Kennedy

iTrader: (2)

What does than even mean? Yes we're all aware it cost money to drive a car... but that's true irregardless of the fuel it requires...

My old diesle Jetta would have killed my TL. It was smaller, lighter faster, and had LOTS more torque. Not sure you'd be looking down your nose at the end of the race, especially when I explained it was an oil burner that trounced you.

and most diesels can run biofuel out of the box. I had a buddy that modded his diesel to run vegetable oil... It's WVO (waste vegetable oil) diesel on his VW TDI.
Here's the link to the kit:
http://greasecar.com/

If I can the same or better performance for less fuel costs, and MUCH better "tunability"... Diesel all the way.

BTW, my predicition is already coming true. I just saw a commercial from Mercedes where they're offering 2 new Diesel SUVs this year... It won't be long!

6spMike

You didn't have better acceleration performance.
The diesel has low end torque, which feels good off the line, but hp is what accelerates you.
Your modded jetta had 3200 lbs/141 whp = 22 lbs/hp. The TL has 3700 lbs/maybe 220 whp = 16.8 lbs/hp.
Don't bet the farm on a race.
...Don't get me wrong; I think diesels are the way to go too; I like the way they give you a kick when you first hit the gas. However, it's simply not true that they have the same performance as gas engines.

Black_05_TL_6SP

Torque is what accelerates you down the track, the more torque, the faster the acceleration. You will hit red line faster with a diesel, but you will already have the jump. This is where the gearing comes in.

BTW, horsepower is what maintains your speed, it is not what accelerates you. It is mearly a calculated #.

Power (hp) = Torque (ft-lb) * RPM / 5252

This is the reason diesels do not produce the same amount of hoursepower, they normally do not rev past 5252rpm. At that point, torque and horsepower are always equal. I have seen plenty of diesel 4x4 trucks dust the hell out of a car (race and street). A streetable Ford F-250 at 8600lbs running a 8.5 in the quarter. Diesel is no joke when it comes to tuning. You do not have to worry about timing, it is either timed or its not. To get more power, you need more fuel and more air, period!! Then if you really want a extra boost, throw some propane on it.

Do not think that a diesel car will not out run you, cause they can and will.

jcondon

Bone stock the Jetta diesel doesn't seem that fast. However without too many mods it looks like it is very fast.

If you believe the numbers...

http://www.dragtimes.com/Volkswagen-...slip-6114.html 15.9 quarter mile

http://www.dragtimes.com/Volkswagen-...slip-4150.html 14.5 quater just over 100mph Chip and exhaust. Pretty impressive I think.

6spMike

Umm... No. Torque is important, but it is useless without rpm. Say you had infinite torque and 0 rpm. The car would go nowhere.
The definition of horsepower is the rate of doing work (work/time). The more horsepower, the more work you can do. Work is accelerating the car or climbing a hill, or pushing air resistance...
The definition of torque is a twisting force. That force has to move something over time in order to create work. That's where rpms come in. The higher the rpms at the same torque, the faster you can do work.

Look at Kennedy's modded Jetta motor graph. The torque peak is around 250 at 2600 rpm, and the torque drops off with higher rpms. That's why the hp peak is only 141. If it was able to make the 250 ft-lbs at 5252 rpm, it would make 250 hp.

Torque is multiplied by the transmission and differential gears before it is applied to the rear wheels. If the engine makes torque at higher rpms, you can use a lower gear (higher numerically) to multiply the torque more and accelerate faster.

So Kennedy has to use 4th to be at his 2600 torque peak, but one could be in 2nd getting 2x the torque the the rear wheels at 5200 rpm.

In a sense, you are right that it's rear wheel torque that accelerates the car. More horespower means you can apply more torque at higher vehicle speeds.

In order to do an 8.5 quarter with 8600 lbs, a vehicle must have around 2800 hp, diesel or not. It must be modded all to hell, seeing as how the stocker can't be much over 350. All the reliablilty of a hand grenade...

Horsepower is what creates performance, not just torque. Whichever car makes more horsepower and is geared to use it will win.

Black_05_TL_6SP

Yes, the longer you can go without shifting the gears and still produce reasonable amounts of "torque", the better off you are. But as you stated, HP is the measure of how much work you "have done". This is not what propels the car down the road. The torque (measure of rotation) is turned into force.
But by keeping you vehicle in its power band, you take advantage of the torque curve at that point. Two stroke engines are the same way, high torque low horsepower.

With a engine like that in the Honda's, you first have to get into its power curve, which is above 5000RPM, and you must keep it there the whole race. A diesel produces it power down low, getting you there quickly and then shifting to keep it in that curve. Yes you loose time to shift, but you make up for it in the lenghts you gain on the take off.

HP is not as near as important as everyone makes it out to be.

Then please explain to me how I have seen a lightly modified diesel truck run a 8.5 in the 1/8th. I have seen this personally and looked at the truck. It was not highly modified and was driven there as a dailey driver.

Here is just one example of a diesel running in the 1/4. Diesel truck vs a mustang

There are plenty of examples of this. This truck was only producing 720hp! Not your estimated 2400hp. A 10.41 is pretty damn good for a truck of that size. I watch a highly modified Cummings turbo diesel run in the 9's in the 1/4 at a Nopi event.

Here is a prime example of high horsepower vs torque. A viper vs a Ram, the Ram wins!!

Ram vs Viper

6spMike

You are confused between a constant force (torque) and the rate of doing work (horsepower). Torque * rpm *5252, like you stated, equals horsepower. Torque AND rpm is what makes horsepower. Only horsepower wins races.