Removing The Egr Valve on a GMC Syclone / Typhoon
The exhaust gas recirculation (EGR) system is an emissions reduction system. The EGR valve is operated via vacuum passed to it from the EGR Solenoid. The computer sends a signal to the solenoid (during part throttle cruise conditions) which send vacuum to the valve, causing it to open at a varying amount. Its purpose is to reroute burnt exhaust gases back to the intake air. The effect of the introduction of inert or incombustible gas increases gas mileage by displacing burnable oxygen/fuel withought effecting the air/fuel ratio. It decreases cylinder temperature (less boom, less heat), increases gas mileage (less oxygen, less fuel needed), and reduces the amount of NOx getting into the atmosphere. So, why remove it then?
A negative effect of the EGR, is that it introduces hot exhaust into the intake. This heats intake air temps, and can heatsoak the intake manifold causing reduced wide open throttle performance. That is the reason for this mod, where a plate replaces the valve, eliminating intake air mixing with hot exhaust.
**NOTE* This modification is not emissions friendly (or technically legal). If you have regular testing in your area/state, this modification will cause you to fail. This is a race-only modification. The author or website is not responsible for any outcome that may come due to this modification.
- EGR block-off plate - Available from Sportmachines.net (or modify the valve to make it inoperative, i.e, JB Weld)
- EGR gasket (Fel-Pro 70978)
- Chip or recalibration of chip - The stock chip will set a code at highway speeds if the EGR is inoperative.
- Vacuum Cap - This blocks the vacuum source to the EGR
Removal of the EGR Valve
Remove the vacuum elbow from the valve.
Begin to remove EGR valve. The bottom bolt might be a bit of a struggle. Using a closed ended wrench reaching around the back of the valve to loosen it helps.
Optional: Remove the 2 (two) vac lines shown below, one from the solenoid to the valve, the other from the vac harness to the solenoid.
Block the vacuum line off with a nipple. If you want to go the cheaper method, you can use a screw and push it into the vacuum line to prevent a leak. A good place to bloc off the line is where it meets the main harness above the passenger valve cover with a nipple over the end of the "T" that fed it.
Optional: Remove the solenoid. There are 2 (two) screws hold it onto the bracket that holds the solenoid and coil. Remove those 2 (two) screws and unplug it from the wire harness. Tuck the connector away, and your done.
Using the new gasket, bolt the EGR delete plate (or if you have choose to make the EGR valve inoperative) back onto the upper intake.