Anybody have any feedback for the RS motorsport supercharger? Can it be installed with the engine still in the car? Also, would there be any advantage either way to boring out an engine with the super or keeping stock cylinder thickness for added strength?

Wasn't thrilled with discarding my working air cond. system, and leary of the possibility of an overly peaky power curve so... I put my $3.2K down and ordered a Design 1 turbo system a couple of days ago. So I guess that's my vote....
I wouldn't get worked up about boring the engine out, maybe pop in some forged slugs and freshen things up. Just let the supercharger do its boost thing.

I want a supercarger setup like the 3800's. I like the ones that bolt on the intake like that.

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Thanx for the replies. I don't have AC in the first place so there's no loss there. How is this thing so peaky? I thought s-chargers were much more linear in the power rampup. Is the power increase worth it?

RSM uses a Rotrex made unit which features a centrifugal compressor. The compressor is actually a tubocharger item. Since it is belt driven to the crank thru a planetary ball arraingment at about 13 to 1 drive ratio, its boost will be very RPM dependent.
Turbos (i.e. turbo-supercharger) also use a centrifugal compressor, but they use the volumne and speed of waste engine exhaust gases to spin the exhaust turbine/compressor assembly. Its boost making ability isn't strictly engine RPM dependent. So I think a turbo has the POTENTIAL for making a little better mid range power than the RSM Rotrex unit. However, with a turbo, there will always be a bit of lag before the boost kicks in due to the inertia of the rotating parts.
You should also know that the only supercharger(that I'm aware of, anyway) that gives full, or almost full boost off idle is a Rootes type/positive displacement blower.
I might have gone ahead and bought the RSM unit anyway if it wasn't for the air cond. thing!

i like the whole idea behind the RSM Supercharger. it looks really simple to install, and for 70HP upgrade that's pretty decent.
imagine if you had forged pistons, and ported manifolds, as well as upgraded exhaust system, you could add more boost than you would need!

still $3000 is way out of my budget

kent wa you dont need air just an umbrella

If you're using boost, turbo or blower, what you don't want is a motor with the compression rasied. If you are rebuilding the motor before putting the boost on make sure the pistons are bought with boost in mind. If anything you want to lower the compression. Not raise it. Even plaining the block and/or heads will raise it.

On a stock motor you want to run some of that decarbonizer thru it frist. The carbon can raise comrpession and create hot spots either of which can make it knock.

What if a motor is rebuilt to basically stock specs? Will it then work with a turbo? I'm about to get my motor rebuilt, but can't afford any forced induction right now and I'm not sure if I want it in the future. I don't want to have to rebuild again in a few years just because I want mo' power.

MM,When you build your engine make sure you use strong enough internal pieces to hold up under more stress caused by the increase in horsepower you may get by any means.If your crank is cut it should be radiused at the journals if possible for more strength.The rods should be as strong as your money will allow,forged pistons.Don't use a camshaft with a lot of overlap(a stock cam would be better).You don't need to spend a lot of money on getting your heads polished,just port match all your intake and exhaust openings.If you go to a turbo in the future just make sure you remove any resistance to air flow the incoming air will see as it enters your engine.That's also a good idea for a naturally aspirated engine.When it comes time to add some form of boost to your engine don't be afraid of a turbo.It's basically free horsepower,the plumbing may be a nightmare though.A good idea for any air system would be to visually check the path of the air into each part individually,if you see something that would disrupt the smoothness of the airflow and cause turbulance smooth it out or remove it if possible.With a turbo this eliminates lag.

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Hey,my 300th post.

[This message has been edited by hugh (edited 10-22-2000).]

Here in Toronto I've seen an 85GT with a turbo run 13.47 with basically a stock engine (no rebuild or performance parts) It is just as fast as my Northstar V8. Go turbo, as was mentioned it is free HP.

Like Hugh was saying, I'm running about 9.2 CR with the Stang, and about 13-14lb of centrifugal boost. Haven't had a problem yet....and oh boy does she run. Do I expect it to last forever? Nope, but thats my choice. Anything from the factory with forced induction will have low compression for obvious reasons. Anything in the low 8's for compression and you'll get soggy performance when it isn't boosted, so plan ahead before you do anything.

[This message has been edited by BBBAD GT (edited 10-24-2000).]

.....and a Top Fuel engine life is 2-3 minutes at full power....... Anything is *possible*, but mostly impractical.... My dad can.....

If you are going to blow on it and you can't afford to replace the engine, Theogre is dead on. Drop the compression to about 8.0:1 but not below 7.5:1 unless you like absolutely no low end torque (Quad 6!). Detonation you can't hear kills.

If you keep the boost under about 6-9 PSI then the stock 8.9:1 is ok, but the spark will need to be retarded to the 10-15 degree range at WOT.

More boost? Get the compression down otherwise you will just need to remove more spark and lose power. I notice 2 degrees on my Buick SC. I can't run above 12 degrees beyond 3000 RPM on 92 octane. I'm running about 11-13 PSI on an overspun M-62. The stock compression ratio is 8.5:1.

I know a guy....

According to the turbocharging book I just read, building a motor specifically for turbocharging is not necessary unless you plan on running the boost past 11:1 (or so). hugh was right on with his discription but it may be overkill if you plan on keeping boost below 9 psi.

Like terryk mentioned, if you are running a higher compression motor, you will need a spark management system to keep your motor from detonation. I have been looking at vaious systems that automatically adjust the timing based on a knock sensor. This type should provided maximum timing (a.k.a. max power) without damaging your motor. And, as an added benifit, if you increase the octane rating of your fuel, it will automatically adjust the timing as well.

To beef up the motor to handle more boost, you may consider early 327 SBC rods that have been resized to fit. You can still buy peened (sp?) rods for this motor and their strength should be sufficient. Forged pistons are best but can be VERY expensive and difficult to find for 2.8 and 3.4s. Hyper tech pistion are better than cast and will buy you a couple more pounds of boost.

Stock exhaust manifolds will work great. Using headers may slow the exhaust gases which will slow the spool time of your turbo (a.k.a turbo lag). A free flowing exhaust after the turbo is a good thing if your going to be running high boost numbers.

If your serious about making a turbo system for your car, I encourage you to buy a book on the subject and do a little homework. If you like, I'll dig up my turbo book and tell you the author and title. Or, do like I did and check with yor local speed shop. They usually carry books that tell you how to build almost anything... including turbocharging. Expect to pay about $20... but money well spent.

Roy