[Closed] Engines

My guess is their management, choice of turbo and other ancillaries will be fine tuned for the vehicles intended use.

In a van you might want a different torque curve to a passenger car because of the higher proportion of time it spends "heavy " with a full load or trailer. Result is different noises.

Differences in vehicle structure and sound proofing levels may also play a part in changing the sound of the engine and there may be differences in other aspects of the engine not obvious to a consumer.

The hilux is presumably primarily designed but not necessarily sold as a commercial vehicle don't forget

Allsorts really- I mean, you can get 2 different inline 4 engines in 2 different cars that'll sound completely unalike. You can get a transit with a derivation of my mondeo's engine but the tune's completely different so it sounds and feels different in use (though, they both sound like a bag of spanners at idle) Not sure exactly what's different inside the engine

AS you get bigger, the engines'll tend to get stronger and more durable, for the obvious reasons- and also because there's less point building a lightweight engine for a 20 ton bus. And bigger too- like, volvo do a 6 piston 12 litre engine for buses, which revs low and fat and makes about 450bhp in an incredibly unfussed manner. Good for economy and emissions and lifespan and of course torques.

Truck and bus engines are very similar, developing very high torque at low engines speed (1000rpm) and having max speed of 2000rpm. Most commonly 6 cylinder and design life of 1 million km or more

Passenger car engines rev to much higher speeds and have greater refinement with features such as dual mass flywheels. Generally 4 cylinder and much less long lived

Dunno but the VAG diesel engine in my car sounds like a petrol engine. Actually, it sounds better than that. So quiet and smooth.

Weirdos like myself find diesel engines things of beauty, heres an example of one of Manchesters finest:

No idea.

The 30.l V6 in my pick-up is a load smoother than the 2.5 4cyl in my old one - however, you could almost redline the old one before it sounded like you were thrashing the living daylights out of it - this one sounds like you are caning it above 3000rpm

The drivetrain makes more noise than the engine in this one

http://m.youtube.com/watch?v=8d2lADAhegY

Who else remembers being able to know the make of the car by its exhaust note and sound of their transmissions?

Now we have homogenised products that all sound the same. Albeit distinctly more reliable, safer to drive and drier and more comfortable.

Not that that answers the OP's question, mainly because it's already been done above 😀

molgrips - Member

How do different diesel engines in different applications differ?

My mate had a diesel engine in his Hilux, sounded like a van and not like a car. Why?

Well for starters most Hilux engines are van engines. The ones I had were identical in every aspect to the 2.4 and 2.8l engines found in the Hiace so that's why they sound like vans.

In terms of why they sound like they do though, a combination of cam timing, compression ratio and exhaust manifold that'll be most immediately noticeable.

molgrips - Member

My mate had a diesel engine in his Hilux, sounded like a van and not like a car. Why?

Probably his Hilux had a mechanical fuel injection pump = old style, traditional clattery diesel, rather than the current electronic 'common rail' system which can play clever tricks to reduce the amount of detonation noise, and generally smooth things out (like injecting a small amount of fuel to get the fire lit a few microseconds before the main squirt of fuel that generates the power).

Not a great article, but...

http://en.wikipedia.org/wiki/Common_rail

Older tech where fuel is injected into the pre-combustion chamber (indirect injection) can be quieter than direct injection (the Di in TDi) where the fuel goes into the main combustion chamber

Hydraulic pressure activated injectors tend to be noisier

Smaller engine, smaller surface area, less noise

Who else remembers being able to know the make of the car by its exhaust note and sound of their transmissions

Anyway, back to the original question.
The biggest difference between truck and car engines is that truck engines can work at near their maximum power output almost indefinitely.
A 2 litre car engine might be rated at 200bhp at 8000rpm, but if you drove it up and down an autobahn like that, you'd soon kill it.
A 12 litre truck engine typically produces only 400bhp at 2000rpm, but it will do that all day, every day, for years on end.

I've noticed that the current generation of small VAG diesels used in Polo, Ibiza etc. sound very rorty like a tuned up sports car. I assume that's because they probably are very highly tuned in a special way to give maximum fuel economy with minimum emissions.

I've noticed that the current generation of small VAG diesels used in Polo, Ibiza etc. sound very rorty like a tuned up sports car. I assume that's because they probably are very highly tuned in a special way to give maximum fuel economy with minimum emissions.

The 1.9tdi kind of sounds like it has playing cards in its spokes

Older gen pre-direct injection engines sound more rattlier / agricultural, like tractors, as they suffer from a lot of pre-ignition where the air fuel mix explodes rather than burns. This sets up an acoustic vibration through the engine which makes the classic pinking noise. Direct injection engines inject the fuel directly into the cylinder, at the optimal time, to better control the burn of the fuel which makes for a more refined and petrol engines like smoothness and avoids pinking. I'm probably wrong but I can't imagine a Hilux has the very latest high tech Diesel engines fitted.