Not that I can remotely grasp what Oldman is trying to say, where does diesel truck engines fit into that formula of high rpm = more power?

 

LMAO!!!

 

As you may have heard before, be careful what you ask for...

 

As per another post-

"Once your motor reaches 100% V.E. the torque per engine size is maxed out.
650=55lbs 730=61lbs 800=67lbs"

"Did I not say at 100% V.E.?

Show me a dyno chart that exceeds these numbers I have posted.
Motorcycle or atv, on gas, non air-boost and 4 cycle."



Both torque and HP will continue to climb as V.E. increases past 100%. 100% V.E. is very often exceeded on N.A. motors as well.

My 760 has most likely seen more dyno time than just about anyones, and in it's mild state of tune [stock sized valves] it consistantly made 69-71 lbs. I have the paper dyno sheets, but they don't scan well.

BTW- HP is a result of torque. HP = TQxRPM / 5250

At 5250 RPM, if the motor can be messured at that RPM, HP and TQ will always be equal.

 

760 X .061 = 46.36 x 1.5 = 69.54hp

Great job Don. I trust your data, I was just trying to instruct forum members that torque is directly proportional to compression, size of motor and V.E. To get higher than 1.5 is where things get really technical.

Too many people think that a bigger cam will make more torque. The duration of the cam has to be in balance with motor size, rpm range and head flow.

When I saw you reply my first thought was dam its cold outside today, should of got some smarts like Don and headed to the southwest. Happy Holiday

 

The real key to going fast no matter where you race is making as much torque and you can at peak horsepower. If my bike is making 80hp and 50ft-lbs at 9000rpm and your bike is making 85hp and 45ft-lbs at 9000rpm I will smoke you on any hill, circle track, drag strip, moto cross, etc. All else being equal of course.

What makes more tq on the DS? It depends where your at right now. If bone stock then a carb and end cap will scare you with how much tq they add. Then big bore would add the next big step in tq. These upgrades add tq all across the rpm range which is something to think about if you want best bang for the buck.

 

Oh going back to the age old rule (More Displacement) to get more torque, now here a silly question, is a stock slug @ 12 :1 compression, or a 11:1 compression with 105mm pistion (730kit), which one will provide more torque?

 

OMR, thanks that actually makes sence to me. My question is, does the formula stay consistant or are there variables that fall into that? This will help loads in desiding what directions I want to go.

Couple of questions though:

Can you explain what NA is?

Also VE?

Thanks

 

NA= naturally aspirated( non- boosted)
VE= volumetric efficiency

do some searches on the web for a deeper understanding of VE , there are a lot of good articles out there.

 

Ok, thank Majorecho I did find a lot. Now to see if I have the picture correct. The better your VE, the better your overall power out put. Ok, that makes since. But how to get a better percentage of your VE. If I understood whatI read correctly there are some variables in this. The main being your cams, carb, and intakes. More air and fuel in to the chamber the better. The cams controlling how long the intakes are open, and the intakes, and carbs having unobstructed flow to get the most out of what we have. How much effect do the cams really have, anyone can help there?

Then the higher compression pistons really do give a bigger bang for your buck, with a more volitile explosion right?

So with all of that, does anyone know what the VE is on a stock DS?

Am I catching the boat here, or did I miss my flight?