Rage

What is "extruded honed" in the context of intake manifolds?

Plum_Crazy

Check out http://www.extrudehone.com/oem.html.

Nordicflame

It's like a big Playdough machine. It pressures gritted media (clay like) through the runners removing all casting flash and smooths all surfaces for better air flow. They seem to get some good results with the 454/502MAG/HP500 MPI stuff.
You would have to add a larger throttlebody on the 496 manifold to reap the benefits.
We use them (Extrude Hone) for some of our aerospace stuff as well.
Dave

Iggy

That's a process I haven't heard about in a long time. I thought it was the cats a$$ when it first came out. For polishing and flowing an intake, I can't think of a better way to do it. Works good on cyl. heads too.

bn

It sounds like this can also be done for the exhaust manifolds. Has anybody ever tried it on their exhaust?

FOUNTAINATLAST

I had a 502 MPI manifold done recently and it looks beautiful.. The shop that did the honing said there test results on there dyno reported 30-40hp increase on a stock motor application. Thats a pretty impressive increase for a stock motor, and 1/4 the price of headers...... Imagine the increase with headers???

articfriends

I looked at the extrude honing also and chose to hand port my 502 mpi intake because I'm too cheap. I had the local expert head porter (lapouttre racing) look at the cross sectional area of my 502 mpi intake BEFORE I ported it and he said the head's intake port would have to 420 cfm before the intake manifold would be any kind of restriction. The 502 runners do stick .800 above the intake plenum flloor which disrupts flow,I milled mine off so they were flush and radiused them which should be the biggest gain,I doubt the actual porting is going to give you much gain,Smitty

stevesxm

fountainatlast...
do you really belive that knocking the casting flash off the inside of your intake manifold bought you almost 8 % more power... really ?

having built, perhaps, 600 motors of every type i think i can say that thats simply not going to happen unless somebody at merc forgot a ratchet handle in there or something when it was first built. realistically, the extrude honing in my experience has been worth less than one percent on manifolds run back to back...before and after. it does, in fact knock the sharp edges off and tend to open cross sectional areas that are smaller than adjacent ones but that is NOT neccessarilly a good thing. intake manifold VELOCITY if much more important than volume... and shape is the absolute key to performance... and i can tell you authoratatively that a while a mirror finish on the inside of an intake port or intake manifold will FLOW bigger numbers it will not make as much hp as the very same manifold with a mat ( bead blasted) surface. the slight grain on the surface tends to keep the fuel in suspension making the mixture better as opposed to the mirror finish which tends to promote separation ....

it is important in engine building to think combination and package... NOT magic bean. there are no magic beans. and combination is everything... take a nice clean sharp 450 hp motor and put a bigger cam in it without changing anything else and all you will do is make less power and use more fuel.

and think about it for a second.... merc is in the business of selling you stuff.... do think for an INSTANT that if they could extrude hone their intakes and make 30 hp that you wouldn't see that in full page ads as far as the eye can see ?

sorry... no easter bunny, no tooth fairy and no free 30 hp.

FOUNTAINATLAST

So your telling in me that three well know engine builders (some on this site) that all came up with similar numbers don't know what there talking about????? I guess that there dyno numbers are lyes. While I do agree that that a coarse surface is better for atomization of fuel you can't tell me that a manifold that is far less restrictive is going to be worse then stock. With your theory of thinking then all aftermanifolds are useless.

I have built many motors and yes combination is key but you can't tell me that you won't gain anything from this process. Now I havn't witnessed these numbers personally, I was only extending what I had heard as pertaining to the question of this honing procedure...

P.S. and your going to tell me there is no Easter Bunny, common who you trying to kid....

stevesxm

there was a racing series some years ago that was for " stock " production gt cars.... and the corvettes featured seriously in this. there was a factory supported team located near me an evry so often a tractor trailer would show up with crate upon crate of engine parts from gm.... hundreds of blocks cranks rods intake manifolds etc etc... and from these the engine builder would hand select the very best ' stock cylinderheads, intake manifolds and the like... and the dyno proved the efficacy of this approach.... the better part of 50 hp over a factory assembled off the production line motor. and then we took and extrude honed a handfull of the cylinder heads.... less than 1 % and then we took and extrude honed some intake manifolds...less than 1 % and not repeatable at all..
those manifolds are essentially identical to map mpi 502.

these results have been repeated on other assemblies as well....

and my question remains ( easter bunnies aside ) if merc could spend 50 bucks per manifold and get 8 % more power and suddendly their 502 is nudging 500 hp a REAL selling point... that they would say " oh hell, never mind, we don't care about that " i am telling you that any engine builder that tells you he is going to bolt a 502 to his dyno and do baseline runs and then unbolt the manifold , extrude it, bolt it back on and see 30 more hp in the same conditions is .... well.... not being completely candid with you. not on this planet