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-   -   1979 300D 0-60 time auto vs manual trans. (http://www.peachparts.com/shopforum/diesel-discussion/409153-1979-300d-0-60-time-auto-vs-manual-trans.html)

tmessenger 11-11-2020 03:49 PM

1979 300D 0-60 time auto vs manual trans.
 
I've finished my auto to 4 speed manual transmission conversion and have completed 0 to 60 mph runs with both transmissions. And yes the manual transmission is a bit quicker. 0 to 60 with the auto trans was 18.5 seconds and 17.2 seconds with the manual trans. I would think if I wanted to abuse the car at launch the manual trans time would go below 17 seconds.

This is a low mileage car (87,000) and fully serviced including injector timing and rebuilt injectors.

Manual trans video here: https://www.youtube.com/watch?v=PCxcreZvmPQ&feature=youtu.be

Auto trans video here: https://www.youtube.com/watch?v=zJh2bx2Jk_4


Tim

jsb357 11-12-2020 07:55 AM

What's the differential gear ratio of a '79?

Stock sized tires? I'm running 195's

I doubt I could get to 60 in 20 sec but really have never timed it.

oldsinner111 11-12-2020 08:02 AM

so 1/4 mile under 5 minutes ?

jsb357 11-12-2020 09:07 AM

Quote:

Originally Posted by oldsinner111 (Post 4111284)
so 1/4 mile under 5 minutes ?

what's your point?

:grin:

tmessenger 11-12-2020 09:55 AM

I have the stock differential it's 3:48 ratio and I'm running 205/75 tires. My GPS says 60 on the speedo is actually 59 so quite close with this set up. The trans I used was a Getrag 4 speed from an 83 240D.

The really noticeable driveability difference is the ability to always start-out in first gear instead of second gear with the auto. Why Mercedes set the car up that way I'll never understand. If you watch the video you'll note with the manual trans the 300D is now reasonably quick from 0-40mph.


Tim



Quote:

Originally Posted by jsb357 (Post 4111281)
What's the differential gear ratio of a '79?

Stock sized tires? I'm running 195's

I doubt I could get to 60 in 20 sec but really have never timed it.


tyl604 11-12-2020 10:43 AM

Doesn't that automatic tranny shift to second at a full stop and then shift down into first when you hit the pedal?

When you drive don't you get three distinct shifts? Into 2nd, into 3rd and then into 4th? I thought that was the way they were designed.

jsb357 11-12-2020 11:01 AM

Quote:

Originally Posted by tyl604 (Post 4111339)
Doesn't that automatic tranny shift to second at a full stop and then shift down into first when you hit the pedal?

When you drive don't you get three distinct shifts? Into 2nd, into 3rd and then into 4th? I thought that was the way they were designed.

On my '79 300d I get 2 shifts from a complete stop 2-3 & 3-4

UNLESS I floor it enough to engage the kick down switch.

Then three shifts

tmessenger 11-12-2020 11:06 AM

There are two ways to start in first with the auto trans that came with my car. (1) manually pull the shift lever to low, it will start in first and shift to second, then you have to manually move the shifter to drive. (2) Floor the accelerator when starting out, there's a electric kick-down switch that engages and the trans will start in first gear. I didn't find either of these methods acceptable for normal driving.

Tim


Quote:

Originally Posted by tyl604 (Post 4111339)
Doesn't that automatic tranny shift to second at a full stop and then shift down into first when you hit the pedal?

When you drive don't you get three distinct shifts? Into 2nd, into 3rd and then into 4th? I thought that was the way they were designed.



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