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

[Steve]

OK you win, you got the biggest one.

I havent heard one person who likes the 2540.

[Steve]

True Roy, BTW, the prices I quoted are not back yard rates, but a legit business with shop overheads and all the rest.

Intersting though, I think that unfortuneately for retailers, and fortuneatly for consumers, that people are being more savvy with their money, and I-business is becoming more and more a reality that needs to be accepted.

End of the day, you order over internet, or overseas, and you take whats coming - you buy from retailer and you know what you are getting and exactly how much it will cost

sorry a bit off topic.

[DoughBoy]

Although the price vs performance is an important factor, it's not really going to help a company that exports from Japan much. Garrett being much more of a global company would have more resources and opportunities to reduce overheads manufacturing these components. I wonder what retail prices of Garrett turbos are in Japan?

[meshmesh]

I prefer Garrett turbos because they provide compressor maps and I can therefore easily match them to my requirements.  HKS don't provide compressor maps and I refuse to guess as to whether they will suite my requirements or not.  BTW Apexi, Blitz and Trust don't provide compressor maps either.

HKS say that their turbos are designed to work efficiently at over 1.5 bar.  I never run more than 1.3 bar in my engines, there is simply no need.  I can match the Garrett compressor airflow to make all the power at that boost level I need.  I know that airflow makes power, boost is merely a measurement of resistance to airflow.

While I am having a whinge, I am not impressed with the magazines that continue to avoid answering this question.  They have the resources to do it, have scouted the edges a couple of times.  But they haven't gone and done a true back to back, same size turbo comparison from different manufacturers or rebadgers.  It is something their readers want to know, but maybe their advertisers don't.  Next time you are sending an email off to Zoom, HPI, Fast Fours, Speed etc why don't you ask them.

Sydneykid & others, "just a thought??"

I am willing to put up my GTR for a back to back comparison between the commonly used HKS 2530's, & the closest Garret equivilant "maybe the garret GT25", You say that you can match specs to suit requirements?? let me know what you need to know, & I will be willing to buy a pair of Garret turbos if someone can supply the HKS 2530 for the compare.

I'm sure the boys at ICE could orgainse something with ben from racepace for some dyno time. My mods are your basic gtr mods such as:

Power FC

HKS EVC IV

Full Exhaust "stock dumps"

Cam Gears

Don't know how difficult or big a job this would be between the two makes, but it's just a thought.

[Steve]

Would be good if you could get it done - very interested to see the results.

[Merli]

I have a GTR with GT-SS turbos going on in the next few weeks, and am willing to partake in the comparison as well.

[JimX]

Although the price vs performance is an important factor, it's not really going to help a company that exports from Japan much. Garrett being much more of a global company would have more resources and opportunities to reduce overheads manufacturing these components. I wonder what retail prices of Garrett turbos are in Japan?

Garrett makes HKS turbos. So if they save money on manufacturing I expect they would pass along at least some of these savings to HKS (and any other big customers of theirs). It's not like they'd be charging HKS anywhere near full retail price for their turbos anyway.

[MattSR]

Hi Sydneykid,

Quote:- "Hi Freebaggin, I can read a compressor map and choose a compressor and cover to suite my application. I then tell the turbo expert (we use GCG) what I have chosen and the engine spec and armed with this information he picks the turbine and housing to suite."

I've just got a quick question for you, I hope you can help. I know how different A/R's affect the turbine, and I have learnt how to size a compressor for the job, but I don't know what effect the compresor A/R has...

If you could explain this to me that would be great.

Cheers,

Matty.

[R31Nismoid]

Sydneykid & others, "just a thought??"

I am willing to put up my GTR for a back to back comparison between the commonly used HKS 2530's, & the closest Garret equivilant "maybe the garret GT25", You say that you can match specs to suit requirements??

I am up for that too.

I'm just about to have a GT30 installed within the next 2-3 weeks.

the exact turbo spec im not 100% on 'just' yet. But by installation time i will.

I need to get a set of injectors first so we can push the power up as i still have stockies, and that'll be approx 4 weeks later.

i'd probably need a PRF or something donated, i've only got a standard ECU with a chip to modify things.

Anyone in Vic wanna swap a HKS to my motor ?

i'll provide the car so we can get more details on this HKS/Garrett argument.

Same dyno, same day.

I've got ALL other mods, exhaust/cooler/intake etc.

And maybe can someone get HPI to cover it?

that way we can do the reasearch, get the figures over a few beers one day. and finally say,

Well that is that.

[Steve]

Thats what is needed, a bit of magazine coverage.

Something that I am sure would be a valuable and interesting read.

[Merli]

Absolutely... I'm sure we can get Ben to cover a comparo, and perhaps source some turbos for us to swap with.

High mount turbos like the GT30 on an RB25 would be a VERY easy swap to make with an HKS GT3040. But to make use of the HKS's higher boost and rpm threshold, you'd need to have done internals (at least pistons and rods)

I only had stock internals and the HKS GT3040 pulled all the way to 8000rpm without any sign of dropping off power, but that's not so good for stock rods

[Merli]

Actually, I was thinking about these HKS GT2540s having different compressor housings depending on what application they're for...

Apparently:

GT2540 for RB26DETT has HKS specific comp housing, GT2540 for RB25DET has modified Garrett comp housing with aluminium insert.

How can that be? Obviously the two compressor housings aren't the same. So how can they both be GT2540s if they're different turbos??

Hmmm........

[R31Nismoid]

Absolutely... I'm sure we can get Ben to cover a comparo, and perhaps source some turbos for us to swap with.

High mount turbos like the GT30 on an RB25 would be a VERY easy swap to make with an HKS GT3040. But to make use of the HKS's higher boost and rpm threshold, you'd need to have done internals (at least pistons and rods)

mine will be a low-mounted GT30

but yeah, i aint go internals at this stage.

that may hold us back a bit

[Guest INASNT]

have fun making it fit without hitting the block with the to4 manifold

[DoughBoy]

HyperRev #37

[Roy]

Garrett makes HKS turbos. So if they save money on manufacturing I expect they would pass along at least some of these savings to HKS (and any other big customers of theirs). It's not like they'd be charging HKS anywhere near full retail price for their turbos anyway.

On the surface that seems about right, but having worked in the manufacturing industry tells me that this may not be the case. If you look at a highly automated production line then the cost and down time associated with doing smaller runs using different components, Garret GT25/GT28/GT30 vs HKS GT25/GT28/GT30 turbos may in fact increase the costs.

Then on top of actual manufacturing costs HKS want their slice of the pie, just like anyon ein business they have their mark ups on top to make the whole thing viable.

[Merli]

Actually, I was thinking about these HKS GT2540s having different compressor housings depending on what application they're for...

Apparently:

GT2540 for RB26DETT has HKS specific comp housing, GT2540 for RB25DET has modified Garrett comp housing with aluminium insert.

How can that be? Obviously the two compressor housings aren't the same. So how can they both be GT2540s if they're different turbos??

Hmmm........

[Roy]

Apparently:

GT2540 for RB26DETT has HKS specific comp housing, GT2540 for RB25DET has modified Garrett comp housing with aluminium insert.

How can that be? Obviously the two compressor housings aren't the same. So how can they both be GT2540s if they're different turbos??

Hmmm........

Perhaps whilst they are physically different housings, the end result is the same, ie the internals have been machinded to be identical, so same compressor wheel with idential clearances etc etc????????????

[Warpspeed]

MattSR, in reply to your question about compressor cover a/r.

The cover is at least as important as the wheel trim in deciding the shape of the compressor flow map. All flow maps lean to the right, and the efficiency islands vary quite a bit in shape depending upon the wheel and housing combination.

Small compressor cover a/r will give a flow map that is tall and narrow. The efficiency islands will be stretched out along the tilt of the map. This works really well at high boost with a largish turbo, where the flow line rises at a steep angle through the centre of the tilting flow map. Matching will be pretty critical though, and the wastegate will remain shut right up to almost redline. This sort of matching would be used where the exhaust turbine is very large and you want maximum top end power at relatively high boost levels. (drag racing).

A larger a/r cover would produce a flow map that is not as tall, but much wider. The efficiency islands will be rounder, and there will be a much wider flow range between the surge line and the choke region. This works best where you run a small exhaust turbine and arrange for the wastegate to open at lowish engine RPM and hold boost constant up to redline.

In this type of matching the flow line on the map will be horizontal, because boost is constant over a fairly wide engine RPM operating range. Also boost will probably be lower for this type of application (street car).

I had a long discussion with a Garrett applications engineer (Geoff Lotterman) in the US on this topic, a few years ago.

I have no idea, but the fact that HKS are supposed to be better matched for higher boost levels suggests they may be using smaller a/r covers, I don't know this for sure though. The Garrett GT turbos seem to have huge covers, and can be a bastard to fit in some installations.

Does anyone know for sure about the comparative a/r of similar trim HKS and Garrett ? It might explain a few things.

It may very well be, that a Garrett GT may actually be BETTER than an HKS for a low boost road car ? Wouldn't that be something !

I strongly suspect Garrett have optimised their turbos for mass produced OEM applications, and HKS for all out racing applications. Both are good, but one might be more suitable for YOUR application.

[GiJOr33]

Good info Warpspeed... thanks for that. That's answered a couple of questions i've had for a while about flow maps.

Cheers,

Andrew