I've eluded to this before, but the advantage to the modern injected cars when modifying, is that anything you do to increase airflow is automatically compensated for. In the old days, you would have to rejet and other carb, and maybe even ignition curve mods.

The cold ram air would provide pressure feeding air to the intake, rather than relying only on the vacuum in the engine to draw in air. As you draw more air, the system automatically adds more fuel to go with it.

If you could get effective ram air, I can see where you could easily add 15% power at 60 mph or so. I also easily see how this would be a real problem on the 124 car, where do you put it to be effectively pressurized at speed? I can also see that you would be cleaning your K&N about every 5,000 miles.

Good luck,

Larry and Donald,

Can these modifications be made to a 420SEL? I am pretty sure I will need a valve job in 2001 (or so they tell me) and I figure that when the heads are off it would be the most cost effective time to have the porting and matching done. Also, as far as extra air I know that the 560SEL air filter housing has two "scoops" that go right to the front of the car around the grill. The 420SEL only has one. Could switching to the two scoop model make a difference?

Thanks,

__________________
Jason Priest
1999 E430
1995 E420 - retired
1986 420SEL - retired

Jason,

These engines have extremely nice ports from the factory. Portwork on an American engine can turn up reasonable amounts of additional flow. On an MB engine there is very little room for port improvemnt.

I really believe that the cost, related to the possible reward is not at all worth it. If it were a small block Chevy, it would be a different situation.

Good luck,

Larry, sorry I took so long in repling, I wasn't aware there were three pages and couldn't find you. You are right in that with more air the electronics adjust the injectors quanity of fuel. So more air can do no good. That is for electronic fuel injection. The 103.983 engine is mechanical fuel injection with electronic idle control via the lambda device. The only adjustment that can be made is the idle speed. This is done by the adjusting of the percentage of base voltage from the O2 sensor. This enrichens or leans the idle control mixture and the idle speed and smoothness. Any increase in intake pressure does not change the fuel mixture. The amount of fuel is controled by the position of the throttle and it's position on the control piston in the fuel distributor. Double check me on the model 103.983 engine if you will. Happy Trails Beep Beep from Houston!!!

Donald

Momentum, noticing your concern of "getting off the line"; is your transmission a start in second gear? My W124030, 1987 300E is. For "off the line" starting in first gear, I have a momentary SPST switch attached to my swift lever with a twin lead wire across the kick-down switch's wires. You know the ones under the gas pedal. If I want "off the line" first gear I just press the switch, releasing and manually up-shifting using the shift lever. You may consider this to help you a little bit. Happy Trails Beep Beep from Houston!!!

Donald

Donald,

Sorry to disagree. But the way that the air valve works is as more air flows, it opens further which automatically adds more fuel to compensate. This is, in effect, a mechanical mass air flow sensor. So the theory of increased air flow is the same. I can see where some things could be done that would not be properly compensated for, such as an extremely radical cam grind, but the things we have talked about in this thread, such as portwork, K&N, exhaust flow improvements, would all, if effective, result in further air valve opening, resulting in additional fuel proportionally added. Therefore the flow improvements would be automatically compensated for.

In the case of a carburetor, increased air flow will have to be compensated for by jetting and other changes. With the KE Jettronic, or most any fuel injection system that monitors airflow in some way, this is not a problem.

Don't get me wrong Donald, I'm not trying to pick a fight, I've enjoyed very much our discussion and exchange of information.

Larry, the position of the "mechanical mass air flow" valve is as yuour throttle setting. The pressure outside the MSV is MSL and is adjusted at full thottle or engine OFF. The pressure inside, which is negative MSL is depended on a multiple of items, i.e. condtion of engine, cam lift and duration, ingnition timing and elavation(MSL). The area of open position of the throttle valve depends upon the valve's and without ram pressure is at atmospheric; except the 124030 HAS ram air and is static dependant upon the cars forward motion. This static air is increased as the cars speed increases and at a set throttle position the fuel is not increased as the pressure at intake increases because the fuel valve has not moved in relation to the throttle valve(sounds like double talk to me, HUH). What I want is another snot that would let the intake system obtain it's volume of air without taking such a deep breath or a larger throttle position. Since there is no chip to reprgram, any little item that aides the Volumetric Effciency has to be tried. Happy Trails Beep Beep from BURP Houston!!!

Donald

420SEL, I'm sorry I haven't responded sooner. As you can see Larry and I have been trying to find a method that allows the engine with added intake ease; hang on something constructive will pop-up. Relative to your engine needing a valve grind, I wasn't aware that could be predicted such as 9 months for a new baby Benz. Usually valve guides go with the valve grind. That area where the guide is in the intake or exhaust passage might need some attention. Larry feels the port to gasket areas relieving isn't cost effective. Here's hoping whatever you decide to do, is what you want, because don't let anyone steal your JOY. Happy Trails Beep Beep from wish mine had 2 snots and a dirty K&N Houston!!!

Donald

Don't get me wrong. If you have the head apart for a valve job and have the time and a flex shaft, go for it. If I had had the time when mine was apart, I would've done it. What I'm saying is that if you are taking it to someone and paying them for the port work, it would be a VERY expensive horsepower gain.

The air valve that I'm talking about in the injection system is the one in the CIS system. The throttle valve is in addition to the air valve that goes down as air flow increases. I expect that there would be a wide open throttle compensation of some sort that would be necessary if the flow is adequate to bottom out the air valve quickly. I don't know if it does or not. If the air valve just bottoms out with the flooring of the throttle, then it seems to me that the air valve needs to be larger.

My $0.02, and have a great day,

Larry everything you have said is a it is. By design the 103 induction system has Ram Air. We laye people just want to aide an old horse with his breathing difficulty. Bring him down from 20,000 ft. to Death Valley. And the freq. of cleaning the K&N filter, heck it's gauranteed for 1,000,000 miles. Happy Trails Beep Beep from Houston

Donald Duck, quack quach

I believe that if you could manage an effective ram air system, frequent K&N cleaning would be a small price to pay.

Have a great day,

Donald in your experience what causes rear main seals to fail?
thanks,
engatwork
'95 E320
'97 Honda CRV

Engatwork, my 300E has 168,800 miles and the rear main seal does not leak critically today. Considerring the type of seal we have, a seal that doesn't leak a little runs dry and I believe failure is forth coming. I've always thought the reason the 103 engine stays as dry as it does is due to the crankcase venting system by maintaining negative pressure in the crankcase. Maybe this will bring some other thought to the forum. Happy Trails Beep Beep from Houston.

Donald
With diapers?

Hey Donald, I did the "y" pipe conversion today and I liked the outcome. The muffler guy charged me $60 to do it. After I did this I think I can feel some improvement performance wise. I have one more question well my car pass smog. The mechanic said that I will pass smog. My muffler does sound a little deeper at around 40mph. I am really satisfied with the outcome.

it is extremely unlikely that modifying the exhaust post cat so to speak will have any significant effect on smog emissions. Whats burned and modified happens up front. If anything the car may run better.