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Post by scooter on Oct 12, 2014 5:58:20 GMT -5
What RPM do you prefer at wide open throttle while accelerating?
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Post by Paladin on Oct 12, 2014 7:04:03 GMT -5
Scoot has an CVT. It chooses the RPM, not me. I don't even know the RPM, don't got a tach, don't care, but know that I had a rev-limiter that kicked on at about 64 mph.
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Post by dmartin95 on Oct 12, 2014 10:38:50 GMT -5
The manual for my scooter list the engine specs as follows:
6.3kw/7500r/min
That means I produce 6.3kw (8.44 H.P.) at 7500 rpm's
So my target is 7500rpm's at WOT.
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Post by xyshannen on Oct 12, 2014 10:54:40 GMT -5
I'm installing an A11 cam that the graph below shows it's torque curve at 6000 to 8000 RPMS so with that in mind I plan on adjusting my CVT with the use of sliders and the contra spring to cruise at 45 MPH (my normal cruising speed) at 6000 and my WOT to run at about 8000. wildswede.se/Baotian/Cam_horsepower2.jpgI chose the A11 because IMO it has the best mix of low end torque combined with the best top end. It's actually better than the A9 that everyone seems to use. Where the A11 peaks at 8000 the A9 (not peaking quit as high) has to go to 8500. I don't think I would like having to push my engine to 8500 to get full use of my cams curve. |
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Post by JerryScript on Oct 14, 2014 0:21:50 GMT -5
I'm considering trying an A8. It gives the highest torque early on, which is when you really need it for acceleration. The difference at high RPM is only 4 on that chart, and the A8 is not overtaken in torque till you are getting close to high RPM (around 6500, 4/5ths of the available RPM range).
I plan on doing a top end replacement to take care of some valve float with a better head, think I'll try the A8 then, will post my observations, though it's better to do testing while only replacing one part at a time. Anyone here running an A8 care to chime in?
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Post by xyshannen on Oct 14, 2014 8:08:44 GMT -5
Jerry the a8 is my second choice and one I plan on trying on the next generation of engine mods I'll be doing over the next month or so...I want to try both the a8 and a11 to see which one I like best. I'm not too concerned with top speed so getting there faster is more what I'm trying to accomplish.
An important note that needs to be made is one of wear on the rocker assembly. Each cam has a specific wear on the rocker assembly so mixing cams with rockers that are worn to another cam isn't a good idea. It's best to have a rocker assembly for each cam you want too try.
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Post by wilds on Oct 14, 2014 11:19:28 GMT -5
That's my graph :-) I would also go with the A11 cam. A8 isn't bad at all, a good choice. The A14 wasn't that good as people might think. Very high lift! It compresses the valve springs to the max, almost too much... I measured the intake and exhaust lift of all three cams: And as you see the A14 is a bit flat on the top on both intake and exhaust, that is exactly how the lobes look like! (Green=Original cam)  |
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Post by xyshannen on Oct 14, 2014 11:47:21 GMT -5
wilds I forgot where I saw that graph but book marked it as I knew that to be very valuable info! Tossed you a bone for the info Wilds, Thanks man!
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Post by rcq92130 on Oct 14, 2014 13:13:20 GMT -5
Have an RPM question for you guys.
My scoot is running very well - great off-the-line accel, good enough top end ... but it's running way below the max power curve at all times in terms of RPM. Only on very rare occassions can I get up to 7K; normally I'm at 6200 or so at WOT (high 6Ks off the line). So I'd like to shift the place where it's operating to a higher RPM without messing up either the low speed or high speed performance.
Currently at 11gr sliders. If i drop that down I'll probably get higher RPM at take off, but probably NOT at high speed.
If I put stiffer springs in the clutch I'll probably get, again, higher RPMs at low speed but no effect on top end (other than maybe a slight BAD effect on max speed).
Is this a time to put in different gears?
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Post by xyshannen on Oct 14, 2014 13:58:28 GMT -5
Have an RPM question for you guys. My scoot is running very well - great off-the-line accel, good enough top end ... but it's running way below the max power curve at all times in terms of RPM. Only on very rare occassions can I get up to 7K; normally I'm at 6200 or so at WOT (high 6Ks off the line). So I'd like to shift the place where it's operating to a higher RPM without messing up either the low speed or high speed performance. Currently at 11gr sliders. If i drop that down I'll probably get higher RPM at take off, but probably NOT at high speed. If I put stiffer springs in the clutch I'll probably get, again, higher RPMs at low speed but no effect on top end (other than maybe a slight BAD effect on max speed). Is this a time to put in different gears? I'm probably bout to have this problem so I'm gonna wait to see how this pans out for you.   |
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Post by alleyoop on Oct 14, 2014 14:00:52 GMT -5
Here is my .02 on it RC,
If you are satisfied with the low end and top end and your getting it at low rpms that is a WIN WIN situation really. Your motor is not working hard at all and is just purring and will last a long time running those speeds at low rpms. High rpms is what wears out and damages motors. That is how I have mine setup, runs 50mph at 5100-5200, 60mph at 6100-6200, for every 10k rpms it gains 10mph. My rpms hardly ever reach 7K once in a while I will open up the throttle all the way and get to around 7200rpms but that is to fast for the trike even though it is on a 250 frame and weighs in at 350lbs I still think it is not save at thjose speeds, I usually cruise around 45-55.
Alleyoop
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Post by xyshannen on Oct 14, 2014 14:04:29 GMT -5
alleyoop What cam are you running? Stock?
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Post by alleyoop on Oct 14, 2014 14:23:30 GMT -5
Yes stock cam that was in the 157QMJ motor. Alleyoop Here are all the goodies on my Trike was your basic stock 157QMJ 149.6cc motor now a 182cc motor: 62mm BBK 60mm Stroker Crank Primary is 43 teeth 16/37 Hoca Tranny Gears – Original were 13/40 K&N Air Filter with a Short Stack SuperTrapp Muffler 1 1/4 Header Pipe 24mm Carb #122.5 Main Jet #38 Pilot Jet Peformance Coil/CDI NCY Performance Clutch&Bell Manual Choke Iridium Plug Koso Variator 12g Dr. Pulley Sliders 205/65-10 Kenda Load Tires-3"s taller than OEM 29 tooth Drive Sprocket-came with 24 tooth. DID 428 Pro V Series O-Ring Chain Givia 29" tall Windshield All Led bulbs Except the Headlights-I do not drive at night 4 way Flasher Turn Signal Beeper Relay for the Beeper connected to the Brakes VIP Trunk with Led lights Brake light Flasher on the Trunk Wing Radio with Remote, SD card,MP3 connections Came in at a sweet 200PSI:   |
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Post by xyshannen on Oct 14, 2014 17:13:24 GMT -5
alleyoop That's one heck of a list of mods! If I may tho, why a stock cam? I'm now kinda thinking that an a8 would be best for a motor that is only meant to turn 5-7K RPMS. That's to say if you wanted something "more" than stock, yet want a motor that's going to be good for more than 10K miles. Then again, I don't know what the spec readings are for a stock cam. You see my curiosity stems from the fact that my future motor build. Not this one but the one I'm building wile I drive this one. Wile it's going to be a 232cc oil cooled (possibly water cooled to) motor, I want this motor to last and the reason I want so many ccs is so I can have that extra oomph and still be able to keep the motor at low RPMs, hopefully making THAT motor good for a very long time. I am getting an A8 and a new set of rockers next month so I can swap out my a11 with the a8 for comparison. Thoughts? (sorry to hijack this thread, but hopefully this discussion would be of use to others.)
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Post by rcq92130 on Oct 14, 2014 17:31:28 GMT -5
OK, makes sense. But aren't I losing a lot of potential power? If I read the graphs correctly, the power drops off pretty significantly going from, say, 7500 down to the low 6k's (looks to be about a 13% drop off).
Have no need to get to a higher speed - this little scoot (200 lbs about) does not have a suspension safe at 65 - not even at 60 if there is anything other than smooth pavement. But I WOULD like to have a bit more reserve power to get to desired speed more quickly, or to hill climb w/o losing as much speed.
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..BAD TO THE BONE..