What ratio diff do most 450 116's have

[John S]

Before I purchased my 450 I bought a couple of the Brooklands books on the 116 road tests, and ALL listed the diff ratio as 3.07 in their technical specs.

However my diff was stamped 3.06! I checked a few diffs at Pick & Pay Less, one was stamped 3.07 but the other 3.06!

Does anyone know why the difference? What diff ratio is in other Forum members cars?
Are there similar differences in the 6.9’s diff ratios?

 

[SEL_69L]

I don't know the ratio of the standard 6.9 diff, but I have driven a 6.9 with the lower 3.07 450 back axle fitted to it. On paper, the car would have a lower top speed, but because this particular car makes it's changes at lower speeds, in the normal driving environment, it actually makes no difference to the fuel consumption. It DOES, however, make a significant difference to acceleration in average surburban driving conditions. There is no opportunity to make use of it's top speed, anyway. It is to me, obviously faster from the lights than any other 6.9 I have driven, and I have driven a few of them.

 

[B13]

I put a 3.46:1 diff from a 350SL into my 450SE race car and its made the world of difference. Unfortunately its revving outside its economical range when doing 110kh/h on the freeway it now pulls 3550rpm and chews thru petrol, more than my 6.9 does.

Wouldn't change it for the world though. Really transforms the car for track work esp. coming out of corners in 2nd gear.

I.

 

[Styria]

Hi B13, I have always found that the smaller engined V8s are really not that economical - in fact, I'd go so far as to say that, in many instances, Gleaming Beauty returns better fuel economy than most - I am talking of the 1970s range of V8s. Regards Styria

 

[Michel]

The difference between 3.06 and 3.07 is negligible.

 

[John S]

That's exactly my point Michel, why the two ratios when they are so close together? The only thing I can think of is that the ratio is really somewhere between the two, say 3.065 so one supplier stamps their production 3.06 and the other stamps theirs 3.07, but they are both actually the same ratio.

Has anyone a 450 diff that is prepared to count the teeth on the crown wheel & pinion?

 

[abl567]

6.3's came with 2 diff ratios, 2.82 and 2.85, the change came about due to different size and number of teeth on both the crown wheel and pinion.
I cannot remember which came first but the change was to add strength to the components, the ratio change was a by product.
Maybe the same for 450's?

 

[John S]

Thanks for that info abl567, now you have me wondering how often changes like that happen. I had heard that the 6.3 diffs were marginal, so a change in the teeth profile to strengthen them does not surprise me, but I now wonder why the ratio change was required.

 

[SELfor50]

That sounds like a logical explanation abl.

I'm with Ian on the ratio change, i'm yet to test it.. but going from the 3.07 to the 3.46 ratio, and having it locked.. I've been told it's good for anywhere from 1-4secs a lap.. driver permitting.

 

[c107]

Just saw this old thread.
For future reference, the change was made from 3.07 to 3.06 in January 1974.
Lots of tech specs list the original 3.07 because that is what the cars were launched with.

 

[Patrick_R]

Not really much of a change.

 

[Michel]

Just for the record the 6.9 had a 2.65 ratio.

 

[c107]

Not really much of a change.

Went from 46:15 to 52:17

Presumably this was to rationalize parts, as I don't think the rear axle itself fundamentally changed. Or possibly they were trying to solve some other problem like a resonance.

1980 USA models 450SEL and 450SL/SLC went with 2.65 also due to the CAFE laws they had at the time. Must have been slugs off the line with only 160hp. 450SE had been discontinued in the USA by then.

 

[Styria]

Sad to see that SELfor 50 is no longer with us. Top guy, full of laughter personality and mischievioness. Sorry, I have had three goes at spelling this. What a horrible word. Regards Styria