I have spent may hours porting my S4 n/a intake. I still have many other things to do before I install it. But I was wondering if anyone has dyno sheets or anything with their results.

the keg is a stock 6 port S4, 2.5" mandrel exhaust w/ functional aux ports, and emissions removed.

 

you just screwed it up.

 

without a flow bench and experience with flow dynamics you are only pissing in the wind by taking material away from the intake. you may actually hurt your horsepower by messing with it.

 

Port matching would be the best thing to do. Honestly though, I don't think it would make much difference anyway.

 

Hope you have a spare, on a stock port engine you have almost nowhere to go but down with the power. The biggest issue is runner length when you go to a ported engine. The best thing you could do would be hang an S5 manifold on it.

Oh, and I have a flow bench.

 

Perhaps I should have been more specific. I polished the intake and smoothed transitions. All I really did was polish the outside radius of the bends and lightly smoothed bumps for less turbulence.
I did not hog out anything, and I ran a flex hone down the straights just to knock off the really big imperfections. I basically did the same thing that Extrude Hone would do. but it took me much more time. Although I did remove quite a bit of material from the UIM injector bosses. It's more a ramp now than a wall.

I find it hard to believe that smoothing things out would hurt anything. On every piston engine I polished, I felt the difference immediately. One my first Rx7 (12 years ago) I did something similar to the UIM only. It was hard to tell, but it felt smoother accelerating, and seemed to rev a little faster.

This intake was actually one of three spares. I do have the UIM and plenum from an S5, but I have been unsuccessful in finding a LIM for a fair price. I would rather run that with the bends smoothed. I thought about modding the S5 uim/S4 LIM to match up the ports. But it didn't look feasible.

 

Tweaked ............. your on the right track I have been porting manifolds and engines for 40 years and port matching and intake port cleaning are ways of improving your engines out put, as long as you use your gaskets for reference ,and not go nuts you will make an improvement in its ability to suck in more air, and gain a small advantage in air flow you should also be aware that your porting should not be to polished as well,most porting, should be based on what you will be doing with the engine , EG if you do low speed driving a lot , don't port your primary's to much, if you like to stomp it once in a while, port your secondary's for more top end pull, If you want full race open it up big time (see P port) works with both manifolds Intake and exhaust, as well as engines after all these are just air pumps,and most engines have casting flaws that can be cleaned up.... most guys call it blueprinting ............................ good luck ...........FP

 

This is primarily a Solo II car, though I do drive it on the street. My gasket's ports seemed to be too big, so using calipers and rulers, I port matched without going all the way to the edge.
I only polished to a shine (with 320 and brass brush) in the bends that don't see fuel. After the primary injectors I went with 120 grit. That isn't smooth enough to make the fuel puddle or hinder flow.

Has no one on this board polished the intake? I would really like to hear other's results. If that's true, it makes an opportunity for a How To.