The 300 I6 and egr and cats

[86 12 Brutus]

Ok guys, i have some questions because i am at the point where it's either get rid of them or keep them. But mainly talking about the 4.9 in this case. I've heard many many conflicting info on this. First off, I do believe Brutus came with california emissions, i'm not sure, but when i see the pics of the exhaust breakdowns, the one that is for Califonia emissions looks like mine. When Brutus was new it had all kind of strange emissions contraptions on it that rusted away and or broke and just didn't do anything about it, we did get rid of the smog pump.

I had to buy a new intake and exhaust manifold and am waiting for them to come in.

As far as the egr valve goes. There is a pipe that goes from under the carburetor's egr plate and goes to the back of the exhaust manifold. Is there any benefit in getting rid of this contraption? Some say yes, others say no, but can never get any real definate information.

Now to the cats, Brutus has a funny looking cat right at the beginning of the exhaust, followed by the cat. From my understanding, or at least what i have read, the smog pump is what helps keep the cats clear, and if the smog pump is removed it wil cause the cats to clog up. it has also been said that removing the cats off the 300 will make the engine noisy. That i dont want, when Brutus was new, he ran quiet like my crown vic does and want to keep it that way if at all possible.

So i guess here is my questions. Should i get rid of the egr and the cats?

I have looked around and have found nothing, and if i do decide to get rid of the cats it looks like id have to take to an exhaust shop and get him to do it. I do know a guy that will do it am not worried about that, but me, I'd rather do it myself, but cant find a pipe to connect to the manifold and bend and run under the truck body, if i can find this, i can get this done myself.

Sorry i'm so long winded today, but before i get this thing put back together, i want to make my decision as my next stip is the new AC and once thats in, its just in the way.

Thanks guys

George

[myrl883]

Getting rid of cats won't cause any problems. But, the reason for the EGR system is that you can run a leaner mixture successfully without detonation. EGR can be deleted, but you should have the distributor recurved by someone with experience, and you'll likely need to rejet the carburetor as well.

If you are subject to emission testing, there's a good chance that passing will be difficult if not impossible.

[86 12 Brutus]

Getting rid of cats won't cause any problems. But, the reason for the EGR system is that you can run a leaner mixture successfully without detonation. EGR can be deleted, but you should have the distributor recurved by someone with experience, and you'll likely need to rejet the carburetor as well.

If you are subject to emission testing, there's a good chance that passing will be difficult if not impossible.

I'm not against keeping the egr on, the compute would probably have a fit if i took it off. I'm just really curious about the whole thing.

[ArdWrknTrk]

I'm not against keeping the egr on, the compute would probably have a fit if i took it off. I'm just really curious about the whole thing.

My personal experience with the I-6 is that the exhaust note is fine with just the cat and no muffler.

But if you decide to eliminate the Cat you'll probably want to use the biggest muffler possible.

Without A.I.R., you're not going to get the Cat up to temperature, and it WILL clog.

EGR is not a hindrance. It just allows leaner mixture at cruise without detonation.

It essentially makes the mixture richer by displacing O2 in the charge.

[86 12 Brutus]

My personal experience with the I-6 is that the exhaust note is fine with just the cat and no muffler.

But if you decide to eliminate the Cat you'll probably want to use the biggest muffler possible.

Without A.I.R., you're not going to get the Cat up to temperature, and it WILL clog.

EGR is not a hindrance. It just allows leaner mixture at cruise without detonation.

It essentially makes the mixture richer by displacing O2 in the charge.

I guess that would explain why it isn't that loud with the muffler that needs to be replaced ( there is a big hole n it) one thing about the I6, they eat exhaust systems

probably going to leave the egr alone

[FuzzFace2]

I guess that would explain why it isn't that loud with the muffler that needs to be replaced ( there is a big hole n it) one thing about the I6, they eat exhaust systems

probably going to leave the egr alone

Ok my system 1981 factory intake and carb.

I am running EFI exh manifolds with a factory replacement Y pipe, no cat(s).

Into what I am guessing is a factory replacement exh system (mid pipe / long muffler / tailpipe out behind the right rear tire) all off my parts truck as it looked pretty new.

It is really quite, little to for my liking but it will do till it falls off.

Now because I am running EFI exh manifolds that EGR tube had no where to hook up to so I removed the adaptor and used a pipe plug in the hole.

I also used a small freeze plug in the intake to seal off the EGR and put the EGR valve back in place just to make it look "finished"

I believe Cali used 2 cats on the 300 motor from I had seen when looking for Y pipes.

Because of the EFI manifolds I run a hot water plate on the bottom of the intake and I had to use copper tubing wrapped around the manifold for the choke heat asst.

Do what you have to with that tube, put it back or plug the holes. Don't worry not running a cat(s) and it being to loud as it will not. I had a straight six with a 3+3-2 long tube headers into a made Y pipe into a turbo muffler it sounded good till you got the RPM up pretty high then it would bark.

On my truck and yours this will never happen.

Dave ----

[86 12 Brutus]

Ok my system 1981 factory intake and carb.

I am running EFI exh manifolds with a factory replacement Y pipe, no cat(s).

Into what I am guessing is a factory replacement exh system (mid pipe / long muffler / tailpipe out behind the right rear tire) all off my parts truck as it looked pretty new.

It is really quite, little to for my liking but it will do till it falls off.

Now because I am running EFI exh manifolds that EGR tube had no where to hook up to so I removed the adaptor and used a pipe plug in the hole.

I also used a small freeze plug in the intake to seal off the EGR and put the EGR valve back in place just to make it look "finished"

I believe Cali used 2 cats on the 300 motor from I had seen when looking for Y pipes.

Because of the EFI manifolds I run a hot water plate on the bottom of the intake and I had to use copper tubing wrapped around the manifold for the choke heat asst.

Do what you have to with that tube, put it back or plug the holes. Don't worry not running a cat(s) and it being to loud as it will not. I had a straight six with a 3+3-2 long tube headers into a made Y pipe into a turbo muffler it sounded good till you got the RPM up pretty high then it would bark.

On my truck and yours this will never happen.

Dave ----

Thanks Dave. my manifold is the oem replacement so it has the hole, i'm just going ot hook the egr up and leave that be. The cats, they are going to go, but if i cant find the correct pipe from the manifold, ill just have to take it to an exhaust shop.