very basic supercharger question

[DrSmith]

Hi All,
My automotive experience has been restoring austin healy sprites and keeping a 47 plymouth running. I have just purchased an 06 gt, and I'm wondering about a supercharger. My question is: What do you all mean about changing things in the engine to get the most performance out of the supercharger without blowing the engine? Sorry for this basic question, if you want to point me to some websites or books, that would be fine. Is it just a matter of a new crank and pistons? As my car is brand new, and will sit for the winter, I have time to figure this out. Also I won't mod this car until the three year warranty is up.
I have to say, I love this flipping car, it is just great. (well at least the 80 miles I've put on it so far) I had always wanted a mustang, this "ride" I"ve started is just great.
Any input would be great.
Doc

 

[RandyB]

Doc,

There is actually one supercharger out there that has its own 3yr/36k warranty. It is the Roushcharger by Roush Performance. The way it works is very similar to the '03/'04 Cobra setup except the supercharger is the smaller M90 unit (vs. M112). This system is said to make 415hp/385tq @ 5-6 psi on an otherwise stock engine. Since Roush does some R&D for Ford, the kit looks like it could have come from the factory that way - very clean install. This kit is designed to work within the limitations of the original reciprocating assembly (crank, rods, pistons) which is one reason why they can offer a warranty. They offered an 8 psi pulley and tune option for their previous generation 6 psi kit, so I would suspect they would do the same this time around for additional power. The downside is that the warranty would be voided if you changed the pulley during the covered period.

To answer your question about the engine internals, to take full advantage of some of the more serious hp making superchargers out there, it's a very good idea to employ a Cobra crank(or similar), premium rods and forged pistons. If you don't want to worry about that sort of stuff for a while but you are interested in supercharging, you should take a good look at the Roush kit. It is also one of the nicest kits you will find available in terms of fit, finish and engineering. It does have some limitations due to the size and type of supercharger they use, but I suspect you could ultimately make up to 500 fwhp with the 8 psi pulley, ported heads, exhaust and a good tune, etc.

Another possibility for more power in the future from this system might be the next generation of eaton roots blowers like the one used on the upcoming GT500. These hybrid revised 5th generation superchargers have a re-designed rotor and port design for increased adiabatic efficiency. So hopefully they will offer an M90H that uses the same case as the M90, which would allow it to be retrofitted, but I'm looking down the road a bit admittedly.

If you have 500+ hp aspirations and don't mind replacing your crank, rods and pistons, one of the other superchargers would be a better choice. Below is a pic of the installed Roushcharger on a new GT. I hope this info helps you out some. Enjoy your car!

View attachment 492837

 

[DrSmith]

yes thank you, this is very helpful. I see the claims for some of the superchargers, but wonder what else they did with the engine. While I have your attention, what would you imagine a ball park price for a cobra crank and forged pistons would be? I'll check the mags I have at home for prices.
My research on this will be long, as I'll probably wait until the three year warranty is up, but if Roush will stand by their work.....who knows.
My last "bargain" with my wife is a supercharger for a new bedroom set. Not a bad deal.
Thanks again,
Doc

 

[RandyB]

yes thank you, this is very helpful. I see the claims for some of the superchargers, but wonder what else they did with the engine. While I have your attention, what would you imagine a ball park price for a cobra crank and forged pistons would be? I'll check the mags I have at home for prices.
My research on this will be long, as I'll probably wait until the three year warranty is up, but if Roush will stand by their work.....who knows.
My last "bargain" with my wife is a supercharger for a new bedroom set. Not a bad deal.
Thanks again,
Doc

Probably figure somewhere in the neighborhood of ~$3k for a Cobra crank, premium rods and forged pistons along with the labor and any machine work needed to put it together. I'm guessing here, but that's probably pretty close. The factory parts simply won't put up with much abuse at the high hp levels and there is no room for error on the tuning side. I personally don't mind adding good internals, but I want to get a long life out of my stock shortblock first.

Happy researching - that's the fun part. I have been doing plenty of it myself lately and I'm getting ready to purchase the Roush kit I think. It seems ideal for my goals that I have for this car. I have been the centrifugal route before and have been wanting a positive displacement blower for quite some time.

 

[bigcat]

alot of what you have said so far also applies to the saleen supercharger. have you looked into that one as well? i believe that it is even cheaper too! i have also heard rumors that the roush will not meet emissions standards. just something else to look into.

 

[RandyB]

That's true. The Saleen supercharger has a lot of the same redeeming qualities minus one - the 3yr/36K mile warranty. I suggested the Roush as an alternative to waiting until after the original auto warranty had expired to supercharge his car. The Saleen actually has more potential for power since a superior twin screw compressor is used. That said, I still like the overall Roush kit better enough to get it even if I have to give up some power and pay a little more to boot. With the latest Saleen price increase and the Roush kit coming down in price, the difference is getting close to negligible. I can get the Roush kit for $5500 to my door.

Getting the right parts on my car is more important to me than saving a few benjamins. Mac headers for example, are cheaper than Kooks for a reason.

As far as emissions certification, Roush is undergoing that currently if my sources are correct.