[sear]

What are all the possible things that could cause timing drops?

I'm still seeing timing dips post shift with my FBO 6MT 135i running the Vishnu PWM kit. I'm able to see some logs where timing will stay flat at 10deg throughout the gear, but very often timing dips to 2-3deg then slowly climbs back to 9-10deg by redline.

Car still feels strong, but the logs seem to indicate that it could be better.

What things should I look at in order to figure out the source of these drops?
-traction control: Had all off for the logs I took
- IATs: climbed in 1rst before meth turned on, then were steady at 15c.
- Gas: running shell 91 + oct boost (how to tell if its good/bad)
- knock: (what to look for ?)
- Other?

Any thoughts on how to figure out the root cause is appreciated.

Other relevant setup info:
Rev 2.5 V5 running PWM Map 4
Start Boost: 50%
IC: 0%
Injection mode: 20

Will post a log to illustrate the situation shortly...

[OpenFlash]

Originally Posted by sear

What are all the possible things that could cause timing drops?

I'm still seeing timing dips post shift with my 6MT 135i running the Vishnu PWM kit. I'm able to see some logs where timing will stay flat at 10deg throughout the gear, but very often timing dips to 2-3deg then slowly climbs back to 9-10deg by redline.

Car still feels strong, but the logs seem to indicate that it could be better.

What things should I look at in order to figure out the source of these drops?
-traction control: Had all off for the logs I took
- IATs: climbed in 1rst before meth turned on, then were steady at 15c.
- Gas: running shell 91 + oct boost (how to tell if its good/bad)
- knock: (what to look for ?)
- Other?

Any thoughts on how to figure out the root cause is appreciated.

Other relevant setup info:
Rev 2.5 V5 running PWM Map 4
Start Boost: 50%
IC: 0%
Injection mode: 20

Will post a log to illustrate the situation shortly...

If you are only running 15psi and still getting timing drop outs when running meth or race gas, there is most likely a hardware issue causing the timing instability. You can all but rule out insufficient octane an this point. So the first thing i would do is install new spark plugs. If one or more plugs are worn/bad, you will see the same timing instability you are describing. After that, make sure you are up to do with factory recalls. If you qualify for the fuel injector recall (like so many), definitely get that done as a bad injector can also cause what you are seeing. That would be a good place to start.

[sear]

Originally Posted by shiv@vishnu

If you are only running 15psi and still getting timing drop outs when running meth or race gas, there is most likely a hardware issue causing the timing instability. You can all but rule out insufficient octane an this point. So the first thing i would do is install new spark plugs. If one or more plugs are worn/bad, you will see the same timing instability you are describing. After that, make sure you are up to do with factory recalls. If you qualify for the fuel injector recall (like so many), definitely get that done as a bad injector can also cause what you are seeing. That would be a good place to start.

Shiv,
Thanks for the quick reply. I just changed plugs right after installing the kit. I was seeing some misfires and they cleared that up, but these timing drops did not go away. Also note that I'm only runnning 15psi becasue I'm at 6k ft of altitude. My car was just at the dealer in the last week and is supposedly up on all the recall work. Could an injector or something else be bad? Sure, but all of the basics have been covered and thats why I'm asking for some additional thoughts Any other thoughts?

[sear]

Here's a log to support post #1

[OpenFlash]

Originally Posted by sear

Shiv,
Thanks for the quick reply. I just changed plugs right after installing the kit. I was seeing some misfires and they cleared that up, but these timing drops did not go away. Also note that I'm only runnning 15psi becasue I'm at 6k ft of altitude. My car was just at the dealer in the last week and is supposedly up on all the recall work. Could an injector or something else be bad? Sure, but all of the basics have been covered and thats why I'm asking for some additional thoughts Any other thoughts?

At 6000' altitude, your atmosphere pressure is about -5psi. So when you run 15psi of boost, your actually running 20psi of boost. And you are on 91oct which is going to be iffy. So it may just be a issue of running to aggressively for your particularly extreme conditions. First thing I would do is lower boost to 13psi on meth and just see if things clear up a bit. If they do, you can start inching upwards from there.

And yes, a bad injector can cause what you are seeing. But if you have had all the recall work done and aren't tripping any strange injector-related codes, I think you are fine.

[Ilma]

Wondering why your meth flow rate is sitting around 40?

Mine pegs at 30 as most other PWM logs I have seen do.

[sear]

Originally Posted by Ilma

Wondering why your meth flow rate is sitting around 40?

Mine pegs at 30 as most other PWM logs I have seen do.

Good question? Does the Injection flow user parameter control this? I've got it set to 20 as prescibed by vishnu.

[Ilma]

Originally Posted by shiv@vishnu

At 6000' altitude, your atmosphere pressure is about -5psi. So when you run 15psi of boost, your actually running 20psi of boost. And you are on 91oct which is going to be iffy.

Just last week I filled up with a quarter tank of 91 octane instead of my usual 94 and low to mid rpm timing dropped a couple of degrees - which surprised me considering meth was in the mix too!

But it's true.

[Ilma]

Originally Posted by sear

Good question? Does the Injection flow user parameter control this? I've got it set to 20 as prescibed by vishnu.

Mine's set at 20 as well

[sear]

Originally Posted by shiv@vishnu

At 6000' altitude, your atmosphere pressure is about -5psi. So when you run 15psi of boost, your actually running 20psi of boost. And you are on 91oct which is going to be iffy. So it may just be a issue of running to aggressively for your particularly extreme conditions. First thing I would do is lower boost to 13psi on meth and just see if things clear up a bit. If they do, you can start inching upwards from there.

And yes, a bad injector can cause what you are seeing. But if you have had all the recall work done and aren't tripping any strange injector-related codes, I think you are fine.

Base atmospheric pressure here typically reads about -2.5 to worse case -3psi. IIRC, 17.5psi was recomended for map2/4 I just backed off that much for my settings. I can certainly try backing boost down and stepping back up, but I should be OK where I'm at. Its been a little while since I looked up the pressure drops by altitude, but I'm sure I;m not -5psi at 6000ft.

[OpenFlash]

Originally Posted by Ilma

Wondering why your meth flow rate is sitting around 40?

Mine pegs at 30 as most other PWM logs I have seen do.

The newer super-compact flow meters provide a little different output than the older ones. Flow is the same but they provide a higher nominal freq output signal.

[sear]

Originally Posted by Ilma

Just last week I filled up with a quarter tank of 91 octane instead of my usual 94 and low to mid rpm timing dropped a couple of degrees - which surprised me considering meth was in the mix too!

But it's true.

This would be consistent with what I'm seeing. Did your drop as much as mine in 3rd gear?

[OpenFlash]

Originally Posted by sear

Good question? Does the Injection flow user parameter control this? I've got it set to 20 as prescibed by vishnu.

Since your flow numbers peak at 40, you can raise the injection mode value closer to it. Try 30. This will prevent the tune from getting full aggressive at too low of a meth flow rate.

But you simply may be bumping up against octane limitations at your altitude. Just for testing purposes, you can try running 100oct plus meth to see if the random timing drop goes away. I suspect it will. At that point, you have no option but to run a lower boost pressure or perhaps run a stronger mix of meth. What meth brand/type are you running? What mix?

[sear]

Originally Posted by shiv@vishnu

Since your flow numbers peak at 40, you can raise the injection mode value closer to it. Try 30. This will prevent the tune from getting full aggressive at too low of a meth flow rate.

But you simply may be bumping up against octane limitations at your altitude. Just for testing purposes, you can try running 100oct plus meth to see if the random timing drop goes away. I suspect it will. At that point, you have no option but to run a lower boost pressure or perhaps run a stronger mix of meth. What meth brand/type are you running? What mix?

I'm running 75/25 mix of SUNOCO meth and distilled water. If I can find some race gas nearby I'll see how that works out, not sure if there is a source closer than an hour drive. If not, I can drop boost a few psi and log from there.

I guess I can also try injection mode to 30 as well. should I try this first?

[OpenFlash]

Originally Posted by sear

I'm running 75/25 mix of SUNOCO meth and distilled water. If I can find some race gas nearby I'll see how that works out, not sure if there is a source closer than an hour drive. If not, I can drop boost a few psi and log from there.

I guess I can also try injection mode to 30 as well. should I try this first?

Sure, try it. It won't change your octane limitation. It will just make it so that your Procede waits for more meth flow before it transitions fully over to the aggressive map. It's worth trying. I'm not familiar with Sunoco meth. Is it true/pure meth (99.9%) or does it have some additive mixed in? Ie, is it like VP racing M1 (which is recommended) or VP racing M3 or M5 (which isn't recommended)?

http://www.vpracingfuels.com/vp-drag-racing.html

[sear]

Originally Posted by shiv@vishnu

Sure, try it. It won't change your octane limitation. It will just make it so that your Procede waits for more meth flow before it transitions fully over to the aggressive map. It's worth trying. I'm not familiar with Sunoco meth. Is it true/pure meth (99.9%) or does it have some additive mixed in? Ie, is it like VP racing M1 (which is recommended) or VP racing M3 or M5 (which isn't recommended)?

http://www.vpracingfuels.com/vp-drag-racing.html

my understanding is that its like M1 for concentration of METH. I get it at a local Speed shop. Its the only METH supply in under an hour drive that I could find.

[OpenFlash]

Originally Posted by sear

my understanding is that its like M1 for concentration of METH. I get it at a local Speed shop. Its the only METH supply in under an hour drive that I could find.

Then that should be perfectly fine. You should be able to get some 100ct at that same speed shop. Give that a try as well. If the timing drops stop, the you know you are simply dealing with an octane constraint when running 91oct+meth at your altitude.

[sear]

One related question on your point about the proceed switching maps based on METH flow. Is the inital map being used Map 1 (that is effected by user settings from Map 1), or is it just a conservative derivative of Map 2 settings?


In someone else's PWM post last week, it was speculated that Map 1 settings would have an impact until the switch occured. If this is true, I have IC at 85% on Map 1. (Altough this isn't how I thought it worked)

[sear]

Originally Posted by shiv@vishnu

Then that should be perfectly fine. You should be able to get some 100ct at that same speed shop. Give that a try as well. If the timing drops stop, the you know you are simply dealing with an octane constraint when running 91oct+meth at your altitude.

Thanks for support Shiv

[The Ghost]

Originally Posted by sear

One related question on your point about the proceed switching maps based on METH flow. Is the inital map being used Map 1 (that is effected by user settings from Map 1), or is it just a conservative derivative of Map 2 settings?


In someone else's PWM post last week, it was speculated that Map 1 settings would have an impact until the switch occured. If this is true, I have IC at 85% on Map 1. (Altough this isn't how I thought it worked)

From their documentation, map 4 is a mode. When in "Map 4", it runs map 1 boost/timing/fuel until it reaches the meth flow threshold, then linearly transitions from map 1 to map 2.

Now that I have meth, I leave map 1 conservative (100% IC, 13psi), and leave the fun stuff for map 2 (0% IC, 18psi).

[edit]
I found the direct quote from their Documentation:

When running on Map4, the Procede will transition between Map1 and Map2 boost/fuel/timing settings based upon monitored methanol flow. If there is no meth flow, the Procede will follow Map1 settings. Once meth flow exceeds the value defined in the “Injection Mode” adjustable, the Procede will have fully transitioned to Map2 settings. This transition is linear as a function of methanol flow. It is not an abrupt on/off transition.

[Tzu]

Meth with 91oct @ Map2 of 15psi, I got some pretty bad dropouts. With 94 timing is fine.

Like others have stated however, your elevation is whats killing you. You high altitude guys have to run much lower boost in general.

[sear]

Yea, was able to drop boost to 45% today and saw a reasonable improvement in the drops. Timing still isn't completely flat at 10deg, but its only dipping to ~7deg and ramping up to 10deg by redline.

Power fells strong and smooth all the way through 3 gears now