Hi guys. I bought a g35 with a stillen roots supercharger back in July and have been busy modifying it ever since. As we know this supercharger is a bit low on oomph I decided to go to stage 4 and put a 25mm overdrive crank pulley on and was expecting a mild increase in boost but got more than expected and now get 5psi @2000rpm and a peak of 8psi over 4000rpm. This has transformed the car and very happy with the mod just thought I would put it in print as I don't see many people going the crank pulley route for added boost

 

Just keep up with your gear oil changes on the compressor. Those things are stout but still need fresh fluid every 20k iirc. Spinning them faster I would change the fluid change interval to 15k.

The stillen unit got a bad reputation because it's peak numbers couldn't compare to a centrifugal which basically costs the same. But it all depends on how you drive the car and where you want the power, the centrifugal units are pretty gutless in the 2k-3k range where the car probably spends most of it's time.

 

Good advice man. The car had only done 5000klm in 8 years when I bought it so have changed all fluids on the car. After owning cars that come on boost at 4500rpm this set up is so much more useful with boost from idle.

 

Do you have the part number for that ATI damper that you used?

 

Also, are you having any issues with the AC compressor being overdriven?

 

It's the ati Street series at z1 @ 389$. It's making 8psi now up from 6.2 before. The biggest difference is how early it comes on boost. The stillen stage 4 is 8.5 so am within the roots efficiency range as at 10psi or over they blowing hot air. There is no need to redline the car because 5th pulls like 3rd and I'm always having to check what gear I'm in because it feels so strong I think I'm in a lower gear.
A lot of the response is from the drive line mods I completed this week......
Gktech diff brace
Whiteline diff bush kit
Dss one piece alloy drive shaft
Z1 solid gearbox mount
Lightweight flywheel fitted by previous owner.
A bit more vibration etc than stock but sooo tight.

 

The ac pully is actually under driven on the ati so some people complain of lower ac performance.
​​​​​​I have done a AC delete stripped interior etc. Weight is more important than power as it helps everything.

 

All done on the driveline.....

 

Are you SURE about the AC pulley being underdriven? Does it come with a different AC pulley in the kit?

If you run a larger diameter crank pulley then you overdrive all the other components which on the normal DE engine shouldn't be an issue but on my rev-up which is already turning 7k might be an issue. Since that ATI pulley is 1" larger diameter it would be turning the accessories at the equivalent of 8000rpm engine speed on the stock pulley.

A normal DE engine which only turns 6500 rpm it probably wouldn't be an issue, I'm mostly interested in the rev-up though.

 

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On the Standard crank pulley the ac is only a few mm smaller than the main belt and on the ati it almost looks half the size of the main
Standard ac 140mm. Ati 95mm. I was surprised at the difference because I wasn't using it I didn't take much notice other than smaller.
The 15% overdrive will run the altinator and PS a little quicker so maybe not good for a race car but in the real world we are only redlining for a few seconds every now and then.
The ac will work once moving but I heard its weak at idle

 

Awesome thanks for the info.

 

Infinti

 

iirc Stillen pulley back in the day were black - stage 1, gold - stage 2, red - stage 3, and BLUE was the stage 4 smallest diameter pulley.

I know somewhere along the lines Stillen changed their pulley colors though, I think the newer blue pulleys for other non-DE systems is one of the larger diameter and lower boost pulleys though so there will definitely be confusion when you're searching for something like "Stillen S/C blue pulley".

 

Hi. Stage 4 on the blower snout cause to much slip. I did it with a 15% overdrive crank pulley and got better results than any stage 4 results online.