Supercharged and Carb Converted
Thread Starter
Instructor
Joined: Mar 2006
Posts: 174
Likes: 1
From: Bettendor Iowa
Supercharged and Carb Converted
I've searched with no results. Looking for anyone that has converted from TPI to Carb and then supercharged. Please respond here or PM me. Thanks.
Melting Slicks
Joined: Mar 2001
Posts: 2,149
Likes: 303
From: Timra, Sweden
What do you want to know?
Supercharging thru a carb is no differnt on a Corvette, f-body or any other chevy engine.
You have to modify the carb for boost. How you do that depends on what carb you have.
Supercharging thru a carb is no differnt on a Corvette, f-body or any other chevy engine.
You have to modify the carb for boost. How you do that depends on what carb you have.
Thread Starter
Instructor
Joined: Mar 2006
Posts: 174
Likes: 1
From: Bettendor Iowa
Let me start by outlining my engine:
Car is an 85
355 all forged internals
10:1 compression
Dart aluminum heads, 190cc, 2.02/1.60
Hydraulic roller cam (Comp), 230, 230 @50, 540, 540, 110
Matching retrofit roller lifters
Harlan Sharp Roller Rockers, 1.6
Edelbrock performer intake
Holley HP 750 cfm double pumper
TPIS Ceramic coated longtubes
TPIS full exhaust, including flowmasters
Gutted Cat
MSD ignition: billet mechanical distributor, blaster 2, 6AL box
Set up with 175 shot nitrous
Wanting to find out:
1) what additional performance gains I can make via supercharger
2) recommendations for a set-up that will work well with my engine
3) approximate cost
4) installations and tuning tips
5) need for carb modifications
6) any disadvantages to a supercharger
Thanks for any help you can give me!
Melting Slicks
Joined: Mar 2001
Posts: 2,149
Likes: 303
From: Timra, Sweden
A rule of thumb is that for every 3 psi boost, you increase the power by 20% compared to the N/A engine. with 15 psi boost you will double the power.
You must keep the engine from detonation if you want it to last.
On any given engine you need to lower compression to be able to run more boost.
When supercharging or turbocharging it will cost about the same to run 3 psi boost and 20 psi boost. $3000 just to throw out a figure.
10:1 compression is a bit on the high side and you will not be able to use much boost. Without lowering compression you don't get much for the $3000 spent.
8.5:1 or 9:1 compression will allow you to run a lot more boost, problably 10 to 20 psi without detonation.
When going into the engine you could probably select a cam more suited for a supercharger too.
You must keep the engine from detonation if you want it to last.
On any given engine you need to lower compression to be able to run more boost.
When supercharging or turbocharging it will cost about the same to run 3 psi boost and 20 psi boost. $3000 just to throw out a figure.
10:1 compression is a bit on the high side and you will not be able to use much boost. Without lowering compression you don't get much for the $3000 spent.
8.5:1 or 9:1 compression will allow you to run a lot more boost, problably 10 to 20 psi without detonation.
When going into the engine you could probably select a cam more suited for a supercharger too.
Thread Starter
Instructor
Joined: Mar 2006
Posts: 174
Likes: 1
From: Bettendor Iowa
Thank you for the info! Can you give me an idea of what cam specs I would be looking for? I've learned through my research that my compression is high...will likely switch from 64cc heads to 76cc. Any recommendations regarding brand? Been looking at the Vortech stuff...they have a generic kit for an older sbc with carb.
Melting Slicks
Joined: Mar 2001
Posts: 2,149
Likes: 303
From: Timra, Sweden
One issue with a generic kit is that they often use an extra pulley in front of the stock crank pulley and the supercharger brackers are designed to align to the new pulley. On the Corvette there is very limited space between the pulley and the steering rack. You might be better off using brackets and pulleys from a Corvette TPI kit. Then you get a carb hat do some plumbing.
Vortech and ProCharger are good brands.
I am not a cam expert but you usually use a cam with less overlap with a supercharger. You can also use a bit less intake and more exhaust duration compared to a N/A cam. With the supercharger the air has a lot of help getting into the cylinder but not any more help getting out, and there is a lot more exhaust to get out of there.
Vortech and ProCharger are good brands.
I am not a cam expert but you usually use a cam with less overlap with a supercharger. You can also use a bit less intake and more exhaust duration compared to a N/A cam. With the supercharger the air has a lot of help getting into the cylinder but not any more help getting out, and there is a lot more exhaust to get out of there.
