-7/9s Or -5s Garretts

[R.3.2.G.T.R]

that good response for 2530, stocker 26 or stroker?

[discopotato03]

Just for the record RB26 specific HKS GT2530's are not the same as -5s , the cartridge is very similar BUT the compressor wheel is different - 60.1mm 63 trim .

Sorry for the boring history lesson but .

Garrett developed the compact ball bearing center section and based its bearing housing around their T25 bearing housing . This is why those ball bearing center sections were/are known as the GT25 BB center section . Its in all of them from the current smallest GT2554R to the largest (in that frame size) GT3582R .

Now back in the late 80's when Garrett were developing these things they initially used the TB25 turbine and a bit later in the GT (Garrett Technology) era their GT28 turbine wheel . Now at that stage they called all these turbos using the GT25 BB center section with TB25 or GT28 turbines GT25xxR turbos ie GT2530 . Often HKS cut the "R" off the end , all the R means is rolling element or ball bearings .

Later on Garrett chose to change their numbering system to reflect the difference between the TB25 and GT28 turbine based turbochargers . Note here that the TB25 turbine was only offered in 62 trim where the GT28 turbine can be 62 or 76 trim . If you look at the "turbobygarrett" web site and specifically these "GT"25 and GT28 based ball bearing turbos look closer at the turbine wheel diameter and trim numbers . From memory the TB25 turbine is 53mm where the GT28 ones are ~ 53.8mm diameter . Its easy to confuse the TB25 turbine in 62 trim and the GT28 turbine in 62 trim because looking at the numbers its only that sneaky extra 0.8mm that's different and if you don't have the turbos or pictures up the butt of them its easy to miss it . BUT , they are very different turbines and do different things . All else being the same the TB25 one will be more responsive if a tad more restrictive but in OE apps it works quite well .

Garrett uses the 62 trim GT28 turbines in turbos like the GT2854R/GT2859R/GT2860R (707160-7) . Their intention was to have a slightly lighter (9 blades vs 11) more open bladed turbine so they could trade a small amount of turbine response for a bit less exhaust gas restriction through the system . Its the way to give up a bit right down low to make a bit more power through the mid range and top end - remember everything's a compromise .

Everyone seems to be talking about the 707160-9 turbo or in HKS speak the RB26 specific "GTSS" .

A lot of smarts in these turbos , they are designed to start a bit earlier than the R32 spec GT28 bush bearing turbos and have a bit more flow potential once the engines loaded up . If you look at their specs they are ALMOST the same as the 707160-7 turbos . Look closer at the compressor wheel diameters and trim sizes , the -7 is from memory 60.1mm 55 trim where the -9 is 59.6mm 56 trim . Then look at the compressor maps , big difference and given a choice I'd always take the -9 version .

This is what happens when a turbocharger manufacturer puts more effort into developing a given turbo to match a specific engine and performance ask . Everything in these -9 turbos is Garret and unlike some other turbos developed by Garrett for HKS there are no HKS custom housings that Garrett won't supply . The result is you can buy a Garrett turbo for a Garret price and miss the "HKS" tax at the register .

Now to the larger 76 trim version of Garrett's GT28 turbine . Its the one used in the HKS spec Garrett GT"2530"/GT"2540" and Garrett's own marketed GT2860R 707160-5 and GT2860R 739548-1/-5/-9 and all the GT2871R turbos inc the HKS spec GTRS . Also in the HKS spec SR20 version of the GTSS which has the GT28 76T turbine with the 60.1 mm 60T compressor found in OE SR20 turbos . Its hard to find cartridge no is 446179-53 .

When you use the larger 76 trim GT28 turbine based turbos twinned on a std capacity RB26 you will lose a lot of the bottom end that nice turbo street cars have . Its the payoff for having turbines (x2) large enough to generate 600+ crank Hp with . The trouble is that if for what ever reasons you don't run them up near that power level then the turbine lag you put up with is basically all for shit . You have to decide if you can put up with an engine that wants to haul from 3500-4000 revs and not be anything special up to maybe the mid 3000's . To me that's an unacceptable compromise in a 1480 Kg Skyline if its used 99% of the time on public roads . I think if it were me I'd want to feel some useful torque maybe from 3000 up and if it nosed over around 7 I wouldn't feel short changed . I couldn't hack a heavy car that wouldn't go much under 3500 , turbos stuck in angel gear mate ?

But anyhow that's me and I'm not a GTR person , if I had been it would have been conservative R34 BB turbos or those 707160-9/GTSS ones .

To complete the story the HKS spec GT2510 has the TB25 turbine (54mm 62T) teamed up with the 60.1mm 63 trim compressor from their GT2530 . Basically a 2530 without its GT28 76T turbine .

Clear as mud ?

Cheers A .

[Count Grantleyish]

Hi all,

Couple of people have PM'd me asking me to put up the dyno sheet.

R33 GT-R.

HKS GT-SS

Apexi Power FC

HKS 3" front pipe

3" Gutted cat

3.5" HKS cat-back exhaust

HKS pod filters

302rwkw at 18.6psi (controlled by HKS actuators, no boost controller).

I reckon I could go further, just need fuel pump, injectors, Nismo AFM and boost controller.

Hope these are much of a help in your turbo selection.

[Ten Four]

Non-stroked.

Sydney Kid RB26 build

8.8 to 1 compression ratio

ACL 86mm Forged pistons

Eagle H Beam forged rods

ARP Rod Bolts

ACL rings

ARP head studs

ARP main bearing studs

600HP Head work

Stainless Steel Exhaust Valves

Adjustable Cam Gears (set to standard at the moment)

Balanced rotating mass

Sump Extension - Extra few Litres with full baffles

HKS 2530 Turbos

700cc 12A Turbo Injectors <Were maxed, so new ones put in, unsure what, I don't own the car anymore)

80mm AFM's

Apexi Power FC with Hand Controller

Apexi AVCR Electronic Boost Controller

K&N Pod Filters

HKS Billet Flywheel

HKS Twin plate rebuilt by Jim Berry

Full Redline Racing oils except engine, which has Royal purple changed on the 26/3/2010.

Ceramic coated exhaust manifolds, turbine housing, dump pipes and Y pipes (Big $$!!)

Bosch 044 Race Fuel Pump

N1 oil pump

New cambelt pulleys

Wide oil pump drive flange

Oil flow restrictors

New Cambelt

Block O’rings

New Exhaust - 4" I believe.

New Radiator

Iridium Plugs

[R.3.2.G.T.R]

Hi all,

Couple of people have PM'd me asking me to put up the dyno sheet.

R33 GT-R.

HKS GT-SS

Apexi Power FC

HKS 3" front pipe

3" Gutted cat

3.5" HKS cat-back exhaust

HKS pod filters

302rwkw at 18.6psi (controlled by HKS actuators, no boost controller).

I reckon I could go further, just need fuel pump, injectors, Nismo AFM and boost controller.

Hope these are much of a help in your turbo selection.

thanks mate, i assume ur hks actuators where the heavy duty variety

[Nee-san]

Their intention was to have a slightly lighter (9 blades vs 11) more open bladed turbine so they could trade a small amount of turbine response for a bit less exhaust gas restriction through the system . Its the way to give up a bit right down low to make a bit more power through the mid range and top end - remember everything's a compromise .

Hey Disco,

What relationship is there between blade number and I'm assuming higher usuable surface area and the actual weight and therefore inertia of the turbine wheel ?

Will removing blades result in a decreased angle of attack as each blade surface would be larger for a given turbine size ? and is this the reason for the increase in output as opposed to an arrangement of smaller more agressive blades and profiles or is actual overall wheel inertia the limiting factor certainly in response ?

[Count Grantleyish]

thanks mate, i assume ur hks actuators where the heavy duty variety

Yep they are heavy duty (part of kit).

Still need more power though!

[J - Rad]

I need help.

I was sold on the gt-ss/-9 until I got some priced up at $2,900 with actuators. Now I can get the -5 for $2,500.

Car is a daily driven 120,000km 32R running 9psi with front pipe,catback and pods. I've bought cam gears, 040 and eboost street to go in with the turbos.

Now. The car will be driven to and from work everyday and might see the track on the off chance at Mallala. Car won't be boosted (probably 14psi) but will have a high boost setting for some fun when I need it. Goal is to hopefully crack the 300 mark on higher boost but still make 260ish for the daily duties.

Should I spend the extra and go with the responsive turbo or save money and go for one than has some in reserve for when/if I want more and spend the money left over trying to bring the lag down?

Could I get the -5s to be as responsive as the -9?

[silva33]

Yep they are heavy duty (part of kit).

Still need more power though!

How does it drive compared to the stock turbos? I am considering -9's for my 34

What is your duty cycle for the injectors? i am guessing they are maxed out?

What clutch are you running?

Thanks

[Harey]

I need help.

I was sold on the gt-ss/-9 until I got some priced up at $2,900 with actuators. Now I can get the -5 for $2,500.

Car is a daily driven 120,000km 32R running 9psi with front pipe,catback and pods. I've bought cam gears, 040 and eboost street to go in with the turbos.

Now. The car will be driven to and from work everyday and might see the track on the off chance at Mallala. Car won't be boosted (probably 14psi) but will have a high boost setting for some fun when I need it. Goal is to hopefully crack the 300 mark on higher boost but still make 260ish for the daily duties.

Should I spend the extra and go with the responsive turbo or save money and go for one than has some in reserve for when/if I want more and spend the money left over trying to bring the lag down?

Could I get the -5s to be as responsive as the -9?

Simple answer no you cannot get -5s to be as responsive as the -9. They are a bigger turbo. Saving $400 in the scheme of things is quite minor, I would prefer to pay $400 more to have the correct setup you are after.

Paulr33's signature:

Skyline GTR Twin Turbo - Garrett turbocharger equivalent models

Garrett 2860R-7's 0.42a/r (60.0mm) compressor 0.64a/r rear (HKS GT-SS equiv) = 300 to 330rwkw range

Garrett 2860R-9's 0.42a/r (59.4mm) compressor 0.64a/r rear (HKS GT-SS equiv) = 300 to 330rwkw range

Garrett 2860R-5's 0.60a/r compressor 0.64a/r rear (HKS 2530 Equiv) = 360 to 420rwkw range

Garrett 2871R-10's 0.60a/r compressor 0.64a/r rear (HKS GT-RS Equiv) = 440rwkw to 500rwkw

[discopotato03]

Probably the question to ask yourself is do I want a car that's good to drive 75% of the time or 25% of the time . Obviously you can't get around in hero mode all the time and expect to keep your licence , I think a car that has some stick at sub light speed will be more fun more often and that why you drive an enthusiasts type road car .

A .

[Count Grantleyish]

How does it drive compared to the stock turbos? I am considering -9's for my 34

What is your duty cycle for the injectors? i am guessing they are maxed out?

What clutch are you running?

Thanks

These turbos are bloody fantastic! I was considering -7s or -5s but I was offered pair of HKS GT-SS for decent price and couldn't pass it up. I felt it is more responsive than standard turbos.

I'm currently on standard injectors, at 302rwkw the duty cycle varies from 90-97%, I know I'm pushing it to the limit. Bigger injectors and AFM (in my case) are needed to reap the benefits of GT-SS. Would love to run on E85 and see how much power I could coax out of these.

I'm using real man's clutch - OS Giken Triple Plate. Was told Nismo Coppermix twin plate is the clutch to buy.

[R31Nismoid]

Probably the question to ask yourself is do I want a car that's good to drive 75% of the time or 25% of the time . Obviously you can't get around in hero mode all the time and expect to keep your licence , I think a car that has some stick at sub light speed will be more fun more often and that why you drive an enthusiasts type road car .

A .

+1

[J - Rad]

yeah the 9s are what I really want. Got to wait till after November for them apparently according to MTQ. That will give me time to sort out a clutch and dumps and what ecu I want to run at the end of the day.

[Juan_2_3]

hey J-Rad

if you want get -9's earlier may be you should try one of traders here 'Kudos motorsport'

[MrStabby]

I was sold on the gt-ss/-9 until I got some priced up at $2,900 with actuators. Now I can get the -5 for $2,500.

<snip>

Could I get the -5s to be as responsive as the -9?

Agree that in the scheme of things $400 is nothing. But if you only ever want 300kw then get the -7s and save the 400. The -7s will have the spool of the -9s with the price of the -5s, its just that they're not as good as the -9s if you want to push past ~320kws. I'm running -7s at 16.5psi and getting 305kw.

[some_cs_student]

I need help.

I was sold on the gt-ss/-9 until I got some priced up at $2,900 with actuators. Now I can get the -5 for $2,500.

<cut>

Have you tried PM'ing some forum sponsors like Hypergear for a price? I did notice the -9 does have a premium on it

[GTRsean]

Okay. Got a tune done the other day.

Bad news is the stock actuators I put on the -9's can't control the wastegates properly so the boost is wavy lol, even boost controller couldn't keep it steady.

So new stronger adjustable one's are on order.

So good news is the car runs pretty well now and good response, mid range torque is great!

Boost peaked at 18PSI and 288RWKW @6500PRM to 8000.

10psi at 3300

15psi at 3700

18psi at 4000

16 at 4900

15.5 at 5300

16 at 6400 etc.

So that was with stock intake, stock fuel system, stock AFM's.

Non standard parts: boost controller, -9's, Power fc, intercooler, front pipe, and 3 inch cat back, and compliance cat.

[J - Rad]

hey J-Rad

if you want get -9's earlier may be you should try one of traders here 'Kudos motorsport'

Have you tried PM'ing some forum sponsors like Hypergear for a price? I did notice the -9 does have a premium on it

Lol! Stupid me! A few months ago I pm'd afew of the sponsers and the cheapest I could find from them was $2,600 from BoostnImports. I had totally forgot about it until this morning.

Looks like I'll be buying from him!

[Count Grantleyish]

GTRsean, bin the compliance cat and replace it with hi-flow unit while you're at it.

And why use standard actuators?