Prasith32

Well I was just thinking about how to reduce drivetrain losses and couldn't find anything about this in any of the searches.

Many tuners seem to have lots of products that will increase the engine horsepower but how about getting as much of that horsepower as possible to the wheels.

What is robbing so much power in our automatics? Has anybody looked at the programming of the speedshift? How about the torque converter?

I don't know much about how auto tranny's work. Do they have a flywheel?

Also anything that can be done to the drive by wire to increase throttle response? How about the brake assist module?

I would think that to seriously race this car those items should be thought about.

The LSD is definitely a step in the right direction.

If anybody has any knowledge about this please post away. I would love to learn more about how we can make this car better.

Prasith

MrBonus

There really isn't much you can do to eliminate parasitic drivetrain loss. The best solution to giving your drivetrain more punch would be to add a stall converter with a higher stall (I don't know if any aftermarket companies make them for MBs).

Automatics have a flexplate instead of a flywheel.

I think any additions to throttle response wouldn't add any power and could potentially screw with the factory ESP. It's basically the drawback of any drive by wire system.

Prasith32

well in general the more lightweight your transmission and the more efficient the moving parts, the less the parasitic loss.

We are basically riding on the MB standard trasmission with different computer software.

I doubt mercedes looked at making their auto tranny on the normal sedans as efficient and light as possible.

How does the flexplate work? I do agree that messign with drive by wire will probably do somethign to esp but all of this is under the predication that I would want to turn that off anyways. In an ideal world we are just reducing slip to the wheels and thus esp shouldn't engage anyways unless we do something stupid but that doesn't seem to be the case so far.

Prasith

MrBonus

Basically, the flexplate performs a similar function as a flywheel, connecting the engine's power and inertia to the torque converter.

Honestly, it probably isn't economically feasible for an aftermarket company to design a transmission with marginally less parasitic loss for such a small group of enthusiasts when it is so much easier to make more power with the motor. I would be curious however if anyone makes a reasonable stall converter in the range of 2800-3500 stall.

Prasith32

mrbonus,

do you by any chance have any diagrams on how an automatic is put together?

you do make a good point about the cost vs. how many people would realistically want it.

However, I think if we can reduce even 5% and maybe 10% (far off) parasitic loss that is a big deal. If you consider that our motors can make 450 hp and maybe even 500 5 - 10% of that to the wheels is not an insignificant number.

PTG does similar things to their M3's by modifying DBW programming and things like that. I don't see why it couldn't be done for ours.

It's a pity that none of the merc tuners want to take it to that level.

Prasith

MrBonus

Heck, man. You could probably get a rebuild but it would probably be a hard time getting any more power out of it. The sheer cash it takes to develop a completely custom transmission is utterly ridiculous. As a current Evo owner (And a soon-to-be C55 owner), I've spoken to shops about building a stronger transfer case, which is decidedly simpler than an automatic transmission, and they're hesitant to touch the project simply because the market isn't big enough.

Here is a great reference for the workings of an automatic:

http://auto.howstuffworks.com/automa...ansmission.htm

If you're really wanting increased performance, perhaps Precision Industries can make a custom stall converter. You won't pick up power but you'll shave a few tenths off of your quarter mile and even pick up a few MPH. Your dyno numbers won't change but the seat-of-the-pants feel will.

http://www.converter.com/

Good luck!

Prasith32

mrbonus,

thanks for the auto-tranny link. It was a good read.

I see your point and it is a well taken one.

However Renntech did come out with a manual tranny for the C-Class. I am not sure how expensive it was (probably extremely) but I think its doable. I mean look at what AMG did. Speed up the programming of the computer and probably changed some parts if even that.

Most of this is just conjecture at this point but I was just wondering if anyone was planning on taking it to the next level. I am just trying to do some research and find points where the car can be more effective.

Since most of the Mercedes gearboxes are similar a tuner can make one application and sell across various product lines. That can cut costs down and make it more accessible to more people.

some food for thought.

Prasith

misu55

What's an automatic? Do automatics shift automatically?

JK

Prasith32

ok I am trying to revive this thread again.

From the LSD thread I found that the planetary gears on the MB is "truck size" so that is a potential lightening and efficiency point.

Anybody else that knows more post here.

It will serve as a good point of reference few years down the road for when I really make this MB my project car.