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Discussion Starter #1
Does anyone have a Jim Cook or similar type supercharger unit mounted on an L28 engine? What increase did you expect/get? What is the driving experience like (any lag in response, etc.) ? Are you happy with it or what would you do different ? Snow on the ground, Z in the garage, thinking about spring. Thanks...
 

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On average you should see very close to 10 hp per 1 pound of boost. So on a stock L28 with maybe 135rwhp with 7psi possibly 200-205. As the rpms climb the 10 hp becomes less due to heat and friction losses. This is just bench racing though so take it for what its worth.

Matt
 

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Discussion Starter #3
my L28 is currently doing 209 at the wheels (mods and $$). So according to your calculations I should see 270 or greater..interesting. Now if I could get someone who's done it and liked the results to reply I could decide which way to go.
 

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Sounds like you've done a good job on that engine. This supercharger kit gets talked about almost on a daily basis but is seems no one really has any factual data. There's only a handful of them runnin around and they don't seem to be on this board.

I can give you #'s for a L28 with a Powerdyne & intercooler.

My only question is with the power your making normally aspirated your compression has to be fairly high, I run 11.5:1 @ 243rwhp, are you going to have to reconfigure your engine for less compression? Theres no way I could run boost without tearing up my engine.

Matt
 

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10hp per psi sounds a bit high to me. The stock ZXT with 7 psi has 180hp at the crank, for about 145 to the wheels. There is no way the supercharger alone will put 200hp to the wheels of a stock z at 7 psi. That would be nearly 250hp at the crank, almost a 100% increase in power over stock.
 

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If you are looking for something you can sqeeze more out of in the future don't get it. Do the factory turbo manifold and run a T4. You can't intercool a roots type SC and they are pretty inefficient even compared to a non intercooled turbo. If you just want a little more and can be happy with that and not want more down the road then get the SC. for an idea of power comparred to boost. With a t3/4, intercooled on a stock turbo block and head with aftermarket efi running 12 psi I made 244hp and 271 ftlbs. of torque. This is later upgraded.
 

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10 hp Per psi is a bit high. HP per pound is a function of displacement and the z's don't make enough. Your fuel systems and compression have been fiddled with in order to get the horsepower you've already got so your performance by percentage won't be as great. Generally boost is regarded as better for horsepower than compression so with regards to that you'd be wise to get the big-bore 3.1L kit with a large head and squeeze as much out of the charger as you can.
 

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Check Canada, EH?

Guy up in Ontario, Lynn and Ed Burkhardt---I believe it's Lynn (or was it Ed?) that has the JCR unit on his 240. That thing I personally witnessed pulling the 300TT's in less than half a mile when the 300's hit their speed limiters at 155! That car SCREAMS. He was running only 12# at the time because of the long trip, closer to home, he normally runs 17#! It was raining at the last convention, so I didn't get to see him run at the track. He does NOT use that Pro-Jection setup, he uses the Electromotive TecII for fueling.
 

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Discussion Starter #9
Re: Check Canada, EH?

I will try to track down one of the Burkhardt's and see what I can find out. Thanks for everyone's input. My L28 is a Rebello 3.0L w/50mm SUs. I have nothing against turbos other than I don't want one in my Z, so either I go up to a 3.1L stroker w/triples or I try the supercharger route. Again thanks...
 

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Re: Check Canada, EH?

Well, I'm one of those guys who did (some) research on the JCR Supercharger, a few years ago. I was going to buy the kit with the pro-jet holley but heard that there was problems with the analog system they had. Also something about too much heat,with the feul and air being combined together. It is a Camden Supercharger now based in Seattle. Jcr no longer sells it with the Holley carb. I have the manifold and the supercharger now, and the belt. Now I'm looking into feul injection. The big question. Injectors in the manifold just before the head, or injectors before the supercharger. One thing I'm not sure is, You hear one thing then another. Too much heat with the feul, or feul helps cool the air?
 
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