Direct Injection?

[Mintmaster]

OT:
At my community college auto dept. we recently got a chassis dyno
The instructor for my class ran his 2004 mustang cobra with a few mods(exhaust, smaller SC pulley, k&n system and reflash) and the type of dyno we have is the kind where you set it to a certain speed to apply the load and he was makin 280HP before it startin spinnin the tires (at 70MPH 4th gear) and today he tried it in 5th at 80MPH and he made 230 before the tires startin spinnin.
wtf is up with the traction of that?
It's rated for 500HP yet it doesn't have enough traction to hold over 230hp!

Well actually the physics works out quite well (unless I made a mistake).

500hp at 80mph (or 373kW at 36m/s) works out to a force of about 1 tonne (10 kN). Since the engine is at the front, I don't think there will be more than 700kg at the rear wheels. Add in driver train inefficiencies and a friction coefficient of 0.7, and this means you're traction limited at half power.

Take the speed to 150mph and then the 500hp gets useful Actually, the main reason for an engine this powerful is probably so that you can take full advantage of your traction at all RPM ranges, even when your power is only 60% of its peak. Also, when you're accelerating, the weight transfer should help traction significantly.

A very illuminating example, though. I never realized how much power 500hp really is.

 

[covermye]

That's what I thought. Obviously it depends on the application but does going from dual to quad cams make a "large" performance increase?

Not in my opinion. Marketing gimmick written all over it.

 

[Moloch]

Well actually the physics works out quite well (unless I made a mistake).

500hp at 80mph (or 373kW at 36m/s) works out to a force of about 1 tonne (10 kN). Since the engine is at the front, I don't think there will be more than 700kg at the rear wheels. Add in driver train inefficiencies and a friction coefficient of 0.7, and this means you're traction limited at half power.

Take the speed to 150mph and then the 500hp gets useful Actually, the main reason for an engine this powerful is probably so that you can take full advantage of your traction at all RPM ranges, even when your power is only 60% of its peak. Also, when you're accelerating, the weight transfer should help traction significantly.

A very illuminating example, though. I never realized how much power 500hp really is.

But I've seen twin turboed vipers making 1000HP on chassis dynos.
The problem is the roller is too slick, even though it's rated for 500HP.
On the street (i.e road) if you can burn rubber at 80MPH in 4th gear.. you've got some serious power, or bike tires on.
The one difference for the dyno is that instead of like running the engine from 3000- redline to get a dyno plot, you instead pick a speed and when it gets to the that speed it starts applying a load.

 

[mkillio]

I was watching Sports car revolution and they have an 2005 A4 2.0T that they are modding. The episode that I watched they reprogrammed the ECU and gained over 45hp from it. That's nearly a 25% increase in HP. I was looking at their website and it told what they did to it on each episode and apparently they did more stuff to the computer later on and got even more HP out of it. So I guess you really can pull alot of power from DI if you desire to. I hope they tell what kind of mileage it gets after everything they do to it.

 

[Moloch]

Audi R10 TDI le man racecar : http://www.audi.com/audi/com/en1/experience/motorsport/r10.html
cliffs:
TDI 5.5 liter turbo diesel le man car producing 650HP and over... 800 foot pounds of torque:smile:
Useable rev range is 3000-5000 rpm.

 

[_xxx_]

I hope they tell what kind of mileage it gets after everything they do to it.

Certainly not very high.

 

[_xxx_]

Not in my opinion. Marketing gimmick written all over it.

No. That only makes sense if they are adjustable, that helps for the better distribution of torque over rpm and also reduced emissions and lower consumption. It also allows for higher degree of freedom for engine control functionalities like exhaust gas recirculation and so on.

Noone would invest all that work for just a gimmick