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Why was the 6.3 quicker than the 6.9?

Started by raueda1, 15 June 2018, 11:50 AM

TJ 450

Indeed. The 6.3 throttle diameter is about 70mm.

I have no doubt a huge amount of thought went into all these factors and the end result would have been exactly what they wanted at the time.

What you say about skewing the experience further towards comfort and sensible driveability, but with prodigious acceleration when required I would say is on the money.

The best thing about it is ambling around with unsuspecting passengers, then putting your foot down and scaring the crap out of them!

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

TJ 450

Rumb, that doesn't surprise me. So the 6.9 really is faster, just not 0-60mph.

I suspect the comparison between the ECE 560SEL and the 6.9 is a similar thing. The 6.9 still had more torque and you can readily feel the difference.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

oversize

1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

oversize

Pity the MB engineers fell just a little short of unleashing the animal within the M100.  They went to an enormous effort to keep it all under the standard bonnet line, at the expense of outright power.  But what a beast it would be (even by today's standards) with decent airflow and/or a supercharger/turbo, plus a modern transmission......
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

oversize

Geez I must be tired...  I already knew the 6.3 was faster 0-100kmh but somehow I started being convinced otherwise!

6.3 6.5s 220kmh top speed
6.9 7.4s 234kmh top speed...
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

oversize

560SEL 7.8s 242kmh (not sure if that's ECE).  The ECE had more power, but less torque than the 6.9.  Could it be there's no substitute for the right gear ratios (and not cubes)???
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

oversize

Some sites put the ECE 560 at 6.4s 0-60mph, 6.7s 0-100kmh and 250kmh top speed.  BTW 100kmh is actually 62.1371mph.
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

oversize

1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

TJ 450

Yep, the 6.8 sounds about right, it's definitely quicker than the 6.9. The first gear start on the ECE is quite brutal.

When cruising though, you have to kick down for overtaking if you're in a hurry. The 6.9 just requires a slight pressing of the accelerator and you're off with no fuss.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

carl888

The 6.3 works out about 300 kg lighter plus the 6.9 has a longer first gear than the 6.3 has in second!   

If you look at the contemporary road tests the 6.3 was quicker up to about 140 kmh than the 6.9 for the European versions. 

Interestingly, the USA specification 6.9 was slower in acceleration and top speed to the European 450 SE/SEL. 

oversize

1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

TJ 450

Just compare B Pillars and you can see where the kilos are. The 116 body is pretty serious.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

carl888

I was a bit out sorry, fueled ready to go according to the factory is approximately 220 Kg.

1,765 vs 1,985.

European versions.