[BAB]

Does anyone have any experience with the extrude honing process? Would it make much of a difference in a set of Ram Air exhaust manifolds? Just looking for some documented information of flow rates or approxiate cost. Thanks

[BAB]

Does anyone have any experience with the extrude honing process? Would it make much of a difference in a set of Ram Air exhaust manifolds? Just looking for some documented information of flow rates or approxiate cost. Thanks

[Will]

From everything I've seen, it's an expensive process. For what you would gain on a set of RA manifolds, I don't believe it's worth the money as the same money could be put into other areas of the car for far greater gains.

[Cobrabill]

Ditto what Will said about$$$$.The heads on H-O Racings S/C motor in the mid-eighties were done using this process and it worked well.Doing JUST the manifolds will be a waste of money.

[Jack Peters]

There was an article in a now defunct Muscle Car Review that they did last year. Got about 10 HP on a HEMI. There were prices there too. Quite high. Too much for the return unless you have money to throw at the car.

[Cobrabill]

Jack-they did just the manifolds?or heads also?

If it was just the manifolds,keep in mind that the Hemi exhaust manifolds were extremely well designed to begin with.So picking up "just" 10 hp is not as miniscule as it sounds.

[Jack Peters]

Cobrabill,

Exhaust manifolds only. I think they took a new pair and extrude honed them and did a chassis dyno on the w/old and then bolted the new on and re-dynoed w/new.

FOUND IT !!!!

November 2001. The one with the gorgeous Orbit Orange Judge in it! Starts on page 20.

The following is a quote from the magazine. These are exhaust manifolds only.

RESULTS: EXTRUDE HONE MANIFOLDS INSTALLED--NO OTHER CHANGES
PEAK HORSEPOWER: 447@5600 rpm + 3
PEAK TORQUE: 465@4600 rpm + 3

RESULTS: EXTRUDE HONE MANIFOLDS INSTALLED, RICHER JETS, AND ACCELERATOR PUMP
PEAK HORSEPOWER: 456@5400 rpm + 12
PEAK TORQUE: 471@4600 rpm + 9

end quote

They said with the second changes that the hp & torque was up across the band up to with torque up 14-20 lbs across the board. They even have sidebars with the dyno figures. It seemed to help at the lower rpm's.

HOWEVER, on a side bar here was the costs.

8 Cyl. Aluminium Intake Manifold $365
8 Cyl. Cast Iron Intake Manifold $465
8 Cyl. Aluminium Heads $750
8 Cyl. Cast Iron Heads $995
8 Cyl. Cast Iron Exhaust Manifolds $500

So, for $500 that is what you get. The article is neither critical nor proporting the method it seems they just reported what they observed.

Anyhow, there you have it.

[Will]

So it looks like they picked up 3 horsepower for $500. What a deal. Now if I can just figure a way to sucker that kind of money out of people for something that hardly costs me anything to perform, I'll be a happy man.

[78 Trans Am]

Extrude hone is when you are serious into racing. It is used when you already have your combo maxed out and are trying everything possible for any gain that is there. Very expensive process.