Twin turbo upgrade R33 GTR

[r32-25t]

I remember driving it the first time with the gt-rs and my comment was the only thing I’d change is go to 2530s

[Dose Pipe Sutututu]

On 25/04/2022 at 10:14 AM, Piggaz said:

If I dig deep enough I could find that post too… but that was circa 2009 man. 🤣. 

Those words always come back to haunt you.

[Piggaz]

On 25/4/2022 at 10:21 AM, Dose Pipe Sutututu said:

Those words always come back to haunt you.

[BK]

On 25/04/2022 at 8:13 AM, joshuaho96 said:

Is the GTIII-SS actually mismatched between compressor and turbine? I've never been able to find any information on it. Only thing I know is the exhaust housing a/r is 0.54. 

Yes if you consider every other low monut offering. 0.54 a/r turbine housing ? - This in itself is quite ridiculous with a reduced in size 52mm turbine wheel. Nissan moved to a 0.64 a/r on the N1 and Nismo turbine housing in the 90s, so even Nissan themselves realised a 0.64 turbine housing was a more appropriate size. Going any smaller than 0.64 on turbine housing is a bad idea regardless of what you do with the compressor side.

Regarding specs the MHI GTIII-SS which I have found is a smaller turbo overall compared to the HKS GT-SS or Garrett-9. The GTIII-SS falls into the trap of using a billet compressor wheel as its selling point and then makes both wheels smaller and uses a journal chra ?! WTF were they thinking doing this as an improvement ?

Specs on all, noting original HKS GT-SS is slightly bigger on comp wheel than -9 so not exactly 100% equivalent but close.

Garrett-9 ball bearing chra

Compressor: 0.42 a/r, Inducer - 44.5mm, Exducer 59.4mm, trim = 56t

Turbine: 0.64 a/r, Inducer - 53.9mm, Exducer - not listed, but has to be 47mm as trim = 62t

HKS GT-SS ball bearing chra

Compressor: 0.42 a/r, Inducer -  46.6mm, Exducer - 60.1mm

Turbine: 0.64 a/r, Inducer - 53.9mm, Exducer - 47mm trim = 62t

HKS GTIII-SS journal bearing chra

Compressor: not listed a/r, Inducer - not listed, Exducer 56mm

Turbine: 0.54 a/r, Inducer - 52mm, Exducer - not listed

[BK]

Holy Quintuplet post batman - stupid middle of Australia internet

[niZmO_Man]

On 25/04/2022 at 12:22 PM, BK said:

Holy Quintuplet post batman - stupid middle of Australia internet

I've hidden your spam posts

[BK]

On 25/04/2022 at 4:48 PM, niZmO_Man said:

I've hidden your spam posts

Thank you sir Ravi you are awesome and I um retarded 👌

...

[joshuaho96]

On 4/24/2022 at 7:20 PM, BK said:

Yes if you consider every other low monut offering. 0.54 a/r turbine housing ? - This in itself is quite ridiculous with a reduced in size 52mm turbine wheel. Nissan moved to a 0.64 a/r on the N1 and Nismo turbine housing in the 90s, so even Nissan themselves realised a 0.64 turbine housing was a more appropriate size. Going any smaller than 0.64 on turbine housing is a bad idea regardless of what you do with the compressor side.

Regarding specs the MHI GTIII-SS which I have found is a smaller turbo overall compared to the HKS GT-SS or Garrett-9. The GTIII-SS falls into the trap of using a billet compressor wheel as its selling point and then makes both wheels smaller and uses a journal chra ?! WTF were they thinking doing this as an improvement ?

Specs on all, noting original HKS GT-SS is slightly bigger on comp wheel than -9 so not exactly 100% equivalent but close.

Garrett-9 ball bearing chra

Compressor: 0.42 a/r, Inducer - 44.5mm, Exducer 59.4mm, trim = 56t

Turbine: 0.64 a/r, Inducer - 53.9mm, Exducer - not listed, but has to be 47mm as trim = 62t

HKS GT-SS ball bearing chra

Compressor: 0.42 a/r, Inducer -  46.6mm, Exducer - 60.1mm

Turbine: 0.64 a/r, Inducer - 53.9mm, Exducer - 47mm trim = 62t

HKS GTIII-SS journal bearing chra

Compressor: not listed a/r, Inducer - not listed, Exducer 56mm

Turbine: 0.54 a/r, Inducer - 52mm, Exducer - not listed

Isn't the trim for the GTIII-SS listed somewhere? The tag for it says 5652 55T 01786 on mine. I'm guessing the 55T is for the compressor.

I don't understand, I thought when you make a smaller turbo for smaller power output everything gets smaller. 0.64 a/r on a -9 but 0.83 or 1.01 a/r on a single turbo is not unusual. Stock is 0.48 turbine a/r so it's pretty much right between stock and an N1 or GT-SS. I was never really interested in it for "billet", I just want a tiny turbo to make very pedestrian levels of power. Pretty much stock, just without the ceramic turbine wheel. Each turbo only has 1.3L of displacement to work with after all. I think more than anything my concern is I make an irreversible change to the car that really affects reliability or driveability. It would've been nice to have the same turbo but ball bearings instead of journal bearings but I'm willing to bet that a larger ball bearing turbo is ultimately going to have more lag than a smaller journal bearing turbo. Even if there's more drag from the bearings, the issue is more the inertia of the turbine/compressor wheels.

On 4/24/2022 at 5:10 PM, Dose Pipe Sutututu said:

A few twin turbo advocates here turned single turbo activists.

That's saying something. One guy *cough* Pig.. *cough* gaz famously said "I wouldn't change a thing" on his twin GT-RS RB26 with Tomei brap cams.

Well not sure whatever happened to that setup.

I don't know if I'd ever recommend a bolt-on turbo for the kind of power that the GT-RS turbos are targeted at.

Edited April 25, 2022 by joshuaho96

[BK]

Exhaust housing are one area that shouldn't be underdone. If that is compromised the whole turbo / engine package is compromised.

Seriously i give up dude, you just dont grasp what I'm trying to get across. Dot points:

-standard ceramic turbos suck

-trying to imitate the standard turbo results with something else also sucks.

-Gt-ss or -9 is only an improvement over the standard ceramic turbos everywhere in reality - there is no downside however you might think to the stock units.

Post results when GTIII-SS installed and tuned please.

On 25/04/2022 at 7:16 PM, joshuaho96 said:

I don't know if I'd ever recommend a bolt-on turbo for the kind of power that the GT-RS turbos are targeted at.

Single turbo realm mate, as Piggaz above.

[joshuaho96]

On 4/25/2022 at 3:44 AM, BK said:

Exhaust housing are one area that shouldn't be underdone. If that is compromised the whole turbo / engine package is compromised.

Seriously i give up dude, you just dont grasp what I'm trying to get across. Dot points:

-standard ceramic turbos suck

-trying to imitate the standard turbo results with something else also sucks.

-Gt-ss or -9 is only an improvement over the standard ceramic turbos everywhere in reality - there is no downside however you might think to the stock units.

Post results when GTIII-SS installed and tuned please.

Single turbo realm mate, as Piggaz above.

Genuinely confused here, I've never seen a dyno result where -9s/GT-SS didn't give up a pretty substantial amount of response relative to stock turbos. I figured staring at turbine maps that you want to size it to the actual amount of exhaust CFM you expect or else either you have really awful response or the turbo becomes entirely backpressure limited. Everything I can find suggests that for the same exact turbine wheel, adjusting the turbine a/r moves the choke point up and down. The turbo definitely chokes somewhere around 18-21 psi up top from what I've seen but for my purposes that's actually ok.

Funny enough looking at the BMW S55 the turbos they use stock are comparatively tiny. 51mm compressor exducer, 43mm turbine inducer:

[CefiroA31]

On 4/25/2022 at 9:20 AM, BK said:

Yes if you consider every other low monut offering. 0.54 a/r turbine housing ? - This in itself is quite ridiculous with a reduced in size 52mm turbine wheel. Nissan moved to a 0.64 a/r on the N1 and Nismo turbine housing in the 90s, so even Nissan themselves realised a 0.64 turbine housing was a more appropriate size. Going any smaller than 0.64 on turbine housing is a bad idea regardless of what you do with the compressor side.

Regarding specs the MHI GTIII-SS which I have found is a smaller turbo overall compared to the HKS GT-SS or Garrett-9. The GTIII-SS falls into the trap of using a billet compressor wheel as its selling point and then makes both wheels smaller and uses a journal chra ?! WTF were they thinking doing this as an improvement ?

Specs on all, noting original HKS GT-SS is slightly bigger on comp wheel than -9 so not exactly 100% equivalent but close.

Garrett-9 ball bearing chr

Compressor: 0.42 a/r, Inducer - 44.5mm, Exducer 59.4mm, trim = 56t

Turbine: 0.64 a/r, Inducer - 53.9mm, Exducer - not listed, but has to be 47mm as trim = 62t

HKS GT-SS ball bearing chra

Compressor: 0.42 a/r, Inducer -  46.6mm, Exducer - 60.1mm

Turbine: 0.64 a/r, Inducer - 53.9mm, Exducer - 47mm trim = 62t

HKS GTIII-SS journal bearing chra

Compressor: not listed a/r, Inducer - not listed, Exducer 56mm

Turbine: 0.54 a/r, Inducer - 52mm, Exducer - not listed

On 4/26/2022 at 12:35 AM, joshuaho96 said:

Genuinely confused here, I've never seen a dyno result where -9s/GT-SS didn't give up a pretty substantial amount of response relative to stock turbos. I figured staring at turbine maps that you want to size it to the actual amount of exhaust CFM you expect or else either you have really awful response or the turbo becomes entirely backpressure limited. Everything I can find suggests that for the same exact turbine wheel, adjusting the turbine a/r moves the choke point up and down. The turbo definitely chokes somewhere around 18-21 psi up top from what I've seen but for my purposes that's actually ok.

Funny enough looking at the BMW S55 the turbos they use stock are comparatively tiny. 51mm compressor exducer, 43mm turbine inducer:

Looking at HKS GTIII-SS specs and as they are MHI based, then 56mm compressor exducer and 52mm turbine inducer should be from TD004H or HL turbine family :

TD04H turbine : inducer 52mm exducer 44.2mm.

TD04HL turbine : inducer 52mm exducer 45.6mm.

TD04 turbines are usually 12 blades fom MHI, but also available aftermarket upgrade with 11 blades and 9 blades.

Compressor exducer 56mm can be 15T (inducer 41.9mm), 16T or 15G (same inducer 43.4 mm but different blade profile), which compressor maps show max flow of around 29-31 lb/min at 1-1.5 Bar of boost. However its possible that HKS uses newer TD04 compressor from MHI which may flow a bit more.

That BMW S55 MHI upgrade should use similar compressor as above with TD04L turbine inducer 47mm exducer 41.3mm. I have read TD04L maxes out about 220-250whp in other engines on e85 or pump gas + methanol mix.

OEMs such as Volvo, Saab, uses these sizes TD04s for engines around 220-280 max hp usually at lower boost than 1 bar. Biggest OEM TD04HL is a TD04HL-19T which has 46mm/58mm compressor with max flow around 37 lb/min at 1.3 Bar of boost

Garrett turbo closest in wheel sizes to TD04HL is GBC22-350 which has 44mm/56mm compressor max flow 37 lb/min at 1.7 Bar of boost and 50mm/46mm 9 blade turbine and also journal bearing as TD04s or next step larger GT28 series in journal or ball bearing.

Other close sized option is Holset HE221W which has 43.4mm/61mm compressor max flow 38 lb/min at 2 bar of boost and 52mm/45.7mm 11 blade turbine, with T2 internal gated turbine housing sized at 5cm/6cm/7cm, so will bolt on to RB26 stock exhaust manifolds, but piping and downpipe will need to be custom made.

Compared to GT28 ball bearing turbos, TD04s has smaller turbine inducer, exducer, shaft and compressor bore diameter so should have lower inertia which may allow it to spool comparable to GT28 ball bearing turbos, dependent of housing sizes. I have read infos from various platform which said TD04HL-19 T is close to GT2860R in response and max power.

So my take on HKS MHI based GTIII-SS is it should work well if hp target around max 500-600 engine hp. Although if insisting on twin turbos then GBC22-350, TD04-HL-19T and HE221W will work just as well if not better and definitely cheaper.

However, if no legal/emission compliance reasons, instead of upgrading twins, going to a similar rated power twin scroll single turbo such as GTX3071R/GTX3576R Gen 2, GTW3476, S257SXE, Holset HX35/HE351W, will be simpler and lighter although likely similar cost wise as need to buy proper t3/t4 divided manifold and external wastegate, and with similar HP should be faster car. This is what I would do.

[joshuaho96]

On 4/25/2022 at 5:25 PM, CefiroA31 said:

Looking at HKS GTIII-SS specs and as they are MHI based, then 56mm compressor exducer and 52mm turbine inducer should be from TD004H or HL turbine family :

TD04H turbine : inducer 52mm exducer 44.2mm.

TD04HL turbine : inducer 52mm exducer 45.6mm.

TD04 turbines are usually 12 blades fom MHI, but also available aftermarket upgrade with 11 blades and 9 blades.

Compressor exducer 56mm can be 15T (inducer 41.9mm), 16T or 15G (same inducer 43.4 mm but different blade profile), which compressor maps show max flow of around 29-31 lb/min at 1-1.5 Bar of boost. However its possible that HKS uses newer TD04 compressor from MHI which may flow a bit more.

That BMW S55 MHI upgrade should use similar compressor as above with TD04L turbine inducer 47mm exducer 41.3mm. I have read TD04L maxes out about 220-250whp in other engines on e85 or pump gas + methanol mix.

OEMs such as Volvo, Saab, uses these sizes TD04s for engines around 220-280 max hp usually at lower boost than 1 bar. Biggest OEM TD04HL is a TD04HL-19T which has 46mm/58mm compressor with max flow around 37 lb/min at 1.3 Bar of boost

Garrett turbo closest in wheel sizes to TD04HL is GBC22-350 which has 44mm/56mm compressor max flow 37 lb/min at 1.7 Bar of boost and 50mm/46mm 9 blade turbine and also journal bearing as TD04s or next step larger GT28 series in journal or ball bearing.

Other close sized option is Holset HE221W which has 43.4mm/61mm compressor max flow 38 lb/min at 2 bar of boost and 52mm/45.7mm 11 blade turbine, with T2 internal gated turbine housing sized at 5cm/6cm/7cm, so will bolt on to RB26 stock exhaust manifolds, but piping and downpipe will need to be custom made.

Compared to GT28 ball bearing turbos, TD04s has smaller turbine inducer, exducer, shaft and compressor bore diameter so should have lower inertia which may allow it to spool comparable to GT28 ball bearing turbos, dependent of housing sizes. I have read infos from various platform which said TD04HL-19 T is close to GT2860R in response and max power.

So my take on HKS MHI based GTIII-SS is it should work well if hp target around max 500-600 engine hp. Although if insisting on twin turbos then GBC22-350, TD04-HL-19T and HE221W will work just as well if not better and definitely cheaper.

However, if no legal/emission compliance reasons, instead of upgrading twins, going to a similar rated power twin scroll single turbo such as GTX3071R/GTX3576R Gen 2, GTW3476, S257SXE, Holset HX35/HE351W, will be simpler and lighter although likely similar cost wise as need to buy proper t3/t4 divided manifold and external wastegate, and with similar HP should be faster car. This is what I would do.

I do have legal/emissions compliance to keep in mind unfortunately. But even if there were no such concerns the things I want out of a single turbo RB26 doesn't really exist as far as I know. Short runners, low-mount, proper heat shielding instead of just having an exhaust manifold + turbo inches away from heat-sensitive components, real thought given to minimizing the changes to things other than the turbo + manifold + intake piping, and twin scroll. Basically look at a BMW B58 or N55, that's the goal in my head. I know that's a really tall order but this is a street car, not a track build. Someone I know has gone through stock turbos -> HKS GT-SS -> GTX3576R gen 2 and he absolutely loses power at the critical ~3000-4000 RPM area where I spend a lot of time at on the street contrary to what Motive found. 

[R.3.2.G.T.R]

On 27/4/2022 at 7:46 AM, joshuaho96 said:

I do have legal/emissions compliance to keep in mind unfortunately. But even if there were no such concerns the things I want out of a single turbo RB26 doesn't really exist as far as I know. Short runners, low-mount, proper heat shielding instead of just having an exhaust manifold + turbo inches away from heat-sensitive components, real thought given to minimizing the changes to things other than the turbo + manifold + intake piping, and twin scroll. Basically look at a BMW B58 or N55, that's the goal in my head. I know that's a really tall order but this is a street car, not a track build. Someone I know has gone through stock turbos -> HKS GT-SS -> GTX3576R gen 2 and he absolutely loses power at the critical ~3000-4000 RPM area where I spend a lot of time at on the street contrary to what Motive found. 

I had HKS gtss with cam gears dialled, stock cams, 3800rpm all in @22psi, night and day difference over stock turbos and any perceived “response” loss

8374 efr + vcam is another level of ass kicking again if you inclined 

[joshuaho96]

On 6/1/2022 at 6:14 AM, R.3.2.G.T.R said:

I had HKS gtss with cam gears dialled, stock cams, 3800rpm all in @22psi, night and day difference over stock turbos and any perceived “response” loss

8374 efr + vcam is another level of ass kicking again if you inclined 

From what I have seen/heard the oil control issues involved with huge power is just too annoying to deal with, I'd rather keep power targets conservative for that reason. I am planning on running VCAM whenever I finally get around to it though. I have seen enough charts to conclude that within the bolt-on turbo design space there is no free lunch, more power up top means worse response down low. Doing the same optimization with a stock turbo would yield better response than GT-SS. Emissions and OEM engineering validation are issues that I need to be concerned about so going single turbo isn't really something I want to do either.