Port and Polish Intake Manifold Discussion

B6/7 S4/RS4
#1

Here is some information provided to me by a guy named Tim Miller (Silver RS4). Please review his documents and discuss. I’ve heard positive results from fellow members and most seem happy. For $650, I don’t think this is a very expensive modification and for the little extra performance it provides it seems like a nice addition.

http://i834.photobucket.com/albums/zz269/NY07RS4/2007%20Audi%20RS4/Port%20and%20Polish/1.jpg

http://i834.photobucket.com/albums/zz269/NY07RS4/2007%20Audi%20RS4/Port%20and%20Polish/2.jpg

http://i834.photobucket.com/albums/zz269/NY07RS4/2007%20Audi%20RS4/Port%20and%20Polish/3.jpg

http://i834.photobucket.com/albums/zz269/NY07RS4/2007%20Audi%20RS4/Port%20and%20Polish/4.jpg

#2

Just to play devil’s advocate, what are the opinions on this from wiki:

"The “Porting and Polishing” myth

It is popularly held that enlarging the ports to the maximum possible size and applying a mirror finish is what porting is. However that is not so. Some ports may be enlarged to their maximum possible size (in keeping with the highest level of aerodynamic efficiency) but those engines are highly developed very high speed units where the actual size of the ports has become a restriction. Larger ports flow more fuel/air at higher RPM’s but sacrifice torque at lower RPM’s due to lower fuel/air velocity. A mirror finish of the port does not provide the increase that intuition suggests. In fact, within intake systems, the surface is usually deliberately textured to a degree of uniform roughness to encourage fuel deposited on the port walls to evaporate quickly. A rough surface on selected areas of the port may also alter flow by energizing the boundary layer, which can alter the flow path noticeably, possibly increasing flow. This is similar to what the dimples on a golf ball do. Flow bench testing shows that the difference between a mirror finished intake port and a rough textured port is typically less than 1%. The difference between a smooth to the touch port and an optically mirrored surface is not measurable by ordinary means. Exhaust ports may be smooth finished because of the dry gas flow and in the interest of minimizing exhaust by-product build-up. A 300 - 400 Grit finish followed by a light buff is generally accepted to be representative of a near optimal finish for exhaust gas ports.
The reason that polished ports are not advantageous from a flow standpoint is that at the interface between the metal wall and the air, the air speed is ZERO (see boundary layer and laminar flow). This is due to the wetting action of the air and indeed all fluids. The first layer of molecules adheres to the wall and does not move significantly. The rest of the flow field must shear past, which develops a velocity profile (or gradient) across the duct. For surface roughness to impact flow appreciably, the high spots must be high enough to protrude into the faster moving air toward the center. Only a very rough surface does this.

A developed velocity profile in a duct that shows why polished surfaces have little effect on flow. The air speed at the wall interface is zero regardless of how smooth it is."

#3

id pass unless you just want to get everything you can for the car. i had my intake done by tim and while is showed MINOR gain, its really only 3-5 hp worth. something that wasnt even felt on the butt dyno, i will say tho it did rev more freely up top. id say its a toss up. i only did it cus i had a spare intake manifold sitting around

#4

He makes really nice graphs.

#5

I’ve actually read this article before. There are many “counter” arguments in writing out there too. Hard to confidently pick a side without real world personal experience. Which is why I don’t take too much of what is out there as fact vs. trying it out myself or know someone first hand and witness the testing etc. All good info being shared though.

#6

I thought you had one but wasn’t 100% sure. I’ve heard similar feedback from others. Most felt, for the relatively small investment, the little gain was a nice addition to the overall mods in place. I’m sure if it hurt performance no one would be happy. Is it “worth” it, not sure. i think it depends on the individual and their perception of value. Kind of like the 034 MAF hose. Will it help in the end in conjunction with other mods - most liekly. Of course that mod is sub $100 so it’s hard to compare from a price standpoint - my purpose was more from a performance standpoint. Either way, I wanted to bring it here to discuss so thanks for providing your experience and input. I agree, if I had an extra I/M laying around I would probably have it P&P.

#7

lol, tongue in cheek.

I agree, he does make nice graphs.

That’s why I brought it here, so members like Richi can provide real world feedback. Maybe someone here has done a before and after 1/4 run to verify the nice chart. Who knows?

Maybe JHM or CV has some info to share? Maybe they contemplated this process/mod/offering and decided against it for “X” or for it for “Y” but more work or research is needed? I haven’t a clue. Either way I wanted to discuss it so we can all share experiences and learn from them.

#8

i dont think jhm saw any gains or benefit. after i did mine, i sent them my other intake manifold and judging by the fact that its been well over two years ago that i did that, theres still nothing from them on that front. leads me to believe they saw it as a dead end

#9

speaking of which… those fuckers still have my intake manifold lol

#10

I bet he has really shiny floors.

#11

I can’t speak from experience or anything so I thought I’d throw him a compliment. He was a pretty bright guy who understood some of the intricacies of the RS4. Shame he sold it.

JHM looked pretty hard at teh intake manifold and didn’t find any gains worth selling. Just because they don’t think 3-5 hp is worth the $650…doesn’t mean some customers won’t. They just thought it was too labour intensive for almost no gain, so they didn’t do it. I guess a bunch of guys have done this mod. All the power to them. There are worse ways to spend your $650 (like 1 carbon fibre front fender without paint or labour, which saves you less weight than a large bottle of Coke vs. the aluminium RS4 fenders)…and people have done that before. People have paid PES $15,000 for 30-40 hp for christ’s sake…so anything is possible!

The B6/7 S4 manifold sucked, so they (JHM) found a way to improve on it, and charged $1000 for it. It adds a legit 15-20 whp though.

#12

I have to call BS on this though

He claims 4 tenths shaved from 0-60 - that’s impossible with a tiny little mod like this and to 60mph you are mostly in first gear from 0-40 (about 3 seconds) and then briefly at the top of 2nd gear to the mid 7000s at 60 mph…so how on earth is a flow mod (top end efficiency) going to make you shave 4 tenths?

He claims 5 tenths shaved from 0-100 - again…that’s just not right for the reasons outlined above

He claims he shaved only 1 tenth in the quarter mile (which is odd considering he gained half a second to 60 and 100…where’d he lose that other 3-4 tenths? Does the modification rob you of top end from 7000-8000 rpm in 3rd gear or something (100-110 mph)?

He claims he gained almost 2.5 mph in the quarter mile. That’s typical on an RS4 of a mod that picks up 20-30 whp…but not this one.

Unfortunately I don’t know what his testing method was but I’d not hesitate to say that those gains sound like bad runs ‘stock’ vs. sunday best launches when modded. He said he did the acceleration tests 3 times each and averaged them but they just don’t add up…especially the discrepancy between the 0-100 mph run shaving 5 tenths and the quarter mile tun (basically 0-110) shaving only 1 tenth. Shows there’s some kind of flaw hiding in the data (or the modification kills the car in the 3 seconds between 100 mph and 110 mph.

http://i834.photobucket.com/albums/zz269/NY07RS4/2007%20Audi%20RS4/Port%20and%20Polish/3.jpg

#13

but he does make nice graphs

#14

Might be. I couldn’t comment either way - I wasn’t there for the testing and have no idea where, how, with whom it took place etc.

#15

Good to know regarding JHM. I happen to agree, for the amount of work involved it probably didn’t make sense for them.

#16

;D

#17

well its weird because he’s a smart guy…I wonder why he wouldn’t say ‘whoa, that doesn’t look right’ or ‘weird, the mod adds very little torque and certainly doesn’t make the car launch harder, but it shaved the equivalent of B6 S4 vs. B7 Rs4 in 0-60mph performance…maybe I should re-think this’

#18

pretty graphs sell

#19

I read that as Polish as in someone from Poland.

#20

That made me lol.