I am installing a Edelbrock performance series cam/hydro lifters, intake and carb (600 cfm)to my 77. I need to know should I go with EGR or non, the series is offered in both. I have also recently installed straight 1 3/4 pipe to flowmaster muuflers.

Russell

I have a '78 L82. I installed an Edelbrock Performer intake without EGR, rebuilt my Q-Jet, and installed a true dual exhaust system. A prior owner installed a somewhat warmer cam which made necessary some jetting changes to the carburetor. The car runs excellent and about ten degrees cooler than with the EGR system. Taking off the EGR and related parts also eliminates potential vacuum leaks.

I think you're gonna be quite happy with your choices. Edelbrock makes some great stuff.

As a suggestion, since you plan on using the square bore Edelbrock carb, consider using the Edlebrock Performer EPS intake...it's designed specifically for their square bore carbs and gives somewhat higher horsepower and torque numbers than the standard Performer which is somewhat a compromise design for both square and spread bore carbs. Check with Edelbrock to make sure the EPS intake with fit under a stock Corvette hood. If so...I say go for it!

EGR can be friend or foe.

What is does is allow exhaust gas back into the intake. This exhaust is already burned, and can't burn again. It is now an Inert gas, it does not react in the compustion chamber.

It does this to cool the combustion process without changing the fuel mixture. At about 2500 degrees F. the engine starts to ping and creates NOX emissions. If the mixture ran rich, it would cool the cylinder on it's own, but use more fuel and raise emissions of HC and CO. If the mixture is run lean, NOX and cylinder temp go up, and ping gets worse. By adding inert gas it reduces the cylinder temp without changing the fuel mixture. It just reduces the total volume of mixture by dilution. This does cut mid-range throttle power and response. It will respond quickly but not as crisp.

It's like having a charcoal grill. When the charcoal is surrounded by a lot of ash, the ash does not burn, but the coals put off less heat then when the flames are present. Same concept.

So EGR does cool the cylinder, but it also heats the intake manifold, which can cause other problems. In some cases this can raise engine temp. Other times it lowers engine temp, depending on conditions. In all cases it lowers cyl temp.

EGR does not operate at idle. There is no need and it would make the car run rough or stall. EGR does not operate at wide open throttle. It would reduce power, which we don't want at WOT, and is not needed due to WOT enrichment designed to get more power. It only operates (or should) at mid range throttle.

Now it depends on you carb operation, fuel mixture adjustments (not at idle, the jets) cam shaft, and engine cooling system.

If you biggest concern is fuel economy and emissions, and you are running primarly stock engine components, keep the EGR. If you are running a non-stock cam, buy one for a non-EGR, richen the jets a bit, don't use EGR, and you will like the response and power.

Choices, choices. My stock 75 L-48 will keep the EGR for now, but when I put an upgraded cam in and add the true dual exhaust, the EGR will go. That's going to be a while. Too many other things to do first.

also

how stringent are the emissions regs in your state ?

i wouldnt change anything that could raise emissions in CA