Nathanknorr

Hey All,

I just purchased a 2012 GS with a Magnuson supercharger. has the factory Main pulley and the 96mm supercharger pulley. I would like to put on a smaller pulley and add meth. Is there anyway to know what boost levels to expect with the different sizes of pullies?
thanks,
Nathan

Dano523

Yes,

Send an email to Magnuson, and they will send you the charts on the super charger for volume/pressure amounts per rotation speeds.

As for getting rotation speeds per pulley sizes, it just a mater of figuring your drive ratios of the main pulley size to the charger pulley.

Your stock HB has a drive size of 7.5"=190.5mm.
93mm pulley is 3.66".

so quick down and dirty list for sea level that will get you close on a 6.2L stock motor since the base line of a 3.8" pulley is about 6.0 psi WOT.

- 3.60" pulley: expect 2.0 psi. more boost over stock pulley -Total boost 8.0 psi
- 3.40" pulley: expect 4.0 psi. more boost over stock pulley -Total boost 10.0 psi
- 3.20" pulley: expect 6.0 psi. more boost over stock pulley -Total boost 12.0 psi
- 3.10" pulley: expect 7.0 psi. more boost over stock pulley -Total boost 13.0 psi
- 3.00" pulley: expect 8.0 psi. more boost over stock pulley -Total boost 14.0 psi
- 2.90" pulley: expect 9.0 psi. more boost over stock pulley -Total boost 15.0 psi
- 2.80" pulley: expect 10.0 psi. more boost over stock pulley -Total boost 16.0 psi
- 2.70" pulley: expect 11.0 psi. more boost over stock pulley -Total boost 17.0 psi

Also, need to account for Atmospheric pressure equations at your altitude for all over all boost pressure to the motor that you would get at sea level, since sea level is 14.7lbs, while at Alberta of 2,200 feet above sea level, the Atmospheric pressure is only about 13.5lbs isntead.

Short version here, the thinner the air, the more you can over spin the blower since its the final PSI boost level that the motor is seeing against a 14.7psi base line pressure that really counts in the end.

CMY SIX

you've just got to be kidding! Do you mean you could actually contact the MFG. and get information from the builder of a certain product? MAN WHAT A CONCEPT. My hats off to you sir. BRILLANT! SIMPLY BRILLANT!

Curt D

Go to the Magnuson thread in the FI forum. The guys on there know everything that works and what you need to upgrade.

Unreal

Boost is irrelevant and other mods will effect it. You can estimate it at sealevel, in a specific density altitude, on a bone stock car, but in the end it doesn't matter. Headers/cam/heads/mufflers/outside temp/elevation/belt age/etc etc all effect boost.

Nathanknorr

WOW! thank you that was very helpful... I contacted the installer and magnuson and havent had a reply from either yet.

Dano523

Totally agree, but with just the base line of what the unit should produce, goes a long way on initial pulley sizes to get you close to start with, as well as the target area of where the supercharger will be most effective as well (before it just wants to become a heat pump by being spun to close its max range before wash instead).



P.S, both Magnuson and Eaton are producing a TVS-2650's, and truth told, 2650 would be the better unit over a 2300, since the 2650 will produce more volume pressure before they start to turn into heat pumps instead. Hence sweet spot of 1.7 pressure ratio/1800 mass flow of the 2650, verses the 2300 @ 1.6/1200 instead.

Don't get me wrong, since on a ls type motor, you can spin a tvs-2300 to over 24lbs of boost very easy (your into built LS9 territory with lowered compression to throw this much boost at the motor), but the 2300 is creating a ton of heat when spun that hard. The 2650 can be spun well over 34lbs of boost, but since it only going to be spun to about 20lbs of boost on the street at most, way, way less heat produced since your still closer to it most effect range instead.





P.S, Nathan, don't get any ideas of huge boost levels on a stock motor, even with a meth kit. The compression on a stock motor is too high to start with, the bottom end is not built for that kind of pressure, and even a Ls-9 is only built to hold about 750'ish hp long term safely (not strip running for a few second each hit that you can produce higher levels of HP, but 45 min or longer runs where you are in to the boost hits to red line every few seconds again and again isntead).

And before someone post how they are producing much more HP on a stock motor, post your lap records on a high speed road course like Sebring or such, to prove that the motor will hold up long term lap after lap for a event without failure at that HP amount, and not just a short boost-hit race strip, rolling race, or Dyno few pulls armchair bragging motor instead.

CI GS

Does your car have headers? I’m assuming that you have a stock cam?

With a stock cam, headers and the LS9 injectors that come with the Hbeat, you’re going to be limited to a 90mm pulley before you run out of injector, and even then you’ll need at least a BAP to help maintain sufficient fuel pressure/volume. That combo will produce around 8.5 psi (a bit higher if you’re running stock exhaust manifolds). At that level you won’t need meth either, unless you wanted to use it to cool the IAT’s well below ambient and get additional octane to add timing.
There’s about an 1 psi difference in boost between each 3mm incremental size of pulley.
Also, it should be noted that the smallest pulley that will fit on the C6 version of the Heartbeat is an 81mm/3.2”. The Camaro/Caddy Hbeat blowers can take a significantly smaller pulley, as well as use a much bigger lower pulley on the harmonic balancer compared to the C6.

3R1$C

According to Order@ZPEGriptec.com
"The smallest pulley size that you will be able to go do on this particular supercharger is a 2.97”. Please let me know if you have any questions."
So another 2 PSI!