NO rev limiter??
- Thread starter Kooldino
- Start date
Little Beavis
Member
- :
- 2001 MP3-T (#911)
For what it is worth, on my old sportbike(s) and other people's we use to hit the kill switch while the bike was cruising down the road (slap another guys kill switch and take off). With the engine in gear and running, fuel was still being pulled in through the carb. As soon as the guy flipped the kill switch back to run, BOOM, and you would shoot flames out the exhaust (not too great for the engine), but that was a definite example of a spark only "limiter". Backfire every time!
Kooldino---What RPM's do you have your map going up to on the right side? Is it going to 7k or more?? If you have all that RPM on the side, then you could be adding fuel with the xtra injectors after the stocker where cut off.
Beavis--I used to do that s*** when I rode, we would be going through a small town or something and hit the kill, pump the throttle a couple of times then turn it back on and BAMMMM!!!! It was pretty cool because you would get a good little flame out when you pump the throttle. We also did the kill thing to each other and also put the kickstand down on others bikes right as the light would turn green or if we were going slow enough. Man I miss those days, that s*** was fun!
Beavis--I used to do that s*** when I rode, we would be going through a small town or something and hit the kill, pump the throttle a couple of times then turn it back on and BAMMMM!!!! It was pretty cool because you would get a good little flame out when you pump the throttle. We also did the kill thing to each other and also put the kickstand down on others bikes right as the light would turn green or if we were going slow enough. Man I miss those days, that s*** was fun!
Installshield 2
Gothenburg Superiority
Kooldino said:
I was going to ask about that...could have simply been an off boost torque problem?...overly retarded ignition timing at low rpm can cause it to bog and run poorly...as well as idle poorly...and obviously you knew that...
Yeah, I have an LX ECU, so I'm not sure what kind of idle timing it ran compared to the MP3 ECU. Either way, I'm running 94 octane instead of the 87 that the ECU is designed to run. The only problem I'm having with the timing so far is that I'll stall pulling into my garage sometimes.Installshield 2 said:
Basically if I lightly rev the car to maybe 2k, then let off the gas, then repeat, eventually when i let off the gas it will end up stalling.
Do you think 2* is a good number to add? If not, then what?
Note: when adding timing with the MPI tuner, it's calculated timing addition, AFAIK.
You could always check the max rpm experienced thats on the Global Settings...
reset it every now and then.
That thing was happening to me too. Im now running extra injectors only and FM clamp and that problem is now gone. Im just adding fuel when needed.
Record a log file, and try to remember when that happens and watch the Analog Output voltage on the replay.
Now my issue right now is that, sometimes the car tries to pull the fuel or not send enough on some gears then it hits a fuel cut. My other issue is the aditional injectors lag.
Have you ever experienced this?
reset it every now and then.
That thing was happening to me too. Im now running extra injectors only and FM clamp and that problem is now gone. Im just adding fuel when needed.
Record a log file, and try to remember when that happens and watch the Analog Output voltage on the replay.
Now my issue right now is that, sometimes the car tries to pull the fuel or not send enough on some gears then it hits a fuel cut. My other issue is the aditional injectors lag.
Have you ever experienced this?
Installshield 2
Gothenburg Superiority
alright this is starting to make sense...
Think of the advantage of 94 octane rated gasoline...the octane rating compares the gasoline to a completely different mixture, that handles compression extremely well without undeclared ignition...but this stability has a side affect in which it can be more difficult to ignite properly...its not so much that the gasoline needs more heat or more compression to ignite properly...it still has a very similar flash point...But the stuff in the gasoline that "stabillizes" it acts like a buffer to slow the reaction, and overall make is more difficult to ignite initially...
this i the number one reason why economy engines use lower octane gasoline (aside from price)...they are not performance engines, usually running relatively low static compression ratios, and retarded timing...all of which are great for lower rated gas...it is usually misunderstood that running higher rated gas in these types of engines will give more power, my guess because the gas is more expensive...so the owner thinks it will be better...it isn't...in less performance engines, it can actually make streetability worse...because the gasoline, for lack of better terms, is too stable for the engine...
so this is the point...Dana, your engine off boost is most likely behaving very close to a near stock engine...there are some changes to low load A/F's and things like that...but its not a whole lot different...But you are required to run 94 octane rated gas because once that turbo spools, your engine transforms into a fire breathing demon that devours small children and their pets...
But back to off boost...you said you advanced the timing and that has fixed it...that makes sense...if you had the timing overly retarded, the gasoline was simply having trouble expanding "powerfully"..the gasoline is extremely stable, but being used in a condition where you have a very low static CR, and retarded timing (economy car like condition)...Once your turbo spools everything smooths out, because the dynamic compression is much much greater, the volumetric efficiency is above 100% (you FI bastards)...and the retarded timing is actually needed because of how much more air and fuel is in each chamber...
anyway...2* sounds pretty good... you could get away with even a little more, as long as its well below your boost threshold...and that could potentially help a lot with turbo spool, and overall low rpm off boost torque...just make sure the timing is being trimmed back especially in the critical 4-5k rpm area...
I don't have too many ideas on why it didn't happen all the time though, before you advanced the spark...It may have just been almost were it needed to be, timing wise...and would simply sometimes get into a cycle of choking off (engines can do that...chain reactions can get started when one bad cycle throws things out of wack, and the next compression stroke is extremely weak...then causes another poor expansion do to poor compression...etc etc etc...can end up taking a few thousand rpm higher before it "works itself out")
Think of the advantage of 94 octane rated gasoline...the octane rating compares the gasoline to a completely different mixture, that handles compression extremely well without undeclared ignition...but this stability has a side affect in which it can be more difficult to ignite properly...its not so much that the gasoline needs more heat or more compression to ignite properly...it still has a very similar flash point...But the stuff in the gasoline that "stabillizes" it acts like a buffer to slow the reaction, and overall make is more difficult to ignite initially...
this i the number one reason why economy engines use lower octane gasoline (aside from price)...they are not performance engines, usually running relatively low static compression ratios, and retarded timing...all of which are great for lower rated gas...it is usually misunderstood that running higher rated gas in these types of engines will give more power, my guess because the gas is more expensive...so the owner thinks it will be better...it isn't...in less performance engines, it can actually make streetability worse...because the gasoline, for lack of better terms, is too stable for the engine...
so this is the point...Dana, your engine off boost is most likely behaving very close to a near stock engine...there are some changes to low load A/F's and things like that...but its not a whole lot different...But you are required to run 94 octane rated gas because once that turbo spools, your engine transforms into a fire breathing demon that devours small children and their pets...
But back to off boost...you said you advanced the timing and that has fixed it...that makes sense...if you had the timing overly retarded, the gasoline was simply having trouble expanding "powerfully"..the gasoline is extremely stable, but being used in a condition where you have a very low static CR, and retarded timing (economy car like condition)...Once your turbo spools everything smooths out, because the dynamic compression is much much greater, the volumetric efficiency is above 100% (you FI bastards)...and the retarded timing is actually needed because of how much more air and fuel is in each chamber...
anyway...2* sounds pretty good... you could get away with even a little more, as long as its well below your boost threshold...and that could potentially help a lot with turbo spool, and overall low rpm off boost torque...just make sure the timing is being trimmed back especially in the critical 4-5k rpm area...
I don't have too many ideas on why it didn't happen all the time though, before you advanced the spark...It may have just been almost were it needed to be, timing wise...and would simply sometimes get into a cycle of choking off (engines can do that...chain reactions can get started when one bad cycle throws things out of wack, and the next compression stroke is extremely weak...then causes another poor expansion do to poor compression...etc etc etc...can end up taking a few thousand rpm higher before it "works itself out")
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Wow, great post.... That's how I have it setup right now. Under 3K I go from 1-2's in advancing the timing, then to 0 and the I start retarding it. I've noticed a better spool time, and a much smooother ride while under "non boost" driving in low gears. Next step is to try making the non boost areas 0's in the fuel category.
Installshield 2
Gothenburg Superiority
yeah we may be on to something for the studdering problem...but why he isn't bouncing off a rev-limiter is up in the air...I have no idea...but I feel it has something to do with the secondary injectors...
Ok, I figured out my random studdering problem. After driving around for awhile with my laptop plugged in and running, it finally did the studdering thing again after a week or not doing it.
Here's an email I sent to Perfect Power describing what happened:
I'm having an issue with either my MPI tuner or my MAP sensor (which I
believe is from Perfect Power). I am running 15psi on my car right now,
on what I believe is a 1.5 bar MAP sensor. Attached is an image of my
Sensor Calibration for the AMP scale, which is using my MAP sensor as an
input. I never exceed the box labeled ".77" with the amount of boost I
run. Obviously the amount of boost I run directly affects the duty cycle of
the additional stand alone injectors that ONLY the MPI Tuner version of the
SMT-6 knows about.
99.9% of the time, I have no issues, and the AMP scale works as it should.
It stays in the bottom most cell (1.80 Volts, Position 0, Tune Map = .00,
Scale = .30) anytime I'm off of boost, and the moment I cross the boost
threshold, it steadily climbs all to way to Position 10 (3.93 volts, .77
scale) which is 14-15psi on my car.
However, on occasion while crusing OFF OF BOOST (ie, in position 0, 1.80
Volts) and a very low RPM and throttle position, it will start spraying fuel
through the injectors due to the fact that the red indicator on the AMP
column is now suddenly in position 15 (5.00 volts), which, until I set it to
"0.00" tonight, was at "1.00". And it would stick there for about a minute
until it would go back to a proper AMP column cell. Since changing its
value from 1.00 to 0.00, it has corrected the problem during cruising, but
now, on occasion, under boost it will also "stick" there for some reason and
add no fuel at all under boost.
So in short, I'm not sure whether I have a faulty MAP sensor, or whether
there is a software glitch. Either way, I wanted to bring this to your
attention.
Here's an email I sent to Perfect Power describing what happened:
I'm having an issue with either my MPI tuner or my MAP sensor (which I
believe is from Perfect Power). I am running 15psi on my car right now,
on what I believe is a 1.5 bar MAP sensor. Attached is an image of my
Sensor Calibration for the AMP scale, which is using my MAP sensor as an
input. I never exceed the box labeled ".77" with the amount of boost I
run. Obviously the amount of boost I run directly affects the duty cycle of
the additional stand alone injectors that ONLY the MPI Tuner version of the
SMT-6 knows about.
99.9% of the time, I have no issues, and the AMP scale works as it should.
It stays in the bottom most cell (1.80 Volts, Position 0, Tune Map = .00,
Scale = .30) anytime I'm off of boost, and the moment I cross the boost
threshold, it steadily climbs all to way to Position 10 (3.93 volts, .77
scale) which is 14-15psi on my car.
However, on occasion while crusing OFF OF BOOST (ie, in position 0, 1.80
Volts) and a very low RPM and throttle position, it will start spraying fuel
through the injectors due to the fact that the red indicator on the AMP
column is now suddenly in position 15 (5.00 volts), which, until I set it to
"0.00" tonight, was at "1.00". And it would stick there for about a minute
until it would go back to a proper AMP column cell. Since changing its
value from 1.00 to 0.00, it has corrected the problem during cruising, but
now, on occasion, under boost it will also "stick" there for some reason and
add no fuel at all under boost.
So in short, I'm not sure whether I have a faulty MAP sensor, or whether
there is a software glitch. Either way, I wanted to bring this to your
attention.
