MoTeC Global Forum

ok the dual rpm limit, question,
what does it mean buy polarity, does putting 12v into the switch (dig19 pin out) activate the lower rpm limit, if so why does it say high volts will open the switch and low volts will close it, can i earth the wire or does it have to have a 12v source to switch it. And if i apply 12v will it actually make the rpm lower limit come into play

Second question, rpm rise rate, really unsure what that really means, as doesn't it instantly go back to the normal rpm limit once i remove my finger from the switch, or if not then do i select the highest revs possible to allow it to go back to normal operating rev range

Random question, in the normal high rev range cut parameters it mentions RPM randomizer, what is it and what is it doing while its being random

I believe it means the switch when pushed grounds 12 volts to the ecu while releasing or pressing a latching type switch shuts off the circuit.
Its saying high volts ( switching to ground and completing the 12 volt cicuit ) 'activates' the lower rpm limit while pressing the button again breaks the circuit and closes the switch thus allowing 0 volts "deactivating" the lower limit.
Obviously you need to have a rpm limit already set to have a lower one activate.



Rate of change is the speed at which the rpm changes when accelerating the engine, you can find this out by logging the rpm in I2 and measuring across the bottom axis in time mode (not distance) how fast it accelarates.
Jamie from Motec can explain this further as I have forgotten exactly how its done

thanks heaps for your reply, only thing is i don't have software like yours, i only have old school dos in the m2r , and I'm only using the interpreter not the i2 .
IM attempting to try to make some sort of two step drag launch control, the selection i need to do for switching it is two choices, high volts or low volts i need to chose one, but i don't know if they mean i need to put 12v in for selection 1 which also says its gong to be open
Or if i select option 0 its low volts and its going to be closed
Or the wire coming out of pin number 19 can i just earth it , if so what is the logic polarity i choose 0 or 1 , i really need to be told in simple terms do i shove a 12v momentary switch into pin 19 or is it a earth momentary switch for pin 19

rpm rise rate i still don't see what it will have to do with it once i release a switch that has been activating the lower limit . As in microtech it just goes back to its normal rev range and operating limit , that's the sort of area i have come from

i still don't know what is the randomizer for the normal rpm limit cut , not the lower limit cut as it doesn't ask for a randomiser number .


Thanks for any advise fellas, I'm having great success with my drag car now , if i have achieved wiring it up cdi and m2r and its running like clockwork I'm sure with a little help in my new question i can make this work too

OK i have sat back and read your post again, i see what you mean buy a latch switch, flick it one way and the lower limit is now in full effect, but then switch it back and it goes back to the higher limit, and the switch is just wired from the pin19 to the switch then to ground so no input external voltage needed as it comes from the computer . yes / no
that would be a bit hard to use in the heat of the moment, as having a momentary push button switch on either the shifter or steering wheel is more what I'm after, so would that work as well if i just hold down the momentary switch until i launch and then it will go back instantly to the normal higher rpm limit should i put the red wine glass down and read it in the morning

I am currently using my foot to hold 8400 rpm on launch and i would like to hold my foot flat and use the switch, less to worry about on the start line , and then release it to go back to its normal 9000 rpm limit

this is a vid of me car excuse the fella filming, it was his first time filming and he got lost
http://www.youtube.com/watch?v=-KfzMXinNR4


ALso would be nice ot know what the spark is actually doing when cut, what plugs are being cut, this is a touchy subject with rotaries as it can pop the motors real easy if the spark becomes erratic , does it cut rota 1 and 2 and does it cut trailing as well as leading or is it just leading , and does it alternate between rota 1 and two or just cut them both simultaneous .

Sorry for the questions but i genuinely interested

Personally I would set it up on a 3D table or timer in the ecu to do it automatically for you ( not sure what the M2R has in the way of functionality ). You really just want a 2 stage rpm cut, one for launch and one for the full run. I know on the M-series ecu you can run gear dependent rpm limit which would be even better.
What about running launch control which would do this for you by cutting rpm based on wheel slip rather than a lower rpm cut or is it banned ?
You could also set it up that it disengages the lower limit based on gound speed so as soon as the car hits a certain speed ( launches of the line ) it switches to the higher rpm limter.
A million ways to do this just got to find what works best and what you can do with the M2R.
I'm sure the experts who know more than me will pipe up and give you some better info.
Good on you for running a motec on a rotary, great to see I'm not the only one !

hell yes running a motec on a rotary needs to be pushed heaps more, its funny how my piers are still running microtechs and they are still having regular normal "glitches" and they except it as ok
no way would you get me running that boat trailer spec computer on my investment and i just cant get it why people spend 20g on their blocks but spend the cheapest possible on the computer, or maybe the old establishment just don't want to learn new tricks


Anyway rant over

My andra rule book does not allow me to run traction control or ground speed limiting or undriven wheel speed sensors drags can be soo boring but so much fun , so at best its just a two step launch control that i can try to do, unfortunately the microtech units are good at it when it works as ive seen countless users have it work at the garage but not the track
So that's why i am thinking of just running the lower rev cut, i bought the momentary switch today and associated wiring and ill be giving it a go in my driveway tomorrow (im on holidays at work)
I also popped into one of the local motec dealers in Perth today and had a discussion with them about it, they also weren't quite on the same ball as me, as they suggested boost control limits and traction control, either no good as i want heaps of boost to build and the revs to be held stationary on the start line as the tree lights are dropping

Ill give yous updates on how it goes or not

wholly mother of bat s++t bat man it fn works and i nearly set the garden on fire next to me

i got a momentary push button switch and i had to set the value to 0 for closed low volts , all i did is earth it to the chassis as i don't have any extra black grounds inbuilt in my harness , so i hope that's correct so far
When i push the button it holds my pre-set rev cut limit then when i release it it instantly goes back to the full rev cut limit

Next is to try it at the track

ok i tested the limit on the weekends racing, its good but not good enough,
Im still after a way to get it to build good boost when im on the stage limiter. Sooo is there a way that when i hit the dual rpm limit button it brings into stage somehow a -20 deg timing shift and a +50% in fuel input.
This is what other brands do to create a backfire situation in the turbo exhaust housing which doubles as a boost increase before launching from the line at the drags.
Any input would be great

You can hear the limiter just when the tree starts to count down , its good at limiting but its needs more boost building ability
http://www.youtube.com/watch?v=t5pEfInwh3M

Why dont you just set up Over run boost?

i have no boost controller im only running of the wastegate spring , plus im not sure how over run boost would work sitting on the start line, would you be able to explain it to me .
Also where in the m2r could i check out this over run boost function thanks .