^^You and me both!

 

If both engines are stock, I can tell you right now that your 500 has more tq than my 700 diesel did stock. Now, it's a different story but I'm sure a 650 vtwin, 700efi, or thunderkitty would totally spank me in the torque department. But in all reality, traction is going to be your limiting factor when yanking anything.

If you were planning to go sled pulling, I can tell you whatever has the most hp will win. I got totally spanked by 700 and 1000 gassers with bolt-ons :lol:.

Having said all that, I really like my tuned up 700D because it fits what I need perfectly. I can work it hard without having to rev that crap out of if to get into the power band and It takes me 6 months to go through a tank of fuel using it around the shop. Customers always get a kick out of seeing an atv puff some smoke too haha.

 

Yes it does seem strange not to be able to find any torque info, maybe I missed it .
I dont see it in the service manual and cannot find anything on the net.

I would like a set of torque curves to compare the engines.....

With my main useage I rarely go above 1st gear low range, I am not sure if the diesel is that much better than my present gas 500 for this application, my machine is a manual and also I am not sure if the manual or automatic is better for this application.

Speed is not wanted, just pulling power with a smooth throttle response, at a snails pace.

 

I used to have a 02 AC 400M 4x4 and from what I can remember, 1st gear low was very low and engagement was nice and smooth. With my 700D, low range is still very low and between the torque and the gearing, it will pull a house down without a doubt. However, being that the trans doesn't have a wet clutch, engagement isn't always 100% in the same spot and it's not as smooth as my 400 was. I even added weights to the primary so it would engage sooner; stock you reallllyyy had to rev it and then it would "jump".

I don't know how much you use your Cat, but I know one of the things I love about my 700D is the fact that it runs forever on one tank of fuel. 5.5gal lasted me from June until October using it almost daily to move non running equipment into and out of the shop.

The best advice I can give is to find one somewhere and ride it to see if it fits your needs better/worse than your current 500. If you're ever near Ohio, give me a shout!

 

Hp is a calculated number based upon Torque and RPM of the engine. If you know the HP and the RPM you can also back calculate the torque using this formula.

Torque = (HP X 5252) / RPM

The HP is easily found on the C.A.R.B website. For some models the HP is given in KW. You can convert KW to HP by multiplying KW by 1.341022 All the HP or KW values on the CARB website is at the crank.

For instance the 08 Thundercat on the CARB website is listed as 49.1 KW to convert this; HP = 49.1 * 1.341022 or 65.84 HP.
To derive a Torque number we have a problem we do not know what RPM was used to calculate the HP from. HP is often calculated from the peak torque RPM and sometimes calculated from the engines red line RPM. What RPM does the CARB website use? I don't know for sure. I haven't found it discussed on the CARB website anywhere to know for sure. We can guess.

I've read on some sources that peak torque on a Cat engine is usually developed somewhere between 5400-5800 RPM. (5600 Average) Engines with a long stroke develop their torque sooner then a short stroke engine would like the Polaris or Can-am so their peak torque RPM is different. Short Stroke engines also Rev higher then a long stroke engine. This is the reason you'll see a Arctic cat often beat a Can-am or Polaris off the line and be caught up to and passed once the short stroked engine gets its RPM up. The cat engine is making more power sooner or at a lower RPM but not making as much power at a higher RPM or the RPM may be limited on the cat well below the competitor. For any engine, if you increase Torque and the RPM is constant you'll get more HP. Or if the Torque remains constant and you increase RPM you'll also get more HP. The best scenario would be to develop a huge amount of torque at a low RPM and keep this amount of torque high and constant as the RPM is increased. Too bad that is not practical or possible. Because in any engine, Torque starts at 0 increases to some peak value at some RPM the falls rapidly as RPM is further increased.

An example:

There is a couple of things I learned about the Tcat when I was experimenting with the Dynatek Ignition box. Ignition timing at idle is 10 degrees before Top dead center at idle and slopes up to a peak advance of 32 degrees BTDC by the time it hits 3500 RPM and starts dropping or retarding the timing rapidly beginning at 7000 RPM. Since the Tcat starts to retard the ignition timing at 7000 RPM. This serves as a soft a rev limiter. So we could use that as a the top RPM. Once the ignition timing starts retarding, power drops fast and at some point over 7000 RPM it will start to stumble and missfire bad.

So to possible torque values derived from HP and RPM for the 08 Thundercat could be.....

(65.84 X 5252) / 5600 = 61.75 Ft Lbs of torque
or
(65.84 X 5252) / 7000 = 49.40 Ft Lbs of torque

In the automotive community Torque is usually reported as a peak torque value, so if we use the same thinking on the ATVs then the 61.75 Ft lbs of torque is probably the most correct. This is a guess on my part though. Also probably a safe number to assume for other Cat models. Note: In the two above calculations the HP is the same 65.84 HP This shows how torque falls with increased RPM. Wouldn't it be fantastic if the Tcat engine had 60+ lbs of torque at 5600 RPM and kept this same amount of torque on up to 7000 RPM. A flat torque curve?

A diesel will develop more torque sooner at a lower RPM then a gasoline engine of the same displacement. So what RPM would you use to calculate torque from HP and RPM on a diesel? I don't know. Pick one. In a earlier reply in this thread it says the 700D has a rated torque of 30 Ft Lbs you can calculate the HP from this torque value if you have a RPM. The formula is (Torque * RPM) / 5252 If we use 3000 RPM (guessing) then the HP for the Diesel would be...

(30 * 3000) /5252 = 17.14 HP

On the CARB website for 2007 it shows the Diesel rated at 17.4 HP so guessing that they used 3000 RPM for a peak torque RPM is pretty damn close.

This is where the Diesel has an advantage, lots of torque at a lower RPM. I doubt the 700H1 has as much torque at 3000 RPM, maybe even lower torque at 3000 RPM??? Even though the 700H1 delivers a higher peak torque it is at a much higher RPM. Since this thread is asking if the Diesel is better for pulling then a gasoline model. I'm guessing the answer is probably yes but only at low RPMS or at low speeds. For shear pulling power at a low speed, low RPM the diesel should have an advantage.

Sources.
The CARB website. Look under the "Green Sticker: column for desired year, then pick make and model to get the power output.

On-Road New Vehicle & Engine Certification Program

Website that somewhat explains the relationship of Torque, Power and RPM and how to calculate each. Presented in somewhat an argumentative viewpoint of high torque verses High RPM. You can google for countless other discussions pertaining to HP Torque and RPM on the internet.

http://www.vettenet.org/torquehp.html

On Sprucetree's original question about torque on a 06 500. It is listed at 32 HP on CARB. If we assume 5600 RPM as a peak torque RPM, then an estimated torque value for him would be (32 X 5252) / 5600 = 30.01 Ft Lbs of torque. Plus or minus a little and probably pretty damn close to actual. In this case his engine has to be spinning 2600 RPM faster to deliver the same torque as the Diesel 700 at 3000 RPM. Even though the 500 ultimately develops more HP due to RPM, the 500 probably would not be able to do as much work or pull as hard as the 700D does at 3000 RPM.