Lock Out/Lock-Up Tuning

[SlowerThanYou]

OK Guys & Gals,

 

I saw a lot of questions in the shout this morning. There's a few things I want to clear up. If you don't understand something, ask & I'll try to explain it better.

 

There was a couple things I took notice on & gave a quick explanation. Lock-up arms digging into the pressure plate & rotational weight. I said I had fixes for both, but a couple people questioned. Why bring it up & not talk about it. Well, LOL! I will give a couple reasons.

 

I addressed the rotaional weight a little, already in this thread. If someone feels it's important, then

bring it forward. We can go over it a little more.

 

The lock-up arms digging into the pressure plate. They have solved that problem in other motorsports. We are still designing, testing and machining different parts to make the modifications. I'm working with a prototype right now. This all takes time, money, machining & hate to say it again TESTING.

 

While these item are important. There are more important basic things you need to learn first, IMO!

 

I mentioned it in the shout box this morning & I've said in this thread. Hint, I didn't specifically say it was #1, but it was implied as #1.

 

What's the #1 thing that should be done with your clutch & lock-up/lock-out for tuning????????

[SlowerThanYou]

Sprinklerman, If that's the one your looking at, looks good.

 

Powerhouse POW351049 Mini Spring Testers 0-60 lb x 1 lb

[honda863]

Would the powerhouse 0-60 be enough?? I thought and could be wrong that some springs are near 100#??

[SlowerThanYou]

Would the powerhouse 0-60 be enough?? I thought and could be wrong that some springs are near 100#??

 

Everything in this thread is anyones choice to use or not use. Just putting that out there, I'm not upset that you asked questions.

 

The springs are measured at there least amount of pressure for the hieght as installed. As the spring compresses, when you pull in the clutch lever. The spring pressure increases, but we don't worry about that pressure. The 100 lb gauge would probably not be enough.

 

I'll put it this way. You are measuring each spring base lb. at the installed hieght. Then times that X 6 if that's the amount of springs being used. Example: 1 spring measures 60 lbs. at 1" installed hieght. 6 X 60= 360 lbs. I will not get into specific numbers of base pressure in this thread.

 

Speaking from real word experience. 360 lbs of base pressure is more than enough for a 18mm DMX set-up for 300' sand. I'm sure a bigger twin & tripple could use more than that gauge could provide.

 

I hope that answers your questions.

[SlowerThanYou]

Here's some clutch wisdom/experience from a good source. This type of information from other motorsports is what I try & apply to the ATV clutch system(s). There's some very good tid bits that can be picked-up from this information.

 

There's one thing I somewhat disagree with in the information below, but I would like to hear some other's thoughts first.

 

I know, the launch limiter subject was supposed to be next & it's still coming. It's hit on a little bit in this information.

 

 

 

"The most sophisticated drag racing clutch systems allow controlled slippage to get maximum horsepower to the ground with minimum tire spin.  These clutch systems are fully adjustable for spring and centrifugal pressure, as well as wear so that the system can be tuned for the car to meet the track conditions.

 

Adjusting the clutch system requires the use of a data recording computer.  Engine, transmission, and driveshaft RPM graph overlays indicate the amount of clutch slippage and tire spin on both the launch and subsequent gear changes that allow us to make proper tuning decisions.  Without a data recorder, any tuning decision is merely a guess.

 

The most important consideration is how the car will react to the clutch settings when the car is launched.  On the launch, you want to achieve optimum wheel speed without excessive tire spin or clutch slippage.  To accomplish this, the launch RPM needs to be significantly lower than the shift RPM to provide some initial slip while allowing the clutch to gradually applying additional clamp pressure as engine accelerates to the shift point.

 

 

TECH TIP - LAUNCH RPM

Since centrifugal assist is RPM sensitive, increasing or decreasing the launch RPM will increase or decrease the clutch pressure at launch without any actual adjustments being made.  Additionally, increasing the launch RPM increases the inertia applied to the rear tires from the stored energy of the clutch system.

 

Once the vehicle leaves the line successfully, the performance of the clutch can be evaluated on subsequent gear changes.  If the vehicle tends to have no slip on the gear change, spins, or if the tires shake,  reducing the counterweight will provide additional clutch slippage reducing the spin or shake.  Without the data recorder, it is extremely difficult to determine exactly what is happening at these points in the run. Examining each successive gear change, we should see the slip time reduced until there is very little clutch slippage in high gear."  

[ONLY2STROKES]

pretty much base pressure will not be effected by the launch rpm. the lockup arms will not effect the plates much until thew tires are tunring a bit.  therefore if you launch at any rpm you will still only get so much force to the tires. changing the rpm could result in some different launches, being it will change how hard to the engine will push through the clutch when you drop it.

 

this does not apply to our app as much as it would in a different machine.

 

if you care to elaborate, have at it. im not always so good/thourough at online forum explanations.

[SlowerThanYou]

TECH TIP - LAUNCH RPM

Since centrifugal assist is RPM sensitive, increasing or decreasing the launch RPM will increase or decrease the clutch pressure at launch without any actual adjustments being made.  Additionally, increasing the launch RPM increases the inertia applied to the rear tires from the stored energy of the clutch system.

 

 

 

pretty much base pressure will not be effected by the launch rpm. the lockup arms will not effect the plates much until thew tires are tunring a bit.  therefore if you launch at any rpm you will still only get so much force to the tires. changing the rpm could result in some different launches, being it will change how hard to the engine will push through the clutch when you drop it.

 

this does not apply to our app as much as it would in a different machine.

 

if you care to elaborate, have at it. im not always so good/thourough at online forum explanations.

 

I was sensing this was something you wanted to discuss a little bit. I agree, base pressure will not by affected by launch rpm. Changing launch rpm, does have an affect on how the base pressure reacts, slips or doesn't slip. That's why we use launch limiters in our racing.

 

As for the arm/dynamic weight it's slightly affected with launch rpm, but it primarily comes in with wheelspin/wheel speed. Here's an example of arm weight being affected by launch rpm (not good). When a launch rpm is to high for the clutch set-up. The tires will instantly spin, causing an arm spike to cause near instant lock-up of the arm/dynamic weight.

 

Now, we haven't even addressed a couple laws of physics brought into the 1st qoute. I only know some of the basic(s) laws. Going to cover this in a later posts, hopefully!

[SlowerThanYou]

after watching and seeing some of the top automotive based drag cars  i feel that without data logging you are just shitting in the wind.   of course  the differences in your 60's and et's will show in changes to the clutch.  but after having the graphed results explained to me in automotive i can deff see where data log is very necessary if your going to get that serious in the atv track/ drag scene..

 

i'm going to use one on my track bike this year.. 

 

This is just my opinion based from my drag racing experience. I'm sure the above automotive top drag cars got their basic clutch experience without data logging.

 

Clutch tuning for ATV drad racing is still in its infant stages. My self included, with 8 years experience. IMO, LOL! Clutch tuning & data logging like the top drag cars/teams. Will, deffinitely be shitting into the wind for the majority of ATV Racer's!

 

Data logging has it's place & I'm trying to save you a little money, time & aggravation. There's a lot more information/data & incrimental times that the top teams use. There's a vast difference between 1/8 & 1/4 mile motorsports vs. 300' ATVs.

 

Learn basic drag clutch tuning &  basic data logging. That's a great place to start, good luck. 

 

 

i agree on this info being a big help to know whats going on. it would be easier and probably save some clutch plates lives! maybe these systems will be the next $1500 mod to get that extra .100. only time will tell. sorry to stray off topic.

 

You don't have to spend $1500 to data log. A simple adjustable shift light when used right can give a lot of information. We use other simple things to data log our information also. 

[ONLY2STROKES]

I was only giving one simple (example) way to help get data. Not that it matters, but I do data log. It takes a little more time & the results work pretty well. 

how do you use the shift light to help tune tune your clutch?

[camatv]

the logger i am going to use runs about 500-600 bucks.. used if you can find the right one is a lil cheaper.  the setup/ build is very important

 

will graph clutch to rpm  seems the best way to see what the clutch is actually doing.....

 

then as changes are made  the results can be easily seen instead of guessed based of time.

 

of cource this is just me..  and i'm a complete newb to clutch tuning.  in the past i used my weight and tire size, pressure to control wheel spin.. in my humble opinion i feel the transmissions should be ditched all together and just a slipper used....

[Wheelman Chassis]

how do you use the shift light to help tune tune your clutch?

You can use a shift light by the length of time its on during launch until the clutch pulls the motor down. Another way is by using it to detect rpm flare when you leave from your desired launch rpm.You can also use these in combination.

 

A good example would be a power adder car with a loose torque converter. Sometimes when they leave the line the shift light comes on instantly or very quickly when the let go of the trans brake(clutch), then shuts off as the converter pulls the motor from its set rpm.Then after the motor pulls back to the set rpm the light comes back on and the driver/rider shifts.

This is just an example from what i have exp. in the asphalt bike and car racing i have done.

 

 

Chris

[ONLY2STROKES]

the logger i am going to use runs about 500-600 bucks.. used if you can find the right one is a lil cheaper.  the setup/ build is very important

 

will graph clutch to rpm  seems the best way to see what the clutch is actually doing.....

 

then as changes are made  the results can be easily seen instead of guessed based of time.

 

of cource this is just me..  and i'm a complete newb to clutch tuning.  in the past i used my weight and tire size, pressure to control wheel spin.. in my humble opinion i feel the transmissions should be ditched all together and just a slipper used....

yeah that would a trick setup!

 

You can use a shift light by the length of time its on during launch until the clutch pulls the motor down. Another way is by using it to detect rpm flare when you leave from your desired launch rpm.You can also use these in combination.

 

A good example would be a power adder car with a loose torque converter. Sometimes when they leave the line the shift light comes on instantly or very quickly when the let go of the trans brake(clutch), then shuts off as the converter pulls the motor from its set rpm.Then after the motor pulls back to the set rpm the light comes back on and the driver/rider shifts.

This is just an example from what i have exp. in the asphalt bike and car racing i have done.

 

 

Chris

makes perfect sence, thanks alot!

[SlowerThanYou]

Thanks Wheelman,

 

You beat me to the punch. I had it planned that way to drag you back into the thread. LOL!

 

It's really nice having a drag racing background with other motorsports vehicles. It really helps with ATV drag racing. I'm always saying, research & learn from other motorsports. Most of the information applies to the drag quad.

 

Just to tag along with what Chris has already said. It's useful to use different color lights to supplement the shift light for data. Our ignition allows us to trigger 3 or 4 different devices. Plus, we have a shift kill/counter, that can be used for some options also.

[SlowerThanYou]

Hopefully these 2 videos work. I got the idea from another thread in the video section. I was not able to get the link to work there.

 

These are some old 1/4 mile videos with our stock cylinders. We were still learning the clutch set-up. You should be able to pick-up on the difference in clutch settings between the 2 vids. Ask questions or make comments.

 

 

http://s143.photobucket.com/albums/r143/BLK1700/Clutch%20Tuning%20Video/?action=view&current=93006012.mp4

[m671054]

I have a? regaurding lock up arm clearance to the plate. What effect does this have on the clutch tune? Do you just shoot for a certain arm angle when applied for max pressure applied. I think the way to adjust it would only be by changing stack height but i might be wrong. I fully understand changing height will change base pressure.this is refering to a standard direct drive style.