I am in the process of calculating the drive ratio that I need to run my Eaton M90 on my limited coupe.
1. I calculated te motor requires 350 CFM @ 100 % VE
2. I want to run 8psi max
3. Looking at the inlet flow on the graph, spinning the sc 8000 rpm should deliver 350cfm @ about 10 psi, so I would need to run somewhere around 7500 rpm?

Am I way off or what? It looks like the ratio needs to be very precise. Anyone have experience with this?

 

Chucky,

Give these folks your request if you have not done so already

Eaton Superchargers
(269) 781-0469
infosupercharger@eaton.com

If you provide me the ratios (crank pulley to SC Pulley)- I could calculate the engine RPM necessary to produce the required boost for you.

 

I'll try emailing them. Thanks for the link. I'm still interested in learning the formulas if anyone knows them.

 

I have gotten all the info that I need. 1.65:1 will be my starting point with the option of slightly increasing the ratio with smaller sc pulleys. Fabrication should begin this Sunday!

 

let us know how things go! I along with many many others are dying to see this! if you succeed then, well... YOU ARE THE MAN!

 

dude... hes Chuck Norris!

 

oh.. youre right! my appologies...

 

For enquiring minds. The equation below will calculate pulley ratio for roots type blowers.
(14.7 + boost / 14.7) x (engine volume/2) / supercharger volume =pulley ratio

So if I want 8psi of boost.......

14.7+8/14.7 x 3.2/2 / 1.5 liters for my M90
1.54 x 1.6 / 1.5 = 1.642:1
So i need a pulley that will turn 1.642 times for every 1 crankshaft turn
Keep in mind that this is assuming that the supercharger is going to work at 100% efficiency, which in reality it is about 80% efficient. I should get about 6.4 psi of boost which should be safe and near the superchargers lowest output temperature. This should also equate to about 1.43x more power. 215x1.43=307.45HP 230x1.43=329 TQ
These are rough estimates but should be feasible.

After I remove that huge intake there is tons of room for the Supercharger!

 

thanks for the formulas chuck!!!!

 

Just curious - are you capping it to 8psi because you're not running a charge cooler?

 

From what I've read 8psi is about the most boost you can run on pump gas with our 10:1 compression ratio. If you have different info please expand.

 

Chuck is the man!

"Chuck Norris once ate a whole cake before his friends could tell him there was a stripper in it.

When Chuck Norris was denied an Egg McMuffin at McDonald's because it was 10:35, he roundhouse kicked the store so hard it became a Wendy's.

When Chuck Norris falls in water, Chuck Norris doesn't get wet. Water gets Chuck Norris.

Chuck Norris can divide by zero.

When taking the SAT, write "Chuck Norris" for every answer. You will score over 8000.

Chuck Norris ordered a Big Mac at Burger King, and got one."

haha sorry! Couldn't resist! 8]

 

All true. Thanks for helping to keep the forum on the light side! The more laughter and positivity the better.

 

My Crossfire will soon be able to roundhouse kick a 350z into infinity! LOL

 

Any update on the install?

 

I'm looking for a specific size of aluminum tubing for my intake manifolds. Haven't had much time to check all the sheet metal places around me though. Its 1.5x3 inch rectangular tube o.d..

 

I don't think that will happen with just 8 pounds of boost, Chucky Baby.

Enjoy the Ride...
Mike

 

Assuming a proper amount of airflow, 8 lbs of boost should put the NA XF at 330 crank hp. Maybe 340-360 depending on how much the top end is helped by the forced induction. That's unknown territory. Then subtract the loss due to supercharger inefficiency. My opinion is that such a setup would make around 290+ crank hp.

I think Chuck Norris was making a joke regarding the whole roundhouse kick to the 350z remark. Don't you get it? 350z into an Infiniti? (Nissan's luxury line)

You should check out the Chuck Norris jokes Mike, they are pretty funny.

 

I didn't think anyone got that. Probably because I spelled it with a y on the end.

 

I got the last of my tubing ordered so I should be going full tilt boogie on the supercharger conversion in a few days.