mark kibort

im hoping we can get one of the custom intakes from carl or Greg Brown on a NA car sometime soon! so far, nothing seems to help the stock intake system.

ptuomov

Car companies don't extrude hone, they cast... Porsche cast these manifolds exactly the way they wanted for some reasons they had. Cams having no overlap to speak off, the automatic version requiring a lot of torque down low, packaging, access to valve covers, etc. Frankly, attempts to read dead peoples' minds have historically been mostly unsuccessful - thus I think we'd be best off just trying to understand the physics of this intake and what to do with it. As you can see from Dennis Kao's and Jim Corenman's engines, you can make some power with the stock s4 intake manifold and 5.0 short block, but extrude honing is not part of either engine's recipe.

Livio928

So the question that I would have is do I replace the extrude Honed intake with a stock intake. Quite a bit of work to change out the intakes on the dyno. The Extrude honed intake is already on the engine. Is there any conclusive info whether the intake spacers work as well. They look good, but is it even worth it to install them. If it doesn't hurt anything they do give a more cosmetic appearance.

ptuomov

Personally, I wouldn't worry about it too much. Mostly the extrude hone was just wasted money, it probably doesn't make that big of a difference. Think of it as a sunk cost.

Logically, the effect of intake spacers is to move the first torque peak to lower rpms. If you're Sharktuning the car (which you should do anyway since you'll have it supercharged), they won't in my opinion hurt. The spacers may have some benefit if you're using the room that they give you to port the intake runner bellmouths to flow better. Also, you can restore the flappy-closed resonance peaks to the same rpms by filling the plenums with an equivalent volume of right kind of epoxy.

Imo000

That's nto exactly correct. Ford has extrude honed the intake manifolds on some of their SVT models. The Concout SVT had an extrude honned intake manifold on the 24V engine that originally was developped by Porsche for the Boxter (later sold to Ford). Not sure if other models did but I wouldn't be suprised if they did.

ptuomov

I stand corrected. Those are special models though. A production line model such as 929 s4 will not have an extrude honed manifold. Instead, they'll cast it the way they want it to be. As a counterpoint to my own argument, they did port match some of the early GT and CS cats by hand...

mark kibort

the intake for what its designed to do, is fine. it was manufacturable, it increased torque down low for a great around city feeling in lower gears, so , it does the job. its it optimal? no way. but they were not trying to find a way to make 400rwhp, only 275rwhp. Now, the technology is there. the Phil Intake that mark A. used, bolted on a solid 100hp with no other changes! unreal! just shows the restrictiveness of the stock manifold. and by the way, the larger TB, honed intake, and other things that didnt work before, suddenly worked with the new CF intake. thats because, for whatever reason, the stock intake just cant produce the power desired by the strokers or with other mods, unless you really spend some money and time on head/cam work as Dennis did. after all , what would you rather spend time doing.. making a 7500rpm screamer motor that probalby will have oiling issues to make 380rwhp or just bollt on a generic stroker 6.4 liter and get the same resuts not changing anything? i think the costs and risks are way higher with the head and cam and RPM levels needed to realize those same gains.