Inliners International Forums General Discussion Engines Natural vs. Forced Inductiuon on a 292

Hello people,

I'm gonna be rebuilding a 292 to put into a 78 nova. I will eventually do electronic fuel injection on it but plan to use a carb setup in the meantime. I plan to overbore by .60.

The question is whether I should deck the engine to get higher compression or should I leave the compression alone and put a supercharger on it (I've heard you cant use high compression on forced induction engines)

I would like to keep using regular 87 octane fuel if possible..

If I do the naturally aspirated setup I will use three individual throttle boddies from the 3.1 Cavaliers.

If I do the supercharger I'll use an eaton from a 3.8 engine with an intercooler. These superchargers already have one large throttlbody on them.

I will also be using headers and exhaust cutouts.

I do not wish to turbocharge.

Dear Luis;

I would surface the top of the block and then align bore the mains. This will make these lines parallel (exactly).

You can deal with the compression issue later with pistons or in the head.

"Magic Mike" is the expert here.

Good luck, John M.....

hello John...arent you refering to Mighty 6?
I never heard about Magic Mike with a racing 292 as I have read you comment/Post....
There are many here who work on these 292's and many with great advice...

so tell me more about his race vehicle? I have never heard him talk about it.....

Dear Lee;

Perhaps?

He runs a 10 sec. 1/4 with a 37 pick-up. May use different names etc. I have seen it 'Mike G.'too.

"Mighty 6" might be the name of the website that hosts this 'awesome video' showing this.

PICTURE THIS: The 'Christmas tree', L/R of the truck & a digital read-out. When the light turns green, 'action'. Ten seconds later (in real time) the truck is out of sight with the 'clock' showing the time.

It was screened here a while back.

John M....

The Truck being refered to I think Is one we had on the home not to long ago. The Truck is in the Racing photos. And Belongs to a Dave Watkins a 1940 chevy PU 292 with a 6-71 Blower feed by two 1150 cfm holley carbs run on gas with 10lbs of boost. Back with a TH350 tranny & 4:30 9" rear end.Truck tips the scales @ 2850lbs runs 10.8 @122 mph with 1.5 60ft That is it's best times known to me at this time. Hope this helps.
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Ps His memeber #1377 I'm sure If you're a paid memeber I'm sure you can look him up in the Club Roster and Give him a call. He may not mind you bending his Ear.?? about his ride.

Just to clear up one more point. Mike G (me), and Magic Mike are two separate people. His last name may begin with a G but I've always seen his posts here as tagged Magic Mike and mine are always Mike G.

Mike G, AKA Mike G

Gentlemen;

Okay then; Mighty 6 must be the 37 that runs 10:04 in the "awesome" video production.

John M.....

Has anybody actually put any thought into my questions???

For the most part your right Luis BRW. It appears you only got part of answer.
So maybe this will. The stock compression on the 292 should be just fine for what you have in mind. I wouldn't deck the block for increasing the compression. Because any type of forced induction likes the lower compression. The higher the compression is The less PSI you can add. so the lowwer the compression is the more PSI you can add. with 5-7psi(maybe as much as 9psi) you should still be able to run the 87 oct. pump gas any more then that you wil need to increase the oct. level. I hope that this helps Or gets someone else to jump to give you the answers your looking for. Sorry we got a little side tracked.
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good comment Larry/Twisted......we did go off huh?

I'm not completely sure I am going to supercharge anyways, because I've been putting alot of thought into it and it's probably a lot more work than I really want to do; BUT I'm still conjsidering it..

What I want to know is what is more plausible: higher compression with no supercharger?

or leave the compression alone and put in a supercharger?

Where will I get more power using 87 octane fuel, surpercharger or no supercharger?

I know lumps are a MUST for natural induction, are they a MUST for supercharged engines?

A basic supercharger can overcome the following on a stock engine:

Low compression
Stock camshaft
carburation
Induction system/valve sizes

This does not come free; a supercharger takes horsepower to turn it - as much as 100 or more horsepower in a large (6-71 GMC or bigger)/hi-speed situation. A supercharger also adds heat to the fuel/air mixture with detonation problems, and the added complexity of the drive belts/system.

Having said that, in my opinion. it is the SINGLE most effective way to improve an engines performance.

If you add the other basic modifications (camshaft, induction system, carburation/injection), you approcah the physical limits of the engine design, even with strengthened connecting rods, crankshafts and lower block supports.

The above is not intended to cover all aspects of supercharging; many books have been written on this subject and I've just covered the basics in 100 words or less............

go the supercharger route! i did on my oz hemi 277 cu in and have not looked back.i used the eaton M90(same blower as you are looking at)and i overdrive it to the max(blower is made to spin to 14000 rpm)and i make around 10lb of boost.when you floor it ,boy does it surge forward,the V8/WRX boys don't know what to think!

Lump ports and intake preps are important for forced induction engines as they are for n.a. engines. If you have a more restrictive intake tract you'll require more boost to do the same job as a more flowing intake setup - draining additional power from the crankshaft and creating additional heat (bad). Do the forced induction and the intake work for best results.

I would also bet you'd make the most power with the supercharger. I think you'll be limited by the 87 to a low boost level, but still make more than the n.a. engine. And then hey, when you feel like it swap pulleys drop in some 94 octane and go. It's all a cost/benefit thing. For the extra work I'm not sure you'd make THAT much more if you're restrained to 87 .

Just my 2 cents. Greg