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

[Steve]

have just found a link (posted by RS500) to the 'claimed' power of GT-RS and GT-SS turbos on RB26, also links to alot of other HKS turbos at the bottom of the page.

show power at (EDIT) different boost levels. also shows the results seen here are nothing like what they 'should' be doing.

Anyways hope you find it interesting, I did.

http://www.hks-power.co.jp/products/turbo/...rs/ac_gtrs.html (GT-RS)

http://www.hks-power.co.jp/products/turbo/...ss/ac_gtss.html (GT-SS)

[Merli]

show power at 1 bar.  also shows the results seen here are nothing like what they 'should' be doing.  

Sorry, I've only looked at the GT-SS one so far as that's the only one that pertains to me...

The graph shows that it was running 1.4 bar, not 1 bar and why is it "nothing like what they should be doing"???

It's making 574.3PS @ 1.4 bar, which I would be very happy with?

Perhaps you have misread the graph.

The RED line is "pawaa" (power),

The GREEN line is "toruku" (torque), not stock turbo power

[Steve]

oops didnt notice the 1.4bar, I had looked at a few of the GT25 series first

I was saying 'should' because the only dyno on here from GT-RS doesnt look anything like the one on the site. I would be more than happy with 574.3ps, very very happy.

A good turbo will only be as good as its weakest link - and fine tuning can take alot of time and money before the true potential is realised. Hopefully I will be able to back that up with dynos pretty soon, the car is going in for a retune on monday with new 90mm exhaust, intercooler to TB pipe (3" instead of the old 2.5) and a 1 bar wastegate spring, up from the 10psi (or lower) spring that was originally in. (EDIT: even if the dyno doesnt show much improvement, driveability is hugely improved so I will still be happy)

the website shows the potential of the turbos, which is good, as anything less indicates a there could be a problem elsewhere - just like I knew I had a problem with my GT30 setup when you were making more power at lower revs from a bigger turbo:)

[Merli]

Ahhhh... I see by "also shows the results seen here are nothing..." you mean seen here as in SAU, I thought you meant the HKS page

Those graphs aren't too much use as they don't show the curves in relation to the stock turbos, so they look fine as they are, but if you overlaid the stock turbo graph on top of that GT-RS one, you'd see just how much bottom end you're losing.

Even just looking at that GT-RS curve, it looks abysmal for bottom end response... But then again that might suit some people... Depends what you're after really

Also that GT-RS graph is run at 1.8 bar :wassup:

[Steve]

True, but still has a decent wide power band up top, like you say, depends on what you like.

[Sydneykid]

Hi guys, you should really list all the upgrades those nice fresh R34 GTR engines have, I don't think it is fair to simply look at the turbos as the sole reason for the results;

What about the effect of;

HKS 264 degree Camshafts

HKS forged oversized (87 mm) pistons

HKS Exhaust

HKS split dumps

HKs Intercooler

HKS Fcon V Pro

HKS head gasket

No AFM's

Balanced internally (probably)

Ported (maybe)

That's a hell of a lot more than a turbo change. And the $ signs at HKS prices!!!!! I need a drink.

[Steve]

Hmm, so how many of the things that you list would most people have not done already before they update the turbos?

Cooler? probably not

Exhaust? probably not

Split dump? probably not

oversized 86mm pistons? how are 86mm pistons oversized?

ECU - probably not

Balance - not really needed for an 8000redline on a GTR or arguably a GTS

Head gasket? I thought you said the stock one is fine?

Proted? maybe not

Cams? How many big HP engines do you build with stock cams?

Better make it a double:p

[Sydneykid]

OK Steve, what if I did all those upgrades and used a standard pair of N1 turbos? Then did a comparison, would the HKS GTRS's still look that good? Or the other way around? Just stuck the GTRS's on and did nothing else, would they look as impressive then?

An engine is a result of the sum of its parts, and I don't think it is fair to publicise the results of a turbo upgrade costing $6K, when the other parts that contributed to the result cost $20K.

BTW, I don't know anyone stupid enough to pull an engine down to fit forged pistons, bore the block and not balance it while it is apart. And I think a RB engine (any RB engine) needs balancing to run decently at 4,000 rpm let alone 8,000 rpm. They are no better balanced than any other modern engine.

PS; I was editing the typo 86/87 before you posted, so don’t get smug about it, OK? Next time I am in Adelaide it's my shout.

[Steve]

OK Steve, what if I did all those upgrades and used a standard pair of N1 turbos?  Then did a comparison, would the HKS GTRS's still look that good?  Or the other way around?  Just stuck the GTRS's on and did nothing else, would they look as impressive then? 

An engine is a result of the sum of its parts, and I don't think it is fair to publicise the results of a turbo upgrade costing $6K, when the other parts that contributed to the result cost $20K.

Dont know about the N1s, but would like to see a comparison.

You dont think its fair? I dont think it would be fair to fit a $200 fuel pump, stock exhaust, and a ryco replacement panel filter - to try and show what twin 400ps turbos can do.

Wouldnt really give an accurate picture, a bit like only reading a compressor map, and not making sure every thing else is up to scratch, then expecting 700ps. Do you know anyone that would buy turbos touted to produce 710ps, and expect to see 710 on a car that was only making 280 from the factory without changing anything else?

At least they show the mods, not just a dyno printout, or a compressor map;)

PS; I was editing the typo 86/87 before you posted, so don’t get smug about it, OK?  Next time I am in Adelaide it's my shout.

Yeah, I knew it was a typo, just couldnt resist, but I will still take you up on the shout:)

By the way, did you see the dyno for the T51R with 2.8L - if only I had an RB30...

[Merli]

Hi guys, you should really list all the upgrades those nice fresh R34 GTR engines have

Why should all that be listed? I would take all that for granted if you're bolting on GT-RS turbos to your engine. You'd EXPECT the engine that they're bolted on to be a fully built and balanced engine, and most probably bored and stroked as well.

Remember we're talking about HKS's largest low mount turbo upgrade here, rated at 700ps, with the next step up being twin high mounted GT2835Rs.

Also, I don't think it matters what the engine has had done to it. The more the better, as that's showing the TRUE potential of the turbos. All those mods aren't necessary, but help let the turbos run more efficiently and produce what they're capable of.

In fact, I would go as far as saying if you DIDN'T have all that, THEN you should state as much, so we would realise that you're not pushing the turbos to their true potential. Not the other way around like you're suggesting.

[the phantom]

By the way, did you see the dyno for the T51R with 2.8L - if only I had an RB30...

...where???

[Sydneykid]

I can see you point merli, but what if I bolted them onto an RB31 and claimed 600 ft lbs of torque at 4,000 rpm? And full boost at 3,000 rpm? A standard capacity RB26 would never get even close. Would that be fair?

You are classifying the "true potential" of the turbo as merely being its ability to produce a maximum amount of power at one rpm point. To me its "true potential" is its ability to produce power over the rpm range that I use. And those other mods make a big difference to that, arguably more than they make to the maximum power output.

Plus you are right, the GTRS is HKS largest low mount. So that's a bolt on mod (light tune in Japanese speak). But then they pull the engine down (that's heavy tune in Japanese speak). There is an obvious mismatch here. In order to use GTRS's to their capacity you have to do an internal upgrade, the standard RB26 won't handle it. But doing internal upgrade usually means top mount turbos, for the same cost why wouldn't you? There are no rego problems in Japan, so there is no defect reasoning as there may be here.

Let's get out of theory and into the real world, I have spoken to 2 people here that have GTRS's. Both of them are disappointed with the results, most particularly the slow rate of boost build and poor response. Both cars have a fairly full sweat of bolt on bits, cams, exhaust, filters, ecu etc. But neither of them have any internal engine work done. One of them even said to me "that why I bought low mounts, so I didn't have to pull the engine out".

Hi Steve, I don't think your comparison is fair, you are downgrading from standard. I believe standard should be the starting point and list mods upwards from there.

Hope this is still on topic for this thread.

[Steve]

downgrades just used for example. you say upgrades shouldnt be used, but the same applies to an OEM car, bolt on turbos and expect 710ps???? no way. internals? unless its a 2JZ.

You say its not fair, but I can give you another example, my car didnt do what I thought it would when my turbo was fitted. Alot of people pointed their finger at the turbo, one guy who owns a tuning shop here (and its very well known, as he is) told me that the response was actually better than he expected. I knew there was more, and kept trying to work out where the weak link/s were. I found them, now the turbo is realising its potential.

If I had never seen what the turbo could do, I probably would have been happy with its less than optimal performance. Knowing what it could do, I wasnt happy, but at least I knew the problem wasnt the turbo itself.

If I wasnt sure about the turbo, I could have spent alot more time and money trying to fix it - thinking it is not correctly matched to my engine. Would have been a waste of time and money.

Example: B-man, buys a GT30 suited to RB25, garret. Gets it on, it doesnt do what it is supposed to, so, the car is going to be off the road a while longer, he has to remove the turbo, return it (they offered to fix it - kind of the company to do R&D at the customers cost eh?), get it back, fit it again, retune, hope that it works properly. Being an unknown quantity, how could he know what the turbo was capable of doing on his car? Read a compressor map, and then start guessing as to what turbine wheel, trim, housing AR?

How would he know if he hasnt got a problems somewhere else? Its one more potential weak link, or unknown quantity - after all, the performance is, as you stated the sum of the parts - more variables means more R&D, more cost, more time with the car not doing what you want it to.

In the end, instead of the added expense of sending the turbo back and forth, then the added expense of the fit/remove, retune, additional time off the road - he decided to go a HKS3040. How could people recommend them to him? because they know the potential of the turbo. Did he try and bolt it on to a stock engine to get the results he wanted? Of course not.

It is a real shame that the GT-RSs arent working well on the cars that they have been fitted to in Aust. You could look at the info on the HKS website and scream unfair, or you could look at the info and find out exactly what has been done to those cars - compare to your own setup, and then be in a postition to learn and improve your own car.

It doesnt appear to be just HKS that have had good results with the GT-RS, so what are they doing? why not learn from the poeple that started it all?

Or, HKS are full of shit, and deserved to be sued for false advertising

[Merli]

Absolutely that would be fair!! Why do you think it wouldn't be fair? Whatever, you're just proving what the turbos are capable of. If they need a 3100cc engine to work optimally, then so be it!

You are classifying the "true potential" of the turbo as merely being its ability to produce a maximum amount of power at one rpm point. To me its "true potential" is its ability to produce power over the rpm range that I use. And those other mods make a big difference to that, arguably more than they make to the maximum power output.

I never said that. Please don't assume that everyone on these forums are just concerned about peak power, I'm much more interested in area under the curve, so that's quite insulting that you reduce me to such simple mindedness...

And you say that because the GT-RS are a low mount turbo, it's a light tune. How's that? In Japan, "Light tune" means any modification that doesn't involve building the engine. I could strap on a twin GT3240 kit on my stock RB26 without touching internals... Do you then classify that as a light tune, or do you say I'm stupid for using those particular turbos without the engine to support them? Why can't you say the same for people using GT-RS on standard RB26s? Just because they're low-mounts, it doesn't mean that they work best with standard RB26s... The results we have all seen suggest otherwise.

I'm not sure if you read the GTROC UK forum, but they went through these same conversations about 6 months-1 year ago and only realised good results from the GT-RS with bored and stroked engines 2.8L and above... If that's what the turbos need to work efficiently, then so be it. They're simply too big for 2.6L... Doesn't mean that they're crap now does it?

[Sydneykid]

Hi Merli and Steve, a bit of controversy, excellent...........

When I write posts, I write them for the all the people who read, so I apologise if it sounded like I was insulting anybody, I wasn't, I promise.

OK Merli, are GTRS's Light Tune or Heavy Tune? Since you have to pull the engine to get them to work as HKS advertises, then they must be Heavy Tune right?

My opinion and the opinion of the 2 X local GTRS users, prior to buying them, was that they were Light Tune. Otherwise why make them low mount? It's oxymoronic. Obviously the UK forum guys were of the same opinion, otherwise they wouldn't be disappointed.

Look at it the other way, if I built a 2.7 or 2.8 litre RB26 why would I use GTRS's? If I had gone to that trouble and considerable expense, personally I would use a pair of high mounts with an external wastegate. Why? Because I would get a better result (higher average power) for less cost. As I said before the only reason would be rego, which is simply not an issue in Japan.

I honestly think it is misleading advertising. But don't ask me, ask the guys who bought the product what they were lead to believe.

PS; I never said GTRS's were crap, I actually think if I do another road GTR with a 3.1 litre in it, I might give a pair of GTRS's a go. It would save some rego hassles, which seems to be becoming more of an issue every day. Looking at the dimensions, the sizing looks logical, 2530's on a 2.6 litre and GTRS's on a 3.1 litre.

Enough from me on this subject.

[Merli]

OK Merli, are GTRS's Light Tune or Heavy Tune?  Since you have to pull the engine to get them to work as HKS advertises, then they must be Heavy Tune right?

My opinion and the opinion of the 2 X local GTRS users, prior to buying them, was that they were Light Tune.  Otherwise why make them low mount?  It's oxymoronic.  Obviously the UK forum guys were of the same opinion, otherwise they wouldn't be disappointed.

I honestly think it is misleading advertising.  But don't ask me, ask the guys who bought the product what they were lead to believe.

To me, being low mounts, it suggests that they are meant for light tune, stock capacity RB26s... Whether or not that constitutes "misleading advertising" or not is something we could talk about until the cows came home.

Fact is, before I had even read anything official from HKS about the GT-RS, I had people telling me that "oh there's the duck's guts" and promised everything the 2540s were meant to be and so much more... I remember quotes of "Oh they'll spool faster than 2540s and make more top end"... Well now I can think back and say "What a load of rubbish."... 20/20 hindsight

From those (uninformed) reports, I guess I formed an opinion in my mind that they were light tune upgrades and suited for stock capacity RB26s... I'd bet my house on the fact that that's what led the first GTR-owner pioneers when they ordered their GT-RS turbos... Not information from HKS, rather the promise from uninformed sources that they were worth their weight in gold.

[Steve]

sydneykid, if you are building another RB31, have a look at the T51R specs, the dyno is with an RB28

http://www.hks-power.co.jp/products/turbo/...p/waste_sp.html

not so shabby either, less cost than twins:)

[DoughBoy]

sydneykid, if you are building another RB31, have a look at the T51R specs, the dyno is with an RB28

http://www.hks-power.co.jp/products/turbo/...p/waste_sp.html

not so shabby either, less cost than twins:)

Shhh, I wanted to be unique with that setup!

[GiJOr33]

yeah it does look good... boost at 3000rpm full boost at 4000rpm or so and just over 650kw to match! That would be sweet on a 3.1lt you'd probably have full boost by 3200rpm and a nice fat power/torque curve to 7500rpm

[DoughBoy]

Have to wait a few weeks for teh engine dyno chart.....