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2.47 differential to be on 300SDL?

6K views 15 replies 8 participants last post by  ianrandom 
#1 · (Edited)
300SDL has a 2.88 ratio differential. Mine has a large play about 1/4 turn, time to change. Thinking to swap a 2.47 LSD to my 300SDL to make it a real highway beast. Has anyone done this? Which car(s) has a 2.47 ratio that can be a direct swap (same size not taller)? Thanks for your info.
 
#2 ·
The US spec 560's should have a 2.47 with LSD differential that'll suite your needs. Too bad the 300SDL never had a LSD or else I'd like that ratio for my 560 :)
 
#3 ·
I have 2.47 in my 126 with 6-cyl 603 turbo. I formerly had 2.88 but 2.47 is much nicer on highway. Acceleration is also satisfactory with longer ratio.

Euromodel 420 has 2.47 ratio and you might also have to change driveshafts from same car since they are bit different.

I believe no LSD was ever offered to gen.2 w126, only ASD (don´t know about 560).
 
#4 ·
Thanks both of you. I'll see if 560SEL is using same parts number on diff as that in 300SDL. Since yesterday my access to EPC was failed due to "Syntax error". Once it's restored I should be able to find the parts numbers for both. If not, I'll look into euro 420SEL's...
 
#7 ·
I've been thinking of this for some time. I drive 800 mile highway trips twice a month...desert flat for most of it.

What kind of rpms do your 603's turn at say 75mph with the 2.47 rear end? Did it help the mpg?

Thanks
Based on my collective readings, with 2.47 at 80mph it only runs at 2500rpm. It will improve mpg on highway cruise for sure, and smoother/quieter. the drawback would be sacrificing pick-up from green light.
 
#8 ·
Turbo Spooling & 2.47 Rear End

I sure like the idea of lower Cruize RPMS (i.e 2,500)....I drive for hours at 75+ when traveling from San Diego through Arizona. It seems as though the motor is working kind of hard at 3,300 rpms...and with 335k it is old-old-old and has a #14 head to boot!

Question: At 2,500 rpms the turbo should be providing good boost but what happens when we are going 60 mph with RPMs around oh I don't know 1,900. Sounds like things may be a little doggy. Guess there is always 3rd gear?

Thoughts?
 
#10 ·
I sure like the idea of lower Cruize RPMS (i.e 2,500)....I drive for hours at 75+ when traveling from San Diego through Arizona. It seems as though the motor is working kind of hard at 3,300 rpms...and with 335k it is old-old-old and has a #14 head to boot!

Question: At 2,500 rpms the turbo should be providing good boost but what happens when we are going 60 mph with RPMs around oh I don't know 1,900. Sounds like things may be a little doggy. Guess there is always 3rd gear?

Thoughts?
My 603 has around 2000rpm at 100km/h(~60mph). At constant speed you don't need any boost. Actually best mpg is achieved when you don't have boost at all because turbo isn't using energy. For accelerations there is that 3rd gear.

In my situation the best improvement was reduction in noise level, mpg might also be a bit better on highway.
 
#9 · (Edited)
i would guess it's gonna be around 2000. i read some successful stories but yet to find out which cars have the same size diff and having 2.47 ratio so to do a direct swap (i am only interested in direct swap). please look into it and let's share what come up...
 
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