Corellian Corvette

So I picked up an EGR blockoff plate today.

Before I install, I wanted to get some opinions. I have an Edelbrock Performer intake manifold, EGR version, and I was thinking I could pickup a few HP by using the blockoff plate and removing it altogether. Plus, it would cleanup a bit of the engine compartment in that area (using a stock EGR with the performer requires a bit of rigging and it's somewhat clumsy looking)

So, what does the EGR do exactly? I know that it re-circulates some exhaust gasses back into the carb. But, is that a good thing? Is it necessary? Any advantages? I'd like to understand some of the pros/cons.

Finally -- if I do decide to install the plate -- do I need to use any sort of gasket (or gasket maker) over the hole, or is just metal-to-metal OK?

Thanks

mrvette

IMO, block it off and have over with it, in fact most manifolds with that provision are not as good a flowing as one's without it...passages in the way...
now having said that, most smog carbs are tuned with a lean off idle transfer slot/passage way, for the inert gasses of the egr to be introduced.....
somehow this is supposed to make lower emissions....
the things tend to get clogged up and are another failure point in the system...
I preferr to tune carbs/timing etc...for no EGR, and tune it up once in a while...emissions are just as lo that a way....and get better power...
now with the governement in the act, you may have to keep it on there, assuming they check....sometimes a visual is also mandated...most allways if they check anything at all....

GENE

Corellian Corvette

So, there is no advantage to having it?

fauxrs

The only ADVANTAGE I've ever heard is that it will reduce combustion chamber temps and therefore reduces detonation (pinging). This assums that reduced emissions are not an advantage in your book :lol:

Also any potential gain will be minimal at best.


[Modified by fauxrs, 2:33 PM 2/15/2002]

Rockn-Roll

As I recall...the EGR valve is there to help reduce NOx which occurs when the air/fuel mixture burns too fast like with an explosive, and expansion occurs too quickly inside of a static volume, and the combustion creates additional heat instead of an expansion force which pushes the piston down, and some fuel doesn't get burnt because the Oxygen and Nitrogen under those high pressure and temperature conditions form NO and NO3 thus tying up the oxygen that the fuel needs to burn. The addition of burnt fuel slows the burning of the fuel and expansion of the gases, so that the fresh air/fuel will more completely burn. This slowing of the burn is why some racers used to install water injectors...it was determined that water injectors were not the way to go due to corrosion and metering problems.

All of this stuff is for a passenger car engine which will be running for long periods of time under various conditions and the desire is to prolong the life of the car, and reduce any unburnt fuel. Racers compensate for the formation of NOx by squeezing more air/fuel into the chamber, by using better fuels, introducing more oxygen (NOS), etc.

Will it help to have the EGR? Some. Keep in mind that blocking it off will create a slightly rich condition due to the exhaust gas taking up space that air would normally be, therefore to get better performance rejetting is usually required, or some other way to get more air into the chamber.

I have a block off plate...I think I used an EGR valve gasket. I don't have my car with me yet.

Steve

79MakoL82

Personally, I yanked my EGR (it was bad) and rather than pay the outrageous $$$$ they want for a new one, I spent $8 and bought the block off plate. I used a litte RTV to seal it. Does it hurt...I don't think so (we have no emissions testing). Does it help? The only thing it really helped was my wallet. Don't expect any HP gains. If you can, I say keep your $$$ in your wallet until you have to. If for ANY reason I ever need the EGR again, I'll go buy one then.

P.S. Its absence does help clean up the compartment a little

Corellian Corvette

Thanks guys. I have a new EGR, and it works. I'm scavenging for power I suppose, and I was just cleaning out my engine comparment again and realized what a mess it was. I think I'll pull it and see what happens -- I need to futz with my fuel mixture anyway so might as well take care of it at the same time.

THanks!

Noel Carboni

Let's see... Exhaust gases are non-combustible, and hot, right? :confused:

Power comes from combusting a mixture, and we try like heck to make it as cool as possible (cold air intakes, intercoolers, etc.).

It seems clear that mixing non-combustible hot gases into the intake mixture can do no good for power.

Some newer cars are pre-programmed to expect EGR, and will run more poorly if it is not present. These vehicles need reprogramming if the EGR is blocked. The same could be said for adjusting the idle with an older, carbureted vehicle, I suppose.

Any flaws in my logic, here?

-Noel


[Modified by Noel Carboni, 1:14 AM 2/16/2002]