redwhiteblue

So all this talk about torque torque torque and from my understanding and what I read is torque is what really makes a car accelerate and what is truly calculated and hp is simply a number derived from torque and rpms. My question is why the 535d is not faster in the 0-60? Is it because it has TOO MUCH torque that it simply cannot get traction so that slows the time down or is it because the max revs are only 5k and requires 3 shifts to 60 v. 2 shifts for the 535 or what. The listed 6.5 seconds just seems high to me for a car with so much torque and from what people say on here feels fast.

So which feels faster the 535i or d? basically one has more hp and one has more torque-which feels quicker

ipp

I'v driven both 335i and 335d, and I must say i felt faster when you pushed it hard, and d felt faster when you made a sudden not planned acceleration. Don't know if that's clear. Btw. 535d is 6,4s to 100km/h and that's 62mph I think.

BimmerJay

Just from what I know about diesels, which isn't much. I believe they do indeed generate a substantial amount of torque at low RPMs. The higher RPM don't generate as much torque as the low-ends do around the 1 ~ 3k RPM. Standard combustible engines have a consistent range of torque, which will only begin to drop off around the higher RPM range - 5~6K RPM. I think where you lose time in 0-60 is by not having the range of torque throughout the RPM range (.5 thru 6.5 thousands Revs Per Second). Honestly I think were discussing tenths of seconds here... The advantages of having a diesel over a standard combustible engine I think are a matter of opinion and preference. Good luck!

-Jay

HotLap

Tend to agree with your statement...diesels are generally better for low speed power/pulling, as they make more torque at lower rpms (that's why serious trucks are diesels not gasoline powered). Use to think diesels were more economy minded - but don't know if that's really true any more or not? For instance my dads diesel truck is a hog! What are the mpg's on the 535i and the 535d?

olli_535d

The "just economy" thought on diesels is loooong gone.
Now they are about economy and massive thrust.

Diesel economy completely corrupts if you use high revs often.

On the i against d, they'll be pretty par, with the i having a slight edge, probably. (in un-mapped form that is)

On a petrol you need the revs, where on the diesel the shove is pretty imminent, but tails off quicker.

See it that way, only hp are speed and torque is the wave you ride on.
And don't forget that the 535i also is forced induction, so also has a solid amount of torque.

IrishEyes

Torque = instant shove and greater in-gear acceleration.

HP = greater acceleration when ramming it up through the gears .

redwhiteblue

That does not make much senes physics wise.

The best explanation or understanding I have is that Torque is the actual force producing wheels to spin and to accelerate you while horsepower is simply a calculation that takes RPMS into consideration and produce an overall number that is more indicitive of performance.

For example you could have 400foot lbs of torque from 1-5k and have to shift gears at 5k in a theoretical engine which would put you into 2nd gear which due to the shorter gear obviously loses ability to accelerate.

Compared to a car with 280 foot pounds through 1.5- 8k rpms and shifting to second takes place at 8k. You basically got 280 pounds of torque applied for much longer in a low gear v. much more torque applied for much shorter time in the shorter gear. The number that makes this comparable is horsepower. The second car obviously having much more horsepower and being the faster car.

The second car is basically an e46 M3 engine v. maybe a 535d being closer to the 1st one or in a rough sense. Obviously the torque curves do not peak for the entire range of rpms.

So to me horsepower is a better measure of overall ability of the car to accelerate over a high range of speed. To 60mph minimal gear shifting occurs and the torquiest car may win but past that horepower and ability to stay in a lower gear for much longer wins out.

phelix

In a nutshell torque is what makes the car accelerate and horsepower is what gives it top speed. Torque is an instantaneous rotational/angular force value while horsepower represents energy over time.

One reason why diesels don't have great 0-60 times as compared to petrol cars with less torque is the inertia of the engine. Diesels have much heavier flywheels to dampen out the engine's vibrations from each compression/ignition cycle and crankshafts/conn rods/pistons are heavier as well. If you sat it a diesel car and measured the time the engine took to go from 1000 to 5000 rpm in neutral it would be noticeably slower than a petrol engine. The extra rotational energy stored up in a diesel engine at 4-5000 rpm is very significant.

Once the car's at speed (say above 40 mph) that angular inertia is dwarfed by the overall vehicle's inertia and the onset of aerodynamic drag and the greater torque of the diesel comes into play.

Russ1974

I have driven my 535d like a nutcase since 0 miles. Am now at 1,250 miles. Last 300 have been done with the DMS remap. Average mpg since 0 miles, 33.8mpg. That'll do me

westcoast550

Russ, you crack me up !! , what do you mean "like" a nut case . Did you get the wheel fixed ?yet ??