it is a topic that has been talked about a lot on the so cal board because a lot of poeple want to run heads that do not have the heat sink on the heads. the bgasic difference of the corvette and f-body EGR is the corvette one sucks the exhaust gas from a header primary.

i was wondering about theses questions:

posted by demonchild:
ok, i thought of some specific questions that maybe someone can answer.

1) the vortec heads came stock on some year trucks. what kind of egr did those trucks have and how did the valve work? also, compare the amount of exhaust that was allowed to pass through that style EGR compared to the stock f-body EGR say off of a q jet carb.

2) since the corvette EGR it tapped into a primary, is there anything between the tapped primary and the carb (yes CARB, i wanna know for my application) that regulates the gas flow?

3) a little more broad question: exaclty what components make up a corvette EGR system and how do they work as a part of the system.


and recieved this response:

posted by russ- so cal:
#1-Truck engines don't have egr. That is why it is illegal to install a truck engine in a car, and why the Edelbrock and other aftermarket efi units that are smog legal in a truck are illegal to use in a car.

#2-I'm not sure, but I think there is a solenoid valve between the exhaust manifold and the intake manifold. On a carb the egr would tap into the intake manifold below the carb.

#3- I think the components consist of a tube from the exhaust manifold to the egr solenoid, the solenoid, and a tube from the solenoid to the intake manifold egr port.

if anyone want to chime in with any ideas or information they have, go for it.

 

1) I'll agree about trucks not having EGR, but that's not why you can't put a truck engine in a passenger car. The reason is the trucks have more lax requirements overall.

2) The factory didn't make any carb'd engines w/o exhaust cross-over passages. What they did with the early ZZ4/HO 350 conversion kits is take the tube from the exhaust manifold up to the hot air choke boss on the ZZ4 intake manifold. It's in the same exhaust passage in the intake as the EGR source, so it was an easy way to feed the EGR. The flow is completely regulated by the EGR valve flow area, by the way. The solenoid opened/closed the vacuum to the EGR valve diaphragm to open/close the EGR valve itself.

3) Same as 2) above, except it went to the exhaust gas passage in the base via a special boss.

 

does anyone have a part number for a valve i can use to control the flow of exhaust when it isnt supposed to be going to the engine? and possible a picture of it? is it something i can buy from a parts store?

 

Okay, now I'm confused.

The ECM controls the EGR valve. There isn't any need for anything else.

 

ya i know, but how would an EGR off of a vette fit onto an fbody? would the harness need to be repinned for the vavle from a vette to be used on a fbody?

 

I guess I am missing a few things here? If I am seeing this right you guys think that a vortec head truck has no egr? WTF are they on??? they do the valve is mounted on the very front of the eng. above the water pump. it is the same Idea as how the vette does it (run a tube from the exhaust manifold to the intake where it is already has a cast in channel to the egr valve then from the valve to the rest of the intake going to the cyl.s) it is almost Identical to your regular egr setup you just feed in from the manifolds to the intake instead of that cast in spot on the heads (e-bay has good pictures of the tpi manifold for the vettes and shows where it is mounted)

I guess I really don't see the big issue.