Will HKS 2530 give me 250rwkw

[ed]

Sydneykid, do you know the turn around time GCG need to hiflow a turbo? Having a daily driver out of action doesn't appeal to me.

[Sydneykid]

Hi ed, as far as I know they have the common exchange units (RB20/25/26/VG30), so you can swap them over on the spot. If you book in advance they can probably do yours in a couple of days. Ask them I guess.

[ed]

exchange units sounds the goods.

Might hafta give 'em a call

[whatsisname]

Originally posted by Sydneykid

Hi Guys, we have an RB25DET that at 1.2 bar makes 240 rwkw or 320 rwhp or 300 kw or 400 bhp (whatever way you want to express it).  It did a 12.4 at Eastern Creek with standard weight.

Sydneykid,

Any idea of the 60' & terminal speed over the 1/4 for this car? And what tyres was it using? Thanks mate

[Guest INASNT]

sydneykid

i was hoping u would reply to my thread, since u got alot of knowledge in this field!!

So GCG can supply a preety good replacement unit for $1800. Is 1.2 bar the max you could push one of em or is there abit more left in em?

Do GCG have a vic outlet?

Can u supply us with an dyno graph of the 240rwkw r33 also!

cheers

[judd]

GTR-S turbo is the way to go.....be first be original...ppl have proven them with 200sx but no GTS-T as yet. 400PS (not HP)

the specs are awsome.

[Guest INASNT]

Originally posted by judd

GTR-S turbo is the way to go.....be first be original...ppl have proven them with 200sx but no GTS-T as yet. 400PS (not HP)

the specs are awsome.

and so is the price

[Sydneykid]

Sorry Judd, but I have to disagree. If you look at the power curve of the GTRS equiped SR20 closely you can see that it really needs a close ratio gearbox to take advantage of the peaky power delivery. For example, on the gear change up from first to second gear, it drops from 400 ps to around 200 ps. This slows down the acceleration of the car dramatically as it spends a long time at this low power output until the revs and boost climb back.

I believe that the car would be faster accelerating if it had a lower maximum power output but a better power curve. As an example a Garrett GT28BB with this spec;

0.64a/r Turbine Housing

0.70a/r Compressor Housing

48 Trim Compressor Wheel

76 Trim Turbine Wheel

Makes 375 bhp max, but has more than 250 bhp after the gear change up from first to second gear. Thus equipped it would be noticeably faster accelerating than the above example.

Bottom line, I have the compressor map for the Garrett and I can see this result, I don't have anything on the HKS as they don't publish compressor maps. Yeh, I know they say they don't publish them to protect their intellectual property. That's simplistic, the other turbo manufacturers are so busy with their own development programs they couldn't be bothered. Plus if they really wanted to know they would just go out and buy one and pull it apart. They don't help with the necessary information in choosing their product, so I don't choose their product. It's that simple.

Hope that made sense.

PS; somebody asked some questions, see next post...........

[Sydneykid]

Hi whatisname. you asked "Any idea of the 60' & terminal speed over the 1/4 for this car? And what tyres was it using?"

Car was a R34GTST, tyres were Mickey Thompson and the 60' was 1.8 something. I can't remember the terminal speed, it's listed in the HPI drag table.

Hi inasnt you asked "So GCG can supply a preety good replacement unit for $1800."

That was about 18 months ago, so it may be a little more now.

"Is 1.2 bar the max you could push one of em or is there abit more left in em?"

Oh no, we have run ours up to 1.7 bar, but the intercooler had problems in 20 minute races keeping the inlet air temperature under control. We have a bigger cooler now so no problems, but I am training the junior driver so we are keeping the power down. He keeps frying the tyres.

"Do GCG have a vic outlet?"

They do mail order everywhere. Plus a lot of hotup shops use GCG product (Subzero for example), give them a call, they may tell you a Vic outlet.

"Can u supply us with an dyno graph of the 240rwkw r33 also!"

It's an R34 actually, if you are an HPI reader, have a look at Ben's R34 the graphs look very similar. As you would expect since the turbos are exactly the same.

Hope I have not missed anyone's questions.

[jtir]

Originally posted by Sydneykid

Sorry Judd, but I have to disagree.  If you look at the power curve of the GTRS equiped SR20 closely you can see that it really needs a close ratio gearbox to take advantage of the peaky power delivery.  For example, on the gear change up from first to second gear, it drops from 400 ps to around 200 ps.  This slows down the acceleration of the car dramatically as it spends a long time at this low power output until the revs and boost climb back.

Hey dude, where you getting these figures from? I know of at least 3 SR20DET's in the build with GT-RS, I hate to break the bad news to them.

[Sydneykid]

Hi jtir, Some people like the nothing > nothing > bang of a steep power curve, so you won't have to break any bad news to them. They will love it. The dyno will also make them happy since they are only after a maximum horsepower number. The others, the ones that want and can use a stronger power curve, well they will find out for themselves when they put it to the driving/track test.

Here are the specs that HKS publish;

HKS GT-RS - 400 PS Output

COMPRESSOR:

-Wheel- 52 Trim - 51.2 Inducer / 71.1 Major

-Housing- 60 Inlet / 50 Outlet - 0.60 A/R

TURBINE:

-Wheel- 76 Trim - 53.8 Major / 47.0 Exducer

-Housing- GT25 inlet / Internal GT25 outlet; 0.64 A/R

You can tune around it a bit with ignition and camshaft timing and sacrifice a bit of top end for some mid range. The bottom line is the exhaust turbine (76 trim) and the compressor 52 trim) both look to be too big for a low reving (less than 9,000 rpm) 2 litre engine. So you can either increase the RPM band upwards (camshafts, headwork rods and pistons) to get the exhaust flow or increase the capacity of the engine. The better solution would be to use the right sized turbo for your application in the first place.

I would like to see one on a RB25, the extra 476 cc's may make it better, where it should build decent boost at 3,600 rpm compared to 4,500 rpm.

But hey I'm really guessing with all of this, cause HKS don't publish the compressor maps.

Hope that raving made some sense.

[whatsisname]

Sydneykid,

Thanks for the info on the R34. I thought it would have had a pretty decent 60' to run a 12.4 1.8 60' is awesome for a street legal tyre. Nothing special on a MT slick though.

I notice Ben's R34 has fairly low TS's for the ET's it's been running. Most of the published drag info on the car have shown quite low TS's for 240rwkw?

With slicks he ran 12.4 (1.71 60')

With Falken Azenis ST115's he ran 13.4 @ 103mph (2.098 60') And now on NT555 Nitto's it's best published time is 13.10 @ 104mph (1.904 60')

I guess the low tyre pressures would possibly hurt his TS but not by more than 1-2mph max. The weight of the R34 would be a contributing factor too (in comparison to the R33 GTS25t).

I would have expected higher TS's given the power it's making?

Cheers,

Matt

[s15silvia]

GT-RS spools up better than a 2835... response is great. It's not a lag monster, as you have just previously described.

So, I gather you have a GT-RS on your car? your information presented is from personal first hand experience? I gather from what you have said it is purely speculation into the unknown.

[Guest INASNT]

sydneykid

the r34 u r talking about in HPI is the black project car right?

i gotta read my back issues on when they changed the turbo.

I want street driveability not just peak power which is only good if i rev to 7000rpm every gear change!

[Sydneykid]

Hi s15silvia, in a previous post on this subject, I said of HKS "They don't help with the necessary information in choosing their product, so I don't choose their product". It is unfortunate that I have to base my reasoning on the very limited (practically worthless in fact) information supplied.

If anybody with a GTRS on an SR20 wants to post their power curves to prove my reasoning to be wrong, then I will be most pleased to stand corrected.

Hi Inasnt, I have driven the R34 when we were sorting the suspension, and it is very daily driveable. In fact we have specified another for someone else that is basically the same, it was that good a package.

Hope that adds to the discussion.

[Sydneykid]

Hi whatsisname, we were talking to Ben the other day on another suspension project and he was saying that he bought a set of Nittos and did a 1.9 on them first time out. The ET was a bit slow though, a 13.1 I think. I don't remember the TS. Track conditions, ambient temperature, humidity, wind etc all make such a difference when you are talking tenths of a second.

Racing can be frustrating at times.

[Roy]

Everyone has opinions on whose dyno reads high or conservative...blah, blah, blah. According to people of no real authority, just rumour, the CAS dyno does read a little on the optimistic side. This MAY help explain why the car doesnt have higher trap speeds

This in no way takes away from the performance of the car, i cant recall off hand but the final hp figure is a good increase over factory, something like 60%, whilst still giving factory driveability

[RS500]

INASNT,

give Dennis at P.E.T Mods a call on (03) 9464-4225, he should be able to help you out with a good turbo combination for your car.

tell him Gorjan (RS500) referred you.

[Guest INASNT]

Originally posted by RS500

INASNT,

give Dennis at P.E.T Mods a call on (03) 9464-4225, he should be able to help you out with a good turbo combination for your car.

tell him Gorjan (RS500) referred you.

wheres about the located?

have they done alot of other r33 turbo upgrades?

[whatsisname]

Originally posted by Sydneykid

Track conditions, ambient temperature, humidity, wind etc all make such a difference when you are talking tenths of a second.

Racing can be frustrating at times.

Couldn't agree more on both points mate!