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MERCEDES W107 The R/C107 coupe and roadster from 1971-1989 (280SL, 280SLC, 300SL, 350SL, 350SLC, 380SL, 380SLC, 420SL, 450SL, 450SLC, 450SLC 5.0, 500SL, 500SLC, 560SL)

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  #1  
Old 8th April 2014, 05:48 PM
sean sherry sean sherry is offline
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Question low down Torque

Even though my 280 110 engine preforms well, with good compression ,and plenty of Ignition advance, I feel the lack of low down Torque.
Even with a 1st gear start 4 speed Auto I find I have to manually shift back a gear to often. The camshaft timing is 2% retarded on the exhaust and 1% on the inlet. Web information says advance the timing to give more low down Torque. But my experience with a 1913 Rudge Motor Cycle was the opposite.
Factory setting was 10% "A"TDC, inlet, ( steam engine timing ) very late I thought , so I set it ,via a it's fine adjustment facility, to 10% BTDC. Lost all it's low down Torque but gained a lot at higher Revs. A compromise was 5% ATDC.

Which is correct for low down Torque , advance or retard the Camshaft ?????

Sean
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  #2  
Old 8th April 2014, 07:06 PM
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Styria Styria is offline
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Default Re: low down Torque

Sean, you're probably best off to set the timing to MB specifications. It's fair to say that the 280 engine is a revver, developing maximum torque somewhere near the 4000 rpm range. Great for hooning along at 160 on the Autobahn or Freeway, but restricting your speed to recommended limits of 100 or 110, certainly leaves the engine wondering as to what to do next.

Now of course, you're up against a turbo charged Golf, and unfortunately it's become a mind changer for you. I had the pleasure of driving a 2011 turbo charged 4 cylinder Diesel, and to say that performance is impressive is an understatement. In fact, the seamless pulling and accelerative power is absolutly remarkable and certainly cannot be ignored. I also thought the interior (leather) to be beautifully appointed, with well thought out switch gear and quite beautifully presented dash fittings and instrument pod. It's only the exterior that I find too bland for my liking with the VW Golf.

So Sean, that's what your Mercedes competes against. Irrespective of pros and cons, the ball game has now changed, and that's the situation you need to face up to. Enjoy both cars for the difference they present to each other. Regards Styria
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Old 9th April 2014, 06:56 AM
sean sherry sean sherry is offline
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Cool Re: low down Torque

Styria...... you are wise old owl. ( from a children's story )
Yes , I'm again reminded of the comment to the young gung Ho Teen who wanted to improve his V Tech Honda Engine.....

"What makes you think that you know more than 40,000 Honda Engineers " !
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Old 9th April 2014, 03:03 PM
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SEL_69L SEL_69L is offline
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Default Re: low down Torque

Modern cars use seven or eight speed gearboxes in an attempt to get good acceleration at low speed AND power at high speed.
Most modern engines are set up to provide at least 80% of maximum torque in a flat engine revs vs torque curve, c/- 2000 to 5000 revs, via electronic engine management and variable camshaft timing.

The M110 engine was originally conceived as a high speed autobahn burner, at the expense of low speed acceleration. Only four speeds in the gearbox were needed to achieve this. No variable camshaft timing or electronic engine management.

The 6.9 uses sheer brute engine capacity to achieve good acceleration, but this is at the expense of fuel economy. Ya wants power, ya burns fuel to get it. Same happens when turbo boost cuts in, if your car has one. Boosting has the effect of increasing engine capacity.

Too much power, and you break gearboxes or diffs, or both. Add boosting without lowering the compression ratio, and you risk failure in the bottom of the engine. High octane fuel helps to alleviate some of this problem, because the burn rate is slower.

I would guess the some extra torque can be provided at lower engine revs, by altering the timing, but I also guess the the amount of extra torque would not be a great amount extra. Another way would be to alter the diff ratio, or outside tyre diameter or both, to improve acceleration.
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Old 9th April 2014, 03:41 PM
sean sherry sean sherry is offline
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Smile Re: low down Torque

Point taken !

With my new MKV11 Golf 1.4 Turbo Petrol it is possible to up the Power / Torque with a Tuning Box. Increases the Boost and adds Fuel as necessary. There are two Power options available from VW , a 90KW and a 110KW for the same engine. With a couple of thousand dollars price hike. The Tuning Box for $345 does the same job. Boost comes in at 1500 RPM as per standard. Then it takes off with about 20% increase in P & T. I have one fitted and it works well. The Boost sensor and the MAP sensor are fed to the Box for increased signals to the ECU. Any stress generated is taken care of by the knock sensors to retard the ignition if necessary. The Tuning Box from Germany is a quality item and is fully adjustable. The original Factory Mapping is intact and it's a five minute job to remove it should the Car need to visit the Dealer for any reason. I have my cars serviced by a Specialist in all things German. He has all the Factory Level Software on his Lap Top for diagnosis. Chip Tuning is no longer necessary, i.e., opening the ECU and reprograming the chip , permanently. It's a tedious job with todays surface mounted , miniature , 64 Pin Processors , and not for the faint hearted !

P.S. T/Boxes are also available for the 1.8 Turbo GLI , C Class. I won't bother with it , as in the S Position , it has plenty of get up and go.
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Old 9th April 2014, 03:54 PM
BenzBoy BenzBoy is offline
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Default Re: low down Torque

Low down torque?
No problems - http://www.deere.com.au/wps/dcom/en_...tractors.page?
Regards,
Brian
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Old 9th April 2014, 08:24 PM
Helmet Helmet is offline
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Default Re: low down Torque

Quote:
Originally Posted by BenzBoy View Post
Low down torque?
No problems - http://www.deere.com.au/wps/dcom/en_...tractors.page?
Regards,
Brian
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Old 9th April 2014, 09:03 PM
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motec 6.9 motec 6.9 is offline
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Default Re: low down Torque

Hi if you want torque keep it in marque http://www.roadtrains.com.au/article...?ArticleId=234
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Old 10th April 2014, 07:55 AM
sean sherry sean sherry is offline
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Smile Re: low down Torque

What great technology ... I've got to have one !
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Old 13th April 2014, 05:14 PM
sean sherry sean sherry is offline
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Smile Re: low down Torque

Thanks mainly to Styria, I have sorted my understanding of the 107 280 SL.
Nothing wrong with the Engine, the auto trans doesn't do it any favours. Shifts up through the four gears on a light throttle in 50 metres and under 2000revs.
Medium throttle the Engine is still under 2500 Revs. With two thirds plus throttle , ..stretched shifts and 3500 Revs. probably still in third gear. Problem is the calibration of the valve Body or the Governor. Result is light/medium upshifts are way too early , and half throttle onwards the shifts are way too long.. Of course I can control the early upshifts by shifting manually, starting in the 2 position ,locking out forth, and shifting to D as necessary , 2500 Revs plus. Full throttle upshifts are not for a 33 year old car. And down shifting without going to kick down , ...use the Gear lever. I do wonder if the calibration of the Valve Body came from the V8s with their low down Torque. I'm now much happier with the performance , easy to skirt round this minor issue.
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  #11  
Old 20th November 2019, 04:55 PM
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Default Re: low down Torque

Close in torque to my 6.9 Gleaming Beauty - but only just.
https://www.deere.com.au/en/tractors...rack-tractors/

Regards Styria
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  #12  
Old 20th November 2019, 07:03 PM
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Oversize Oversize is offline
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Default Re: low down Torque

I feel confident we’ve all learnt a lot since the 70s (or 60s) when these cars were designed! And I am convinced a lot of issues re power & torque with the early Benz engines falls on the CIS which impacts the whole intake design. And the exhaust can be vastly improved as well... EFI is the only way to go; I just have to prove it (Hopefully I won’t have to eat my words)!!!!

BTW you cannot compare NA with forced induction. Whack a turbo on a M110 & see how it compares then!
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Old 20th November 2019, 07:06 PM
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Default Re: low down Torque

Oh and I fully expect to break a trans, diff, or both!!!!
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87 560L#2020 (Dora 2)
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