Topic: What knd of torque figures are 836 and up making..?

[754]

Trying to explain to some dohc guys that our motors tend to be torquey..

[scottly]

Mine hits a torque peak of 49 ft/lbs at about 6900 RPM.

[PeWe]

Almost 70Nm, 51.6ft/lbs .  I got a little bit more with another cam, 71,5Nm/83Hp

[Ilja]

111nm @ 6000rpm @ 10psi with one bad piston and the old head small valve head   

These engines have quite a long stroke for the bore size.. and a high dynamic compression because of the short duration cam & 8 valve head.

[PeWe]

REALLY NICE POWER!!

[NitroHunter]

WOW...

[RPE Racing]

They make torque alright...lol (1200cc though)

That is over 110 footpounds at the wheel on the right scale...

[Bill/BentON Racing]

Damn, that must pull like a freight train!  Wow. I'm  impressed,  Bill

[754]

So we got two so far with 110 ft lbs..!

[Bill/BentON Racing]

No, the other was 110 n = 81.80 ft lbs

[RPE Racing]

Damn, that must pull like a freight train!  Wow. I'm  impressed,  Bill

Thanks. We have an engine just like this but with a 70mm stroker crank (1340c)....Its deadly!

That one was over 140 whp but the rpm scaling is not right so torque is not true.

[Ilja]

They make torque alright...lol (1200cc though)

That is over 110 footpounds at the wheel on the right scale...

Whatt! That is ridiculous, even for 1200cc lol!
And look where it makes the torque! I thought my cb turbo had a lot of torque down low but this really is something.

Actually I'm surprised, did not think this would be possible with a N/A CB engine.

Is this measured with a Dyna type dynamometer?
Some dyno's don't show the right torque as they tend to show a different one in every gear.
The Dyna ones recalculate the torque and show the same in every gear..which makes a big difference.

Just for comparison a BMW SR1000R makes less torque... 105nm.... but it makes 14000rpm and HP = Torque * rpm... so in the end 180hp.

[RPE Racing]

Dyno dynamics, 4th gear. This dyno gets different reading (Hp) depending on gear. Tq is calculated based on hp, so it also changes. That is why you need a set gear, generally 4th.

From experience, the higher the gear, the higher the reading, but only by a small percentage.

[Captain]

 Excuse me................. You have this the wrong way around.
 Torque is measured and is always the base figure and HP is a subsequent calculation,  big difference.
 
 Captain

[RPE Racing]

Captain,

Round #2 I see 

I agree with you but (this baffles me as well) this is what happens when you operate our dyno - Dyno Dynamics.

Commonly you use roller speed to tell the dyno what rpm the engine is spinning in a given gear. This is done by a simple value in a box you have to define at the start.

Example: Same bike, same dyno, same gear, same everything
1st - You set the RPM - roller speed relationship for example 5000rpm = 100km/h
2nd - You change your RPM - roller speed to 4500=100km/h

Result - The HP will be exactly the same but the torque changes (as does the rpm of course). #2 will show more torque.

I cannot explain it because mathematically I agree with you. But this is experience. I can post dynos if you want

Bottom line, I can mess up the torque reading, but not the hp reading - go figure.

Hope this wans't too confusing.

[Ilja]

Captain,

Round #2 I see 

I agree with you but (this baffles me as well) this is what happens when you operate our dyno - Dyno Dynamics.

Commonly you use roller speed to tell the dyno what rpm the engine is spinning in a given gear. This is done by a simple value in a box you have to define at the start.

Example: Same bike, same dyno, same gear, same everything
1st - You set the RPM - roller speed relationship for example 5000rpm = 100km/h
2nd - You change your RPM - roller speed to 4500=100km/h

Result - The HP will be exactly the same but the torque changes (as does the rpm of course). #2 will show more torque.

I cannot explain it because mathematically I agree with you. But this is experience. I can post dynos if you want

Bottom line, I can mess up the torque reading, but not the hp reading - go figure.

Hope this wans't too confusing.

Yes haha, clear but it seems your dyno works slightly different.

Somehow the dyna dynamometers give the same torque and hp in every gear...I did runs in 3th 4th and 5th with my cb last time, exactly the same reading without changing anything. I looked into it why once because I wanted to build a dyno, but unfortunately forgot again..

The reason I brought it up is because I recently had a big discussion with a guy doing a dyno run on a non-Dyna dyno with a ktm 990 sm.
He claimed 180nm of torque from his stock engine + akra noise canon... and he showed a run with different torque curves in every gear. His HP was correct (or almost  ) at 115hp but torque was WAY off... right torque for him was something like 90Nm... which is still quite a lot for a normally aspirated bike.

So one dyno differs from the other in reading, but they all work to setup and tune your bike correctly which is what they are for.


Btw... do you have more info or a build topic or something on the 1200cc bike? And didn't this bike run on methanol?
Very curious to see how you guys managed to build the cylinder lining and what you did with the cylinder head. That thing is awesome!

[RPE Racing]

Quoting member syscrush from the CBX forums who put it perfectly:

Sorry to derail the thread:

"I don't want to derail this thread, but I do want to push back against this idea a bit because it's a bit of "common knowledge" that's just not correct. You can calculate torque from power and rotational speed or you can calculate power from torque and rotational speed. You could even calculate rotational speed from power and torque but I don't think that there are real applications to that.

Here's an example: if you measure the coefficient of drag of a motorcycle then run it wide-open on the salt flats until it reaches its terminal velocity, you can come up with a pretty good calculation of its power. If you note the engine speed at that terminal velocity, you have the rotational speed and can calculate the torque of the engine at that speed.

On a drum-type dyno, you're measuring the acceleration of a mass with a known moment of inertia - the calculation of torque from that acceleration is exactly equivalent to the calculation of power from the increased kinetic energy - there's no difference. One is not more intrinsic or primal to how engines work, or what power and torque are.

On an old brake-type dyno where there was an arm of a known length actuated through a clutch and pushing on a load cell (or spring/dial), you could certainly claim that you were measuring torque and calculating hp, but on a modern dyno, you'd be more correct to say that you're measuring voltages from a number of sources and taking a bunch of known quantities to calculate time, speed, torque, and hp all together.

Note that you can run a bike or a car on a dyno without hooking up the tach signal and get an engine hp vs wheel mph graph, but you can't get an engine torque vs wheel mph graph - this should demonstrate that hp does not have to be calculated from torque."

Hope this clears it up. 

Oh the 1200...It's fully sick mate!

lol yes its on methanol

[Captain]

 I think that it the above dialogue is potentially misleading and confusing for most and to some maybe actually oblivious to the reality of what all this is about. 
So perhaps it maybe helpful if I clarified the issue and with the help of some previously publish documents perhaps then it will become clearer to all.

 
- Horsepower and Torque - What are they ?

ESSENTIAL CONCEPTS:
 Torque is measured; Horsepower is calculated.

In order to discuss power plants in any depth, it is essential to understand the concepts of Horse Power and Torque.

However, in order to understand Horsepower, you must first understand ENERGY and WORK.

It often seems that people are confused about the relationship between Horsepower and Torque. For example, we have heard engine builders, camshaft consultants, and other technical experts ask customers:

"Do you want your engine to make Horsepower or Torque?"

And the question is usually asked in a tone which strongly suggests that these experts believe Horsepower and Torque are somehow mutually exclusive.

In fact, the opposite is true, and you should be clear on these facts:
1.HORSEPOWER (the rate of doing WORK) is dependent on TORQUE and RPM.
2.TORQUE and RPM are the MEASURED quantities of engine output.
3.HORSEPOWER is CALCULATED from torque and RPM, by the following equation:

HP = Torque x RPM ÷ 5252


An engine produces  HORSEPOWER by providing a ROTATING SHAFT which can exert a given amount of TORQUE on a load at a given RPM. The amount of TORQUE the engine can exert usually varies with RPM.

TORQUE

TORQUE is defined as a  FORCE around a given point, applied at a RADIUS from that point. Note that the unit of TORQUE is one pound-foot  (often misstated), while the unit of WORK is one foot-pound.

HORSEPOWER

HORSEPOWER is the measure of how much WORK can be done in a specified TIME.

 Captain

[Ilja]

They make torque alright...lol (1200cc though)

That is over 110 footpounds at the wheel on the right scale...

So it runs on methanol.. at what kind of compression ratio if I may ask? If I may guess something like 13.5:1 ? 
The torque curve looks like a stock cam with the huge bottom end/midrange.
Not many 4 inline bikes have a stock cam that is as mild as the CB, but this clearly also has its benefits for low end torque. 

I don't think there's ANY other new stock 1200cc 4cylinder bike on the market that make this power and torque so low in the rpm range..

And I also think if you would have a CB engine make these kinds of torque figures below 6000rpm on normal pump fuel, it would ping/detonate it's tits off.. :-)

[RPE Racing]

So it runs on methanol.. at what kind of compression ratio if I may ask? If I may guess something like 13.5:1 ? 
The torque curve looks like a stock cam with the huge bottom end/midrange.
Not many 4 inline bikes have a stock cam that is as mild as the CB, but this clearly also has its benefits for low end torque. 

I don't think there's ANY other new stock 1200cc 4cylinder bike on the market that make this power and torque so low in the rpm range..

And I also think if you would have a CB engine make these kinds of torque figures below 6000rpm on normal pump fuel, it would ping/detonate it's tits off.. :-)
[/quote]

CR is around that yes.

We wanted to forsake some bottom end torque...you can imagine how hard it is to put 110ftlb to the ground through an original CB frame... Corey Forde (our rider) does an amazing job given the circunstances but we are asking to much of the frame here...

We have tried to move the powerband forward with little success. Other cams just lower the curve everywhere...

Agreed - methanol is a wonderful drug. Octane, charge cooling, engine cooling...pity it takes so much of it.

[Ilja]

So it runs on methanol.. at what kind of compression ratio if I may ask? If I may guess something like 13.5:1 ? 
The torque curve looks like a stock cam with the huge bottom end/midrange.
Not many 4 inline bikes have a stock cam that is as mild as the CB, but this clearly also has its benefits for low end torque. 

I don't think there's ANY other new stock 1200cc 4cylinder bike on the market that make this power and torque so low in the rpm range..

And I also think if you would have a CB engine make these kinds of torque figures below 6000rpm on normal pump fuel, it would ping/detonate it's tits off.. :-)

CR is around that yes.

We wanted to forsake some bottom end torque...you can imagine how hard it is to put 110ftlb to the ground through an original CB frame... Corey Forde (our rider) does an amazing job given the circunstances but we are asking to much of the frame here...

We have tried to move the powerband forward with little success. Other cams just lower the curve everywhere...

Agreed - methanol is a wonderful drug. Octane, charge cooling, engine cooling...pity it takes so much of it.

If you want to tune out some bottom end and not loose topend, you can cut back ignition timing in low rpm if you have a programmable ignition map. If you use a TPS referenced ignition table you can link it to throttle controll.

Check out my other topic about the Ignitech units.. fully progammable maps with rpm as function of TPS (or pressure sensor) and a million other options like rev limit and launch and stuff. They are not expensive, I just bought one myself...

Strange that wilder cams don't move the torque curve and loose power.. this in theory means your intake (or exhaust) flow somehow is limited at higher rpm. Too small carbs, valves, ports or exhaust.
For reference my kz1100 is a bit like the cb1200 bore&stroke, also has an 8 valve head, 37mm intake valve, 33 exhaust but the stock camshaft has 280 degrees of duration and 65 degrees of overlap. (Stock CB is something like 220 duration and 10 overlap.)
A bigger engine should be able to take a much wilder cam with much longer duration and overlap and benefit from it, unless the ports or carbs are limiting the flow.
 

[bear]

The Historic Road Racing rules here in Australia preclude the use of programable ignitions.
And yes it's the Hondas head that is the choke point for us, so I would guess it's the same for RPE.

Taking that into account, from memory the "sweet spot" for us is a little over 1100cc @ 69mm stroke & 72 / 73mm bore.



Cheers,
Brian

[scottly]

In order to measure torque, the Dynojet uses the RPM signal from the ignition, and the RPM signal from the drum; this is why it comes out the same in any gear (other than possibly increased tire slippage on the drum in lower gears, or increased clutch slippage in higher gears). The dyno RPE uses evidently has no drum sensor, so the estimated drum RPM must be manually entered? A dyno graph is more easily read when both the right and left scales are the same, especially when using ft/lbs for torque; the HP/TQ curves will always cross at 5252 RPM. Also, I don't see what, if any, correction factor is being used; without the ability to apply a standard correction value, any numbers recorded can't be compared to results obtained using standardized measurements.

[PeWe]

I do not have any knowledge about dyno except its good for measure the relative power and air fuel ratio at the same time. Then change carbs to get best result.

Here is a video I took when one of the Dyno graphs in my earlier post above was done. Action Fours SS-1 cam
Nothing connected to bike except AF sensor sticked into the pipe. I decided to go for Carillo rods when standing beside with my phone and waiting for a rod smash thru the case. APE crank with Carillo rods made the engine to run much smoother!!

[scottly]

PeWe, your graph has RPM on the horizontal axis, so your dyno operator had to have connected an RPM pickup. One my 836, dual secondary inductive pickups, like on a timing strobe, one on the #1 plug wire and the other on the #4 wire worked best; with my Gerex multi-spark ignition, I got inconsistent RPM readings when using a primary pickup.
Your graph is a proper measurement of power and torque, set for the DIN standard. The constant for DIN is 7124, and that's the RPM when your torque in n/m and PS cross, rather than 5252 for ft/lbs and HP. Also, 1 PS=736 watts, while 1 HP=746 watts, so your test would show about 1 less HP with the SAE standard.