denisgav

Okay so thats not exactly honest... its more like activating the secret 4th gear since the stock box is basically a 3 spd. Well that's not really accurate either. Okay well here is my idea to make it act like a normal 4spd. Everyone knows that the W124 starts out in 2nd right? Okay what if one were to change out the gears in the differential to my the final drive ratio significantly longer (like a whole GEAR longer) and then modified the valve body to make it start in 1st always? That seems very logical to me. Mercedes should have done this in the first place. The only downside is that you will be significantly slower of the line (no FIRST first) when you are racing those little riced out civics at the stoplight. Any thoughts?

ptoro01

I think what you're really looking for is a variable ratio differential. That way the helical gear adjust under centrifugal acceleration and matches the rpm's to the transmission's natural shift points. If you then retrofit the factory ASD, you would be able to lock the VRD at preset intervals, for example towing situations or in your case racing.

denisgav

That sound very complicated, expensive, and probably not worth it on my 25 year old, barely running merc. My idea required probably $30 in new parts (not including tranny oil you would have to change while modifying the valve body)

ptoro01

Then you're trading a lot of MPG for less than a quarter second. Is it worth all the effort? My solution could possibly change the beast! I'm talking 3.5 seconds to 60 and top speed of 195mph!!

denisgav

There is no way a 177 HP 4000LB cat will ever do 195mph or 0-60 in 3.5...

denisgav

And I'm not sure I get the first part, I'm trading lots of mpgs for less than a quarter of a second? First of all its more than other way around and second and of all, its definantly more than a quarter of a second.

ptoro01

My point is that if you gear it down and rev it higher, you won't see any benefits. If you skew the acceleration enough one way, you'll build a highway cruiser and a city dog, or a school zone screamer.

Either way, you're gonna run the engine in a range that's not optimized for load and probably burn more fuel on average.

There's a reason trucks have a bunch of gears and funny cars don't.

ptoro01

But, I bet you can't deny that having dual transmission would be kickas$. A lot of shifting but boy oh boy, wouldn't it fly!!

denisgav

What I was proposing would improve efficiency no matter how you look at it. Anything below 2700 revs at highway speeds is an improvment. Its basically the same three speeds with an overdrive.

denisgav

I don't think it's practical effective. The vaccum controlled trans would be confused all the time

ptoro01

Another possible solution would be to replace the starter with a drive motor and turn it into a hybrid. Swap the fuel injection system to efi and disable half the cylinders when not under load. Possibly incorporate stop and go traffic assist. I bet you could squeeze 50mpg out of that system.

But that would only help around town where mileage can drop all the way to 12mpg. Highway would still be a reasonably acceptable 27mpg.

denisgav

50 MPG are you insane? We have dedicated hybrids that weight a THIRD of the Benz that struggle with that! I'm talking about a solution that is practical and cheap. Nobody will invest 10,000s of thousands to properly engineer, build, and test a system like that on a car that's worth 4K in good condition. And how would it ever achieve 27 mpg highway with such a system? If anything with would get less, considering the extra weight of the battery...

Saijin_Naib

27mpg on the highway is about what I get with my m104.980, sometimes up to 29mpg.

denisgav

Wow I don't get anywhere near that with my M103. For a month or two I actually got a 12 MPG average.

Saijin_Naib

In town I pull around 15-18mpg.

ptoro01

You really have to try hard to get 12MPG out of this engine. Around town, about 18 and up is normal.

Saijin_Naib

I take it you don't have Ethanol blend in your area. We have 10% at the pump here :C

ptoro01

5% here and depending on which station, you can get the gooder ethanol, they're not all equal!

It's pretty normal numbers for an m103 that always passes air care with flying numbers. Knock on wood.

denisgav

Do you mean emmisions by air care? I'm sure my car would never pass, it reeks of raw gas when i start it. It starting making a thudding /knocking noise after I took it drifting in the mall parking lot... Sounds like its from deep inside the motor, and the tires are now bald too. I'm just biding my time till the car explodes so I have an excuse to buy another one. This one hasn't been very good anyways, I could never fix its starting/idling issues, even with a new fuel distributor. Moral of the story? Don't let your W124 sit for multiple years without driving it.