VEMS launch control RPM off

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VEMS launch control RPM off

Postby vwnut8392 » Tue Apr 28, 2015 10:09 pm

i was working on configuring launch control now and it seems what i set the RPM in the setting the car VEMS dash is off by 500 RPM roughly. say i set launch control to 4500 it will only rev to around 3800, i set it to 5000rpm and i get 4500. is there something that would cause this? i synced my timing with the IAC lock at 20 degrees today and moved my primary trigger till it matched with my timing light. im not sure that has anything to do with it though. anyhow some insight or if any of you guys have had this problem please help me figure it out.

also when i do use launch control too i dont get any backfiring like i expected, all i get is one big fire ball on decel from the ignition based idle control. i dont want to make it backfire because its cool, i want it to do it because i can normally catch that extra little boost spike during a launch. the car only goes to 10psi on the launch control too, i have a 2.2 bar spring in the gate and i expected more boost than that.
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Re: VEMS launch control RPM off

Postby Marc » Wed Apr 29, 2015 8:05 am

"control range". whatever your target launch rpm is, it will start pulling timing and adding fuel (depending on what you have for those settings on the launch control page) at launch rpm - control range.

backfires are usually when the ecu has cut fuel because you've reached the launch rpm (the control range wasn't able to stop the motor from revving via ignition timing alone). so, if you want backfires you probably have to reduce the control range a bit, or change the ignition retard amount. also try adding a bit more fuel via the enrich % option.
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Re: VEMS launch control RPM off

Postby vwnut8392 » Wed Apr 29, 2015 11:22 am

Marc wrote:"control range". whatever your target launch rpm is, it will start pulling timing and adding fuel (depending on what you have for those settings on the launch control page) at launch rpm - control range.

backfires are usually when the ecu has cut fuel because you've reached the launch rpm (the control range wasn't able to stop the motor from revving via ignition timing alone). so, if you want backfires you probably have to reduce the control range a bit, or change the ignition retard amount. also try adding a bit more fuel via the enrich % option.



Thanks for the info. i actually copied what was working on the setup i created for the stock motronic/WOT BOX setup and i got it to get closer to the target RPM. i only set the retard to -22.5 degrees leaving the fuel at 50% enrichment and the control range at 200RPM. i'll try what your saying though because you know better than anyone.

when i synced my timing yesterday did i adjust it correctly? i locked my timing to 20 degrees, and discovered i was around 12 degrees more advanced than what the actual map is so i moved the TDC after trigger to get the timing light to match my 20 degree lock. it seems like the right thing to do but im not sure.
"The really good drivers got the bugs on the side windows." Walter Röhrl

1984 4000S quattro-AAN swapped
1983 UR coupe quattro
1995 URS6 avant
1992 GTI VR6
1992 GTI G60 X-flow turbo
1986 16V jetta coupe
1985 golf 4 door-AKA the monster golf
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Re: VEMS launch control RPM off

Postby vwnut8392 » Wed Apr 29, 2015 5:26 pm

i tried what you said marc and nothing seems to work. i can get it to hit 4400 but it tapers off to like 4200. Here's a video of it doing what its doing.

"The really good drivers got the bugs on the side windows." Walter Röhrl

1984 4000S quattro-AAN swapped
1983 UR coupe quattro
1995 URS6 avant
1992 GTI VR6
1992 GTI G60 X-flow turbo
1986 16V jetta coupe
1985 golf 4 door-AKA the monster golf
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Re: VEMS launch control RPM off

Postby amd is the best » Thu Apr 30, 2015 7:13 am

vwnut8392 wrote:i tried what you said marc and nothing seems to work. i can get it to hit 4400 but it tapers off to like 4200. Here's a video of it doing what its doing.



You're drowning that thing with fuel. The WB goes off the chart rich. Put the fuel enrich between 10-15%. Set the timing to 50deg. Set control range to 300. Those setting work perfectly for me.
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Re: VEMS launch control RPM off

Postby Marc » Thu Apr 30, 2015 9:32 am

thanks nick.

I asked him for a vemslog as I didn't have a chance to take a hard look at the video. 50% is definitely too much. at that point things are just going to stop firing entirely.

I usually use 50 degrees of retard, 5-10% enrich, and 200 control range. you may need to tweak the rpm based on turbo size, but k24 will be around 3k for full song, bigger turbos 4k or so.
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Re: VEMS launch control RPM off

Postby 88a5tq » Thu Apr 30, 2015 7:56 pm

Marc, according to this pin out sheet I received with VEMS, is my launch control going to be activated when I ground out pin 2 shown below? One more question (well 3), do I disable launch status output settings and enable launch speedbase control while leaving input selector as WSPeed 2? Thank you
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Re: VEMS launch control RPM off

Postby Marc » Thu Apr 30, 2015 10:19 pm

yeah, you will use pin 2 in your case to activate launch control. on the config screen set the input channel to #2.

you dont need the speedbase stuff, just disable that as well as the status output.
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Re: VEMS launch control RPM off

Postby 88a5tq » Thu Apr 30, 2015 10:27 pm

Cool thanks again. Sorry for the minor thread jack. Although now you all know which channel to ground from checking your pin out sheets.
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Re: VEMS launch control RPM off

Postby vwnut8392 » Fri May 08, 2015 9:42 pm

well i had some time to mess with my car again and here's a vemslog from trying to use launch control.
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v3.3_u009465-2013.02.08-22.30.44.vemslog
(92.5 KiB) Downloaded 96 times
"The really good drivers got the bugs on the side windows." Walter Röhrl

1984 4000S quattro-AAN swapped
1983 UR coupe quattro
1995 URS6 avant
1992 GTI VR6
1992 GTI G60 X-flow turbo
1986 16V jetta coupe
1985 golf 4 door-AKA the monster golf
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Re: VEMS launch control RPM off

Postby Marc » Fri May 08, 2015 9:54 pm

the "rpm limit" is just that, a "limit". if other aspects of the launch control slow the engine down fast enough that it never hits the limit it wont cut fuel and spark.

in this case I think your 30% increase in fuel and 50 degree overall retard is causing the motor to load up so much that the revs dont climb to your desired limit. try decreasing your fuel enrich to 5% and see how it goes.
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Re: VEMS launch control RPM off

Postby Marc » Fri May 08, 2015 10:06 pm

oh, and if your quandry is about the rpm target, bear in mind, internally these numbers aren't necessarily encoded in decimal by the VEMS hardware. so if you are noticing an offset simply bump your target so the actual matches your desired.
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Re: VEMS launch control RPM off

Postby vwnut8392 » Fri May 08, 2015 10:41 pm

i went down to 4000 RPM, control range 200, 10% enrich and 50 degree retard and that seems to work. sort of disappointed there is no backfiring though. here's one more vemslog at with the settings above set up and i think i may have rose it to 4500 at the end of the log. the turbo i have is a T3T04E with a .63 AR exhaust housing/wheel.
Attachments
v3.3_u009465-2013.02.08-23.34.36.vemslog
(84 KiB) Downloaded 87 times
"The really good drivers got the bugs on the side windows." Walter Röhrl

1984 4000S quattro-AAN swapped
1983 UR coupe quattro
1995 URS6 avant
1992 GTI VR6
1992 GTI G60 X-flow turbo
1986 16V jetta coupe
1985 golf 4 door-AKA the monster golf
User avatar
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Joined: Aug 12, 2013
Location: PA

Re: VEMS launch control RPM off

Postby Marc » Fri May 08, 2015 10:47 pm

coming to carlisle next week?
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Re: VEMS launch control RPM off

Postby vwnut8392 » Fri May 08, 2015 10:59 pm

im not sure yet, all depends if my S6 stops making knock knock jokes. if i do it will only be an appearance for a day and i wont have the 4000 with me because its not legal to drive on the street at the moment. PA sucks when it comes to registering cars, inspection, emissions testing, and car insurance.
"The really good drivers got the bugs on the side windows." Walter Röhrl

1984 4000S quattro-AAN swapped
1983 UR coupe quattro
1995 URS6 avant
1992 GTI VR6
1992 GTI G60 X-flow turbo
1986 16V jetta coupe
1985 golf 4 door-AKA the monster golf
User avatar
vwnut8392
 
Posts: 338
Joined: Aug 12, 2013
Location: PA

Re: VEMS launch control RPM off

Postby vwnut8392 » Sat May 09, 2015 12:17 pm

i was thinking about this more when i was trying to sleep last night and i come up with a theory. what if the wastegate is opening too soon and its bleeding off what i would expect to be combusted in the turbine housing? i dont have the N75/boost control enabled because im still trying to grasp the PWM settings although someone suggested using the secondary PWM settings/map for controlling the N75 for now because its much simpler to use than the actual primary PWM settings.

anyhow does that sound right to you guys? my brother did notice a rather large ball of fire coming out of the gate pipe under launch control so it seems like thats what would be giving me the undesired operation. so i figure if i put the N75 back into play than i should get the desired effects i want.
"The really good drivers got the bugs on the side windows." Walter Röhrl

1984 4000S quattro-AAN swapped
1983 UR coupe quattro
1995 URS6 avant
1992 GTI VR6
1992 GTI G60 X-flow turbo
1986 16V jetta coupe
1985 golf 4 door-AKA the monster golf
User avatar
vwnut8392
 
Posts: 338
Joined: Aug 12, 2013
Location: PA


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