Fuel cut at 26 PSI. enjoy
09-21-12, 02:57 AM
#1
Fuel cut at 26 PSI. enjoy
quick video of my tuning/logging my new 3 bar setup.
This is for anyone who wonders what it looks like to hit fuel cut at critical moments. I had my ecu set to 1.3 bar and the wastegate wanted to run more than that. (tuning first run)
stock reman 40k miles on it
gt35r 1.06 aspec
This is for anyone who wonders what it looks like to hit fuel cut at critical moments. I had my ecu set to 1.3 bar and the wastegate wanted to run more than that. (tuning first run)
stock reman 40k miles on it
gt35r 1.06 aspec
09-21-12, 10:59 AM
#5
Fuel cut vs. ignition cut:
Fuel cut is suspected as harmful as we all know leaning out the mixture will lead to a lean burn instant failure so wouldn’t it be better to cut to spark and not have any combustion.
However the facts are fuel cut instantly drops the mixture below the combustion point, (residual fuel on the runner and chamber walls is not enough to produce a combustible mixture) where-as ignition cut does not prevent the present combustible mixture from igniting from self ignition “dieseling”.
Fuel cut is suspected as harmful as we all know leaning out the mixture will lead to a lean burn instant failure so wouldn’t it be better to cut to spark and not have any combustion.
However the facts are fuel cut instantly drops the mixture below the combustion point, (residual fuel on the runner and chamber walls is not enough to produce a combustible mixture) where-as ignition cut does not prevent the present combustible mixture from igniting from self ignition “dieseling”.
09-21-12, 11:48 AM
#6
Fuel cut vs. ignition cut:
Fuel cut is suspected as harmful as we all know leaning out the mixture will lead to a lean burn instant failure so wouldn’t it be better to cut to spark and not have any combustion.
However the facts are fuel cut instantly drops the mixture below the combustion point, (residual fuel on the runner and chamber walls is not enough to produce a combustible mixture) where-as ignition cut does not prevent the present combustible mixture from igniting from self ignition “dieseling”.
Fuel cut is suspected as harmful as we all know leaning out the mixture will lead to a lean burn instant failure so wouldn’t it be better to cut to spark and not have any combustion.
However the facts are fuel cut instantly drops the mixture below the combustion point, (residual fuel on the runner and chamber walls is not enough to produce a combustible mixture) where-as ignition cut does not prevent the present combustible mixture from igniting from self ignition “dieseling”.
what makes bouncing off the Rev limiter , say on my miata safe vs not safe on the Rotary , is it because of boost . or just engine design
09-21-12, 12:15 PM
#7
Fuel cut vs. ignition cut:
Fuel cut is suspected as harmful as we all know leaning out the mixture will lead to a lean burn instant failure so wouldn’t it be better to cut to spark and not have any combustion.
However the facts are fuel cut instantly drops the mixture below the combustion point, (residual fuel on the runner and chamber walls is not enough to produce a combustible mixture) where-as ignition cut does not prevent the present combustible mixture from igniting from self ignition “dieseling”.
Fuel cut is suspected as harmful as we all know leaning out the mixture will lead to a lean burn instant failure so wouldn’t it be better to cut to spark and not have any combustion.
However the facts are fuel cut instantly drops the mixture below the combustion point, (residual fuel on the runner and chamber walls is not enough to produce a combustible mixture) where-as ignition cut does not prevent the present combustible mixture from igniting from self ignition “dieseling”.
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09-21-12, 06:45 PM
#15
FD irons with the thick castings will help keep the block straight but they still can fail if you push them.
Last edited by RotaryEvolution; 09-21-12 at 06:51 PM.
09-21-12, 07:00 PM
#16
but i wouldn't suggest setting it so high, running pump gas i assume that is still well into engine breaking territory. the stout FD block is likely the only thing that saved the irons, if it was an FC or earlier it probably would have left a trail of oil behind as soon as it hit 20-21psi and be pissing out about a quart every 30 seconds from a cracked rear iron.
09-21-12, 07:03 PM
#17
Then I need to evaluate my wastegate situation because its hellbent on 26 psi and only lowering the duty cycle to performance detrimental number seems to wrangle my boost in.
I do have pre turbo water injection.
I'm starting to feel lucky that my car is working so well at those peak boost moments throughout tuning
I do have pre turbo water injection.
I'm starting to feel lucky that my car is working so well at those peak boost moments throughout tuning
09-21-12, 07:06 PM
#18
just lower the boost figures in the PFC, it will hit the cut sooner. even with straight water injection i have never pushed an engine that high on pump gas, if it's injecting enough, say 800cc or more it should be ok, but that's still a big if everything is tuned to handle it.
09-21-12, 09:22 PM
#19
Then I need to evaluate my wastegate situation because its hellbent on 26 psi and only lowering the duty cycle to performance detrimental number seems to wrangle my boost in.
I do have pre turbo water injection.
I'm starting to feel lucky that my car is working so well at those peak boost moments throughout tuning
I do have pre turbo water injection.
I'm starting to feel lucky that my car is working so well at those peak boost moments throughout tuning
Are you running a 44mm WG?
09-21-12, 10:07 PM
#21
talking head
Fuel cut vs. ignition cut:
Fuel cut is suspected as harmful as we all know leaning out the mixture will lead to a lean burn instant failure so wouldn’t it be better to cut to spark and not have any combustion.
However the facts are fuel cut instantly drops the mixture below the combustion point, (residual fuel on the runner and chamber walls is not enough to produce a combustible mixture) where-as ignition cut does not prevent the present combustible mixture from igniting from self ignition “dieseling”.
Fuel cut is suspected as harmful as we all know leaning out the mixture will lead to a lean burn instant failure so wouldn’t it be better to cut to spark and not have any combustion.
However the facts are fuel cut instantly drops the mixture below the combustion point, (residual fuel on the runner and chamber walls is not enough to produce a combustible mixture) where-as ignition cut does not prevent the present combustible mixture from igniting from self ignition “dieseling”.
1... DO NOT USE THE REVlim SOFTCUT on older microtechs
it is designed for a 4cyl with non sequential fuel injection
///// it will cut half the injectors,, dropping a 4cyl to 2 cyl.. acting as a softcut
... on a sequentially injected rotary.. this is instant death
2... on a rotary engine,, the stock injector locations are considered as semi direct for primary, but not for the secondary.. on a decent,, very well set up ecu.. you will have injection dwell angle control
this is intended ( on a rotary engine ) to time the release of fuel from a far away injector to coincide its delay in making to the engine port for the window of time in which the port is open
.. on a piston engine it may be timed to instead stall for an engine cycle to cool the valve
however.. its a black art ,, and changing rpms.. changing injector type and pattern,, or position has implication on this working as well as it should...
and to make it worse.. early ecus often totally lack this feature.. combined with changed or moved injectors on a rotary engine ,, its a problem waiting to rear its head at the moment you do a fuel cut
you cut the fuel........... but this far away injectors last gasp of fuel is still potentially ( depends on how your black art math lucked in ) in transit to the engine port for the next engine cycle..........................
...........now at less than the required safe AFR,, but almost certainly still within a combustable mixture zone
3.. on a 25 + year old injector.. do you really think it shuts off nice and clean.. all day everyday...........?
4.. is your tune that good you can guarentee you dont have a wet walled manifold right up to fuel shut off point?
food for thought................ive seen what happens in real life when the dice doesnt roll your way on an old,, or not thoroughly setup ecu ... and or in conjunction with a tired injector
as for IG cuts,, they work well.. cats hate them........
but can ,, especially in a wasted spark scenario , add for an afterburn preturbo when you get the relite... have seen it sheer the to4b type shafts clean in two... .......but save the engine ...
09-22-12, 01:21 PM
#23
but i wouldn't suggest setting it so high, running pump gas i assume that is still well into engine breaking territory. the stout FD block is likely the only thing that saved the irons, if it was an FC or earlier it probably would have left a trail of oil behind as soon as it hit 20-21psi and be pissing out about a quart every 30 seconds from a cracked rear iron.
FD irons with the thick castings will help keep the block straight but they still can fail if you push them.
FD irons with the thick castings will help keep the block straight but they still can fail if you push them.
How many 500hp unpinned REW's are there out there anyway?
