HKS Turbo's vs Garrett Turbo's...

[jezzrrr]

My calculations are as follows: 1PS = .7355KW thus 579PS = 425KW and YES this must be measured at the crank.

Hi Elithar, if the engine is in good condition and the tuning is good, there is no reason why the RB20 won't make the same max power as an RB25 with the same mods, condition and tuning.  So almost 200 rwkw is entirely possible.   Average horsepower is of course a different question entirely, the RB25 is after all 25% larger.

Hi jezzrrr, let me use my sceptical bone here, what if the only reason the HKS supported workshops are using GTSS's is because it's "new" and there is money to be made.   What would be the point of pushing 2530's?  They are "old" news and everyone knows that "newer" must be better.

Looking at the GTSS power claims, 579 rwps, that's around 310 rwkw.  I have seen 330 rwkw out of a pair of 2530's locally in Shoot Out mode on a Dyno Dynamics.  But the extra 20 rwkw is not the point, it's how it gets there that is important.  Somewhere around I have seen the dimensions of GTSS's and they looked remarkably similar to 2510's.  The HKS ratings are;  

GTSS 300 ps

2510 310 ps

2530 320 ps

2535 340 ps

2540 350 ps

2540R 370 ps

2835 380 ps  

HKS rate the GTSS lower than a 2510, and I have driven a GTR with 2510's and it was awesome up to 7,000 rpm then it went flat line.  It felt like it had some boost just above  idle rpm, which is totally alien in a GTR, where the real pleasure for me comes from giving them a rev.  The guy who owned it loved it like that as he just stepped out of a grunter 6 litre Commondoor.  If HKS (and Garrett) had found a combination of compressor and turbine that gives a GTSS the bottom end of a 2510 with a slightly better top end, then for some people that would be perfect.  But I keep going back to the fact that HKS don't rate them with the same max power as a 2510, therefore they themselves are saying GTSS's have a lower top end than 2510's.

So, like many others, I await Merli's results with great interest.

[DoughBoy]

I can recall a post from someone with some credibility on these forums claiming that

we typically see 50 kw losses through 2 wd Skyline and 65 kw losses in 4 wd

. Taking that off the 576.2ps (423.79kw) gives you 358.79AWkw. Quote some number.

[jezzrrr]

I can recall a post from someone with some credibility on these forums claiming that . Taking that off the 576.2ps (423.79kw) gives you 358.79AWkw. Quote some number.

Absolutely, I went for a ride in a car with GTSS's and it blew me away, it was a RB26 DETT lobbed into a GTS-T (ie rear wheel drive) the thing had NO traction in 1st or 2nd and you had to back off in third to get traction. It was pulling around 450RWHP at the time, which is a big figure in anyones speak. Without a doubt one of the most impressive rides ive had in a skyline.

Jeremy

[Steve]

Steve... Those power figures on the Phoenix Power site are engine hp figures, not wheel hp.

that explains a bit, but I was just going off SKs post. still seams like a hell of alot of driveline loss. Also, SK talks of 330rwkw from 2530, so that means, from the same loss, 115kw loss for rw drive (330rwkw for 2530 vs 310rwkw for GTSS)

either way, I still think that SKs sceptical bone needs a recalibration:D:P

[Sydneykid]

Hey guys, give me a break here, it was a hard Saturday night, alright?

OK, this is how I do the engine PS to rwkw calculation in a GTR.

579 ps X 0.9 = 521 bhp

521 hp / 1.34 = 388 kw

388 kw - 78 kw = 310 rwkw

Chris is right I use 60 'ish kw losses for (big gearbox and drive train) rear wheel drive Skylines (R33 and R34) and 50 'ish for (small gearbox and drive train) R32 GTST's. But this was an R34GTR so with them I have found it necessary to run the transfer case and centre diff and disconnect the drive shaft. So I added 8 kw to my usual losses on an R33 GTR in 2wd and 18 kw on an R32 GTR in 2wd. Experience tells me that a GTR looses about 85 kw in 4wd drive, so I don't think 78 kw is too far wrong.

So maybe my sceptical bone is out by a few kw's, Jack Daniels will do that to you. But I don't think it alters the argument.

As for HKS revising their max power outputs on GTRS's, well there are two answers to that one;

1. HKS are so dumb they published the figures first with out testing them properly. But the Pheonix car only made 579 ps (that's 290 ps each) which is a lot closer to the 310 ps rating than it is to 330 ps.

2. HKS want to sell more GTRS's

Either way, it makes my sceptical bone ache a little more.

[Sydneykid]

Hey guys, give me a break here, it was a hard Saturday night, alright?

OK, this is how I do the engine PS to rwkw calculation in a GTR.

579 ps X 0.9 = 521 bhp

521 hp / 1.34 = 388 kw

388 kw - 78 kw = 310 rwkw

Steve is right I use 60 'ish kw losses for (big gearbox and drive train) rear wheel drive Skylines (R33 and R34) and 50 'ish for (small gearbox and drive train) R32 GTST's.  But this was an R34GTR so with them I have found it necessary to run the transfer case and centre diff and disconnect the drive shaft.  So I added 8 kw to my usual  losses on an R33 GTR in 2wd and 18 kw on an R32 GTR in 2wd.  Experience tells me that a GTR looses about 85 kw in 4wd drive, so I don't think 78 kw is too far wrong.

So maybe my sceptical bone is out by a few kw's, Jack Daniels will do that to you.  But I don't think it alters the argument.

As for HKS revising their max power outputs on GTRS's, well there are two answers to that one;

1. HKS are so dumb they published the figures first with out testing them properly.  But the Pheonix car only made 579 ps (that's 290 ps each) which is a lot closer to the 310 ps rating than it is to 330 ps.

2. HKS want to sell more GTRS's

Either way, it makes my sceptical bone ache a little more.

[Steve]

this might make it easier for you http://www.onlineconversion.com/power.htm

convert straight from ps to kw and it comes out 425kw

I think your problem is the Jacks, everybody knows the sphincter of the universe is a much better drop:p

[Sydneykid]

Hi Steve, I can't see Japanese PS on that site?

[jezzrrr]

Hey guys, give me a break here, it was a hard Saturday night, alright?

OK, this is how I do the engine PS to rwkw calculation in a GTR.

579 ps X 0.9 = 521 bhp

521 hp / 1.34 = 388 kw

388 kw - 78 kw = 310 rwkw

Chris is right I use 60 'ish kw losses for (big gearbox and drive train) rear wheel drive Skylines (R33 and R34) and 50 'ish for (small gearbox and drive train) R32 GTST's. But this was an R34GTR so with them I have found it necessary to run the transfer case and centre diff and disconnect the drive shaft. So I added 8 kw to my usual losses on an R33 GTR in 2wd and 18 kw on an R32 GTR in 2wd. Experience tells me that a GTR looses about 85 kw in 4wd drive, so I don't think 78 kw is too far wrong.

So maybe my sceptical bone is out by a few kw's, Jack Daniels will do that to you.  But I don't think it alters the argument.

As for HKS revising their max power outputs on GTRS's, well there are two answers to that one;

1. HKS are so dumb they published the figures first with out testing them properly.  But the Pheonix car only made 579 ps (that's 290 ps each) which is a lot closer to the 310 ps rating than it is to 330 ps.

2. HKS want to sell more GTRS's

Either way, it makes my sceptical bone ache a little more.

1PS = .7355KW

1HP= .7457 KW

Also we are talking about GTSS's here, not GTRS's, must have been a good night in Sydney last night !

Cheers

Jeremy

[Merli]

Hey guys, try this nifty little program for all your conversion needs

ftp://ftp.andrewho.com/pub/warez/convert.zip

[Steve]

SK, didnt realise Japanese had a different ps??? must be the the sphincter of the universe:)

Merli, thanks for the link

[DoughBoy]

Regardless of what some websites claim, I'm still pretty skeptical about the output of GT-SS turbos. Merli's car should be pushing them to their max flow, there's another R33 with them installed without internal mods (apart from cams). Will try to get a copy of a dyno sheet when it's available.

As to manufacturer quotes and idealised output ratings - can you tell me one manufacturer, distributor or turbo sales outlet who's turbos actually put out the power they claim? Even when used in a twin configuration the power is less than the sum of the two parts.

Oh, and I think we're pretty much splitting hairs on the whole GT-SS thing - until you see anything first hand I wouldn't believe it.

[RS500]

just my 2c,

we all know that on the HKS Japan website, they claim that the RB26DETT (with GT-SS turbos) makes 422kw (574ps) @ 7070rpm on 1.4kg/cm2, although has anyone noticed that the engine capacity of the RB26 has been increased to 2628cc over the standard 2568cc along with the 264/264 cams?

Also fyi, the wheel specs on the SR20DET GT-SS differ from the RB26DETT GT-SS where the SR20DET spec GT-SS has slightly larger wheels and an A/R .60 comp housing compared to the A/R .42 on the RB26 spec GT-SS.

http://www.hks-power.co.jp/products/turbo/...ss/ac_gtss.html

personally, i don't think the GT-SS (for the RB26) is rated at 320ps, i believe that it is a marketing thing and that it really is rated at the original 280ps.

again, this is just my 2c, so think of it what you will.

[Merli]

Yup

Truth be told, I don't believe the new 320ps rating either... I think 280ps is more accurate, but I guess we'll see when my engine gets done.

With my engine build, I'll pretty much be able to push these turbos to their absolute limit, so we'll see what these babies can do!

[Steve]

so whens it all happening? too much suspense on this forum:)

[Merli]

GAH... I dunno

Still waiting on some parts... Hopefully within the month!

[B-Man]

Good luck with it Andrew - Can't wait to see the results mate !

Cheers,

[BOOSTD]

Elithrar: 200rwkw is reachable @ 15psi with the stock unit, pfc, fmic and zorst.

Merli: Have you considered 2510's. I have been for a ride in an R with them fitted and I must say lag was not evident at all. The vehicle was fitted with external wastegates in japan. Bit of a strange set up however the bottle neck up top may have been relieved some what with the higher flowing gates.

[Merli]

Boostd: nope, never considered them. For me, the choice was either the larger top end of the 2530s or the response of the GT-SS, and I went for the most responsive turbos I could find on paper, which were the GT-SS.

I also wanted to try something new and not follow the GT2530 bandwagon

[BOOSTD]

Love that train of thought, If you don't try your will never know.