Rotrex is the style, HKS is a rotrex supercharger.

 

​​​​​​Yeah I know. I thought that you were referring to the Rotrex brand. Some strong performers in that lineup too like the the c38-92.

 

For sure, I eventually want to get the the HKS kit, sound nice and are not very common so that's a big plus in my book. Do you feel like it would be easy to squeeze a little more power out of it without getting a different pulley?

 

I wouldn't overspin the blower. My supeecharger spins 100 000 rpm at 7250. I guess the power it makes depends on your supporting mods. Is the engine built, longtube headers, aggressive cams, etc?

If you are thinking about the cost of a pulley. Avoid FI altogether. It ain't cheap...

 

No, no, I haven't started my engine build yet and I'm simply wondering about power capacity of the GTS8555. It's not a cost thing at all, maybe I phased the question wrong? If I'm in the right mindset the pulley for higher boost would spin the supercharger even faster right? I wouldn't want to do this, instead I would want to build everything else up around it, and use an intercooler sprayer, race gas or something along those lines. Ultimately I'm looking to have something closer to 500hp which HKS says the unit is capable of.

 

Spinning the blower over 100000 rpm would shorten it's lifespan. By overspinning the blower it should give you more boost, but efficiency will drop due to higher charge temps.
​​Spinning it slower than 100krpm leaves power on the table with little gains to reliability.
I would suggest longtube headers, e85/racegas, aggressive cams and a proper fueling system. Then you can get over 500 hp+ reliably.

 

Ok thanks for the info, at the moment I have Tomei headers, Berk cats, and HKS exhaust that would likely stay. Obviously would be getting a full fuel system with a built block, cams and maybe a displacement increase. Would have to talk it out with a shop once I get into the build.

 

Your supporting mods will work just fine, quality stuff.
I had lots of issues with fueling. The original basket and a big pump didn't work. I had to use a surge tank and relocate the battery to get a reliable steady fuel pressure.
Do it right once and you will save yourself some money in the dyno.

 

Season has opened and she's running great.

 

And it's that sound (or lack there of) that makes me want the kit. Sounds pretty close to stock, no annoying sounds!

 

Any feedback on numbers from anyone? I'm about to pull the trigger on this kit and plan to run the 110mm pulley. Goal is 450whp until I can get the bottom end built and then go with the 100mm.

 

My car has 450 whp. Check the posts above to see what it takes. I'm running E85, but I bet you could do the same with a more aggressive cam and pump gas.

 

Your engine is built, IDK if I'd recommend running the kit without a built engine unless it's temporary and have another engine being built

 

I'd run 450whp all day everyday on a stock block with a centrifugal supercharger. Its NOT whp that breaks engines its low down WTQ that breaks them. With 450whp you're MAYBE making 370WTQ at peak.

 

I agree that hp won’t zero-out the block...

but I think the corresponding torque for 450hp is closer to 400 to 425. Obviously every vehicle is different and whether you’re turbo’d or supercharged makes a difference and your ignition timing plays a role too.

my experience:

8psi ATI Procharger Build/OEM & Fuel pressure tune(circa 2008’ish)
320tq / 375hp = .853

14psi ATI Procharger Build/Haltech Tune (circa 2012’ish)
420tq / 455hp = .923

14psi Greddy TT Build/Haltech Tune (circa 2016)
447tq / 477hp = .937

17psi Greddy TT Build/Link Tune (circa 2018)
544wt / 568hp = .957

I conclude that that torque is ‘approximately’ .90 x hp...

so 450hp would be 400tq to 410tq...

so would it be fair to say that 400tq to 450tq (or slightly higher) is the break point for an OEM block?

 

I think it's going to all depend on where peak torque is.

If your making peak torque at 2000-3000 rpm then I don't relive that engine will last long at 420+

But if your making peak torque at 4000+ I think the odds are more in your favor.

I made 540whp and 457wtq, but my peak torque was 5k'ish.

Look at Tim Rod he was making 570+ on a stock block for a long time before he started bending his rods.

I honestly believe this is because his torque was made so high in the revs. I would bet a decent amount of money if this would have been on a turbo car. The engine would have made it 5-10 passes before kaput.

 

I agree with you Conway. And there are many variables to consider

(maybe you know where I'm going with this) Was your 540hp and 457tq with your supercharge … and … your kinetix intake? (see where I'm going with this?)

OMZ has brass ********* with the power, torque, and timing he was running on his car! But he too was suffering from parastatic losses of a supercharger(I speculate).

 

You wouldn't recommend running the kit at all without a built motor? Why?

I make 304whp on a stock block with cams. I figure the 110mm pulley without the restrictor plate would be fine, but I'll certainly be paying attention to the torque and when it peaks. Goal is to be sub-400tq and around that 430-450whp mark. Car currently makes 281wtq, so I'll just have to see what happens.

 

With all due respect to Dark - I would say run it, just keep boost under 8 to 10psi...my 2cents...

 

Fair enough. I don't really care about boost. I care more about the tq and when it peaks. With the mods currently on the car I don't see it making over 8psi with the 110mm, regardless. More than likely will be closer to 6 if I had to guess.