Just HOW fast is a 4.5?

[WANT '71 280SEL]

Does anyone know how fast they are, Fred? I have a friend who is looking at one. What would be some common cars that it would compare to? Would it be as fast as a 300E? Or more like a 400E? Anyone know the top speed? I am just curious, that's all. Oh yeah, it is a 1972 280SEL 4.5.

Thanks

David

[tosbt]

David, I took mine out for its first big run today, ran it up to 100 and was not hard to get there and was not hard to stay there. 80 to 100 was quick. I don't know what was left but the car was running strong and I could well see 120 soon but I'm taking it easy with this old car. I just had the air suspension completely overhaled and am so pleased with the ride and handing, so smooth, so strong. Just the slightest drift in the stearing maybe a 1/4 inch drift each way but realy responsive. For those intrested I drove from Austin Texas to Georgetown on Highway 35. I hope to post pictures next week, I'm having fun with this car. There are only a handfull left so I think they are great prizes.

[Gilly]

MB says top speed 200 km/h, and acceleration from 0 to 100 km/h is 11.0 seconds.

Gilly

[MikeTangas]

Have had mine up to 110 mph going up a good 6% grade, with plenty of pedal left to go. The jump from 80 to 100 is real quick in the 4.5 and all I have to do is curl my toes, literally, to make that jump.

[wbain5280]

The main problem is aerodynamics, as in the 108's and 109's aren't. The top speed of a 6.3 is about 140 mph so a 4.5 would be less.

Gilly
I think you have the 0-60 figure wrong. It should be around 9.5.
although 9.5 seems slow when you drive it you will be surprised. It pulls.
The car is fast and when I had it 71 280sel 4.5 I had no problem what so ever on the highways. It is fast from 60 >> and up. I had it up to 110-115 but my front suspension was not up to spec so I slowed it down. It would definitelly go higher.

[jas2wa]

I agree- my M-B shop manual puts the 0-100 km at 9.4 seconds I think- 9 and a half sounds about right, though I agree it does pull like there's no tomorrow. It is the limitation of the 3 speed auto that keeps it from being faster I would say. Spread that torque over even one more ratio and it would probably drop .5 to one second off the time. Of course, the thing does weigh quite a bit, too...

I have had mine up to 110 with seemingly plenty left, but I hesitate to experiment on my current (PO) tires.

[psfred]

Factory top end is 125 mph, will probably go faster (with GREATLY increased engine wear!) with the non-rev limiter rotor -- the limiter cuts out at about 6200 rpm, I think, less with age as the spring gets weak.

IT certainly has all the performace I want, but then I'm satisfied with my 220D when it runs right. Not so speedy on acceleration, but it dives nice once you get going!

Peter

[Gilly]

I stand by the figures listed as being correct as published.
MB of course could have it listed wrong, but it IS what they have listed.
The performance is listed the same for the 280SE 4.5 as well.

Strangely, the times you are throwing around do seem correct for a 280SEL 3.5;
With 4 speed manual, top speed 210km/h, 0-100 km/h in 9 seconds
With 4 speed automatic, top speed 205 km/h. 0-100km/h in 9.4 seconds. One would tend to thing the 4.5 would be faster than the 3.5, maybe not.

The 450SEL 116 chassis has it's 0-100 km/h time listed as 9.9, just for further comparison


Gilly

[psfred]

Gilly:

My numbers are from the owner's manual.

The three-speed has a different rear end ratio, I think, as I remember 3.23:1

Peter

[Gilly]

My numbers are from an MB archive resource disc. No doubt an error when entered or something, but the numbers I gave are correct per what's ON the disc.

Gilly

[psfred]

Mind you, I have no desire to drag race it or see how fast it goes! My reflexes aren't up to racing anymore, and I have no desire to burn the engine up any faster than necessary, to say nothing of the rather greedy apetite it has for fuel when I drive gently!

Besides, until I get the front subframe bushings done, it's a little spooky at high speed.

Peter

From a November 1971 Road & Track road test of the 1972 280SEL 4.5:

Curb weight: 3,775 lbs.

Speed: 0 to time (secs.)

30...............................4.7
40...............................6.5
50...............................8.6
60.............................11.2
70.............................14.8
80.............................19.0
100...........................32.7

Speeds in gears:

3rd gear (5200 rpm)..........118
2nd gear (5800 rpm)...........90
1st gear (5800 rpm)............56

Quarter mile performance: 18.1 seconds @ 78.5 mph

This vehicle was an early 1972 rated at 230 hp @ 5,000 rpm and 279 ft. lbs. torque @ 3,200 rpm and had a New Jersey registration (not a California car).

Now find results from a September 1970 Car & Driver road test of a 1971 Mercedes 280 SE (coupe) 3.5:

Curb weight: 3,623 lbs.

Speed: 0 to time (secs.)

30...............................3.2
40...............................4.8
50...............................6.6
60...............................9.0
70.............................11.8
80.............................14.7
100...........................23.1

Speeds in gears:

4th gear (6100 rpm)..........122
3rd gear (6500 rpm)............96
2nd gear (6500 rpm)...........55
1st gear (6500 rpm)............33

Quarter mile performance: 16.5 seconds @ 85.1 mph

This vehicle was an early 1971 rated at 230 hp @ 6,500 rpm and 231 ft. lbs. torque @ 4,200 rpm and had a New Jersey registration (not a California car).

Comments? Conclusions?

[cbdo]

Interesting--and it fits right in with the original reason for the 4.5 engine appearing at all, which was US emissions standards that came in 1973-74. MB tried to meet the standards with the 3.5 engine but couldn't do it with decent output and then-available technology; they responded by adding a liter to the capacity, and IIRC some tweaking of transmission calibration and axle ratio. The 4.5 SL was no faster than the Euro 3.5, and I think was in fact slower (not taking time right now to look it up) even though the output was nominally similar. AFAIK, the only time a 4.5 engine puts out more than a 3.5 is if they're both non-US versions, which didn't happen much.

[psfred]

Both engines are listed as having the same horsepower and torque ratings. The only difference from the chart is going to be that the 4.5 came with a 3-speed auto -- I don't know if a 4 or 5 speed manual was available in the US, or if it was anyone actually bought one, as there were only about 2000 of them imported.

I'd expect the 3-speed to be just a bit slower and a bit more long-legged, with the top speed around 124-125. Not that I'm ever goign to drive mine that fast or anything!

Peter