Porting 3.0 exhaust manifolds?

[Tim_K]

Are there any gains to be made? I've looked at the set of manifolds I have right now for the replacement engine, and it doesn't look like there is much of anywhere where porting will make a difference.

The only thing that might help is gasket matching the manifold surface, but that's all I saw that looked like it needed work.

Anyone done any porting on these?

Do the 3.0 exhaust manifolds flow fairly well for our engines or are they a big restriction?

[RoadWarrior222]

I wouldn't say they flow well, it's more a case of it's a royal bizatch to get anything presumed "better" to fit.

There might be a small advantage from going from earlier (pre '91?) to later (post '91?) manifolds, because somewhere along the line they went from 2.25 to 2.5 @ the downpipe. However, there's some years have EGR and some don't so you'd hafta be careful if you have emissions inspection.

[lookin]

I had my 95 stock headers and crossover heat stop coated, and it made them flow much better. I think thermal lock is the main problem with the stockers, and coating them really helps that.

[onecrazyphucker]

Quote:

Originally Posted by Tim_K Are there any gains to be made? I've looked at the set of manifolds I have right now for the replacement engine, and it doesn't look like there is much of anywhere where porting will make a difference. ?

When I was thinking about porting mine, I noticed the same thing. I just smoothed mine out the best I could.

[Ondonti]

there isnt much to do on the front manifold and its the only one that really has much to mess with. I think Ed said that a little smoothing of the front manifold and grinding down the humps that make space for the manifold bolts did not show any improvement in flow on the bench. I did all those things but I guess it doesnt matter :P

[RoadWarrior222]

Quote:

Originally Posted by lookin I had my 95 stock headers and crossover heat stop coated, and it made them flow much better. I think thermal lock is the main problem with the stockers, and coating them really helps that.

Interesting, was it internal or external or both?

I was thinking of wrapping everything I could get the tape round, guess the manifolds won't really take it too well. I've got this rattle can stuff I picked up on sale, aluminum finish high heat stuff, claims to have ceramics in it. Doesn't make any claims for insulating, but since ceramics are insulators, and silver is a poor color for radiating, I figure a few coats might just do a little something. For the bits the wrap misses anyway.

[c2xejk]

Quote:

Originally Posted by Ondonti there isnt much to do on the front manifold and its the only one that really has much to mess with. I think Ed said that a little smoothing of the front manifold and grinding down the humps that make space for the manifold bolts did not show any improvement in flow on the bench. I did all those things but I guess it doesnt matter :P

The exhaust flow coming out of the head is pretty much all on the port ceiling... The nubs are on the floor... Their impact is negligible at best.

[lookin]

Quote:

Originally Posted by RoadWarrior222 Interesting, was it internal or external or both? I was thinking of wrapping everything I could get the tape round, guess the manifolds won't really take it too well. I've got this rattle can stuff I picked up on sale, aluminum finish high heat stuff, claims to have ceramics in it. Doesn't make any claims for insulating, but since ceramics are insulators, and silver is a poor color for radiating, I figure a few coats might just do a little something. For the bits the wrap misses anyway.

It's an internal and external ceramic/titanium coating that looks dull bronze. This stuff really does insulate quite a bit. They don't stay cool, but they get no where near as hot as they did before.

It is also pretty durable. It's been on there a couple of years now, and there is not a mark on them anywhere.

I heard that wrap doesn't prevent thermal lock, and in fact it even holds heat in and worsens the problem. Int/ext coatings work by stopping the metal from heat soaking. Must be something to it, because my ems also cool down way faster after shut down since they were coated.

[Phatfoto]

I port matched and smoothed the nubs on my 87 exhaust manifolds. And later swaped in a post 91 rear that I did the same to. By that point though, I'm not sure it helped as I also swapped in roller rockers and started playing with Turbo 1 fuel injectors at the same time.

[DustyR/T]

I'm interested in these "coatings" that were mentioned. Especially in FL, it gets REALLy hot here and would make things like Radiator and A/C work a LOT better if the exhaust wasn't dissipating NEARLY as much heat. Anyone have a good link or good experience w/ a product?

[lookin]

I have definitely had a good experience with both heat stopping and heat dissipating coatings.

The heat stop really does keep engine compartment temps down; and whatever is coated with heat dissipate coating heat soaks a lot less, because a lot of the heat is quickly dissipated. The later is great for radiators, oil coolers, intake manifolds and plenums, and any other metal you want to radiate heat away from.

As for links. I suggest you just Google for "automotive engine coatings" and add "your area, e.g., "Miami Fla or wherever". That way you can find out who does it in your area.

Hope that helped.