BPG_Austin

Mark robinson did a full-on extrude hone job on an S4 intake a few years ago. Zero gain far as I know.

RyanPerrella

nice link, even better prices too!

yeah i dont think it could hurt honestly any manifold ive removed the runners were gummed up with oil and dirt. So anytime you remove the intake manifold you need to clean the crap out of them anyway before you repaint, so why not take an extra step and use this type of hone to try and debur i guess or smooth the runners. You may increase the ID slightly, but i think you at least would even out the ID to a more uniform size throughout.

I think i will try it on the next manifold i pull.

mark kibort

I dont think a simple extrude hone will do much either. I think there is some pretty significant grinding that needs to be done at the horn level and around the bottom air feed from the dual "U" area. you hog out all that material and make some major openings out of them, you will get some gains, in conjuction with the side plates.

what does the extrude hone do anyway? .1"? not much. I think you need some major porting work, like which is done to the US to euro conversion for the " U" to match the euro throttle body.

mk

Jim bailey - 928 International

The extrude hone process is much like a concrete pump used on construction sites to move liquid concrete from the truck back to the work site. The steel manifolds on the pump that hook to the hoses wear out over time from the abrasiveness of the gravel /sand in the mix but get very smooth inside during use until they blow apart when they get too thin. In the extrude hone process they actually hand port the parts of the manifold that you can see and reach with a diegrinder carefully opening up the runner but not getting too thin. Then they pump the mud through the intake polishing and slightly enlarging the runners again trying not to get it too thin and destroy the parts. It is one of those things which just SOUNDS like a good idea....

RyanPerrella

yeah i agree the standard ***** i dont think will really work, so as i originally posted i would ideally find something with a more aggressive media at the ends.

the only issue i see with porting by hand is that there are some very difficult parts of the runners to get to and i an not sure how you really would work those areas. So this in theory would be much easier, run it up and down the hole a million and a half times and your bound to remove SOMETHING

who knows, ideally the tool i am thinking of have a bunch of small cutting heads on the ends and not those little abrasive *****.

bcdavis

Yeah, the difference between manually porting a head or manifold, and extrude hone, is that the extrude-hone media "flows" through the manifold. So it grinds away at the areas of highest resistance. It's like how a river erodes a cliff. So it would seem to follow the laws of fluid dynamics in some regards. While still having a set input and an output location for the media. But as everyone pointed out, you can have a very smooth manifold, that flows as good as it can, but the valves, heads, and cams won't let your engine take advantage of that improved flow.

RyanPerrella

as for extrude hone, what does it cost?

when was the last time anyone got an estimate to have it done to an S4 and later manifold?

IcemanG17

It seems the limiting factor in the S4 intake is centered around two things....the side plates are too close to the 1-5 cylinder and 4-8 causing a restriction & the throttle body is too small & especially the dual oval shaped ports that feed the main intake....

Of course the airflow requirements on a race stroker are far different than a stock 5.0L..... It would be interesting to see how Andersons CF intake performed on a stock 5.0L.... or Louies ITB...

It will be interesting to see what new intakes 2009 brings us..Doc Brown has one in the works, others are working on modded stock intakes and Adam has that modded M5 individual runner intake that looks promising....

RyanPerrella

I think this is solved by the use of spacers (which Carl has had made available fairly cheaply) OR by perhaps a rounded side plenum cover which seems like a great idea but which no one has prototyped yet.

I also think the intake horn shape leaves allot to be desired. I was considering somehow cutting out the horns alone and installing some aluminum ones. But now that i think about it, maybe filling the porous parts around the horn would be a good idea first, then you could get into shaping and trying to make them as round as possible. But that will always be a compromise as they werent milled on a lathe which will ALWAYS produce a nice round smooth finish, porting will never leave it perfectly round unless its CNC and it would be a ton of work.........

Is this really a problem? If it is, this is really a fairly easy thing to fix with porting. This could be done quite simply by bolting up the throttle body to the intake and then porting from the opening thats available when the side covers are removed. But i am not so sure these oval ports arent already large enough? I honestly cant recall anyone commenting on THIS part of the intake before.

Again, if it is yet ANOTHER problem, it is easy enough to fix, especially when compared to hogging out the runners.

I would guess you would also look at enlarging the throttle body itself and putting in a larger plate. I know there are guys that do this but last i checked the 928 has one of the largest TB's i can recall seeing on just about anything.


Has anyone else thought of getting together a bunch of pipe in what 2 1/4" diameter and making a new manifold to mimic the shape of the factory part? You can add the plenum boxes on the sides and route the runners exactly as you would the factory piece. Any guy that makes headers should be able to do this in short order. But i guess if your doing all that you probably just go for a different, simpler design?

One thing is for sure, as you said Brian, 2009 sounds like a great year for the intake and we may have a great new invention and development on our hands here, hopefully a couple solutions will be available soon! We all seem to agree that the intake is a relative mess and something thats not often been addressed.

ptuomov

Iceman --

You write: "It seems the limiting factor in the S4 intake is centered around two things....the side plates are too close to the 1-5 cylinder and 4-8 causing a restriction & the throttle body is too small & especially the dual oval shaped ports that feed the main intake.... "

The jury is out on the side plate spacers and it looks like we'll get some dyno results later this year.

On the throttle body being restrictive, I think many people have bored their throttle bodies to a larger diameter. I have never seen anyone document any dyno gain from boring the throttle body on a 5.0 or a stroker. That may just mean that I am the newbie that I am.

Do you have any evidence of any gains from a larger throttle body when used with the stock S4 manifold? I would like to see it and learn. I already learned today that past 5000 rpm, it makes no difference whether the flappy is closed or not.

ptuomov

ptuomov

Sterling -- Deep end, definetely. Just trying to learn. What's your view / experience / evidence on your overbored throttle body? Best, ptuomov

RyanPerrella

check out his website, link in the signature......ENJOY!

ptuomov

Ryan -- I have been following the 928 sg project for some time, as well as many other 928 projects. I just recently bothered to register on rennlist after mistyping the text in the picture five times in the row to search stuff. The reason why I have been actively asking questions here over the last couple of days is that I am about to go on a mad 928 spending spree. ptuomov

IcemanG17

The bored throttle body has been done.....Devek did some work on this and I know of a local 928 with GT cams that puts down 330whp without serious sharktuning...just the old way of an adjustable fuel regulator......I'm sure Jim or Louie could get at least another 10whp out of that car...easy

ptuomov

What were the other modifications to this car? Was the throttle body the only modification?

I know that many people have bored their throttle bodies. I just don't know yet, noob that I am, whether any benefit has been demonstrated.

This is a completely honest question, I just want to know the answer. It makes sense that if the TB is the bottle neck, then boring it out will help. But is the TB ever a bottleneck with the standard s4 manifold, stock (say gt) cams, and stock s4 heads? I want to know the answer so that I know whether to do this.