Im thinking about a port polish - PeachParts Mercedes-Benz Forum

lorainfurniture · #1 07-27-2009, 02:09 PM

I was at pull a part and picked up an intake +++ extras for my m103.

I was thinking about honing the inside to make it smoother/bigger. I know what you are thinking, I have plenty of time. I was going to polish the outside as well for cosmetics. Am I wasting my time? Will my "port polish make a difference? What adjustments will I have to make after?

#2 07-27-2009, 02:42 PM

First of all when doing port work on the intake side, polishing past the point where fuel is atomized into the flowing air, is not a good idea. It's all about port shape.

For the older US cars, there was a lot to be gained by good port work because the ports were so rough to start with. In the case of a Benz, ports are very carefully thought out and cast very accurately. There might very well be flow improvement to be had on an MB, but you would REALLY have to know what you're doing to get it, and if you DON'T know what you're doing, you might very well decrease flow potential.

As for polishing the outside for cosmetics, if you're into spending the time on such things then I say go for it.

lorainfurniture · #3 07-27-2009, 02:48 PM

So ill probably do more harm than good.

are there any things I can do to improve performance/efficiency without spending big bucks? m103 engine.

#4 07-27-2009, 03:27 PM

A similar answer to your follow up question. In Germany cars are taxed based on engine size. As a result the German car makers number one design goal for engines is to get as much power from as little displacement as possible. As a result, these engines are at their maximum state of streetable tune.

An engine is a pump. When the pump can flow more fuel/air in and exhaust out, it makes more power. Your M103 flows at least as good as any two valve streetable engine in the world of it's size.

There's just not much room for improvement unlike an American engine of the same vintage.

lorainfurniture · #5 07-27-2009, 03:32 PM

I was thinking that mabey there was something that they didnt do because it was too expensive labor wise, or it wasnt worth for the little amount of difference.

I have a 92 260e in greece, I have to lock it up in customs for 6 mos. out of the year to avoid costly displacement tax. (german plates also.)

mbdoc · #6 07-27-2009, 03:54 PM

Having the inside polished by extrude-hone should pick-up the HP a tad.

pifcat2 · #7 07-27-2009, 11:48 PM

I have a enlarged displacement M103 modified by RENNTech. The cost of their labor, expertise, and parts was shy of $14k and that was 15+ years ago. If you have the time and money, you may be able to R&D or reverse engineer what they or AMG did but most will not or do not relative to the car's current value and the cost of a 500E. If you modify one thing, you need to modify all the matching components i.e. enlarging the intake won't help without enlarging the valves or head flow, and exhaust, and...

I thought of polishing the intake but then it's buried under the air cleaner and parts so that you wouldn't see it.

pawoSD · #8 07-28-2009, 12:46 AM

I think the only real way to get more power (a real amout of extra power) would be the addition of a turbo and all related changes. = Huge $$....just buy a 500E.

As though the M103 stock can't get you in jail from speeding....it can! easy! I've seen 128mph in mine....it was a one time deal...it still had more to give but I got paranoid.

Ivanerrol · #9 07-28-2009, 02:59 AM

How's the old saying go? There's no substitute for C.C.'s.
If you want more power buy a car with more power or a bigger engine.
If you want a car to drive like a sports car - buy a sports car.
M.B. designs their cars as a whole. If you modify one part, you must modify all the parts to suit. e.g. The 260e uses a different transmission to the 300e - why is this so?

lorainfurniture · #10 07-28-2009, 09:51 AM

Mabey I should shop for a m104.

Hit Man X · #11 07-28-2009, 09:21 PM

Well the cats are certainly a place for improvement. Ditch the precats and get a good high flow main cat. Won't help low speed power, but expect some nice top end HP difference (3400rpm to redline I guess). Pipes are dual 1.75" so you'll be able to track something down easily via Random Tech or Carsound/Magnaflow. The factory ones you can probably sell for scrap to make this mod a wash cash wise.

The stock torque converter stalls FAR too low in the W126 cars considering where the power comes on via the cam, call up ProTorque in NY and have them restall it. This will cause some fuel econ loss, but it's not like the M103 powered W126 shines there anyway. Go at least 2500rpm to have a noticeable difference in acceleration. This car could also use a first gear start, I THINK Jonathon on this board does it for the I6 cars. I can't think of his screen name but here is his site - http://www.blueridgemb.com/

I agree with the others, I'd just assume leave the inlet track alone sans a port match between the intake manifold and the head ports. You can do more work with the exhaust side as I stated, port match the manifolds. A well thought out header would work nicely but it'll cost you more than the car is worth to have built unless you have the skills and time.

The most major obstacle in power is the CIS, it's just not efficient. If you have some time convert the car on over to MegaSquirt and reap large gains in power and economy.