I had a few questions about the setup that I'm building for my 85 IROC. It's a blow through 5.3 LM7 with a 76mm On3 turbo, Brian Tooley spec'd cam, springs, pushrods, and ARP rodbolts and head bolts.

1. How do you control boost with a carbureted setup?

2. Is 3 inch piping too big for my setup? And can the intercooler be too big?

3. Can you control boost with an MSD 6LS box? I know you can set a boost timing map, but I was wondering if you can actually control the boost with it.

It may be some stupid questions to some people, but I've never messed with anything boosted before, and you've gotta ask to learn.

 

Somebody at least tell me they were stupid questions or something! lol.
I just need some kind of feedback.

 

You control boost with a waste gate and a boost controller

 

1. How do you control boost with a carbureted setup?
ANS: Wastegate valve dumps extra exhaust bypassing turbine. Controlled by intake pressure and spring in wastegate

2. Is 3 inch piping too big for my setup? And can the intercooler be too big?
No and No

3. Can you control boost with an MSD 6LS box? I know you can set a boost timing map, but I was wondering if you can actually control the boost with it.
No. See answer 1


Why the On3 turbo instead of Borg Warner S400CW75 ?

 

On3 because of the major price difference. I was just wondering how the boost controller wires up to a carbed car?

 

You have alot of research to do before you can start.

Here you go:
http://lmgtfy.com/?q=how+to+install+...controller&l=1
http://lmgtfy.com/?q=how+to+install+a+boost+controller

 

What is the cost of the On3 76mm?

Are you talking about controlling boost max PSI, or boost spark timing?

Boost Max PSI is "normally" controlled all mechanically using a wastegate. There are no wires. Just some exhaust pipe and some intake silicone rubber lines. Look up turbo wastegate. It is just a valve that is in parrallel of the turbine to bypass the exhaust going through the turbine. The valve is controlled mechanically by a spring and diagram sensing intake pressure (boost). BUT you can get fancy with an electronic wastegate controller if you want.

 

On3 76mm is 340 shipped to your door brand new.