310D Engine Tune for Torque

[Mercforever]

Hi All,
Thank you for your previous interest and advice.
I have Merc 310D panel van, 1995 with 5 cyl engine. This engine is a good one, hardly burns any oil between services, rev's freely, goes pretty well. Intend to keep it at least ten years. Think the mechanical fueling is great, trouble free and simplistic compared to the electronic control problems one frequently reads about!
The area in which I would like improvement and advice - well, previously I had an old 307D, 1984, bomb proof, approx only 64 bhp, but it had much more low rev torque and would pull better, tow better, especially up a bank.

1. As I don't like or want to rev right up to the limit, which burns more fuel and causes more wear, how do I get more bottom end torque?

2. A friend has seen a 300D engine from a 124 series car installed into a similar van - says absolutely brill performance and economy -- any thoughts on this idea?

all thoughts and comments welcome!

kind regards
A

 

[Bolide]

I think the only way you're going to get what you want is with a turbocharged diesel engine. Non-UK W124 models had these

Nick Froome
www.w124.co.uk

 

[wireman]

Even though the diesel is famed for low speed torque it is advantageous to allow it to run at higher speeds because they are more efficient at higher speeds ie 1/2-3/4 max RPM.
Once above the idle speed the torque (on full throttle) is more or less constant regardless of crankshaft speed but the combustion efficiency is better at speeds well above tickover and will use less fuel for a given power whilst running faster.

A turbo would only help significantly at speeds aproaching half max and above, it does nothing to help at speeds much below 30%, it can in fact reduce the efficiency at very low speeds. Modern electronicaly enhanced diesels tend to buck this but do you realy want a box of transistors and sensors on your engine they only seem to cause larger service and repair bills to me.

You might try increaseing the fuel pumps maximum delivery settings (pos expert help required) which will give more torque at all speeds but at the risk of spoiling the emmisions levels on full throttle, = MOT fail.

Squeezing the six pot in sounds like a fun idea.

 

[Mercforever]

Comparison...

Thanks Bollide and Wireman!
The reason I was wondering about more grunt at lower revs comes from truck engine experience a few years ago. The company I worked for ran a couple of artic's on low loader, a most arduous job often at the heavy end of cargo. Originally the first truck had a Cummins NHC250 engine (250 bhp), which went well, revved to 2500 rpm and was 'ok' on fuel. We got a new one, 1979, when the first 14 litre 'big cam' engine came out, named the E290, which was completely different and required very different driving characteristics. It only revved to 1900 rpm and developed max torque from around 1300 rpm.
We were instructed to let the engine slog right down the revs to 1200 instead of previously changing down at just under 2000 to keep the power going, much to his surprise, the driver reported amazing performance, good pulling power at low revs was not heard of very often. This did wonders for economy. Oh, the E290 was turbocharged, the NHC250 was not.

So, I was wondering if it was possible to 'put' some of the same characteristics into my 310D, by using such as a modified cam shaft or whatever anyone could recommend who has had good experience with tuning diesels.
I do accept that the engines could just be too different to compare, as mine is indirect injection, non turbo, much higher revving etc but, again, all suggestions welcome!
kind regards
A