carbster09

Anyone tried to extrude hone a BB exhaust manifold? I want better flow, but I don't want to go with headers as my BB car is hot enough. Plus the extra performance would be welcome. I plan on a cam swap, some ... but to realize the performance of a cam I need headers, maybe a set of manifolds properly extrude honed would work? Any ideas? Any ideas who could do this? There is a shop here in that I talked to and they are keen on doing it.

Another thing is that I would like to keep the car stock, or close to stock looking.

carbster

MR L88

Carbster
Go to www.gesslerheadporting.com,he's the man when it comes to stock appearing parts that make serious HP!!!
Wayne

Grinchia

Sorry, I've never heard of that process. Care to elaborate?

Corey_68

Basicly you remove material from inside of the manifolds, I've seen guys use a strong acid on their ram horns. Seemed to work fairly well.

427Hotrod

The name of the Co is Extrude Hone...so you might check with them. It's a process where a "slurry" of abrasives is pumped back and forth through the casting to polish off the inside without enlarging it a lot. Especially helpful in cases where you can't get access to the inside to port it.

Last time I heard it cost around $600 or so to do a set of manifolds. Not sure if that is a good "bang for your buck" mod. I saw a test of a 489" Hemi once that picked up around 6 RWHP with set honed. He had to use stock appearing stuff for class racing and he had a pretty scienced out combo. I doubt you will gain all that much without similar efforts.

I don't see headers as a bad issue. Especially if you spend the $$ to have the Jet Hot coated..the heat is a non-issue for sure.

If you are really determined to use stock stuff, Brezinki does porting too of stock manifolds.


JIM

CGGorman

The exhaust manifolds on my DD are extrude honed from the factory.

Basically, they take a clay compound and mix in an abrasive, so that it's like sandpaper putty. Then they pump this abrasive mixture through the parts. It's thick enough that it removes the ridges and rough spots before it changes the size of passage. The putty puts pressure in the same areas of the pasages that air would, so there should be a significant improvement in ultimate flow capacity AND velocity. I've never heard of anyone having this done. I'd be real interested to hear what kind of results it would yield.

An acid would remove material indiscriminantly and would only serve to increase the volume of the passage. Kind of like going from a 2" crush-bent pipe to a 2 1/2" crush-bent pipe. The Extrude Hone would be like going from a 2" crush-bent pipe to a 2 1/2" mandrel-bent pipe.

PROSOUTH

Have you looked at Sanderson Cast Iron Headers for the Corvette? They may be what you are looking for. They do not have a stock appearance, but they are free flowing and Cast Iron. For $610 they come with a ceramic coating already on them and might be what you are looking for.

On a big block Corvette I would also consider sending the front pipe sections to Jet Hot for ceramic coating as well. This will help contain the heat to the pipes and move it toward the rear for exhaust instead of allowing it to radiate under the cockpit floor as a heat source. It is easier to contain the heat and move it than to address it after it escapes under the floor.

http://www.sandersonheaders.com/page...num/qp2000.htm

Taijutsu

I read an example where they did the process to a 4 cyl ford. They did the intake, heads and ex. The end result was 10% at the wheels spread through the whole curve, very nice. I can't imagine the price for all that! But it did work!

Rick

Twin_Turbo

Some guys have had their cross fire manifolds 4extrude honed and it did work, very well actually. The process is used quite extensively for medical tools and stuff where the metal needs to be absolutely smooth so that no contaminations can stay behind.

carbster09

This really opens up some options. Gessler has a good web site with great info. I am tempted .. I also like the sanderson headers.

Thanks guys.

carbster