Drag or Hill shoot? twin cylinder or single? what type of fuel? NOS? Turbo?

 

sounds like you want a nice flat early torque for hills. I figured that , but what will give you that other than cc's, cams with less lift and more duration or vice versa?

 

I understand TQ VS. HP and the argument will alwasy be there. We have the same arguements in the diesel world.

In my opinion you're splitting hairs. I feel that hill shooting and drag racing are the same. It just puts more load on the motor going up a hill. Now if the conversation was about TT racing and drag/hill racing... motors could be different in that they are purpose built.

Make as MUCH hp and tq as you can make and bring it to the hill. If you do build a high HP and a low tq motor.... then you'll be screwed up the hill. Then again, overall weight will mean the difference in both scenarios.

I need a 80/80.... figure that will get me going pretty good. Of course that doesn't count the 25shot for good measure.

My .02

 

so 222 i understand the torque is the force that moves things but speed of accelaration is what will win the race, assuming there is enough torque to move the vehicle, i have a 6.0 diesel, and 454 vortex they both move out pretty well, and will pull a lot, but the small 350 and 326 seem to out run them, but can't pull near the load, so how do we pull the load and accelerate fast or even faster?

 

300ft drag
600ft drag
1200 ft drag
600 ft hill fairly stable incline
1200 ft hill fairly stable incline
600 ft hill with more incline at the top
1200 ft hill with more incline at the top

gas burning natural aspirated single cylinders with any engine mods as long as they have the same peak horsepower.

 

i'm not following were you are going, with all those things are you saying you are setting up for each distance or are we able to kill a bunch of birds with one stone (or set-up) ?

 

an 80hp 250r would absolutely rape a 80hp 4-stroke. Too many variables comparing a 2-stroke vs. 2-stroke.

As far as the hill vs. flat track motors, they can be setup different to perform better for an application. Being that there is less of a load on a flat drag bike the torque isnt quiet needed to sustain speed. Rather RPM and sufficient hp can equally run as well as a larger slower revving motor.

On the hill though a large displacement motor will run better then a smaller strung out motor. Im sure you all saw the video of bomber at 4sw. Notice the smaller bike pulled ahead first? But half way up the hill the extra cc's and torque kept the motor pulling hard.

 

Beech, I'd have to disagree with you on the 2stroke vs. 4stroke at 80hp. If all things were equal (weight) the 4 will smoke that two with the same output. Math is Math. If both are produceing the same hp number but the 4 is producing more tq.... machines being of equal weight (which is rare) the 4 will dig harder (tq) and finish as strong (hp) as the 3. Again, everything would have to be equal including riders.

Where two strokes kill us with like hp is weight. A striped banshee that's piped and geared correctely will come in probably 225pds less than a piped DS. That's WAY too much to overcome. Again, Math is Math.

then again, looking at your signature.... you know what you are doing. Still waiting for more pics! :biggrin:

 

Yep, you hit it right on the head Big daddy. Equals across the board, 4 stroke wins. It keeps its effeciency longer, meaning keeps torque over a longer period.

As for the 4sw race, the 4fity was lighter, easier to move less weight.

 

It is both amazing and amusing how much emphasis is placed on making the most horsepower and torque is ignored more often than not. If you figure out how to hold your torque curve longer, horsepower will take care of itself. Horsepower and torque have a mathmatical relationship. Horsepower is the result of torque multiplied by rpm. It doesn't matter whether you are building a hill shooter or flat tracker, torque curve is king. In either case if you can make more torque and hold it longer and setup is optimal for the type of racing you are doing, you will be faster than a lower torque, shorter torque curve bike.

You might have to run higher gears and or more paddles with more torque to achieve that magic hook-up equation and setup is totally different between groomed track and the big hills but one thing is for sure, if you set setup aside and just look at raw power, you would never say that since more torque is for hill shooting that it will slow you down on the flat track.

Bottom line, if your power peak is at say 8k.......the more torque you still have at that rpm, the better times you will turn in either type of race assuming your setup and hook-up are optimal for that type of race.

Later