another rev limiter option ?
- Thread starter frank
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frank
Club Member
aye, but i dont have a car to test it on atm, mine,s pretty mental @ 6k, i would be really pushing my luck @ 8k
someone will test it fully, hopefully
I need to de limiter mine to re limit it with the bee r. How hard is it?
after reading in the fsm that "the engine speed is detected by measuring the time the slit needs to pass the optical sensor"
so we tried shortening the slits with tape
The shorter the slots the lower the limit Frank?
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frank
Club Member
its just tape on the optical disc motty, 1/2 hr job ?
some of us have taped over the 5th hole to delete the limiter, but with varying success (1 member lost 2NM on back to back dyno runs recently)
and matt (mph) said to join the 5th hole with the nearest slot iirc (to raise it a bit) but that 5th hole is the tdc cyl#1 reference pointer !
elongating the slots will probably raise the limiter, but will probably effect the load x rpm tables (fuel and spark maps) maybe to your favour ? maybe not ? maybe shortening the slots will give gains as a result ?
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frank
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i guess so paul, i would have tested mine fully, maybe after sunday/shakies
i guess so paul, i would have tested mine fully, maybe after sunday/shakies
This might be really handy
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frank
Club Member
i dunno what that would do kris, the fsm says
"4 long slits are provided on the rotor plate (1 for each cylinder) to detect crank angle, this is done by detecting the starting point of each slit when passing the optical sensor"
so i guess moving that tdc one, and/or moving the starting point or finishing point of the slots will have some effect on the spark or fueling or rpm.
probably of interest to the oval and grass racers, with their engine modification limits
its my belief that the distance between 4th and 5th holes determines the rev limit. the optical sensor will only work to a certain frequency. i think that when you get to 6800 (or whatever the rev limit is) the optical sensor can't see the metal between these holes, making it seem like the 4th hole was significantly longer. this would retard the firing of that cylinder, thus creating the rev limiter. i think.....
you could potentially raise the rev limiter by extending the 5th hole away from the 4th (towards the 1st).
you could possibly work it out, but there's a lot of unknowns.
you could potentially raise the rev limiter by extending the 5th hole away from the 4th (towards the 1st).
you could possibly work it out, but there's a lot of unknowns.
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frank
Club Member
nah, i think the rev limit is programmed into the ecu tom, Ed asked me what limit i wanted when he fitted and mapped my nistune,
i just took 3 of the pieces of tape off and left the cyl# 1 slit narrowed, and the tacho still reads over 2 x normal (thats a big difference for a 5mm slit adjustment eh)
i just took 3 of the pieces of tape off and left the cyl# 1 slit narrowed, and the tacho still reads over 2 x normal (thats a big difference for a 5mm slit adjustment eh)
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frank
Club Member
it revs ok, but does have a minor missfire tom (which the tacho responds to, so a signal break eh) i,ll try a slightly longer than stock slot next.
you can see on that pic ^ that its a disc that i cut the cyl 1 slot right up to the 5th hole, to test my original 1.0 engine to the limit.
and i never could understand why it was valvebouncing before it hit the limiter
( it sounded dreadful, and it damaged/marked the pistons too ) the tacho was no doubt under-reading, and i was revving @ 8 or 9 k probably !.the problem with covering the 5th hole, is that the ecu loses the cyl#1 TDC reference point, and the injectors will revert to batch firing, the fsm does say that they only sequential fire once the engine has started, and if the sensors are reading ok.
the plugs are always fired sequentially from the rotor arm, but the injectors rely on that 5th hole eh
solarice
Ex. Club Member
i dunno what that would do kris, the fsm says
"4 long slits are provided on the rotor plate (1 for each cylinder) to detect crank angle, this is done by detecting the starting point of each slit when passing the optical sensor"
so i guess moving that tdc one, and/or moving the starting point or finishing point of the slots will have some effect on the spark or fueling or rpm.
probably of interest to the oval and grass racers, with their engine modification limits
Yeah i would suspect so.
It was just on the assumption, that that's the only difference to an otherwise even layout...if you put the disc in backwards (flipped over) the car runs awful, which was where the idea came from. Unfortunately i didn't want to test my idea on my car, in case i broke anything lol.
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