jonnylaw

iTrader: (3)

As far as the car in Japan that Itozann and IanP mentioned as having a larger intercooler, that is the HKS Z500SC demo car.

It is listed as using the GTS7040, which is the same blower on our kits. It also looks like it used a slightly smaller pulley (doesn't look quite as small as the GTM 85mm pulley, looks like a 90mm pulley). There is a full size intercooler and the intake location is different.

I haven't been able to find the exact mods for this car and how its making 500ps (about 493 hp). I'm really baffled, b/c HKS lists the max hp rating on the GTS7040 as 400hp and the Z500 is making 90hp more than that-how is that possible? The only obvious modification is the larger intercooler and change in air intake location (there is an "air dam" in the lower part of the front bumper and the actual air filter is located in the battery box area (battery is relocated and the traction oil resevoir is right next to the air filter in the battery area)

I have read that the engine is not stock with upgraded HKS pistons/rod/cams/and headwork--but this was only listed on one blog and I haven't seen a complete comprehensive breakdown of the Z500.

Some pics of the Z500--you can see the GTS7040:

ITOzann

iTrader: (30)

I also found out they that the hks Z500sc demo car have build internals and they are using an electronic fan&speed controller as well. (http://blog.hks-power.co.jp/blog/200...entry-21437701)

however, do you guys think they are using the 80mm pulley? I think i read somewhere before that there is a bracket adapter for the larger blower. I'll try to find the link

I'm really interested in how they are achieving the high numbers without over spinning the blower..

jonnylaw

iTrader: (3)

At least from the pictures, the blower looks like a GTS7040, not a GTS8550. Also, the pulley looks like a 90mm or 85mm at smallest--you can see from the very slight gap outside the pulley. So if the pictures are indicative of the car's setup that is achieving the 500ps, it is not bc of overspinning the blower or a larger blower (which is very confusing since the 500ps is on par with what the GTS8550 is capable of). And since the GTS7040 is rated by HKS as having a 400ps power max, I'm baffled over the power achieved. The only other variables are the engine work, larger intercooler, and air filter/piping reworking.

jonnylaw

iTrader: (3)

The pulleys and the GTS8550 should be readily available from HKSJapan. The pulleys are ~$150 with yen to dollar conversion. I would recommend rhdjapan.com if anyone is looking to order--I'm always been please doing business with them and they are very close to HKS headquarters.

jonnylaw

iTrader: (3)

Itozann, do you have a reference to the adapter bracket for the larger blower?

I also have a feeling that there may be problems with clearance and piping due to the larger compressor section on the GTS8550. But if there's a way to make it work, that would be great. Larger blower for more power without having to string it out like we are doing with the GTS7040.

ReV2Red

iTrader: (9)

The car is making 500PS at the crank, so that's around 420 at the wheels. That's only a bit more than Jonny is making on his blower, and you can guarantee they have some serious engine and headwork going on too. It is a demo car after all, so they have to "demonstrate" what they can do. Also remeber they have much better pump gas than you guys.
I'll bet if Jonny got some decent headwork and a decent set of cams, and slightly better fuel, he would hit 420whp without a problem.

IanP

iTrader: (2)

Thats a different car to the one that I mentioned

http://www.importtuner.com/features/...50z/index.html

^^ Was the one that I saw

ReV2Red

iTrader: (9)

Ok. He's running 100 octane gas, and that was the old rotrex supercharger. So you really can't compare them.

IanP

iTrader: (2)

My original post about this car was about the full size fmic & not the power its running.

I'm pretty happy with my power figures for now

jonnylaw

iTrader: (3)

Yea, 400hp/353trq is about on par with the old rotrex unit and 9 psi pulley and ported compressor housing. Using race gas and this is about what can be achieved with the new HKS SC and the GTM upgrades.

About the intercooler, it may be a mixed bag. I'm pretty sure there would be more pressure drop and I don't think you would gain power without increasing boost, but I could be wrong. I mean those numbers are achievable with the GT kit with the 85mm pulley, GTM spec blower, GTM pulley, and race gas without an upgraded intercooler.

Interesting on the blow-off valve. I wonder how that would work and affect our setups if swapping on the bypass valve for a blow off valve. I thought that it wouldn't be a good idea not to recirculate, but I guess I could be wrong.

IanP

iTrader: (2)

SSQV will work on our setups.

This is an email I had from HKS europe about fitting one

I had a ssqv but my tuner advised not to bother fitting it

jonnylaw

iTrader: (3)

Yea, not recirculating will likely cause idle issues I already have idle surge issues with the bypass valve

Have you/can you e-mail HKS Europe in regards to the larger blower (GTS8550) and whether it could be fitted to our bracket/piping without major modification?

cdoxp800

iTrader: (12)

Wow. Great info guys. Keep it coming.

IanP

iTrader: (2)

Not done it yet but I will do it tonight

jonnylaw

iTrader: (3)

cool. Thanks!

jonnylaw

iTrader: (3)

One thing to keep in mind, my best numbers (415whp/415trq.) was only achieved by greatly overspinning the blower (ATI crank pulley and 85mm pulley). I really wanted to keep this power band, but was concerned over the longevity of the blower by overspinning it at 5900 rpms and up and by 20,000rpms over by redline. Although, no one could really tell me for certain--dyno graph of this:



So I swapped out the ATI crank pulley for the OEM one and lost a bunch of boost and power and was having belt slip:





So I'm putting back on the ATI crank pulley and trying the stock 95mm SC pulley. This will give me more belt wrap and the impeller speeds will still be kept in check. I am tempted to try to the 90mm pulley, but this would begin to overspin at 6300rpms and over 13,000rpms by redline

jonnylaw

iTrader: (3)

So I found out some more info from HKSUSA today.

I was told that the larger blower and the smaller pulleys are not available to the general public and are only available to companies/manufacturers developing their own kits, utilizing those parts and in volume numbers. Of course, I haven't tried ordering one of these pulleys from a japanese vendor so I don't know for sure.

I was also told that the red 350z that originally had the GTS7040 on it for debut, then had a RS twin turbo built engine setup. After that, HKS fitted the larger GTS8550 on to it and debuted the car at an event in Las Vegas earlier this year/late last year. However, I was told that extensive modifications/custom parts (bracket/pipes) were needed to get the larger blower fitted on the Z (took 6 months). After all was said and done, I was told that was not much more power achieved with the larger blower, compared to the GTS7040 with the smaller pulley--a matter of sizing and efficiency.

_ink

iTrader: (2)

Let me know how you go with this Jonny.

Do you know how much smaller the ATI crank pulley is compared to stock?

Also, the 90mm pulley sounds like an idea as i'll still be able to use the stock belt correct? I'll just need to adjust the belt tensioner more?

I have my rev cut at 7000rpms, but shift at 6500rpms, so over revving for 200- 700rpms (which you arent always doing) should be ok i think?

Can anyone confirm the questions above?

jonnylaw

iTrader: (3)

The ATI crank pulley is larger than stock by a little less than an inch. This will increase boost/impeller speeds, so I'm swapping the 85mm pulley for the stock 95mm pulley to even it out.

I thought you were using the stock HKS (95mm pulley)? With a 5.74" crank pulley and 3.74" supercharger pulley , 9.444 step-up ratio, you shouldn't be overspinning the blower at all, even at 7,000 rpms. You are at 101,460 rpms and the stated max impeller speeds is 110,000--so you are well under the max impeller speed.

If you use a 90mm pulley and stock crank pulley you will still be under max stated impeller speed by 7000rpms (~107k)

Using a 85mm pulley (GTM) and stock crank pulley, you will be at ~113,407 at 7,000 redline. So this is about ~3400 rpms over max stated limits, but only for a very short period of time (6800-7000). You could always adjust your redline if you are concerned about that, it's about a 3% increase over max stated limits and only for a short period of time.

No one seems to know the exact amount of wiggle room in overspinning the blower. But I would feel much more comfortable with 3% overspinning, than 12% overspinning (which it was doing with the ATI pulley and the 85mm GTM supercharger pulley), or don't overspin at all if you want to be 100% safe.

See:

http://www.928motorsports.com/servic...ingpulley.html

_ink

iTrader: (2)

Thanks Jonny!

All my pulleys are stock size with whatever came with the kit.

If i change my stock crank pulley with the ATI and replace the 95mm SC pulley with a 90mm pulley will i be able to retain all the stock belts? Or will they need to be replaced?

What will be the gains of upgrading these pulleys and will this require a retune?