F30 320d a good choice for me to switch from Passat CC?

[takayoto]

PhD from Imperial College, London in Advanced Engineering.....how can be wrong?

Thqnks for sharing. I feel likes learning more n more here

 

[Quentin]

So when someone said something like "This car is soo torquey!" what does that mean ? This car can accelerate soo fast ?

And when looking at car spec the most important thing to look at if you want to know the performance, is the acceleration right ?
Like a car which has 400Nm wouldn't mean a thing, if a car with less Nm has better acceleration, am I right ? :trytofly:

 

[E46Fanatic]

Good point. When comparing a modern petrol turbo (like the F30 328i) and a turbo diesel of the same capacity (even with the BMW performance powerkit), it's almost certain that the petrol unit will out perform the diesel in terms of performance numbers by a good margin. Where the diesel wins is in fuel consumption.

 

[jwah]

So when someone said something like "This car is soo torquey!" what does that mean ? This car can accelerate soo fast ?

And when looking at car spec the most important thing to look at if you want to know the performance, is the acceleration right ?
Like a car which has 400Nm wouldn't mean a thing, if a car with less Nm has better acceleration, am I right ? :trytofly:

I think when comparing a series of petrol car, what you should look at is the TORQUE instead of the power, because the Torque describes how strong your engine is. However, how hard the acceleration also depends on the transmission system (gear ratio).. See the following table

Engine Transmission output torque:
Torque 1st 2nd 3rd 4th 5th
RPM (lb-ft) 3.54 2.13 1.36 1.03 0.72

 

[Hillgosh]

HP= Torque/5252 x RPM

You can treat Torque as a constant of a car or imagine the Muscle of the car. While RPM is an engine variable.
HorsePower is to describe how fast you can move a thing from one point to another point. or how much work can be done in a specified time.

Petrol car , lower Torque , higher RPM 8000rpm
Diesel car , high Torque, lower RPM 5000rpm

Both also can achieve a 200hp like this
309.73lb-ft (420NM) Diesel
200hp ~= 309.73lb-ft x 3400rpm /5252 , At a gear ratio

184lb-ft (250NM) Petrol
200hp ~= 184lb-ft x 6500rpm /5252 , At a gear ratio



You can see that the Diesel generates 200hp at 3400rpm whilst Petrol at 6500rpm. So how is the performance? Shall petrol goes faster? you shall see how the transmission work for you. For Petrol car because of lower torque, requires higher final drive ratio to compensate, on the other hand, Diesel car lower rpm range shall compensate with lower final drive ratio, but lucky it has huge torque.

check out this link, you can see the diesel final drive ratio is lower and therefore engine don't need to work as fast as petrol car. (let me know if I am wrong)
http://www.e90post.com/forums/showthread.php?t=101507

Well done!

 

[BlackE90]

Hi Bro Jan999, here's another video to assist your decision making process. Just listen to your heart for the choice of car.

 

[jwah]

When we buy a car, we shall consider the soul of the car. Why the engineers built this car? What is the history?

For example evo is a good car....

The 3series is damn good at the winding road, yesterday we did a bukit tinggi climb at high speed, great control vs power, then shoot up to Ulu yam from Raub, narrow and twisting roads at 60-80km/h although being set to 40km/h due to traffic at last quater. Our leading car can even driving with one hand steering one hand walkie to report traffic. Personally I cannot forget the feeling of flying up Genting road with the powerkitted 420NM, much like a plane just leaving the ground.

 

[tIANcI]

jwah ... yesterday me went up Genting via Ulu Yam, had to keep revs at 5.5k at least. My 325 has a fair amount more HP than the 320d for sure. But I wished the 325 was a diesel. More torque!

 

[Quentin]

So higher torque is needed for those roads like in Genting ? Why ? :trytofly:

 

[jwah]

320d powerkitted has 200hp 420NM with hardware and ECU upgrade, have yet put in the DTUK, 0-100km/h 7.0s. The car accelerates hard with high torque and better than 325i with higher power rating. I test drive the 325i after the powerkitted, the only thing I like for 325i is the engine sound only. if put in the powerkit+performance exhaust+K&N filter it may be 210hp, carlsson's ride.

320d DTUK with correct map setting produces 201hp 475NM (maniac's ride)

Go up Genting with High Torque Machine is because you can use higher gear. I remember my ex-car have to down shift to 1st or 2nd gear whenever there is a climb. This 320d don't even bother to use manual gearshift, was in D mode. Probably 3rd or 4th was used for conservative speaking. That is why it shooting up like a plane.

let do a math then for 325i and 320d for the Torque at the wheel
Total Ratio = Gear Ratio x Final Drive Ratio (FDR)
Wheel Torque = Total Ratio x loss x FlyWheelTorque
Assume loss is 20% after the DriveTrain

5500rpm , shall have 250NM of torque being generated by Inline 6 Engine
Gear/Gear Ratio/FDR/TotalRatio/HP/Wheel HP/FlyWheelTorque/Loss/Wheel Torque
1st 4.32 3.07 13.26 215hp 172hp 250NM 20% 2652NM
2nd 2.46 3.07 7.55 215hp 172hp 250NM 20% 1510NM
3rd 1.66 3.07 5.09 215hp 172hp 250NM 20% 1019NM

320d powerkitted
4000rpm , shall have 420NM of torque being generated by noisy Diesel Twin Turbo Engine
Gear/Gear Ratio/FDR/TotalRatio/HP/Wheel HP/FlyWheelTorque/Loss/Wheel Torque
1st 5.14 2.56 13.15 200hp 160hp 420NM 20% 4418NM
2nd 2.83 2.56 7.25 200hp 160hp 420NM 20% 2436NM
3rd 1.80 2.56 4.60 200hp 160hp 420NM 20% 1545NM

Clearly can see 2nd gear wheel torque of 320d is about the 1st gear of 325i 2652NM. That is why I say 320d can use 3rd gear to go up Genting

 

[tIANcI]

So higher torque is needed for those roads like in Genting ? Why ? :trytofly:

Quentin ... Torque is evident when a vehicle is loaded. Load can come in the form of weight or when going up an incline. Does not matter what gear it's in. Diesel fuel creates more torque due to the nature of the fuel. That is why lorries etc use diesel, the other reason is consumption of course which comes into play with the fact that it's cheaper than petrol.

When going up Genting I am shifting between 2nd and 3rd a lot to get the revs on my 325 up at about 5k-6k. If it were a diesel, I may, just may be able to hold 3rd longer and yet be able to have my car pull itself with more ease up the hill. Loosely said, torque gives your car the grunt.

Yeah a big warning about coming down Genting. About 3-4 corners before the bottom police post, there is a nice left hand corner. It's wide and looks great, just be aware that it's full of sand. Carrying too much speed into it, with late braking will ensure that you shall be filling up the insurance claim form.

 

[jwah]

would be better to mark the area with google map please

 

[tIANcI]

would be better to mark the area with google map please

jwah ... My nuts were pretty kecut at that point in time for me to remember exactly which one it is on Google Earth! I really thought I had to make an insurance claim. Approaching it from 50 meters away it looked so clear. When you are about to drop a gear or two to enter it, you realize there is sand. I may go up again this weekend and take some pics of it and try to locate it for you all. There were 5 cars coming down, 4 were caught off guard ...

What I learnt was this ... You may be the best driver with the best car but You are not in control of many elements when you try to be a hero on the road. Some oil could be spilt the night before ... Not your fault, you know the road well but some oil was spilt and that is it.

 

[carlsson]

Ah, I had a friend who hugged his clk on the nice wall there. Clk took almost a year to get fixed.

Quentin ... Torque is evident when a vehicle is loaded. Load can come in the form of weight or when going up an incline. Does not matter what gear it's in. Diesel fuel creates more torque due to the nature of the fuel. That is why lorries etc use diesel, the other reason is consumption of course which comes into play with the fact that it's cheaper than petrol.

When going up Genting I am shifting between 2nd and 3rd a lot to get the revs on my 325 up at about 5k-6k. If it were a diesel, I may, just may be able to hold 3rd longer and yet be able to have my car pull itself with more ease up the hill. Loosely said, torque gives your car the grunt.

Yeah a big warning about coming down Genting. About 3-4 corners before the bottom police post, there is a nice left hand corner. It's wide and looks great, just be aware that it's full of sand. Carrying too much speed into it, with late braking will ensure that you shall be filling up the insurance claim form.

 

[tIANcI]

Ah, I had a friend who hugged his clk on the nice wall there. Clk took almost a year to get fixed.

Oh oh ... I was very lucky then!

 

[999jan]

I'm so sorry for asking such stupid question...i should get my ass kick by other members here...lol...

 

[jwah]

:rock::rock::thefinger:

 

[jan999]

I'm so sorry for asking such stupid question...i should gt my ass kick by other members here...lol...

999jan? clone of me?

 

[tIANcI]

If you ask so called stupid questions you will learn. If never ask then never know la.

 

[jwah]

Feb666 also coming.....I hated PangSai car