Dyno Results for HKS GT III - SS Sports Turbo - Twins

[Dumpe]

3 hours ago, oea said:

I am happy with the power, I wasn't really going for outright numbers and was after something responsive, stock-looking and not too loud since I drive the car several times a week. The past 6 years I've owned it it's been stock, so the almost double increase in power is enough to keep me happy for now. The car feels like stock to drive and the GTIII-SS have a nice whistle to them, even with the stock airbox.

I was told by the shop that 400kW was achievable, they believe the stock airbox, restrictive exhaust (HKS Hi Power Silent) and fuel hat are the last bits to get from 377 to around 400. 

In hindsight, I might have gone for the similarly priced HKS GTIII-2530 or GTIII-RS, however if you've done a similar set up to me, you're only a turbo change away from achieving much more power.

Made 420rwkw at 23psi on E85 and link build/ dyno run can be found here... https://www.facebook.com/DEZIR3DR34GTR  Another 12months ill go stage 1=Vcam and maybe some PRP cam gears.

Bigger kw's is nice but I need reliability first, a build that I can afford and horsepower I can use everyday..

[joshuaho96]

19 hours ago, Dumpe said:

Made 420rwkw at 23psi on E85 and link build/ dyno run can be found here... https://www.facebook.com/DEZIR3DR34GTR  Another 12months ill go stage 1=Vcam and maybe some PRP cam gears.

Bigger kw's is nice but I need reliability first, a build that I can afford and horsepower I can use everyday..

VCAM doesn't allow for cam gears on the intake. And never ever forget to retorque all fasteners to spec on the exhaust side, I've seen cam gears slip on the dyno and it usually destroys the head in the process.

[morboost]

On 02/07/2022 at 12:50 AM, Dose Pipe Sutututu said:

No, I would throw out the twin turbo junk from day 1 and pop on a twin scroll modern single turbo.

wrong 

[Lithium]

4 minutes ago, morboost said:

wrong 

You're saying he wouldn't, and instead would inexplicably opt for sticking with rubbish transient response and generally ineffecient low mount twins despite knowing better?

Edited April 28, 2023 by Lithium

[morboost]

On 20/01/2023 at 6:15 PM, oea said:

HKS GT3 SS

Made 377rwkw at 23psi on E85

 

W/

Link G4X ECU

HKS GT3 SS turbos

HKS SS-Cam 264 deg

HKS inlet/exhaust cam gears 

HKS fuel rail

1,250cc injectors

Walbro 525 fuel pump

Ported stock exhaust manifold 

HPI dump pipe

Tomei equal length titanium front pipe

HKS Hi Power Silent catback

Nitto sine drive oil pump

Nitto forged pistons

Nitto H-beam conrods 

Nitto head oil drain

Nismo plenum

Nismo conrod and main bearings 

Nismo twin plate clutch

Nismo R-Tune air duct

Nismo air inlet piping

Nismo intercooler piping

Plazmaman 76mm intercooler

Stock airbox

this is how you do gtr engine bays, good power, no dumb 4" dose pipe, no stupid screamer that makes you back off on the slightest hint of boost  - well done

[morboost]

5 minutes ago, Lithium said:

You're saying he wouldn't, and instead would inexplicably opt for sticking with rubbish transient response and generally ineffecient low mount twins despite knowing better?

nos makes everything better but its wrong on a street car. no interior makes everything better but it wrong on a street car. no exhaust is better and so on.

[Lithium]

5 minutes ago, morboost said:

nos makes everything better but its wrong on a street car. no interior makes everything better but it wrong on a street car. no exhaust is better and so on.

This is completely irrelevant to anything.  Dose pipe was saying what he prefers for his own car, your opinion is irrelevant there.  Also you mentioned a bunch of things where there is a compromise for a car used on the road, single turbo makes driveability and maintenance better than twins so is basically win win for a street car.

[GTScotT]

I came across this thread looking for info on the GTIIISS and find myself reading another twin vs single debate.. 

 

If it means anything to anyone who still uses a forum.. I too watched the motive video of the 35R against the “-7s” and was sold. I then read the SAU gospel and witnessed the infamous “twins in the bin” meme. Unable to disobey the word of the lord our saviour, I installed the fabled 8374 at considerable cost and have unfortunately resigned to the fact that it’s not all it’s cracked up to be. 
 

The Motive video in question alludes to the fact that the -7s are high flowed but doesn’t give any specs. The car makes 500whp in the video, more than what -7s should make. It’s anyone’s guess what the specs are or how those twins actually perform.. Meaning the video could be showing that half ass twins aren’t as good as a 35R. Like much of the GR Yaris content from the same source.. A crock of shit. 
 

I’m running a bar of boost through my 8374, the car is fast.. But my friends almost identical GTR running a bar of boost through R34 twins is faster. More under the pedal, more when you want it, more over a wider spread. 
 

I’m certain if I threw another 40 grand at the car I could see the 500rwkw that would make the 8374 show how amazing it is compared to other 500rwkw turbos.. But it’s not the “better in every way” dream this forum and the internet at large portrays it to be. 
 

I find it really difficult to find information from Japan, but I have seen a lot of evidence that Japanese tuners are reverting back to twins and aiming for less power. This brings us to the GTIIISS… 

 

I am still legitimately interested to know if they would be better than -9s, and if so by how much? Another thing I am curious of is if a smaller single would keep the simplicity but give back the drive. Adam LZ did the video of the G30-770 on his VCT equipped RB, the graph shows it standing up at 4 and the driving scenes aren’t much different. Perhaps better than the bolt on 8374.. But not by much. 
 

Keen to discuss sub 350kw 98 only RB26. 

[morboost]

that unfortunate gtscott, unfortunately there is a small vocal minority that like to disrupt any discussion on twin turbo setups normally rb25 owners so it muddies the waters. Look at japan's 2 major tuning shops nismo omori factory and mines spend there days throwing single setups in the bin and reverting back to twins.

 Motive dvd is a sales man he will hold his thumb on the scale to sell you sponsored products and say its the only way.

I think its reverting back to twins as consumers are looking more and more for slightly modded gtr's that they can do mods slowly and enjoy the tuner aspect, start off with a nice jdm twinturbo back exhaust, why would you want single when you just dropped 2-4k on jdm dump and front pipes, now you want to capitalise on your exhaust with some bolton twins to go with z32 mafs or hks deletes on the stock airbox with some sort on carbon nismo component. The car ends up looking fantastic under bonnet has good usable power doesn't sound like a vl turbo with and exhaust leak and is appreciated buy a large audience, and if life goes sideways you can sell the car quick.

 

where's that single in the bin meme.

[GTSBoy]

3 hours ago, GTScotT said:

I’m running a bar of boost through my 8374

The real question is....why only a bar of boost? Why not wind it up to where it is supposed to be?

Look at the comp map for the 8374, and then the r34 twins, and tell me that they are both equally close to optimal performance at 1 bar.

[Dose Pipe Sutututu]

12 hours ago, morboost said:

vl turbo with and exhaust leak

You can plumb back the external gate, also you'll find most that race on the circuit primarily plumb back their gates to comply with noise regulations and also reduce distractions whilst racing.

Not all of us here on this forum are drag racers/street racers/roll racers so your generalisations are just that, a generalisation.

[GTScotT]

10 hours ago, GTSBoy said:

The real question is....why only a bar of boost? Why not wind it up to where it is supposed to be?

Look at the comp map for the 8374, and then the r34 twins, and tell me that they are both equally close to optimal performance at 1 bar.

It’s simply where I stopped at the time. I was developing the car in stages and then bought a GR Yaris, so the GTR stayed at 1 bar longer than expected. 
 

As said, and to the point, the power at that level isn’t disappointing.. Its what it’s like to live with if not wringing it’s neck. The turbo comes on easily and drives well, has gotten me in a lot of trouble in the 3 years it’s been on the car, but again the standard R34 units make similar power and do it better in every way. 
 

I highly doubt me turning it up 10psi will make the driving experience better aside from the fact it will be a lot faster. 10psi more boost won’t make the turbo come on 1000rpm sooner, and another 5-10k on a V cam to do what R34 bolt ons do seems ridiculous (my engine is completely standard).

I simply don’t want big power and converting to the single has showed me I actually just want a GTR in its natural GTR format with a few bolt ons. So I really understand the tone of the minority defending twins in this thread. I understand because I’ve done the thing and wish I didn’t. 

[UWISSH!]

34 minutes ago, GTScotT said:

It’s simply where I stopped at the time. I was developing the car in stages and then bought a GR Yaris, so the GTR stayed at 1 bar longer than expected. 
 

As said, and to the point, the power at that level isn’t disappointing.. Its what it’s like to live with if not wringing it’s neck. The turbo comes on easily and drives well, has gotten me in a lot of trouble in the 3 years it’s been on the car, but again the standard R34 units make similar power and do it better in every way. 
 

I highly doubt me turning it up 10psi will make the driving experience better aside from the fact it will be a lot faster. 10psi more boost won’t make the turbo come on 1000rpm sooner, and another 5-10k on a V cam to do what R34 bolt ons do seems ridiculous (my engine is completely standard).

I simply don’t want big power and converting to the single has showed me I actually just want a GTR in its natural GTR format with a few bolt ons. So I really understand the tone of the minority defending twins in this thread. I understand because I’ve done the thing and wish I didn’t. 

That 8374 was an absolute terrible choice for a complete stock engine. Who on earth told u that it was a good idea?

[Piggaz]

Remove 8374, replace with 7670, G series/PTE/choose your poison equivalent.
Bit silly to be running such a large snail that’s capable north of 500awkw like a church mouse sneezing then complaining that the -7’s which is basically a stock sized snail (N1’s) do the low end stuff better. 😖

[GTScotT]

As said I was building the car in stages and got side tracked. The 8374 went on ahead of time when the factory twins bust a couple of gaskets. 
 

The point is I was never chasing 400kw+ and it doesn’t seem like the cost benefit is there with this setup. The 8374 let’s the 26 rev past 8 as it should, but without a stroker or V cam it doesn’t come on well enough. -7s on the other hand will come on well enough and make over 300kw on an unopened engine, so really is it worth doing all the fancy stuff?

 

Where I’m at right now is; probably not. 

[UWISSH!]

18 minutes ago, GTScotT said:

As said I was building the car in stages and got side tracked. The 8374 went on ahead of time when the factory twins bust a couple of gaskets. 
 

The point is I was never chasing 400kw+ and it doesn’t seem like the cost benefit is there with this setup. The 8374 let’s the 26 rev past 8 as it should, but without a stroker or V cam it doesn’t come on well enough. -7s on the other hand will come on well enough and make over 300kw on an unopened engine, so really is it worth doing all the fancy stuff?

 

Where I’m at right now is; probably not. 

Again if that was your power target why did u choose a turbo that is suited to 500+kw?

u didn’t need 8374 to rev past 8k when I originally had 2530s back in 2009 I was able to rev my engine to 9k happily.seems like u had no proper guidance from the start and I’m not surprised that ur unhappy with how a 800hp+ turbo is driving at only 15psi

[Lithium]

36 minutes ago, GTScotT said:

The point is I was never chasing 400kw+ and it doesn’t seem like the cost benefit is there with this setup. The 8374 let’s the 26 rev past 8 as it should, but without a stroker or V cam it doesn’t come on well enough. -7s on the other hand will come on well enough and make over 300kw on an unopened engine, so really is it worth doing all the fancy stuff?

Not at all.   And this is a key point, aside from my wind up comments I made last night a few rums in after seeing morboost's smarta55 comment to someone who was simply stating their own preference as an opening to be a smarta55 myself - I have always been a huge fan of matching parts of a build to suit the purpose.  

I ultimately completely agree with you in terms of the stock R34 twins, or a mild twin setup for a mild fun street friendly setup.  I'd never go out of my way to convince someone to go single turbo if they're aiming for under 350kw on a mild RB26 - the reasons I suggest a single turbo is better than a twin setup are not applicable at this point and if I myself were building a GT-R for that kind of purpose it's also how I'd probably do it.   This again comes down to me mostly being pretty agnostic about brands or methods of doing things, and just trying to identify the most appropriate combo to achieve a purpose... which can include satisfying things the person who is going to drive it prefers even if they aren't specifically about peak performance.   

So yeah, realistically having an EFR8374 and saying that a single turbo or a EFR8374 isn't a great choice when you're using it for <350kw is bizarre when framed as a "people said and EFR/single turbo is best but its not" when it's a painfully poor match for what you're using it for is a kinda odd take.   I'd never argue that you made the right choice going for that for this setup, or any single (though there are singles which would be wayyy better suited).

The whole single turbo debate for me has LONG been about where people are running twins and trying to bend physics to make them work in highly restrictive setups and ending up needing to over turbo, massively engineer and strain the hell out of things to achieve numbers because of packaging limitations with the low mount twins - you end up with turbos not work in a balanced manner and both having to work WAY harder due to operating in temperatures and pressure ratios that a single turbo wouldn't have to when trying to move enough air to make >400kw @ wheels as you can package it well enough to draw in air and dump out exhaust without dealing with major choke points or trapping heaps of heat.   That is not relevant in the case of what you're doing.... as such I am very pro twins in the right situations, and very pro single turbos in the right situations, and the same goes for picking brands of turbo, split/single pulse exhaust housings and the rest.    

One size fits all is not a thing that works with tuning cars, and having a personal preference is a very legit reason for choosing one thing over another - which again was the only point I made a dig, because two things that get my on my soap box are people choosing the wrong things for a job and then saying they're shit because they don't do that job properly, and people telling people their opinion is wrong

 

Edited April 29, 2023 by Lithium

[Dose Pipe Sutututu]

Very common theme with people building older cars, no defined requirements and goals down pat from the start.

You need to define what the car's intent will be, what you require in terms of power delivery, etc. E.g. you want a responsive street/circuit car, with a wide powerband for the circuit but also want it all in at 4k rpm so you can take corners in 3rd gear. Once that's all defined, at that point is where you go and look at your car's constraints and limitations. What can you do to work around them, e.g. you don't have VCam or VCT, then you might look into advancing the intake cam, etc. to bring it on earlier and knowing you're happy to sacrifice top end because you don't need to ring it's neck out at the track.

Often you see people just chasing a kW number and not thinking about anything else at the start of the build to be awfully disappointed at the end result.

[djvoodoo]

15 hours ago, GTScotT said:

I came across this thread looking for info on the GTIIISS and find myself reading another twin vs single debate.. 

 

If it means anything to anyone who still uses a forum.. I too watched the motive video of the 35R against the “-7s” and was sold. I then read the SAU gospel and witnessed the infamous “twins in the bin” meme. Unable to disobey the word of the lord our saviour, I installed the fabled 8374 at considerable cost and have unfortunately resigned to the fact that it’s not all it’s cracked up to be. 
 

The Motive video in question alludes to the fact that the -7s are high flowed but doesn’t give any specs. The car makes 500whp in the video, more than what -7s should make. It’s anyone’s guess what the specs are or how those twins actually perform.. Meaning the video could be showing that half ass twins aren’t as good as a 35R. Like much of the GR Yaris content from the same source.. A crock of shit. 
 

I’m running a bar of boost through my 8374, the car is fast.. But my friends almost identical GTR running a bar of boost through R34 twins is faster. More under the pedal, more when you want it, more over a wider spread. 
 

I’m certain if I threw another 40 grand at the car I could see the 500rwkw that would make the 8374 show how amazing it is compared to other 500rwkw turbos.. But it’s not the “better in every way” dream this forum and the internet at large portrays it to be. 
 

I find it really difficult to find information from Japan, but I have seen a lot of evidence that Japanese tuners are reverting back to twins and aiming for less power. This brings us to the GTIIISS… 

 

I am still legitimately interested to know if they would be better than -9s, and if so by how much? Another thing I am curious of is if a smaller single would keep the simplicity but give back the drive. Adam LZ did the video of the G30-770 on his VCT equipped RB, the graph shows it standing up at 4 and the driving scenes aren’t much different. Perhaps better than the bolt on 8374.. But not by much. 
 

Keen to discuss sub 350kw 98 only RB26. 

I was told to go a GTX3576R Gen2 on my 34 - Stock RB26 bottom end but with a refreshed head, baby HKS Cams, flex tune, usual mods. Have a 4 inch dump, 3.5inch exhaust running through 2 massive Reaper engineering mufflers. Very very quiet, until the wastegate and screamer come on song (which i love).

I couldn't be happier with the boost threshold, transient response and driveability. My goal was to try and compete with R35's for street duties (R35's are still quicker down low compared to my setup). 

Cant do much with my tune locked... But datalogging, doing a few pulls in 4th gear, last years winter, E85 and on flat highway loading the car up from 2400 rpm or so.

MAP sensor showing 155.8 kPA at 3569rpm -which by google translation is 22.5psi of boost. Pretty responsive if you ask me. Tuner said on the dyno was getting full boost (around 26-27 psi by 3800rpm)

 

[GTScotT]

A lot of assumptions are being made about my use case and probably my experience level, too. I didn't come to write war and peace, just to try legitimise the query so that people could actually talk about the new gen twins without being shut down with "twins in the bin" stuff.

 

Originally when I was building my GTR I didn't imagine myself going down the paths I did, or owning more cars that serve other purposes. At that time the GTR was meant to be an all rounder, street and track duties and would only ever run on 98 (personal choice). I wanted to simplify the engine bay, make it easier to work on, max out what can be achieved on 98 ron while keeping the setup overall simple. Thermal management was a consideration and not overworking things, so smaller turbines were less desirable and made me steer away from the 7670 although it was a serious consideration. Compressor flow was also an issue as I didn't want to rev an RB26 to 6500 when it was made to rev to 8000 or more. On paper the IWG .92 T4 8374 looked like a great choice, and over time a motor rebuild with a sensible stroker kit and fancy cams (if not V cam) would spice it up a lot and make the ownership experience more special. 

 

Fast forward 3 years, numerous builds done for others and more cars in the fleet serving different purposes, I'm not feeling the big single vibe any more. If I went down the path I said above and added the V cam, built the motor, maxed out whatever it can do on 98, would I be in a net position higher than bolt on twins that justifies the expense? Going in circles now; likely no.

 

If I was to put the car on ethanol and push high into the 400rwkw range I believe it would out shine twins being used for the same purpose - but that was never my intention. THAT SAID, my intention still warranted more than the average set of twins AND the advice was definitely that the single will do it better. With the experience gained over time and driving the car with the turbo in place of twins I am satisfied that a mid 300kw build should still consider twins and the GTIIISS are an interesting new gen option. Again I'll say, single was not all it was cracked up to be. Without spending a ship load more it left more on the table than desired and the obvious benefits were outweighed without pursuing the extra 100kw - which would also warrant the significantly more expensive twin external gate option.

 

I should probably also note that I consulted some very big names on this before buying anything, and the consensus was landslide. The setup I have would outshine any bolt on twins at anything much over 300rwkw. At this point it did not, and I dont think it will. 

 

FS 8374?