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

[kwazza11]

rb20 calais, whats your expected power output from that turbo?

[kwazza11]

rb20 calais, whats your expected power output from that turbo?

[warrick]

Sydneykid,altering your original example,out of the following 2 turbos which would give the best street driven performance,hks2835pro or gt25r,allowing for the fact that i am aiming at a max. 250rwkw.i take it from your example that the gt25r would need less boost & spoolup quicker or am i wrong in this assumption?which would stress the engine less?which would you choose?forgetting the cost of the turbos.the mods you listed are the mods on the car.

thanks for your excellent advise as always.

cheers

warrick

[JimX]

RS500, out of interest why would you stay away from the T04E? That's what my turbo is and it seems very similar to yours with regards to full boost (at around 1 bar) and power output. I think that the Cosworth engine is only 2 litre as opposed to my 2.5L, but keep in mind that my power output of 214rwkw is at 1 bar and also with a weak wastegate actuator. I'm pretty sure I can get the same power with less boost once I replace it with a stronger one.

[Steve]

Originally posted by RS500

......proof for me was when i had my engine tuned with the following spec turbo;

* T04B 60-1 compressor wheel (in A/R .60) and  

* T03 sierra exhaust wheel (in T03 A/R .84 housing)  

this combo on my car/engine (sierra cosworth RS500) recently produced 221rwkw .........

......... 'eg, rated 450hp at 1bar' but this to me is all crap, as u see that to get the rated hp (which garrett/hks quote), you need to push the turbo way past 1.3-1.4 + bar of boost  

That is good power, but I have seen better from a HKS turbo (2530 on RB20) so really unless you have both turbos on an identical car, the comparison proves nothing unfortunately.

Where did you hear that HKS power ratings are over 1.3-1.4 bar. That would be interesting as I was under the impression that both garrett and hks rate the turbos at 1 bar?

My evidence is the same HKS 2530 that I mentioned before. Now HKS rate this turbo at 320hp = 235kw.

How is it then making over the rated power at 1.2 bar, ie 230rwkw or 290 engine kw (assuming 60kw drivetrain loss) or 395bhp which is 75 hp over what it is rated at, and it still hasnt reached the 1.3-1.4 + bar that you state is needed?

I dont see why people have to knock a turbo just because they dont have one.

[R34GTT-R]

What about if i bleed the excess boost away from TB and run the turbo ay its premium bar level ??

[RS500]

Originally posted by JimX

RS500, out of interest why would you stay away from the T04E? That's what my turbo is and it seems very similar to yours with regards to full boost (at around 1 bar) and power output. I think that the Cosworth engine is only 2 litre as opposed to my 2.5L, but keep in mind that my power output of 214rwkw is at 1 bar and also with a weak wastegate actuator. I'm pretty sure I can get the same power with less boost once I replace it with a stronger one.

JimX,

i was told this by a friend that had tried a few different T04E wheels on both a 13b rotary engine and a VL (RB30ET) as he didn't get the same results (power/drivability) he did as compared to the T04B wheels.

yes, the cossie engine is only a 2L 4-cyl, and is definietely capable of making a heap more power with a bit more rpm (as max power was made at 7000rpm rev-limiter), boost and tuning, but given that you still have the extra 500cc and possibly the weak w/gate actuator, yes, you should be making more power than mine at any boost level. I would expect that.

btw, what wheels do u have in your turbo?

Originally posted by Steve

i) That is good power, but I have seen better from a HKS turbo (2530 on RB20) so really unless you have both turbos on an identical car, the comparison proves nothing unfortunately.  

ii) Where did you hear that HKS power ratings are over 1.3-1.4 bar. That would be interesting as I was under the impression that both garrett and hks rate the turbos at 1 bar?  

iii) My evidence is the same HKS 2530 that I mentioned before. Now HKS rate this turbo at 320hp = 235kw.  

How is it then making over the rated power at 1.2 bar, ie 230rwkw or 290 engine kw (assuming 60kw drivetrain loss) or 395bhp which is 75 hp over what it is rated at, and it still hasnt reached the 1.3-1.4 + bar that you state is needed?  

iv) I dont see why people have to knock a turbo just because they dont have one.

Steve,

i'll just go in point form so we don't get confused.

i) you have a fair point about the HKS 2530, but my point was that for less $$$ than what you'd buy a 2nd hand HKS 2530 for, you'd make the power you want with a 'brand new' plain-bearing turbo (such as mine for eg,) with less boost. I'm sure the HKS 2530 can make more power than what i did, but it would be at the stated '1.3+ bar' boost unless your engine has decent sized cams and a ported which means more $$$ on top of the expensive HKS2530. correct?

ii) everyone on this thread and this forum is writing that most HKS/Garrett turbos need to be pushed higher than 1.4 bar boost as to be in their 'efficiency range' and to make to rated hp.

Also, a couple of friends have bb turbo's on their cars and they needed to push them a little harder than the expected 1 bar as to make to 'quoted hp'.

Yes, HKS/Garrett turbos theoretically rate their turbo's supported hp at 1 bar, but you tell me how many engines have actually made the 'turbo's rated hp' at the engine on 1 bar boost.

iii) i could be wrong but i don't think the HKS 2530 can make 220-230rwkw on 1.2 bar with a standard engine. cams and a ported head would definitely be required.

I guess this is where we are going, for the bb turbos to run in their optimum/efficiency range and produce close to the rated hp, they would depend on the volumetric efficiency of the engine to be high, hence the requirement of cams, ported heads, etc.

iv) i could've gone for any turbo in the garrett/hks gt range, actually i was very keen on ditching my current turbo and going for a garrett GT30 combo b/c of the same comments/reasons which are mentioned in this thread, but i chose to stay with what i have as i got the same power delivery (if not better) than what i would've with a gt turbo which would've cost me atleast $700-800 more. i guess i can now spend the $$$ i saved on buying the plain-bearing turbo on regrinding my cams and making more power again

anyway, i don't to start a shit fight, but what i was trying to say was that you could get the same power/drivability from the older plain-bearing turbos w/out spending the $$$ on a bb turbo.

[JimX]

RS500, I have absolutely no idea what my wheels are All I know is the AR, which is 0.6. The turbo was identified by an engineer at Garrett in Chipping Norton, because it doesn't have "T04E" stamped onto the housing.

I've got a humungous power/torque spike at around 4500rpm, but then it dips and surges as the wastegate fails to cope at 15psi. I'm looking at getting this fixed relatively soon, but until then I'm dropping the boost to around 12 or 13 psi. The power doesn't feel any less at this lower boost because it wasn't holding maximum boost before anyway.

[RS500]

Originally posted by JimX

RS500, I have absolutely no idea what my wheels are All I know is the AR, which is 0.6. The turbo was identified by an engineer at Garrett in Chipping Norton, because it doesn't have "T04E" stamped onto the housing.  

I've got a humungous power/torque spike at around 4500rpm, but then it dips and surges as the wastegate fails to cope at 15psi. I'm looking at getting this fixed relatively soon, but until then I'm dropping the boost to around 12 or 13 psi. The power doesn't feel any less at this lower boost because it wasn't holding maximum boost before anyway.

JimX,

that's cool re: wheels.

what exhaust housing are u running?

by changing your actuator and the tension on the spring, you will feel a big difference on how the boost comes in as you are possibly getting a lot of boost creep now which would be making the boost come in that late.

a friend had this kind of problem with his R32 GTS-T as he re-used the factory RB20 turbo actuator on his 400hp gt25, but when it was changed to a 1 bar garrett actuator, boost came in much earlier and held it better across the board.

good luck and let me know how you go with it.

[rb20-calais]

kwazza11,

i am hoping for around 230rwkw on 1bar of boost, i hope this is achievable.

Evan

[Steve]

RS500, to address the points you made:

i) I know a guy who picked up a HKS 2530 for $1200, doesnt happen often, but if you hunt around but you are right, you can buy a bush bearing turbo cheap, which is a good thing because some people may not have the budget, or want to spend the money on a BB turbo or HKS turbo - nothing wrong with that, and I dont really think it is part of the argument for/against HKS or BB turbos.

I dont think you read my above post very carefully.

HKS 2530 (rated by HKS at 320ps) made 230rwkw at 1.2 bar boost - that is 395bhp. I dont think that a turbo of this size is going to make an additional 75hp on .2bar (3psi) THEREFORE HKS UNDER RATE their turbos, not over rate them.

Not the beauty of a HKS turbo is that it will just keep going, where a garrett will be at about its limit by now - HKS turbos reach their max efficiency at 1.5BAR + This means that a HKS 2530 at 1.2 bar will be able to make MORE than 395bhp - lets see a bush bearing or even ball bearing garrett garden variety turbo do that.

My point is that while HKS are more expensive if you want the best you will have to pay that bit extra but like every thing else in cars - getting the most out of something, usually increases the price exponentially.

ii) I just dont agree with that statement.

iii) the engine was completely internally stock, no head work, cams etc ONLY FMIC, pod, 3" exhaust, fuel pressure and a fuel pump - This is exactly my point, if you have a very good turbo, not much else is needed.

iv) how can you make such claims, have you driven your car or same type with the same mods, with a properly matched HKS or Garrett BB turbo? Until you do you will never know what you are missing - you are just fooling yourself.

I really just dont know why people insist on trying to say that you can match (with many years experience you may come close) the massive amounts of R+D and the design propriety of a company that lives purely for high performance.

This has only been possible because of the huge consumer market for these turbos in japan, litterally thousands of these turbos floating around in japan, how many cars in aust have turbos fitted? How many years, with access to the facilities that multi million dollar corporations provide, have people in australia had.

RS 500, if you have managed to match a HKS turbo with a bush bearing turbo for performance, using standard off the shelf parts - you will be a very rich man. HKS would probably employ you.

[EVOIV]

This Garrett vs HKS debate has been around for a long time now. To settle this, what really needs to be done is testing an HKS turbo with the near equivalent Garrett turbo on the same car, under the same conditions. Many people say Garrett are just as good as HKS, people say HKS are a lot better than Garrett. I don't think anyone really knows unless they've seen it.

All that I can say is that the world seems that HKS is more reknown than Garrett. For performance cars anyway. Would anyone disagree? Now one possible explanation is that HKS turbos are featured in many more world reknown cars, hence boost their popularity. It's just like "Sony". Obviously they did something right to gain such a name. But just like Sony, HKS turbos are far more expensive than their seemingly equivalent counter parts. Having said that, doesn't necessarily mean that all HKS products are superior. As I am sure you will find that some things made by Sony aren't the best, and there is a lot more competition out there that is just as good, if not better! Same things go for turbos, and everything else on the market.

One thing that I am sure of is that HKS turbos are not the same as Garrett turbos, and therefore there obviously must be a difference. Also, it is well known that HKS turbo are more efficient at higher boost than Garrett turbos. But I have not seen the proof, but if it's such a big "rumour" then there probably is some truth to it. As for which turbo makes more power, or responds better...I don't know.

[JimX]

Originally posted by RS500

JimX,

that's cool re: wheels.

what exhaust housing are u running?

I don't know what exhaust housing it is, but it looks really cheap and crappy! It's just got a single round outlet that's the same size as the dump pipe (maybe 2.5 to 3 inches? a little smaller than the 3.5" for the front pipe and cat-back anyway). Most of the other turbos I've seen have a square outlet with a partition down the middle which would suit a split dump pipe really well, but in my case I think it'd be a waste of money (if it would even fit).

If anyone knows of a way I can cheaply upgrade this to a bigger split outlet, please let me know.

I'll be upgrading the actuator hopefully in a couple of weeks.

[RS500]

well, i am of the opinion that the same kind of performance can be produced by the garrett gt series over the hks gt range, as when doing my own comparisons, i have seen many similarities in wheel trims/dimensions, etc although the difference in housing A/Rs was interesting as the biggest A/R u would see on a hks gtxx turbo is a .60 whereas almost all garrett gtxx turbos have an A/R .70.

this is where the difference in response and efficiency comes into play.

EVOIV is right, it's just that hks has a lot of their turbos on the quick cars in japan, it makes people think that they are better, and that's why people aren't using garrett's equivalents.

Steve,

i have not managed to find the hks equivalent in a plain-bearing turbo but i have seen the equivalents in the garrett gt range.

i'd love to be able to do a direct comparison on my engine b/w for eg, the HKS GT3037S and the equivalent Garrett based core (i have found) with the same HKS housings as to see the real difference, but i don't have the access to these turbos and to buy them outright is a lot of $$$ which i am not prepared to outlay.

[Sydneykid]

Hi guys, I have 2 turbos with identical compressors, turbines and covers except one has a ball bearing core and the other is plain bearing. Surely no one believes that the plain bearing core is going to be as responsive or last as long as a ball bearing one?

A ball bearing core will have at least 75% less frictional load than a plain bearing and it does not required a thrust plate which is the largest area of concern for accelerated wear. In addition a ball bearing core can run for short intervals with low oil pressure(such as on the circuit with oil surge). On the other hand a plain bearing core will fail instantly.

I won't even bother getting into the durability issues of a water and oil cooled ball bearing core versus an oil cooled plain bearing one. It's even more obvious.

What the decision process is all about, is what compressor, turbine and covers work for my power target. Any discussion over plain bearing versus ball bearing was all over 15 years ago for me. I simply got sick of changing T04's on Sierras, 6 in one weekend of racing was rediculous. We stuck a ball bearing core in it with exactly the same compressor, turbine and covers and at the same boost it made 25 bhp more. The response was improved, as was off boost driveability, but they were still crap compared to what we achieve now.

rb20-calais asked "for around 230rwkw on 1bar of boost". My experience is simply, no chance. The resistance to airlfow within an RB20 means they need around 1.3 bar to make 230 rwkw. And that's if they are in good condition internally. Maybe you could make it by improving the efficiency (read previous posts) but why would you bother? Boost at 1.3 bar is not going to hurt an RB20 any more than 1 bar would, as long as you have the appropriate support systems.

RS500, I think I need to re-emphasise my point on improving the efficiency. It has been my experience that upgrading the efficiency of the engine (camshafts, cam timing, ports etc) produces more power in the mid range than it increase the single maximum power output. A faster car is one that has the higher average power over the RPM range used. Chasing the one single higher maximum HP at one RPM point may in fact result in slower acceleration.

Plus there is the issue of response that has to be considered, a more responsive engine of the same max power will always be faster. This is particularly noticeable at gear change points where a poorly responsive engine can loose valuable time recovering.

Hope that adds to the thread

[RS500]

Sydneykid,

point taken although i have a comparison which i usually go by b/w my engine ; a YBD 16v twin cam 2L sierra cosworth engine with the 60-1/T03 sierra wheel (A/R .84 split-pulse exhaust housing) turbo and my friend's 24v twin cam RB20DET with a 400hp Garrett GT25 (-0032 core) with a A/R .64 exhaust housing.

now the drivability of both cars is almost the same (apart from my friend's car having the lower 4.11:1 diff ratio over the 3.64:1 my car has and different g/box ratios) where full boost comes in at about 4200rpm on both engines, but he has slightly more power throughout the rev range.

anyway, my engine managed to make almost the same power as him (me - 221rwkw : 16-17psi vs friend - 227rwkw : 20-21psi) on less boost on the same dyno.

So i'm sure if i was to go down to a A/R .63 exhaust housing on my turbo, it would perform just as good (if not better) as the GT25 my friend has throughout the rev-range.

therefore, i am still of the opinion that a good combo in a plain-bearing turbo will perform almost the same as a Ball-bearing turbo and for the amount of $$$ u save, it's worth going for that option due to rebuilds don't cost very much and there are many interchangable parts.

btw, my turbo is both oil & water cooled and it also has a full 360 degree competition thrust bearing.

P.S. what turbo combinations were you guys using on the sierra's back 15 years ago and what kind of hp were u guys making at what boost levels?

[Sydneykid]

Hi guys, there is something missing here, HKS do well in Japan but I don't think it is because their turbos are superior in all aspects. Fact is HKS have a much higher selling price and they use the difference to promote their products. Advertising, show cars, free product, kick backs to leading tuning houses etc etc. That's Marketing 101.

Also Japan is a very different market to Australia. To generalise, they have a "bolt on" culture. They want the best performance with the quickest bolt on products they can find. Good mechanics charge like brain surgeons, so the quicker the car gets in and out of the workshop the cheaper it is. This can easily outway the higher cost of the product being fitted.

This is simply not the case downunder, our machanics are used to making do with wha tthey have got and charge (generally) much more reasonable rates.

So lets get the facts down as I see them....

1. HKS use Garrett cores unmodified, the ball bearings, shaft, seals, oil supply, water cooling etc are exactly the same. This is the most expensive part of a turbo. This is what determines the durability, so HKS turbos will not last longer than Garrett turbos.

2. The turbine and compressor covers are machined from Garrett castings, so the are no major differences here ie; I can machine a Garrett cover to fit HKS wheels easily. In fact a large number of them are unmodified Garrett covers. As well as performance, this also contrubutes to equal durability.

Leaving the only potential differences being the turbines and compressors. So you tell me how these two parts that represent less than 25% of the cost of a turbo can make the whole turbo cost twice as much? A little bit maybe in R&D. but by far the majority of the money goes into promoting the HKS name.

As for me, unless there is good reason, I am not paying extra simply so that HKS can further promote their name.

[RS500]

Amen

Sydneykid,

did u manage to read my last question to you re: sierra's?

[rev210]

This HKS Vs Garret thread is good to clear up some misunderstandings.

HKS use all Garrett bits, therefore they ARE Garrett turbo's, just HKS spec'd.

The worlds highest profile and expensive racing teams (like CART) DON'T use HKS turbos. They do however use garrett bits like HKS do and other brands and conduct their own research into the best fit.

Regardless of how much research HKS do on the turbo build selection, they are only able to 'best fit' it based on a particular engine spec and combination of parts like cam profile/head flow etc... other than that you may find you engine does not resemble the HKS test engine and will benifit from a little R&D.

Turbo spec. selection can be as fine tuned as you want, it all costs money. HKS have many turbo packages to choose from.

Are they the best ? --- Depends how close your engine resembles their testing base.

[Sydneykid]

Hi RS500, 615 bhp at 9,000 rpm with T04's at 2.5 bar for qualifying. Turbos lasted about 5 laps (ie; less than 10 minutes). That came down to 460 bhp at 2 bar so they would last a normal 20 lap race. At Bathurst, 2 bar but lower RPM for 420 bhp.

BTW, comparing a 4 cylinder 2 litre with a competition designed cylinder head with a 6 cylinder 2 litre mass produced engine is a waste of time. When you bolt a current generation turbo on your car without any other mods, then a comparison would be valid. I have and with no other changes the car was 5% faster and the turbo lasted 10 times longer (ie; 200 laps compared to 20). If it had bee nlegal to run a ball bearing turbo at Bathurst we could have run 480 bhp all day and would have won the race by over 3 laps.

Hope that clarifies