metaldrummer

heres my dilemma. my car came stock with the eaton m90 and im getting ready to install a forged rotating assembly so i can run 13-15 psi. i know the roots blowers make a ton of heat and become inneficient at high psi and that KB SCs are very efficient. my question is what would the hp diference be between my intercooled eaton m90 at 14 psi and the intercooled KB 1.7 at 14 psi.

Birdieman4

First of all, the most boost you'll see out of the M90 is around 12-13 psi. -And that's spinning it really fast. But, lets say we compared the rwhp in both @ 13 psi. The M90 would give you around 410 rwhp, and that's tuned well. The kb would give you around 480 rwhp at the same psi, tuned.

redstanger

well KB with the same size of pulley as the eaton will have anywhere from 40-60hp or more hp than the eaton and im sure with the intercooler it would be even better numbers. KB is just a all around better supercharger why else do u think everyone with a 03 04 Cobra swaps eatons for a KB. KB you could even run more psi if you want because the supercharger can handle it. By the way if you sell the M90 and manifold give me a PM i would be very interested.

redstanger

birdieman do you still have the supercharger of your saleen.

Lee Willis

I'm curious how you figure that, what is the difference in temperature of the air flow? Has to be substantialto make that much difference.

metaldrummer

the eaton is becomes very hot and very inneficient very fast, hence it being known as the "heaton". when it comes right down to it, an SC is an SC and it awsome to have regardless but when you want to make the big numbers you need to discriminate a little.

and red, yeah ill pm you if i end up selling it.

mysticsvtcobra96

where do you get 13 psi is the most your going to get?Ive got the 2.80 and im running 14psi and still could put a lower pulley on the crank after the port job on the s/c..save your 4 grand for a kenne bell and get some head work done

Birdieman4

Typically, most owners who boost their M90's to the max see around 13 psi. If you are getting 14, be happy. That's pretty good for the M90. The problem with the M90 is that it was never intended to be spun that fast. 6-8 psi is it's optimal range before it starts to build heat too quickly. The KB has 2 things going for it ove rthe M90 Eaton roots blower. 1. It's lager in size, and at 13 psi its spinning slower than the eaton at 13 psi, making it more efficient. 2. It's a twin screw, so it considerably more thermally efficient than the Eaton, making it's charge cooler and more potent prior to passing through the heat exchanger.

codyss

My Cobalt SS is running 12.5 pounds of boost via a Eaton M62 which displaces 1.00 Liters. Thats alot of boost for a M62 not to mention a 3.00 pulley will bump it to 15psi and a 2.80 will take it to 18psi. After that it is getting really close to it's max rated speed of 14,000rpm's. In either situation if it wasn't for a very effcient heat exchanger you would see alot of heat and less HP.

The same methods and mechanics can be applied to the M90 and the 03/04 Cobras M112.

The more boost you can get out of less RPM's the better.

The Eaton units were choosen for OE reliability and function. The KB was desinged for raising hell.

metaldrummer

would it be cheaper to port out my eaton for more displacement, add a smaller pully, and get a really good heat exchanger instead of buying a KB? my goals are 600 rwhp daily driven.