Microtech Rev lim/cut? Serious lean issue?
03-22-12, 08:16 PM
#1
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Rev lim/cut? Serious lean issue?
From my understanding a rev lim and/or rev cut can cause a serious lean condition that can damage the rotory motor. Is this a large enough concern to maintain a lack of a rev limiter/cut whatever? I don't intend to bounce it off of it constantly; more of a precaution to prevent over reving under hard acceleration. Any input?
03-22-12, 08:45 PM
#2
talking head
been doing microtechs since before dot .. do not use the revlim ( soft cut 1/2 bank ) , revcut or boost cut ( full fuel cuts ) on rotors
in a perfect world a full fuel cut would and should work
,, but in the microtech rotor world of leaking/ bigger injectors and flows and wet washed manifolds,. you are asking -nay- demanding -for shrapnel
i have seen these repeatedly lean out rotors and kill them
- in 15 years of using microtechs ,, you would think i would spot a pattern by now wouldnt you ??
some drag modified examples will have special flashed software and do an ignition cut
but the vast majority will be fuel only ,,
and you must use the screen 29 setup with timing retard as the two step
if you wish to build in some safety for over rev and for over boost
simply pull about 10 degrees out of the timing and add about 15% more fuel in the rev and boost map zones above your threshold
this should safe the engine enough to cope with the spikes
done right the engine will struggle to make more revs
however the boost control is more fickle ,, done right boost will fall off,, but this will depend on the over fuel
if not done right ( not enough over fuel ) you may get a little more overboost ( due to the retard )
,, but the engine is ' soft tuned ' in this region for ig timing and should make flat power and not overload the engine
( but not load the engine and destroy it,, in effect a mild two step )
in a perfect world a full fuel cut would and should work
,, but in the microtech rotor world of leaking/ bigger injectors and flows and wet washed manifolds,. you are asking -nay- demanding -for shrapnel
i have seen these repeatedly lean out rotors and kill them
- in 15 years of using microtechs ,, you would think i would spot a pattern by now wouldnt you ??
some drag modified examples will have special flashed software and do an ignition cut
but the vast majority will be fuel only ,,
and you must use the screen 29 setup with timing retard as the two step
if you wish to build in some safety for over rev and for over boost
simply pull about 10 degrees out of the timing and add about 15% more fuel in the rev and boost map zones above your threshold
this should safe the engine enough to cope with the spikes
done right the engine will struggle to make more revs
however the boost control is more fickle ,, done right boost will fall off,, but this will depend on the over fuel
if not done right ( not enough over fuel ) you may get a little more overboost ( due to the retard )
,, but the engine is ' soft tuned ' in this region for ig timing and should make flat power and not overload the engine
( but not load the engine and destroy it,, in effect a mild two step )
03-22-12, 09:28 PM
#4
talking head
yes ,, fuel cuts are bad because our manifolds are prone to wet wall
and injectors to leak
or do not shut down total flow with repeatable consistancy
just a little bit of fuel while under heavy load = blown apex seals quicker than you can get off it
and injectors to leak
or do not shut down total flow with repeatable consistancy
just a little bit of fuel while under heavy load = blown apex seals quicker than you can get off it
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