The "Blue Thunder" thread had led to this inquiry;



Disregarding the futility due to back pressure inherent in any street-type exhaust system, aside from "Extrude Hone" type modification (not likely available?) and port/gasket matching, is there any practical way (ceramic internal/external coating perhaps?) to improve the flow of OEM manifolds?

6 VOLTS/POS. GRD. NW INDIANA

Not sure of your question, but?

Why not consider extrude honing of the exhaust manifold? with porting. It would seem like a very viable solution. Then one could also change the size of the entire exhaust pipe to the muffler and out by at least 1/2" larger. This would help, some. And would look almost stock. Don't know exactly what you're after here.

       A  L  A  N   F  R  A  K  E  S   ~  Tulsa, OK    

Actually extrude honing use to be available for exhaust manifolds.  Talk to these people about it as I’ve had them perform their magic on intake manifolds.

 

Extrude Hone Corporation

1 Industry Blvd

Irwin, PA.15642

Ph: 724-863-5900  or 1-800-367-1109

http://www.extrudehone.com/ 

Lorena, Texas (South of Waco)

And it works well enough that it's banned in the pure stock classes, and some "roundy round" racing classes in the Midwest. 

Frank/Rebop

Bristol, In ( by Elkhart) 

Daniel:

I believe Pegleg's car made around 370 horses breathing through a pair of stock manifolds and 2 1/2" pipes and mufflers.  How much flow is required for that power level.  Frank, am I correct on the horsepower figure?

John - "The Hoosier Hurricane"

Had tried to contact Extrude Hone in the past, but never got a response. I assumed they were fully engaged with industrial NASCAR/R&D type work, and not interested in small jobs.



Am I barking up the wrong tree in thinking a slick internal ceramic coating (if proved durable) would not only increase cold flow, but hold in more heat and thus improve efficiency?



The high cost of custom-built T-Bird headers/simplicity of installation/appeal of OEM appearance might tend to suggest practicality of manifold modifications?

6 VOLTS/POS. GRD. NW INDIANA

When contacting companies in general, do not use email as many companies do not respond to that venue of communication.  Phone contact is always recommended.  For Extrude Hone Corporation, my contact was Rick Miller at ext. 277 but it’s been awhile now so that may no longer be a valid contact.

Coating the insides of header tubes works so there's no reason to believe that coating the insides of the exhaust manifolds would not also be beneficial.  It would also make sense to clean up the insides of the manifolds as much as possible before coating.

Lorena, Texas (South of Waco)

Finally got a quote from Extrude Hone ($750). Price of custom headers now looking more reasonable.

6 VOLTS/POS. GRD. NW INDIANA

Pretty nice headers, at that. Wow. I guess, if you need maximum performance with a stock look it's the way to go, though.


Lawrenceville, GA

John you're right on the number. It was hooked to a set of 2 1/2" turbos on the dyno. Also was running out of fuel because I fell for the "6 valve" pump that turned out to be a standard 2 valve. So that was at 5200 rpm. It now goes into the low 6's and pulls pretty hard all the way up there.       

       Mummert has told me that he sees very little difference between the factory log manifolds and the Rams horns on the dyno. So in other words, unlike the FE's and early small blocks, these manifolds work pretty well. 

Frank/Rebop

Bristol, In ( by Elkhart)