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Default Any manual trans JB4 owners having issues with bog when shifting really fast? - 04-18-2018, 10:01 AM

If so we've got something new for you to test.

We made an interesting discovery for torque limiter based shift bog (a common issue when shifting fast) that we believe will lead to dramatically improve manual transmission shift response. Essentially, if the DME does not see the clutch press in during a shift, it appears not to trigger any torque limiters. We are getting scary hard shifts in our development cars. Completely awesome.

We plan to use the JB4 to dynamically shield the clutch information from the DME. But before we fully develop that we need a few customers who have bad MT shift lag to do a little experiment for us. You'll load special JB4 firmware, pull the clutch wire out in the DME connector, set FutureUseD bit4 on letting the JB4 know to enable the new logic, and log a few fast shifts, so we can ensure this solution seems likely to work in all applications. Once we have that data we'll get to work on further refining the logic.



To test it out:

1) Load the attached firmware (note both twin turbo and single turbo firmware attached).
2) Set FutureUseD Bit 4 on and save settings. It's called "Aquamist WMI algorithm" in firmware descriptions but that logic is now part of the WMI flow scaling.
3) Unplug the clutch wire as shown in this photo. Gray connector #18. It can just tuck out the way.
4) Enjoy must better fast shifts!

Side Effects:

1) As implemented, the JB4 is not currently reading gear, so boost by gear has been changed to boost by speed. Where 1st is < 40mph, 2nd is 60mph, and 3rd is 86mph. We've got some ideas to correct this back to true boost by gear we'll need to flush out.
2) With the DME no longer seeing the clutch position cruise control doesn't work.
3) The clutch safety start logic appears fully functional. Test and let me know if you find otherwise!
4) You'll have a shadow code stored for clutch pedal signal not active. Just ignore it.
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BMWSwede BMWSwede is offline
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Default 04-18-2018, 11:23 AM

This sounds interresting.

Sadly I can't do some logs right now.
Just recently got FBO + inlets/outlets and still runnig stock clutch.
Easy to say it didnt like 21psi at map 3 on 50% E85.
Will change my clutch in a week or so.

So if you need more logs at that time, I can help for sure.

Really nice to see that the JB4 still gets new functions and settings. ��
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ShocknAwe ShocknAwe is offline
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Default 04-18-2018, 11:31 AM

I definitely do. What I've noticed is that it seems a little better with boost limited, so it could be momentary wheelspin and limiter causing throttle closure. I'll get a log this weekend if I can.


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Default 04-18-2018, 11:51 AM

The specific torque limiter we've found a work around rears it's ugly head most often when trying to shift really fast, causing RPM to spike up as you press the clutch pedal in, and lasts around a second or so post shift.


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Default 04-18-2018, 12:12 PM

Quote:
Originally Posted by Terry @ BMS
The specific torque limiter we've found a work around rears it's ugly head most often when trying to shift really fast, causing RPM to spike up as you press the clutch pedal in, and lasts around a second or so post shift.
Could this also be why sometimes when I do a fast shift there's no blow-off? It's basically never realizing that the clutch was engaged and due to the blip of the RPMs it just keeps the throttle open?


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Default 04-18-2018, 12:37 PM

I sometimes get bog in that situation, but I'm not sure if it is that type.

Is this similar to the fix attempt where the clutch observation time was shortened in the BEF?

Any consequences if the DME is not doing mid-shift logic since it doesn't know the clutch was pressed? Is this meant for street use?
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Default 04-18-2018, 12:42 PM

Quote:
Originally Posted by Vorsprung_CJB
I sometimes get bog in that situation, but I'm not sure if it is that type.

Is this similar to the fix attempt where the clutch observation time was shortened in the BEF?

Any consequences if the DME is not doing mid-shift logic since it doesn't know the clutch was pressed? Is this meant for street use?
As to side effects I believe we have the JB4 set to mask any of them. But we won't know until more people test it over a wider range of operation.

The previous "bog fix" in the flash software as a flash time option was to trigger the fuel cut off faster when pressing the clutch, to avoid RPM from rising during fast shifts. Our NLS takes a similar (but more effective) approach. This is completely different and instead of attempting to arrest the engine speed from rising it instead gets the DME to ignore it.


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It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please click here for more information on legal requirements related to use of BMS parts.
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NA55 NA55 is offline
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Default 04-18-2018, 05:25 PM

I tried something similar a few years back by disabling the clutch switch, but experienced severe bogging on regular daily driving shifts. It appeared to remedy the RPM increase while shifting fast, but there seemed to be a delay in power once engaged in the next gear. Hopefully you've found a good solution.
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Default 04-18-2018, 05:43 PM

Quote:
Originally Posted by Terry @ BMS
The specific torque limiter we've found a work around rears it's ugly head most often when trying to shift really fast, causing RPM to spike up as you press the clutch pedal in, and lasts around a second or so post shift.
So THATs the reason I get huge rpm surge between shifts when slamming gears?

Would be awesome to have a fix.

But... Is it safe? Is there a reason for the torque limiter in regards to the clutch/transmission/axles? I'd like to hear your thoughts on that Terry.


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Default 04-19-2018, 08:23 AM

I'd be willing to try it out if I can help. My car always seems inconsistent on fast shifts. I've had times when it transisitions power perfectly, and times where it's faceplants for a second. Granted there could be other reasons for that.
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Default 04-19-2018, 09:00 AM

If anyone is able to help just email me for the firmware and directions.


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Default 04-19-2018, 12:18 PM

E-Mail or PM? I have this issue very bad.
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Default 04-19-2018, 12:35 PM

Email.


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It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please click here for more information on legal requirements related to use of BMS parts.
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PrzeChuj PrzeChuj is offline
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Default 04-20-2018, 03:25 PM

If had a similar issue , turned off 2 step and my problem was solved


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Default 04-20-2018, 06:03 PM

Quote:
Originally Posted by PrzeChuj
If had a similar issue , turned off 2 step and my problem was solved
Sounds like a different issue with your clutch wire there.


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It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please click here for more information on legal requirements related to use of BMS parts.
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Default 04-21-2018, 01:33 AM

really wish i could help you out with this as i am suffering from it badly, doesnt look like its caused by 2step nor anti lag.

but i dont have access to my car until june
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Default 04-21-2018, 06:43 AM

What email address must I send.
I have a hard time every time I try to shift to 3rd fast it falls on its face for 1 sec then goes on
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Default 04-21-2018, 08:30 AM

Quote:
Originally Posted by crazyyardie
What email address must I send.
I have a hard time every time I try to shift to 3rd fast it falls on its face for 1 sec then goes on
Added firmware and directions to first post!


Burger Motorsports
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It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please click here for more information on legal requirements related to use of BMS parts.
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Default 04-21-2018, 07:41 PM

Quote:
Originally Posted by mattgu40
really wish i could help you out with this as i am suffering from it badly, doesnt look like its caused by 2step nor anti lag.

but i dont have access to my car until june
Feedback so far has been positive... So give it a whirl when you can.


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Default 04-22-2018, 08:52 AM

Log from our E92 running PS2 turbos fast shifting.
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weebles weebles is offline
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Default 04-22-2018, 12:35 PM

So looking forward to testing this, the poor shifts are seriously one of the biggest gripes I have with this platform (6mt)..

Just need to get my new water pump installed and I will report back! So glad you've continued trying to cure this Terry, thanks for the great work.
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Default 04-22-2018, 03:51 PM

I get a bit of bog. I am a cruise control junkie - I'll take a ton of bog over a lack of cruise, so this is a hard no-go for me.
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Default 04-22-2018, 04:34 PM

Quote:
Originally Posted by Nitrousbird
I get a bit of bog. I am a cruise control junkie - I'll take a ton of bog over a lack of cruise, so this is a hard no-go for me.
The change is for those more concerned with racing performance, right now. Later we'll figure out how to provide the best of both worlds.


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It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please click here for more information on legal requirements related to use of BMS parts.
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Shafer Shafer is offline
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Default 04-23-2018, 06:31 AM

Thanks for putting this together for us MT guys to test out. I look forward to testing this whenever I have a chance to drive the car. Unfortunately, my DD is a 2008 Express van for work...

Once I have some input, I'll provide it. Thanks again Terry.
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islandboi3 islandboi3 is offline
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Default 04-23-2018, 09:32 AM

I DEFINITELY need to try this! I can test it when I get home today. I've just installed the jb4 and rev 3 yesterday. I might need some more info on step 2 though
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