Saying goodbye to the M20 525... and hello TDS!

[Interceptor]

The torque is amazing though.

I agree. 525tds is an excellent car for relaxed cruising together with all the luxury E34 has, at a substantially lower price per kilometer/mile. But, I must admit that I don't feel very secure when overtaking cars at higher speeds - diesels are just not good for it due to their power distribution characteristics.

[jplacson]

but what about start-stop traffic sprints? Wouldn't the diesel's low-end torque be more useful for city sprints, over the 525i?

[Interceptor]

but what about start-stop traffic sprints? Wouldn't the diesel's low-end torque be more useful for city sprints, over the 525i?

Actually - no. Diesel engines have heavier moving parts thus making them lazy and sluggish on start. That's why diesels are used in heavy trucks that require a lot of pulling power. You don't see a race/rally car use a diesel, do you?

[jplacson]

That's actually what I was wondering. Always wondered why with so much low-end torque, diesels don't make good GT cars.

So only the new common-rail ones have any chance of beating their petrol counterparts in terms of performance?

[StuartB]

Bugger...


Went to put the money down today, after the assurances I'd had that they'd hold on to it, and.... they sold it..

Luckily I'm going to look at another one tomorrow, a boston green touring for the same price... though it's got substantially more miles on (118,000)

[Paul_540i]

So only the new common-rail ones have any chance of beating their petrol counterparts in terms of performance?

Even then, like for like the petrol will still be way more powerful. The only reason they're not is due to the fuel economy being much worse. An example being the new 535d has a 3.0 diesel with two turbos, and it's about 260 BHP so probably roughly on a par with the 535i petrol (but with loads more torque). But strap two turbos onto your 3.0 petrol and boy will it shift The reason few manufacturers do so is that 15 MPG doesn't sell too well!

My previous Subaru with just a 2.0 single turbo was putting out about 300 BHP & 300 lb/ft and would waste a 535d. Maybe not at the top end cos the aerodynamics were crap but it would still be quicker.

Put simply petrol is a faster burning fuel so will always be a better choice for power, even if it is pretty inefficient at creating that power. Try getting 850 BHP from a naturally aspirated 3.0 diesel (like 3.0 petrol F1 cars do)