Of course that will happen. The ECU cannot synch in 720 with the engine so it runs in batch fired mode, the result of this is reduced injector duty as all injectors fire.
Thats why I consider it a stupid mod.
Removing Rev Limiter
- Thread starter Flat_Out
- Start date
Of course that will happen. The ECU cannot synch in 720 with the engine so it runs in batch fired mode, the result of this is reduced injector duty as all injectors fire.
Thats why I consider it a stupid mod.
Hmm. I can understand the out of sync part but not the reduced injector cycle. The injector time cannot be half from the other measurement with the same rpm or it would mean AFR to go from 13:1 to 26:1. It wouldn't even run.
The batch fired mode could really explain the behavior on low rpms when the duty cycle of injectors is 20% or lower. With higher rpms the duty cycle is more than 80% so the out of sync does not matter.
One thing still I don't understand is behavior related to rpm. Why it runs ok from the the start and long time if the rpm is kept low, but if rpm is raised high and then back to low, then the problem comes up. With cold engine this problem does not exist. Is there something else in the engine, which the ECU can use as sync signal? I didn't find any clue from web that CG13DE would use crank angle sensor. (I'm at work and don't have the Haynes manual with me.)
If the hole and the slot next to it would be combined, it would mean that the ecu would need to interpret the longer slot as sync signal. Then if the ECU is looking for pulse with a certain length for rpm detection, that could work.
Has anyone checked the injector time through consult interface that it is as expected after the working plugged disc mod?
The batch fired mode could really explain the behavior on low rpms when the duty cycle of injectors is 20% or lower. With higher rpms the duty cycle is more than 80% so the out of sync does not matter.
One thing still I don't understand is behavior related to rpm. Why it runs ok from the the start and long time if the rpm is kept low, but if rpm is raised high and then back to low, then the problem comes up. With cold engine this problem does not exist. Is there something else in the engine, which the ECU can use as sync signal? I didn't find any clue from web that CG13DE would use crank angle sensor. (I'm at work and don't have the Haynes manual with me.)
If the hole and the slot next to it would be combined, it would mean that the ecu would need to interpret the longer slot as sync signal. Then if the ECU is looking for pulse with a certain length for rpm detection, that could work.
Has anyone checked the injector time through consult interface that it is as expected after the working plugged disc mod?
power is torque multiplied by revs (and a static number) so if the power's gone down, so has the torque. you may find that at 8000rpm you make less power and less torque than at 5000 in the next gear.......
and peak power is always a relevant figure to look at........ if you know how to manipulate the numbers, it can give you all sorts of useful information.....
and peak power is always a relevant figure to look at........ if you know how to manipulate the numbers, it can give you all sorts of useful information.....
If you checked the graph, the green curve shows the torque to the wheels. Power is not the one which is accelerating the car, torque to the wheels is. Because on second gear (in Micra with RS5F30A or RS5F31V gearbox) you have 1.5 times more torgue to wheels than third gear, you will need to have 50% torque on third gear at 5000rpm than 7500rpm using second gear, to accelerate better.
On green curve you can see that 5000 rpm has about 40% more torque than 7500 rpm. This fact is also proved by the change from second to third, which is showing drop in acceleration.
On green curve you can see that 5000 rpm has about 40% more torque than 7500 rpm. This fact is also proved by the change from second to third, which is showing drop in acceleration.
frank
Club Member
iirc the k11 maps only run to 4k or something, praps it cant interpolate from then on, without the 720 index ?
I don't understand what you are trying to prove. The injectors need to be fired every 360 deg rather than every 720 in sequential. So Obviously for a given engine cycle the injectors fire twice and so its two bursts of half the injection time. It's quite probable in fact that all 4 fire at once at every combustion event. I haven't looked to see, or even given it any thought.
Sync always makes a difference, even at high power if you had your injectors opening at the wrong time to the valves (you'll never get that out of sync) HC emissions will rise and efficiency will fall. Just because airflow is higher at high rms doesn't remove the benefits of semi sequential or even fully sequential running.
Either way its a nasty fudge at best.
No, 6200 is the last fuel row, after this its interpolated.
Just to add, these values can be changed with a remap.
I was trying get rid of the rev limiter and asking if anyone else is having a workaround for my issue. I was not going to argue if this modification is needed to do for my CURRENT setup.Anyone having a real input to my question?
For the previous post:
I think it's not only the peak power you need to look at...
If we compare the 2nd and 3rd gears the ratio difference is 50%. So you are getting the 50% more torque to front wheel using 2nd gear. The best rpm to shift is when the 2nd gear torque to wheels is the same what you could get from 3rd gear.
It's not a problem if power has dropped already from the peak power if you're still getting more torque to front wheels than with the next gear.
Its power at the wheels you want not torque. Granted torque makes the wheels turn, but power defines how fast they turn.
Not again. If you want to accelerate an object, you need have some force pushing it. That force you get from wheel torque.
Acceleration is defined as:
F = m * a, or in other way a = F/m (the bigger the force or lower the mass means higher acceleration)
Torque is defined as:
t = r * F, or in other way F = t/r
If we then substitute the F in a=F/m, it goes like
a = t/(r * m)
So the acceleration is dependent on torgue to axle, tire radius and vehicle mass. Of course in order to accelerate you need to have more power (not torque) than is needed for friction losses and air drag.
Acceleration is defined as:
F = m * a, or in other way a = F/m (the bigger the force or lower the mass means higher acceleration)
Torque is defined as:
t = r * F, or in other way F = t/r
If we then substitute the F in a=F/m, it goes like
a = t/(r * m)
So the acceleration is dependent on torgue to axle, tire radius and vehicle mass. Of course in order to accelerate you need to have more power (not torque) than is needed for friction losses and air drag.
Now I don't try to prove anything. In the very beginning I had to first prove that it really is a good idea to raise the rev limit even with my current setup. My need at the moment like is was in the beginnin that I am trying get rid of the rev limiter. Before doing anything I would like to understand how the ECU is working in that situation, in which it has no sync signal (and why some ecus work with this mod and some don't).
Having two times the half injection makes sense, thanks for that piece of info.
What I was trying to say that 15ms was reported by Nissan Datascan, which means that all injectors are open 540 degrees at 6000rpm. Based on that I doubt that the sync is not too meaningful in high rpms because the injectors are anyway open three time the duration of intake valves.
Please don't get me wrong, I'm just trying to understand and learn.
You seem to be slightly confused in your application of the above which although what you have said is correct it doesn't explain anything. All you have said is that if you apply more turning force to something that is accelerating it will accelerate faster, or if its lighter it will accelerate faster, but that's obvious.
What you really should be talking about is power. You can apply torque to something stationary and it not move. Thus no work, or energy has been transferred to whatever it is your attempting to do, and hence wont be moving. You would be better of dropping the whole torque discussion, and instead speak of power which is by definition work done/transferred/used.
To put it really really simply in order to accelerate anything, you provide it with energy aka power. The more power you apply the faster you can accelerate what ever it is you are trying to move.
Its fairly widely known I hope, that there are two basic ways to increase the power output of an engine. You can increase revs, or increase torque. Doing either results in more power (obviously).
Motorbikes take the approach of increasing revs - big engines are heavy. Many cars traditionally take the route of increasing torque by means of larger engine capacity either by engines or with turbos etc.
But once that power leaves the engine, In order to accelerate at the greatest rate we need to choose a gear box and ratios that make the most use of the power from the engine, and that isn't the point of greatest turning FORCE from the engine. Its the point of greatest POWER produced by the engine.
Lets throw in some numbers:
If your car makes 100lb/ft at 3000 rpm, but 80lb/ft at 6000 rpm, your going to accelerate much quicker by changing gear around 6-7K and keeping the car in the power band, not by changing gear at 3000 rpm even though torque is higher. Its obvious when you work out power. At 3000 rpm your only making 68hp ((100x3000)/5252). At 6000 rpm you would be 91hp ((80x6000)/5252). As already started power is what moves something, and since torque is in this case a component of power people seem to get confused with the difference.
Gearboxes allow you to convert the ratio of torque/vs/rpm for a given power input. We just want to keep the gearbox power input as high as we can for as long as we can whilst choosing the ratios on the output to keep the engine within this area of maximum engine power output, and thus achieve maximum vehicle acceleration. Torque is a by product of all this.
No. You have a very common misunderstanding. You can check from any measured data, that the biggest rate of change in speed (= acceleration) is in the point of maximum torque, not peak power.
Maybe someone else can explain this a bit better...
http://www.allpar.com/eek/hp-vs-torque.html
Maybe someone else can explain this a bit better...
http://www.allpar.com/eek/hp-vs-torque.html
I have zero interest in partaking in this debate personally. However, if you are going to reference a 3rd party source then I refer you to and invite you to explain the last section titled, 'To The Point', where the author states the following;
'A car accelerates hardest with gearing selected to stay as close as possible to the engine *power* peak, subject to the traction capability of the tires'.
Did you read the whole article?
Couple of quotes from the same article to consider.
1.
Unfortunately, *engine* torque does not tell you the full story. What matters is the torque *delivered to the tires*, including the effects of the transmission. We all know a car does not accelerate as hard in second gear at peak torque RPM as it does in first gear. The transmission amplifies or multiplies the torque coming from the engine by a factor equal to the gear ratio. So to determine how much the car is accelerating at a particular instant, you have to know both the torque output of the engine as well as the gear ratio.
2.
But, you ask, isn't your acceleration greatest at the torque peak? Yes, it is! But only within that gear.
Should we change this to some other topic? I think we all agree that it is the best to accelerate to maximum rpm unless the torque collapses dramatically in the end.
Again I am just trying to find a way to get rid of the rev limiter.
I might have a solution proposal to get the benefits of the rev limit removal and still a working car in normal driving conditions:
- if the cam position sensor signal was conditioned so that the pulse generated by small hole would not be transferred to ecu above 5000rpm
Topau... Stubbornness actually inhibits your ability to learn.
Without wishing to be rude, You have clearly referenced a link to which you have not even read properly, or don't understand. Have a re-read and then let me know what you think.
As Low Rider pointed out above the author of that article also agrees with me on what I have already said:
Ed
frank
Club Member
This one done with electrical tape.
Remove spark leads and distributor cap - 3 screws to find
Remove this screw and slide off the rotor arm.
In my frustration this plastic cover nearly got snapped off but it's secured with two torx screws @ 1o'clock and 7o'clock (with bit shown in it.)
Then remove the screw in the end of the shaft.
This is what you find. The slot in the disc allows it to slide out from the sensor. Hole covered with tape wrapped around the edge and stuck to itself through the hole.
Go back to first pic and see a smear of silicone sealant on rebuild to help the rubber weather seal.
Remove spark leads and distributor cap - 3 screws to find
Remove this screw and slide off the rotor arm.
In my frustration this plastic cover nearly got snapped off but it's secured with two torx screws @ 1o'clock and 7o'clock (with bit shown in it.)
Then remove the screw in the end of the shaft.
This is what you find. The slot in the disc allows it to slide out from the sensor. Hole covered with tape wrapped around the edge and stuck to itself through the hole.
Go back to first pic and see a smear of silicone sealant on rebuild to help the rubber weather seal.
Top guide
Berk question - is that disk removeable, or is it firmly attached to the dizzy?
Ta
Top guide
Berk question - is that disk removeable, or is it firmly attached to the dizzy?
Ta
Quote "The slot in the disc allows it to slide out from the sensor"
I agree, it was a berk question
When I spoke to Matt about the rev limiter removal he said once it was removed you rely in the fuel cut to not blow the bloc, might be this?
frank
Club Member
valvebounce wayne
mine did the same (and i dont think the tacho was reading correctly, due to the disc mod)
euro_micra
Matt :)
There was an old thread, I've lost the link to it now. But it mentioned that someone wired the fuel pump in seperately to avoid the ecu cutting power to it at 8000rpm. I never got around to trying it myself, so I can't confirm it works.
frank
Club Member
and the tacho is still reading accurately wayne ? (1k rpm / 20mph in top ?)
Liking the thread and the info you guys know
That is highly likely to depend on breathing mods. It's still good to hit the next gear at higher rpm.
So as a starter question does a non coil-pack K11 have a rev limiter ?
My observations say "NO" after Custurd reached elevnty billion revs on its emissions test and shat the water pump but I'm open to correction.
My observations say "NO" after Custurd reached elevnty billion revs on its emissions test and shat the water pump but I'm open to correction.
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