Has anyone plugged the Intake Manifold cooling ports?

 

L98?

 

Just a guess, but I think the OP is referring to the throttle body coolant lines which actually provide heat to the throttle body. Their intent was to prevent icing which is a rare possibility under certain atmospheric conditions when the intake air passes through the throttle plates.

The answer is YES. Almost every non-concurs corvette has the throttle body line bypassed. It's really not needed for what is really a "fair weather" car.

 

I ran a loop of hose to each using a second connector for the two size hoses so dirt, bugs won't get in. I assume you are referring to LT1 intake manifold.

 

Easy to delete on an L98. You can just disconnect the hoses from the TB and joint them together or get a longer hose that fits. You can get fancy and take the coolant passage/IAC housing off and cut away the water parts to get rid of the bungs to clean up the engine bay a little.

LT I have no idea. It helps if you put the year of your car in your post.

 

Apologies for the vague post. I have replaced the runners (Jeg's) and ported the plenum to match. All accessories have been removed, AP AC Heat etc, as the car is used for Auto Cross, SCCA and Shows.
Question now LT, can I just run a vacuum hose straight from the EGR valve to the "adjustable" fuel pressure regulator? (skipping the switch)
And I thank you for your response...

 

Could you elaborate on this a bit..

 

NO.

The FPR is operated on manifold vacuum. It needs the vac to stabilize and react to changing intake pressures. The adjustable regulator allows you to set the minimums that it will operate. It will move a little but the "set" screw tells it the min that the internal diaphragm will move. The vac helps it see how much it should move to keep up with demand.

the EGR is ECM controlled. It needs to go thru the switch where the ECM gives it commands to open or close. This is milliseconds and comes at various times in the engines demands. Varying loads and conditions you'd say.
If you just left the EGR on vac full time you'd kill the engine with 99.999% too much EGR time. EGR cycles are actually brief and only come from certain conditions. You never know when or how much, its so little, but necessary as long as that is still part of the program.
You CAN eliminate the EGR entirely ONLY if you write it out of the program so the engines ECM is not looking for EGR to compensate for excess combustion temps that are seen.

Personally, I like having EGR and will keep it in my next build because it helps kill knocking since those dreaded symptoms of excess combustion temps come from the same place nasty exhaust comes from, same time, same place. EGR not only lowers the Nox emissions from hot combustion it also helps with knock which is quite deadly to pistons....ask me how I know.

Run a line from the intake, to a T that goes to EGR and FPR. One vac line should be able to support those 2 systems.

 

Thank's for that Lee... I will try the T with a vacuum line to the manifold and one to the egr and the other to the FPR. eliminating the "switch" correct? Now, can I use a vacuum line from the plenum instead of the intake, because it would be easier, there are two empty vacuum ports rite there in the back right side of the plenum

 

NOPE NOPE NOPE !

misunderstanding !

lemme be clear (er) ?

The EGR absolutely MUST have its vac from the EGR switch. No 2 ways '
bout that. If you go intake to egr the engine will not run. It will keep the egr valve open all the time.

Gotta go thru the egr switch.

AND........
The Vac SOURCE ( my bad) for the EGR switch also MUST come off the T-body underside....
why?
because that's "port vacuum". That means that this vac supply is able to change with the throttle position, or its based on the throttle position, NOT manifold vacuum. That's so the egr valve is not slammed to full open. The varying vac allows it to open only as much as needed, not on/off.

Now, the FPR needs to be on manifold vacuum. That requires a stronger vac source to operate the fpr spring.

I almost caused you to have a problem ! Sorry about that....I was not thinking when I said run a T in there.....can't be done. My mistake !

1. FPR gets a vac hose to intake vac, plenum fitting,.

2 egr switch gets a vac hose to the bottom side of the Throttle body.

Throttle body TO egr switch TO egr valve.