The Tuning Guide Sucks!- Yea, I said it!

[pickens]

Also, let me add to the topic of drivetrain loss. The force to accelerate an object from an initial speed to a final speed is directly proportional to how fast you accelerate it. Therefore, if you have a 200hp drive system, things can only get spinning so fast in a period of time. In a 400 hp system things tend to accelerate alot faster, thus causing more drivetrain losses. So the relationship is definately not static, but its not linear either.

 

[Groomz]

The only accurate solution would be to dyno the engine seperate from the drivetrain and compare the crank and wheel horsepower values. When you begin to mod a car from the factory horsepower rating, its probably a good idea to keep everything in terms of wheel horsepower, that way there isn't confusion when people ask how much horsepower you make. Just trying to say that it doesn't matter what the crank horsepower value is, whatever makes it to the ground is what moves the car, so why even bother with a crankrating unless you want to find out how parasitic the driveline losses are. ( Also want to make sure that the whp dyno's are corrected for atmospheric variables and such )

 

[DSMJim]

Originally posted by pickens
Also, let me add to the topic of drivetrain loss. The force to accelerate an object from an initial speed to a final speed is directly proportional to how fast you accelerate it. Therefore, if you have a 200hp drive system, things can only get spinning so fast in a period of time. In a 400 hp system things tend to accelerate alot faster, thus causing more drivetrain losses. So the relationship is definately not static, but its not linear either.

Right. What I was trying to say was It's not just 18% period. Like hey look I make 1000whp so I must make 1180 at the Crank and now it takes 180hp to drive my driveline. It will take more beause more acceleration causing more heat etc etc. But it's definatly just a set percentage. It's somewhere inbetween.

Basically the point of my post was guys who makes 300whp and add 18% onto it are just trying to make themselves feel good about their crank HP where IMO it's better to claim on the low side. As a matter of fact most guys who do this use 25% for driveline loss so their 300hp is now 375 which sounds better. In a lot of cases this eventually becomes "almost 400". I love seeing guys like that at the track. Nice to see a "almost 400hp" car run 13.5 @ 95mph, . In my experience one thing that goes hand in hand with smack talk is poor driving.

 

[abyrd96]

Originally posted by DSMJim
As a matter of fact most guys who do this use 25% for driveline loss so their 300hp is now 375 which sounds better. In a lot of cases this eventually becomes "almost 400". I love seeing guys like that at the track. Nice to see a "almost 400hp" car run 13.5 @ 95mph, . In my experience one thing that goes hand in hand with smack talk is poor driving.

That is so true. Sad...but true!