egr mods

i hear talk of egr mods alot. what type are avalible for 91 4.3 tbi? and what are some benifits?

Restrictor plate... Will give slightly better gas miledge, and better low to midrange torque. Not used at WOT

What's WOT?

wot = wide open throttle

is a restricter plate just a bolt on or does it replace the egr?

is a restricter plate just a bolt on or does it replace the egr?

Goes between the egr and the manifold...

Using a 1/4" piece of aluminum, take an EGR gasket and trace an outline of the gasket on the aluminum including the large holes.

On the upper pintle hole, drill to the same size as the gasket.

On the lower pintle hole start with 5/32.

Put a gasket on either side of egr plate when mounting. Now, if you set an SES code, simply drill the lower hole 1/32 bigger and repeat till the ses stops coming on. Be sure to clean the egr port on the manifold side before installing. Pick out carbon with a screw drive and run the engine for a minute before installing to blow out any loose carbon (rev a few times)

For the 96-2002 a fitting is required. 2003-2005 essentially the EGR mod is built in.

alright thats easy enough. im going to do it. thanks!

I've never heard of that mod rlith.
in your opinion is it worth it to remove the EGR and bolt a plate in?
I don't have to worry about emissions where I live, and the EGR is the only emissions device left on my Blazer (with the exception of the PVC)

I've never heard of that mod rlith.
in your opinion is it worth it to remove the EGR and bolt a plate in?
I don't have to worry about emissions where I live, and the EGR is the only emissions device left on my Blazer (with the exception of the PVC)

You don't remove the EGR, you add the plate between the EGR and the manifold. We have pretty strict emissions here in PA and we've never had mine fail emissions, and most people that I know who've done the mod have yet to fail emissions.

The reason? EPA standards on emissions call for at least a 10% N0x reduction. GM made there egr holes large enough so they wouldn't have to worry. When you do the mod you're restricting it down to epa standards. The ECM in your truck is pretty savy when it comes to the emissions standards programmed into it. As long as the SES light isn't set you'll most likely pass. GM finally wizened up to the fact that the large egr holes allowed too much carbon build up (see any given clogged egr thread) and actually built in the mod (for all intents and purposes) into their 2003 and up trucks.

Goes between the egr and the manifold...

Using a 1/4" piece of aluminum, take an EGR gasket and trace an outline of the gasket on the aluminum including the large holes.

On the upper pintle hole, drill to the same size as the gasket.

On the lower pintle hole start with 5/32.

Put a gasket on either side of egr plate when mounting. Now, if you set an SES code, simply drill the lower hole 1/32 bigger and repeat till the ses stops coming on. Be sure to clean the egr port on the manifold side before installing. Pick out carbon with a screw drive and run the engine for a minute before installing to blow out any loose carbon (rev a few times)

For the 96-2002 a fitting is required. 2003-2005 essentially the EGR mod is built in.
I did this setup on my 98.I used sheetmetal though.

I did this setup on my 98.I used sheetmetal though.

The problem with that though, to make it truly effective, at least 1/4" thickness should be used to create a proper tunnel vaccume.

will this work on my 91 4.3z?

will this work on my 91 4.3z?

yes