82-T/A

Hey guys,

I just checked out my 84 / 944 and noticed that they have the cast iron exhaust manifold pieces. I ordered a spare set of manifolds off eBay a while back and they were tubular. I was planning on having a set ceramic coated, and then put it in my 944. The thing is, I'd like to know which ones are superior... at least in terms of performance. My first guess would of course be the tubular ones, but I can't seem to find any year specifications that dictated whether a car received a cast iron pair of manifolds, or if they received the tubular ones. On top of that, will either set bolt right up to the same header pipe?


Thanks!!!

jgporsche

i've heard racers say they switched to the tubular exhaust manifolds because they weigh less.

Zero10

The tubular headers are famous for cracking, but they do weigh 5-10lbs less than the cast ones.
IIRC they both bolt up exactly the same, and are interchangeable.
On a street car I would reccomend that you use the cast headers so you don't have to deal with cracking, and the 10lbs probably won't be a big deal.

Just curious why you would ceramic coat the headers? To look nice, or to keep the temps down?...
If we are trying to look nice, then definately go for the tubular headers, but have them checked over, and expect some welding in the future.

sillbeer

either set will bolt up. I think the tubular manifolds are good for 1-2 hp, but they weigh alot less and thats why the racers like them.

Lorax

arent the tubular ones double walled?

Am i confused about that?

If they are double walled then ceramic coating wouldnt have and positive gains really. So ive been told.

MM951

I dont think they are double walled, but i may be wrong


are you thinking of the stock 951 downpipe?

Lorax

I must be, that and the 951 headers I think are also double walled. My bad.

dme

They are only double walled in that they have the heat shield riveted on around the pipes. Interestingly enough, I have a set of cast iron which would fit in place of my original tubular pipes on my 951. Not that I should ever need them especially after getting the expansion joint on my 2-3.

Lorax

actually now that I think about it I am almost sure both the xover and 951 headers are double walled and insulated.

Sorry for the OT

yellowline

+12 ft-lbs torque, as dynoed by Excellence. They bolt on- I've made this upgrade.

Have a shop reweld them before you install. I've had mine in for 1 1/2 years in the Northeast, no cracking issues.

edit- I found this out after installing them, since I did it for the weight loss (and they were bolted to a good cat, which I needed). I will say the car felt *slightly* quicker by the seat of the pants. It's no magic pill, but every little bit helps.

82-T/A

Thanks! I see them on eBay all the time, so I'll probably bid on another set just to have. I'm a huge fan of tubular exhuast manifolds. They are FAR superior in every way (but longevity I suppose) to cast iron manifolds. By ceramic coating them, you will reduce the underhood temperatures significantly. This cuts down on the wear and tear of all the wiring in the engine bay, helps maintain a cooler temperature surrounding the intake, etc...

By retaining the heat in the exhuast more, you actually see increased exhaust velocity at certain RPMS that you would otherwise not have if you didn't have them coated. This aids in exhaust scavenging. In addition, the catalytic converter will work better, giving you better emissions. That's not even to mention that having a header ceramic coated INSIDE and OUTSIDE will help soften rough spots in the manifold, which would otherwise cause turbulance.

I mean, we're not talking big power or anything... but you'll see an improvement in fuel economy, and a horsepower or two over not ceramic coating it.



Well, that seals the deal for me! I can't think of a single reason why I wouldn't want an additional 12 foot pounds of torque!


Thanks guys!!!

944CS

if they are made llike the turbo manifolds, grind away the weld at the port entrance and radius it...you'll want a diamond cutter for that, then go with a sandpaper bit

FSAEracer03

You could definitely see a little extra power out of the tubular manifolds and save a little weight. Double-walled or not, ceramic coat them after you work the flanges and joints to port match it and clean the inside. Have them TIG welded, and then coat them. Might as well do it once, and do it correctly if you're going to do it at all, right?

Techno Duck

When were the tubular headers used in production?

AznDrgn

Tubular manifolds came out in the late cars, post 85.5 for sure but some early 85's had them too.