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Discussion Starter · #1 ·
I got an a couple of emails about the advantages of a supercharger vs a turbocharger for Fuel Injection... how much HP you can make, what the costs are, do we do the work, etc. I thought everyone would find the information usefull so here's the answers I've sent.

If you want to make some serious HP, then Fuel Injection is the only way to go. Since the turbo (supercharger) is only "moving air (not air/fuel mixture), you can use an intercooler... a must if you are going to use much boost.

Turbo's and superchargers both help acceleration everywhere. The supercharger is a bit better for low rpms, and the turbo a bit better for high rpms.

The big drawback to the supercharger is that you always have to turn the pulley on the supercharger. So, when you are just crusin', having to turn the supercharger causes less fuel economy. It is also more expensive... a supercharger is more expensive than a turbo, and we have to make custom rib belt pulleys. (About $2500 for the FI turbo system and about $3500 for the FI supercharger system... installed.)

Yes, we do custom supercharger and turbo installations for FI cars. We've just finished a Miata and it made 250 HP at the rear wheels (dyno tested, not just some wild claim). (No kits for FI)

Personally, I like the instant "grunt" that you get from just off idle with a supercharger. But I'm not sure that it is worth the additional cost.

Also, the Opel GT drive line won't handle the HP (no matter how you make the HP). A stock Opel transmission will only handle about 150 HP, a Getrag 5 speed up to about 200 HP and the differential only about 190 HP. So, even though we think it is easy to make over 200 HP for the engine, it will also take transmission and rear end changes. (Transmission & clutch for 250HP about $5500 and rear-end about $3500). You'll also need an engine management computer and a few hours on the dyno to dial it in... so figure about another $2500 for that.

Stock engine parts are good to about 150 HP... maybe a little more. More than that and you'll need forged pistons, and 'prepped crank and rods. Up to about 6500 RPM you don't need to worry much about the stock valve train as long as it is in very good condition. Figure that a "prepped" short block with forged pistons will cost you about $3000.

So, for about $18K, you can have the "meanest supercharged GT on the block".
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