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Thread: what would cause the car to hit rev limiter when trying to raise the VVL activation

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Posts: 1-10 of 10
2013-12-03 22:45:14
#1
what would cause the car to hit rev limiter when trying to raise the VVL activation
been trying to raise the cam switch point to try and get rid of the horrible dip, shown at switch over as below graphs show.







now when we raise the switch over point, when the car gets to the point of switch over it hits the rev limiter..

car is VZR N1,

using powerland daughterboard on factory ecu,

powerland manifold with custom 3" collector, 5zigen catback. K&N air intake, rest of the car is factory when it comes to power mods...
2013-12-04 02:16:13
#2
Confused, is this dyno chart from the same day? 30HP increase?
2013-12-04 03:44:12
#3
Please clarify your statement - "now when we raise the switch over point, when the car gets to the point of switch over it hits the rev limiter.." Are you suggesting that the car is bogging down at the switchover point, which feels like you are hitting a limiter?

Have you ruled out mechanical problems with the solenoids? What adjustments are being made (fuel/timing maps) in combination with the moving VVL activation points? I would suggest you look at your timing maps at the switch point. It sounds like the map is not optimized properly for the switchover. This often leads to a bog down affect, which feels like hitting a rev limiter.

Often times when people move their VVL activation point around (without tuning for it), they are (without knowing it) just puting the switchover point in a more ideal part of the timing map. Small changes in rpm range can see up to a 5* and more variance in ignition timing.
2013-12-04 09:25:42
#4
Originally Posted by B15NEOVVL
Please clarify your statement - "now when we raise the switch over point, when the car gets to the point of switch over it hits the rev limiter.." Are you suggesting that the car is bogging down at the switchover point, which feels like you are hitting a limiter?

Have you ruled out mechanical problems with the solenoids? What adjustments are being made (fuel/timing maps) in combination with the moving VVL activation points? I would suggest you look at your timing maps at the switch point. It sounds like the map is not optimized properly for the switchover. This often leads to a bog down affect, which feels like hitting a rev limiter.

Often times when people move their VVL activation point around (without tuning for it), they are (without knowing it) just puting the switchover point in a more ideal part of the timing map. Small changes in rpm range can see up to a 5* and more variance in ignition timing.



wouldn't say its bogging down, feels exactly like when it hits the limiter, was trying a few different things yesterday, during road test, and soon as you hit the raised switch point it feel like its hit the limiter and you had to lift off..

interesting you mention about the timing and fuel, only time we got it to rev through to the proper rev limit with raised switch point was when trying a map with a lot of timing removed and fueling richened up in areas, but that lost a lot of power...

I can post up the bin files used if anyone wants to have a look at them


Solenoids are fine, as you can see from the vid from my post below this one, with the current map, cams switching around 6500 it revs fine..just want to improve that dip after switch
Last edited by ragt20 on 2013-12-04 at 09-46-14.
2013-12-04 09:29:17
#5
Originally Posted by Storm88000
Confused, is this dyno chart from the same day? 30HP increase?



yup same day,
2013-12-04 09:40:49
#6


on current map, dyno graph as per earlier post
2013-12-04 16:49:20
#7
Do you have the on and off points the same?

Thats the only time I see that happen on the MSD box.

Makes sure the VVL off is above your rev limiter.
2013-12-04 17:27:24
#8
Originally Posted by SR20GTi-R
Do you have the on and off points the same?

Thats the only time I see that happen on the MSD box.

Makes sure the VVL off is above your rev limiter.



ha, not sure on that, as we are trying to adjust the switch points adjusting the factory ecu, with daughterboard, so not 100% sure on the VVL off points
2013-12-04 19:59:51
#9
Originally Posted by Storm88000
Confused, is this dyno chart from the same day? 30HP increase?


One chart is flywheel hp and other is whp. This dyno assumes a 30hp loss through the drivetrain.



Originally Posted by ragt20
Originally Posted by B15NEOVVL
Please clarify your statement - "now when we raise the switch over point, when the car gets to the point of switch over it hits the rev limiter.." Are you suggesting that the car is bogging down at the switchover point, which feels like you are hitting a limiter?

Have you ruled out mechanical problems with the solenoids? What adjustments are being made (fuel/timing maps) in combination with the moving VVL activation points? I would suggest you look at your timing maps at the switch point. It sounds like the map is not optimized properly for the switchover. This often leads to a bog down affect, which feels like hitting a rev limiter.

Often times when people move their VVL activation point around (without tuning for it), they are (without knowing it) just puting the switchover point in a more ideal part of the timing map. Small changes in rpm range can see up to a 5* and more variance in ignition timing.



wouldn't say its bogging down, feels exactly like when it hits the limiter, was trying a few different things yesterday, during road test, and soon as you hit the raised switch point it feel like its hit the limiter and you had to lift off..

interesting you mention about the timing and fuel, only time we got it to rev through to the proper rev limit with raised switch point was when trying a map with a lot of timing removed and fueling richened up in areas, but that lost a lot of power...

I can post up the bin files used if anyone wants to have a look at them


Solenoids are fine, as you can see from the vid from my post below this one, with the current map, cams switching around 6500 it revs fine..just want to improve that dip after switch



We can rule out the air fuel ratio because the graph shows it's pretty good. I suggest you stagger the intake and exhaust. Have the exhaust come on later around 7000rpm.
2013-12-04 20:41:48
#10
Originally Posted by 5speed
Originally Posted by Storm88000
Confused, is this dyno chart from the same day? 30HP increase?


One chart is flywheel hp and other is whp. This dyno assumes a 30hp loss through the drivetrain.


OHHH, duh. lol.
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