Thread: blocking off egr

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Are there any potential performance issues linked to blocking off egr passages on the intake?? I know the legalities, just want to know if it can damage anything. All other emission equipment has either been removed or plugged. Can I fabricate my own plate to go above the gasket with the old valve housing? Thank you for any replies.

yes you can, and of course it is illegal to modify emmisions equipment on a car!!! I assume you are doing this for off road use only, right?????

as long as your in a state with no emmisions laws beyond a certine year, here in Ny it's 1996 or newer, and catalitic converter present 1975 up, other than that nothing else. easiest way to remove it is get a intake that does not have an EGR port. personally, I wouldn't go through the hassle, for the small amount of HP you will gain, it won't be worth the hassle.

I'll say yes. The only things that are original in this s10 is the VIN and the interior. We live by the seat of our pants here in Tennessee. Thanks Dave

Sorry Matt,
Was replying to Dave while you were posting.

A little bit goes a long way for the dime. Just want to make sure there would not be the potential for engine damage. I am not that familer with specific head design, although I have heard of "egr heads"??? This is a GM crate from '93. All I know is 64cc and center valve cover bolts Any hints on determining if these heads are "egr"? Do I even need to know with this mod?

Matt, any horsepower gains that are that cheap are worth doing..... Most horsepower gains cost big $$$$, I don't ever turn down the cheap or free gains!!!! If you can do 10 little things that gain you 2 horsepower each and cost you little or nothing, you just made the same horsepower increase you would get from a $250.00 intake manifold purchase.....

Originally Posted by Dave Severson

Matt, any horsepower gains that are that cheap are worth doing..... Most horsepower gains cost big $$$$, I don't ever turn down the cheap or free gains!!!! If you can do 10 little things that gain you 2 horsepower each and cost you little or nothing, you just made the same horsepower increase you would get from a $250.00 intake manifold purchase.....

Dave is right on the money here. For instance, eliminating the EGR and PCV might allow you to run another 20-40 psi cranking pressure without detonating on pump gas. Don't hold me to these numbers, I'm just trying to make a point. If you can make 160 psi on pump gas with the crud on the motor without detonation, taking it off might allow you to run 200 psi for instance without detonating.

Grandpa always said the PCV was the only decent thing the engineers ever did ( regarding emissions ) so don't disconnect the PCV. On the other hand, the EGR is shit. All it does is reduce performance ( yes, to reduce the carbon monoxide ) You don't even need to remove it. Just remove the vacuum line.

Originally Posted by firebird77clone

Grandpa always said the PCV was the only decent thing the engineers ever did ( regarding emissions ) so don't disconnect the PCV. On the other hand, the EGR is shit. All it does is reduce performance ( yes, to reduce the carbon monoxide ) You don't even need to remove it. Just remove the vacuum line.

With all due respect to you and your grandfather, if I were building a max effort motor, it would not have EGR or PCV on it if I didn't have to pass any sort of emissions test in my area.

Woah woah woah. I have a pcv valve on the motor I built for my car and a breather on the other valve cover. Removing the PCV gives more horsepower? How come I was never told this?!

Quick: tell me what I need to make more horses. I have an edelbrock 600cfm with the pcv line running to it and the valve covers have the rubber grommets on the edelbrock valve covers. Would I have to plug the hole on the carburator as well? I don't want to have to get rid of my edelbrock valve covers unless I absolutely have to. I still have my old 283 '66 Valve covers that don't have holes punched in them from the factory.

But tell me. If I did remove the pcv.. would I get better or worse gas milage?

Installed the plate today and ended up with a rough idle. The plate is above the gasket and is sealed up good. Seems to be a rat-a-tat-tat at the plate.

Do I need to readjust the idle mixture? Up the idle RPM? Rough at 650 and smooths out at @800.

To correct myself in the initial post, I do have the PCV at the valve cover to the front of carb. I did'nt know that was an emissions piece.

14 degrees BTDC initial advance with timed vac.advance. The full time vac. and the rear vac. port of the carb are plugged off. Edelbrock 1406. Super unleaded 93.

o. kthx

Originally Posted by DennyW

There are different types. I didn't see where you mentioned on what motor this is, and what are you running for exhaust. Application is needed.

Here are the specs:

Engine Part Number: 12355345
Displacement: 350 Cubic Inches (5.7L)
Horsepower: 300 @ 5000 RPM
Torque: 369 Ft. Lbs. @ 3500 RPM
Maximum Recommended RPM: 5500 RPM
Compression Ratio: 9.1:1
Block: P/N 10105123 Cast Iron with straight four-bolt bearing caps, late model 1-piece rear main seal design.
Bore and Stroke: 4.00” x 3.48”
Crankshaft: P/N 14088527 Nodular cast iron, 1-piece rear main seal design.
Piston Material: P/N 12361371 Cast Aluminum
Connecting Rods: P/N 10108688, 1053 Forged Steel
Cylinder Heads: P/N 10159592 Bare Head, Cast Iron 64cc Chambers [Old P/N 12356026]
Valvetrain: Overhead Valve with Pushrod
Camshaft: Hydraulic Flat Tappet Design
Intake Valve Dia.: P/N 10093027 1.94”
Exhaust Valve Dia.: P/N 14088641 1.50”
Advertised Lift (Int/Ext): .435/460
Rocker Arm / Ratio: P/N 10089648 / 1.50 Ratio
Valve Lash: Zero
Engine Idle Speed: 650 RPM
Spark Plugs: R44TS
Spark Plug Gap: .035
Oil Pressure (Normal): 40 PSI @ 2000 RPM


GM aluminum 4bbl intake
Edelbrock 1406 (600CFM) electric choke
Headman swap/conversion headers
Flowmasters (40 series)
No cats.

THM 350.

Denny,
I used 1/8 plate steel and used the old housing. I dont know if the gaskets have the heat provisions. I do have a 1 inch spacer plate under the carb.

Originally Posted by DennyW

Actually, the pcv valve functions the best on idle and part throttle. When you nail it for power, the pcv functions at such a decreased rate, it doesn't matter. I would keep the pcv simply because of the benefits of oil leaks.

Denny, with all due respect to you, when you're on the gas, off the gas, on the gas as in Gymkana, trials, road racing, etc, etc, everytime you're off the gas, you are sucking burned exhaust gases from the crankcase right into the intake manifold to dilute the fresh charge that comes available when you are on the gas again.

I repeat, for a max effort motor where it does not have to meet any emissions standards, I will vent the motor at the valve covers and run the hoses down to the back of the motor to atmosphere and run without EGR.