toydoc
Member
I went and did some reading on your EVO4. Very cool. Id use it as a tuning tool for my driver! Id tap into brake line pressure and brake pedal. Then steering head rotation.
Overlay track times, compare brake timing points (and pressure), wheel degree. Money well spent for $500
Overlay track times, compare brake timing points (and pressure), wheel degree. Money well spent for $500
Bob Vehring
New member
See that's the problem, once you use them, you can't be without it. The EVO 4 is going on my kids big block Chevelle this summer. More then anything, its a time saver, all info, each run. I have two kids that still race big track karts. We leave end of March for Laguna Seca in Calif. New track for us. we don't have days to learn the course, we have an hour of practice or so. With a 3000 mi ride to get there you need info first time out. Karts now have MyChron 4 with GPS, will get MyChron 5's on karts before we go. GPS gives a very exact drawing of the track, you can zoom in on corners and see track lines even when the vary by only an inch. Click the mouse at any point on the track map and all parameters read out at that point. Acceleromitor will read out G Force at that point, you will see how the tires are biting or wt transferring. You can overlay any laps over each other so you see where your changes happened good or bad. You can even ovelay over Google Earth maps to pick out land marks on a long track. When going to a new track, it has a feature that can graph percentage of time spent in any user defined RPM ranges. I always use this first session because for us, sometimes using more gear to pull off corners or up hills is more advantageous then gearing for power at the end of the straights.
They make sensors for throttle, brake and steering posisition, my kids now mid 30's have done this since 8 and are multi times National Champs, now I leave that to them, but on the older ones race sled we did use shock travel sensors, gave them to our shock guy and he set up our shocks on his dyno off the data. He loved the info.
With sled testing, any gauge with the accelerator will graph in either time or distance. you can set it up for say a 500-600 or 750 ft track and again overlay sessions to see your clutch changes. The appear just like the graphs in Aaens book
They make sensors for throttle, brake and steering posisition, my kids now mid 30's have done this since 8 and are multi times National Champs, now I leave that to them, but on the older ones race sled we did use shock travel sensors, gave them to our shock guy and he set up our shocks on his dyno off the data. He loved the info.
With sled testing, any gauge with the accelerator will graph in either time or distance. you can set it up for say a 500-600 or 750 ft track and again overlay sessions to see your clutch changes. The appear just like the graphs in Aaens book
toydoc
Member
Congrats on the championships Bob. All great learning tools for the kids, plus the memory's that will never go away.
Bob Vehring
New member
I'm 66 and spend every weekend with my kids, summer and winter racing, can't ask for more then that.
One more question. I see everyone recommends using OEM belt, which I assume are getting hard to find. When we first got this afew months ago we got a new Ultramax not knowing any better. Whats up with the belts?
One more question. I see everyone recommends using OEM belt, which I assume are getting hard to find. When we first got this afew months ago we got a new Ultramax not knowing any better. Whats up with the belts?
toydoc
Member
I dont run OEM on all of mine.
The best TRACK HP I made was with a Ultramax. 95hp at the track, 750 with same mods you have and Cat driven. The motor dyno at 167hp.
The factory belts have consistency in size, face angle (cut) and durometer. So when you swap factory to factory, everythings good, takes a wild card out.
Thats why most like them. You dont create a problem.
But when you max out on hp with your trusted setup, you have to start looking someplace for the extra hp.
When you swap clutching, cut face angle, swap belt brand.. your changing shift patterns. With track testing you may end up with a curve ball thats hard to dial in, how much time do you have...
On the track dyno I can see what each does and build on it or toss it. If I make 30 dyno pulls in one night, same info would take me most of the season at the track.
The best TRACK HP I made was with a Ultramax. 95hp at the track, 750 with same mods you have and Cat driven. The motor dyno at 167hp.
The factory belts have consistency in size, face angle (cut) and durometer. So when you swap factory to factory, everythings good, takes a wild card out.
Thats why most like them. You dont create a problem.
But when you max out on hp with your trusted setup, you have to start looking someplace for the extra hp.
When you swap clutching, cut face angle, swap belt brand.. your changing shift patterns. With track testing you may end up with a curve ball thats hard to dial in, how much time do you have...
On the track dyno I can see what each does and build on it or toss it. If I make 30 dyno pulls in one night, same info would take me most of the season at the track.
Bob Vehring
New member
We have both a hyd and an inertia dyno here at the shop, but both are for small 4 strokes, I really miss having something for sleds. I do have access to a friends but seldom get time when we can get together on it.
I do have several durometers here from kart tires, do you know off hand the durometer range of the belts?. This sled has a brand new Pol primary on it. On the E dyno for 120 engines the engine, through centifical clutch drives a 350# wheel Scary to watch what the chain goes through turning it
I do have several durometers here from kart tires, do you know off hand the durometer range of the belts?. This sled has a brand new Pol primary on it. On the E dyno for 120 engines the engine, through centifical clutch drives a 350# wheel Scary to watch what the chain goes through turning it
toydoc
Member
I dont have any durometer spec.
Id make sure you dont have a 92 CDI on your sled with your pipes.
Id make sure you dont have a 92 CDI on your sled with your pipes.
Bob Vehring
New member
Not sure whats on it, do know its not a Reichards according to Jeff, Simon. Perry muyengine building friend ordered us a programmable digital ign, same as used on 440 champ sleds for ovals, normally its a total loss ign. Have the same thing on our 600 cc, Pro sprint engine from a few years back when my oldest ran USSA. I'm told with some changes to the stator it will run off the engine in VM Thats a summer project.
Last Sat sled ran 86.7 in 600 ft, water on the track Sled worked well, hooked ok, well better then my other 3 sleds. Did alittle clutching. Unfortunatly data didn't work. Not because of the system, but my laptop would not work at the race so I got nada
Last Sat sled ran 86.7 in 600 ft, water on the track Sled worked well, hooked ok, well better then my other 3 sleds. Did alittle clutching. Unfortunatly data didn't work. Not because of the system, but my laptop would not work at the race so I got nada
toydoc
Member
All I would do is check the CDI part #, if it is a 92 buy a good used 93 CDI. Direct plug in, cheap few hp.
If you feel like splicing wires, buy a 800 CDI and have maybe 2 hp gain plus no rev limiter.
It takes alot of mods (and rpm) to see much advantage to a total loss.
You can swap the yamaha driven for a bear Cat roller and see double the hp gain at the track vs the total loss. They just didnt make tunning parts for that driven so it will be an issue at some point
If you feel like splicing wires, buy a 800 CDI and have maybe 2 hp gain plus no rev limiter.
It takes alot of mods (and rpm) to see much advantage to a total loss.
You can swap the yamaha driven for a bear Cat roller and see double the hp gain at the track vs the total loss. They just didnt make tunning parts for that driven so it will be an issue at some point
Bob Vehring
New member
Biggest decision we face is, all 4 of these sleds were suppose to be trail sleds. Reality is if you live iin South East Wi. for the 3rd year in a row, trails here were usable for maybe 4 or 5 days again. 50's this weekend, 60 on mondays, so it looks like we put our miles on in short quick blasts LOL
Here are those sleds.
[/URL][/IMG]
Now heres the other choices, the lay down sled was raced back in the 90's by my wife, right now has a built 617 Rotax that has never been built. not big enough to be serious today, but still could be fun, it has a bottle on it also. The other option is I have the 600cc engine out of the Regans oval sled. Pro Sprint 600 rules called for fan engine, 600 cc, single pipe and stock 34 mm carbs to keep the speed down. That dynoed at 115, bigger carbs and pipes would bring that up. I have a stripped down SRV chassis, the plan was/is to put it in there. get the chassis down to 375-400 and still look outsides like a SRV.
My problem is I just can't make a decision, and can't keep my hands off whatever is sitting around here
Here are those sleds.
Now heres the other choices, the lay down sled was raced back in the 90's by my wife, right now has a built 617 Rotax that has never been built. not big enough to be serious today, but still could be fun, it has a bottle on it also. The other option is I have the 600cc engine out of the Regans oval sled. Pro Sprint 600 rules called for fan engine, 600 cc, single pipe and stock 34 mm carbs to keep the speed down. That dynoed at 115, bigger carbs and pipes would bring that up. I have a stripped down SRV chassis, the plan was/is to put it in there. get the chassis down to 375-400 and still look outsides like a SRV.
My problem is I just can't make a decision, and can't keep my hands off whatever is sitting around here
Last edited:
Bob Vehring
New member
Biggest decision we face is, all 4 of these sleds were suppose to be trail sleds. Reality is if you live iin South East Wi. for the 3rd year in a row, trails here were usable for maybe 4 or 5 days again. 50's this weekend, 60 on mondays, so it looks like we put our miles on in short quick blasts LOL
Here are those sleds
[/URL][/IMG]
Now heres the other choices, the lay down sled was raced back in the 90's by my wife, right now has a built 617 Rotax that has never been ran with that engine. not big enough to be serious today, but still could be fun, it has a bottle on it also. The other option is I have the 600cc engine out of the Regans oval sled. Pro Sprint 600 rules called for fan engine, 600 cc, single pipe and stock 34 mm carbs to keep the speed down. That dynoed at 115, bigger carbs and pipes would bring that up. I have a stripped down SRV chassis, the plan was/is to put it in there. get the chassis down to 375-400 and still look outsides like a SRV.
My problem is I just can't make a decision, and can't keep my hands off whatever is sitting around here
Here are those sleds
Now heres the other choices, the lay down sled was raced back in the 90's by my wife, right now has a built 617 Rotax that has never been ran with that engine. not big enough to be serious today, but still could be fun, it has a bottle on it also. The other option is I have the 600cc engine out of the Regans oval sled. Pro Sprint 600 rules called for fan engine, 600 cc, single pipe and stock 34 mm carbs to keep the speed down. That dynoed at 115, bigger carbs and pipes would bring that up. I have a stripped down SRV chassis, the plan was/is to put it in there. get the chassis down to 375-400 and still look outsides like a SRV.
My problem is I just can't make a decision, and can't keep my hands off whatever is sitting around here
Last edited: