NEO injectors flow less than stock R33 ones.

[Sydneykid]

Stock NEO injectors flow less than stock R33 ones.

Yep, I have heard that the R34GTT injectors aren't 370cc's like the R33GTST injectors. But (there is always a but) on our R34GTT the standard injectors ran out of flow capacity at ~215 rwkw which is pretty much the same as the R33GTST injectors. Maybe the Neo makes better use of its fuel (more efficient) and the injectors are in fact slightly smaller (maybe 360 cc's or 355 cc's). But it isn't much, that's for sure.

[Roy]

...which do you think is better of for occasional track use? i guess i prefer response as to top hp. hmmm......

If its for the street i suppose you want as much response as possible. And if its for the occasional track day you will also want all the response you can get, doa few track days and you will soon see that the last thing you need at the track is power...corner speed and stopping are what make the difference and are also the cheaper and more reliable ways of getting performance for the track:)

[shonen]

Ok sorry to hi-jack.

But while we are on the topic of these two turbos.

Ive been considering a 2835 Pro S myself and after some internal work and port/polish head and cams was hoping to make close to if not a tad over 300rwkw.

With this in mind, I was also planning on getting nismo 550cc injectors and fuel pump

the fuel pump is rated at 4.1L/min. Now my question is, will these items do the job ?

ie will the injectors max out ? or will the fuel pump not flow enough ?

[Sydneykid]

Ok sorry to hi-jack.

But while we are on the topic of these two turbos.

Ive been considering a 2835 Pro S myself and after some internal work and port/polish head and cams was hoping to make close to if not a tad over 300rwkw.

With this in mind, I was also planning on getting nismo 550cc injectors and fuel pump  

the fuel pump is rated at 4.1L/min.  Now my question is, will these items do the job ?

ie will the injectors max out ? or will the fuel pump not flow enough  ?

It's all in the numbers;

300 rwkw + 60 kw losses = 360 kw X 1.34 = 482 bhp

Six 550 cc injectors are capable of ~550 bhp

No problem there

The correct injector rating is 550 cc per minute

6 X 550 = 3.3 litres per minute

So a 4.1 litres per minute fuel pump shouldn't have much of a problem

Hope that helps:cheers:

[shonen]

Thanks SK.

I love it when I get the mathematical answers, puts everything into perspective