I have an 1985 302 I am rebuilding. I am considering eliminating the EGR if possible. I would be replacing the intake and carb so I would use non-EGR. Also adding long tube headers. Can I eliminate EGR or is the computer going to know and cause problems? Is there anything else I would need to do?

 

Are you replacing the carb with another computer-controlled carb? Or non? The computer will most likely not appreciate removal of the feedback carb...

 

You are about to open up a big can of worms, 85fordf150blue. I'm afraid it is not as simple as removing the EGR and hoping the computer won't know the difference. If you are going to change the carburetor and intake and eliminate the EGR and add headers, you are also going to have to change out your ENTIRE ignition system. Then, of course, your computer is useless and none of your emissions controls are going to work.

Read this:

https://www.ford-trucks.com/forums/1...ml#post9680418

 

Does anyone know a header manufacturer that can provide an EGR connection? So far everyone I've talked to has given me no EGR option for long tube headers.

 

You better also make sure your replacement carburetor is a feedback version, or your truck will not run correctly.

 

A decent welder should be able to fab something up for you that will work. May cost a couple bucks (but not much).

I know that Doug Thorley sells emissions legal headers for my 460, you should check what they sell for your setup.

 

Do not remove the EGR! Trust me I was operating the same as you until I learned. EGR leans out the mixture at cruise which results in better mpgs.

 

EGR is not for fuel mileage. It's for emissions. It lowers the combustion chamber temperature and doing that lowers some sort of NOx emissions.

The problem is the engine is calibrated to run with the EGR. If you take it off, you will need a non-emissions type carb, reset the timing, etc. to eliminate it. Usually if you just take it off, the engine will ping or pre-detonate.

If your truck has a computer, it will definitely throw a code if you take it off.

 

I'll find the thread about EGR increasing mpg because it leans out the mixture at cruise, by allowing more timing without pinging or something along those lines.

 

Here's a decent article on the subject....

Better Breathing: EGR Improvements

 

what a great read that explains a lot, but I was wondering...if you took the egr off and used one of the new (Meth I think)? coolant systems that racers put on the intake to lower intake temps, would this also cool the exhaust temp enough to stop smog formation? just wondering, as I am also thinking of ditching this system as no one can get this 1984/320/f150 to start correctly and Idle correctly at the same time? so now it idles fast, but starts right up? and I also only get 8 to 9 miles per gallon... driving like the old man I am. I had a 68 428 cobra-jet the got 9 to 10 mpg no matter how I got on it? with gas prices on the rise, I feel I have to do something, but what? also what about running the PVC gasses and others through activated charcoal with a drain-able container instead of running it through the carb? or a water bubbler? I know it sound way out there, but just trying to think outside the box... To my old school thinking, high comperssion responds, uh, well fast, and also works like a Jake brake when stopping to save on your real breaks? ( I just love a High compression engine sound!) Maybe we should get on Monsanto corp to stop them feeding corn to cows to cut down the methane gases as they are the worst polluters? maybe I'll just go electric?...just seen a car that took on all bets and won every time, every muscle car out there lost to him... vic

 

Thanks for the link Bill, I learned a lot reading that.

 

I don't agree with what he says about "efficiency" in that article.

1. We all know the higher the vacuum reading, then better and more fuel efficient the engine will be, with the throttle opened the least amount.

2. A EGR system will not work at all without some backpressure in the exhaust. There is no way for the plumbing to supply exhaust gas to the EGR without some restriction in the exhaust to pressurize it. We all know less back pressure in the exhaust creates a more efficient engine.

3. Granted, it may let you advance the timing more, which is a good thing, but better octane fuel would let you do that also. I'll give him that one, since can't get anything now but lousy fuel.

 

EGR does not "lean out" the mixture. EGR was introduced to help reduce emissions. Here is why:

If you run an internal combustion engine a little rich, you decrease NOx emissions, but you dramatically increase hydrocarbon emissions.

If you run it a little lean, you degrease hydrocarbon emissions, but you dramatically increase NOx emissions.

NOx emissions increase when combustion temperatures increase. By bleeding a little exhaust gas back into the intake stream, you slow down the combustion which reduces the combustion temperature. This allows you to run the engine a LITTLE leaner, reducing hydrocarbon emissions, while still keeping the combustion temperatures down to keep down the NOx emissions.

EGR by itself does not lean out the system or make it more efficient or improve your MPG. It does, however, allow you to intentionally lean out the system without making a lot of NOx.

If you remove EGR from a computer controlled engine, the result will be very poor performance. The engine will likely ping a LOT. It will probably run hot, and your NOx emissions will go through the roof.

Also note that the EGR valves on our era trucks are "back pressure" regulated. If you change to headers and a free flowing exhaust, the EGR valve will let a lot less exhaust gas into the intake. The result is like disabling the EGR even though you have it connected.

 

If the engine was built for an EGR valve in mind, it would be best to run it with one.


The reasoning why an EGR valve will give you better fuel economy, although it wasn't designed for it.

Think of it this way. A small easy experiment. Get a measuring cup, some water, and some cooking oil.

Your combustion chamber is the measuring cup.
The Fuel is the water.
The Exaust is the oil.

Now fill up the measuring cup 3/4 with water, then 1/4 with oil. The oil takes one 1/4 of the waters place in the measuring cup.

The combustion chamber on your engine is the same way except it uses gasses. You have to fill the combustion chamber. The EGR replaces a small amount of fuel vapor in the combustion chamber with exaust. It takes less fuel from the carb to "Fill it up". Thereby you burn less fuel with a good working EGR valve. If you remove the EGR valve, more fuel has to be put into the combustion chamber to make up for the lost volume, therfore it will burn more fuel.

Same reasoning with boring and stroking an engine. If you want better fuel economy, stay away from boring and stroking an engine.

You may get more power, but the extra volume in the combustion chamber has to be filled up with something.


The Carb, the timing, and settings on your engine was calibrated with the EGR in mind also. Remove it, and it will throw all these settings off, and the engine will need to be recalibrated. As was already stated. The Exaust is an inert gas. It's already been burned, so it delays the combustion of the fuel by a small amount when it's mixed. This in effect is like running a higher octane fuel. Why also a vehicle can ping severly with a removed or malfunctioning EGR.