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supercharged L-88

 
Old 04-24-2019, 12:33 AM
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c14
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Default supercharged L-88

Anyone know of any l-88 that was supercharged?
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Old 04-24-2019, 12:39 AM
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Gale Banks 80'
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Neither the Compression Ratio or the Camshaft would work very well with a Supercharger. By the time You change everything to work with the Supercharger You don't have a L-88 anymore.
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Old 04-24-2019, 01:19 AM
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The 12 to 1 compression of the L-88 ain't gonna work with a blower. The lumpy L-88 cam isn't right for a blower either. Lower the compression to around 8 to one and put in a cam that doesn't bleed off a lot of the boost and an L-88 would be more suitable to have a blower put on it.
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Old 04-24-2019, 10:07 AM
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No0bs
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Old 04-24-2019, 11:31 AM
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I agree. Most engine builders I've talked to said that if you bolted a blower on an L-88, bring a box to pick up the pieces of your engine after the first pass. I've spoken to Mr. Langdon who agreed as well,although he did know of some blown L-88's used in marine racing applications.My question is, if in 1968, you needed your Corvette to produce a great deal more horsepower than a stock L-88, how would you do it?
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Old 04-24-2019, 11:42 AM
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Originally Posted by c14 View Post
I agree. Most engine builders I've talked to said that if you bolted a blower on an L-88, bring a box to pick up the pieces of your engine after the first pass. I've spoken to Mr. Langdon who agreed as well,although he did know of some blown L-88's used in marine racing applications.My question is, if in 1968, you needed your Corvette to produce a great deal more horsepower than a stock L-88, how would you do it?
To do what you're asking would require the use of a blower. In 1968 your choices for a supercharger were pretty much limited to a roots style blower, if you want to produce a lot more power than a stock L-88 that would be the route you'd want to go. With that being said, you'd want to get an L-88 engine for its 4 bolt main block, its superior crank and rods (7/16 bolt floating pin rods and the forged, tufftrided, and cross drilled crank) and for its big port open chamber heads. Change the pistons from 12 to 1 compression to 8 to 1 compression with forged blower pistons and then change the camshaft to one made for use with a blower. That's what you would need to do in 1968 to make a big block 427 make a lot more power than a stock L-88.

Last edited by TheGreek!; 04-24-2019 at 11:46 AM.
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Old 04-24-2019, 02:26 PM
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^^^^They could make plenty of power then even with ltd choices compared to today.
Joe Sherman was going 9s in early 1970s? with an NA 350. Were spoiled today..nothing like a roots blower to give some attitude, with a BB the power is nuts.
Drove a buddys tubbed 70 nova with a mild 454 6-71 it was pretty difficult to control when it broke loose....thats just lightly rolling into the throttle too.
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Old 04-24-2019, 10:39 PM
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So.... To build this blown L-88 we would start with the 4 bolt L-88 block,crank and rods,drop the compression (different pistons ?) and change out the stock cam. Would you happen to know the specs of a cam that would work with a blower? In 68, the aluminum heads are closed chamber. Would the supercharger work with the closed chamber heads or would it be necessary to modify the chambers and ports? If modification was necessary,would you happen to know what the mods would be? Could the factory L-88 intake be used? Since the stock intake plenum lacks a divider,would this effect the charge distribution to the cylinders? Would the blown engine be able to use the 4150 holley that came stock? Would the carb also need to be modified? Would anyone know on what side of the block the blower would have been located? Now, the main question, how much horsepower would this motor have been able to make and at what rpm? Finally, if the blower was removed and the modified carb replaced with a stock 4150, do you think this low compression,de-camed L-88 would be a more streetable car than a stock L-88?
Thanks again
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Old 04-24-2019, 11:27 PM
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Originally Posted by c14 View Post
So.... To build this blown L-88 we would start with the 4 bolt L-88 block,crank and rods,drop the compression (different pistons ?) and change out the stock cam. Would you happen to know the specs of a cam that would work with a blower? In 68, the aluminum heads are closed chamber. Would the supercharger work with the closed chamber heads or would it be necessary to modify the chambers and ports? If modification was necessary,would you happen to know what the mods would be? Could the factory L-88 intake be used? Since the stock intake plenum lacks a divider,would this effect the charge distribution to the cylinders? Would the blown engine be able to use the 4150 holley that came stock? Would the carb also need to be modified? Would anyone know on what side of the block the blower would have been located? Now, the main question, how much horsepower would this motor have been able to make and at what rpm? Finally, if the blower was removed and the modified carb replaced with a stock 4150, do you think this low compression,de-camed L-88 would be a more streetable car than a stock L-88?
Thanks again
Have you ever seen an engine with a blower? Some of your questions have me wondering. You can't use a stock intake with a roots style blower (pretty much the only style blower you could put on a big block in 1968), you have to use a manifold that's made for a blower. And the question about what side of the block would the blower would be located? A roots style blower mounts directly on top of the engine, not on the side. As for the closed chamber heads, if I recall correctly the L-88's all had open chamber heads. You could use closed chamber heads but the pistons would have to have a pretty deep dish in them to lower the compression enough for a blower. As for the cam, there are lots of different "blower cams" out there, you'll have to look up the specs of them to decide what profile you want (street, street/strip, full race). As for the L-88 Holley carb, you'll need to modify it for blower usage. It will need to have a "boost reference" port added to the side of the carb that taps into the chamber where the power valve is located and then a line needs to be run from the boost reference port to the intake manifold. Look up how to do it on Google. You'll want to run two carbs on a blown big block by the way because one carb won't be big enough to feed it. How much horsepower would it make? That all depends on how much boost you make the blower produce, you change the boost by changing the speed the blower spins at by using different size drive pulleys. The faster it spins the more boost it will make. How much horsepower will it make? The engine could make anywhere from 600-1000 horsepower or more depending on how high you boost it. As for how streetable would it would be without a blower, it would be very streetable with the low compression but you'd want to change the cam again, you'd want to replace the blower cam for one designed to work best with a non-supercharged low compression big block.

Last edited by TheGreek!; 04-25-2019 at 10:08 AM.
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Old 04-25-2019, 12:08 PM
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If you were going to "Do It Right" about the only thing you would use from an L-88 motor would be the block and maybe the crank.
Throw everything else away and replace with components made for a supercharged motor.
Could you put an 871 on an L88?
Sure, if you only wanted to look cool and idle around town.
Good luck finding fuel and as stated earlier, keep a basket in the passenger seat to pick up all the parts if you ever get into the throttle.
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Old 04-25-2019, 12:32 PM
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Wrong engine to use in a supercharged application on so many levels.

Next question!

Adam
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Old 04-25-2019, 03:19 PM
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Three posts since 2009, very active member. I think Paxton was making superchargers back then (just being nice to the bot) so you could use the L88 intake and carb if you knew what you were doing (no internet for DYI'ers)
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Old 04-26-2019, 02:43 AM
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c14
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First, I apologize for confusing a roots type blower with a centrifugal supercharger. I am fairly certain that the supercharger used was a Paxton and it was attached to the left front of the block. I agree with you and the others that have posted that an L-88 is not a good match to a supercharger. and yet it was done.The possible reason it was done could help explain why it was attempted in the first place. First, about the heads, all L-88 engines until mid production 1969 had closed chamber heads. The chambers on the 68 L-88 I'm asking about have been modified. Also ,there are two sets of numbers visible on the head by the chambers. I think the first set may relate to chamber volume. The other set of numbers may have to do with flow, but I'm not sure. The reason I asked about the head mods was I wondered if back in 1968 if that was standard procedure to build a blown big block.Although it's possible a different intake was fitted, I think the original intake was used as it is also modified (port matched) The carb was specially built by Holley for the engine. The carb is gone so I don't know if Holley modified the original carb or supplied a different carb. As you mentioned two carbs might work better but I think only one was used. I asked about streetability because when the car was acquired by the second owner ,after he replaced the modified carb with an original one and changed the rear ratio (4:88 to 4:11} the car became very driveable (blower was already gone). He also told me how he had the chance to drive a Nickey camaro with a factory L-88 and how different that engine felt compared to his. I asked about the cam because I don't know if the blower cam was removed along with the blower or if it is still in place.Finally, I haven't posted about this before because supercharging an L-88 just didn't make sense.

Thanks again for all the replies
Your information is most appreciated
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