A&Q about 350Z
Q:
Well the first post in the thread questions the worthyness of the results.
And while they show that on a spefic engine, when extrude honing combined with an ECU tweak can produce a measurable performance gain, they do not show that the same gain can be applied to all engines, which is what is implied in the article.
It is basicly falsly promoting the benifits of extrude honing, when in reality there may not be any, and in some cases may decrease performance, or have no effect on it what so ever.
This sort of marketing is used far to often in the auto industry, although this is a very mild example, and mostly down to bad journalism.
Remember that as a percentage of the potential market, those of use with advanced amature knowledge make up a very small percentage, so the majority of people who read that will come away thinking extrude honing does wonderful things to any engine, and if you want to make lots of hp its an essential step. When of course the reality is quite different.
Not questioning the use of extrude honing as a performance inhancement, just its use in all applications.
A:
A friend of mine (who I consider one who posseses a lot of "advance Amateur knowledge") and has taught me a lot (especially about the importance of chassis mods - stiffening etc along with engine mods ) had me convinced that I should extrude hone my intake on my 86 Mustang 5.0. As some of you may or may not know the 86s used a 58mm TB and E6SE Heads (These heads are considered to be restrictive). The next model year a gain in perfomrance occured via a 60 mm TB and a different type of head (7E truck heads). These were the significant changes that resulted in 25 more HP and more torque.
He extrude honed his 89 5.0 and is convinced (although he does not have data) that it has significantly improved his performance (well the car's performance anyway). I was planing on doing the same to mine to help compensate for the shortcomings of the 86 set-up.
Now I am having 2nd and 3rd thoughts.
A:
I think you should look at the cost of honing vs the cost of a throttle body, inlet manifold and head swap.
After all you have to remove everything anyway to extrude hone it, the cost of the honing might be as much as, or more than the cost of the replacement parts.
Especialy since as a pretty good general rule, if you remove a head, you rebuild it.
I would get your mates car on a dyno, and see how it compares to.
Often, and Iv experianced it myself, after spending lots of money on parts any performance gain can be largely phsycological.
A:
To be honest the whole car needs to be restored/rebuilt and I was planning on replacing the heads and tb with the improved versions as I have a source.
I still may have piston clearance as my pistons are flat top........but enough of that for now.
In any event I used to be sure that extrution honing "couldn't hurt" but after following this thread I see "the other side" so I will have to research. My friend's car on a dyno would not be relevant as he has made many other mods too.
A:
extruding is like head work. You can't lump all examples together. Some systems will definitely benefit greatly from it, because you removed a big restriction to a system. Other systems may not be so happy with it, because you DIDN'T have much of a restriction there, and you lose all velocity by making it bigger. This can not only give you holes in the power band, it can cause a loss in peak hp also, regardless what you do to the EM.
This isn't so simple as do X and you will gain 30 hp. Nothing is ever that simple when you're discussing air flow through an engine.
If you are doing a very light extrude, just to clean up the machine marks and round off the edges a bit, thats different....and honestly, I doubt it makes much difference.
A:
How exactly is extrude honing "removing a big restriction"?
A:
by removing material?
I don't understand your question. The process involves removing material. The question is, is the material you're removing beneficial or not.
A:
You're claiming it can remove a big restriction. Which requires removing a lot of material.
I don't believe extrude honing is capable of such a feat. It's main claim to fame is surface treatment. Which can not remove a major restriction.
There's a limit to what can be acheived by pumping abrasive grit throgh a passage.
A:
I didn't say it WOULD remove a "big restriction" I said it COULD.
Extrude honing forces a clay like substance (ie, very heavy thick stuff) through a port. When the forcing of it through the shape, if there is a narrowing of the shape, the force is increased. The increased force will apply more material removal there.
There is no limit on how long you leave the machine on. If you leave it on long enough, it'll hone the object to the point that there is huge holes poking out. Thats a lot of material being removed.
A:
So how long would that take?
Days? Weeks?
How much would they charge you?
But the big problem is, it's not targeted, the outside of bends will get more honing than the inside, whether it needs it or not.
Your gas flow may be worse, not better.
Of course this could be easily refuted by dyno tests, but we don't have any reliable evidence.
Do you have any undisclosed interest in the extrude hone companies or methods?
A:
gosh....that sounds familiar
Good luck.
A:
Try reading the whole post in context. It'd help your replies.
A:
I am no expert by any means but I thought the whole point of the honing is not to remove material (although by definition some will be removed) but rather to polish the surface. The amount removed should be insignificant but the theory is that the airflow will be less turbulant and thus less resistive to flow resulting in an increase in airflow. If the honing process removes more material than is necessary to polish the surface then it is probably not being done correctly.
Of course reading through this thread it seems like another "angle" that was mentioned is that the air to metal (aluminium) resistance may be greater than the air to air resistance (created by the non-moving air film that a casting grade smoothness traps) may be less. I am not sure I totally buy this theory because at the molecular level there is still a lot of roughness, but the theory is certainly worth consideration.
A:
Golfballs.
A:
psst, thats exactly what Unclebob has been saying