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Cobb JB4 backend flash?

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themyst

Ready to race!
Location
NYC
Given this platform is progressing virtually identically to the BMW N54 platform I came from, I have an idea here,

Would BMS be willing to come up with a backend flash for the various setups (91 octane, 93 octane, race/meth, E85, etc.)

By having the ECU directly control timing and fuel, we will get more fuel, faster AFR targeting as opposed to the current o2 biasing, and more timing.

Given ATR is out, I'd love to see this come to fruition. Am willing to buy an AP to get the best of both worlds.
 
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0bLiViOuS

Go Kart Champion
Location
Orange County
Guess this is a question for George, but I think with setups that require it, they would.

I think for most setups though, the JB4 can do a lot of it already. I know having values (fuel specifically) hard programmed in the tune itself will allow further adjustment of the fuel trims, but is it proven yet that there is significant reaction time to environmental changes which makes this needed?
 
T

themyst

Ready to race!
Location
NYC
0bLiViOuS said:
Guess this is a question for George, but I think with setups that require it, they would.

I think for most setups though, the JB4 can do a lot of it already. I know having values (fuel specifically) hard programmed in the tune itself will allow further adjustment of the fuel trims, but is it proven yet that there is significant reaction time to environmental changes which makes this needed?
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o2 biasing is inherently slower than the ECU targeting what it should in the first place.

Also, on the timing front, there is clear evidence that excess perceived boost will drop timing like a rock as evidenced by countless JB4-only logs for reasons unknown. By having a higher ceiling (need to dig into the logic a bit more) we can target the timing we want in all situations

There are also VVT tables on the flash side that the JB4 cannot handle on its own which would net significant benefit.

The JB4 is a quality product no question, but we could enhance the benefits of it with a backend flash.
 
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0bLiViOuS

Go Kart Champion
Location
Orange County
I know it's a difference of reactive versus proactive, but I'm just curious if there's evidence having it hard coded on these particular ECUs shows a difference.

I think most of the timing values are a result of IATs. I don't have any issues and my timing is usually at or higher than flash values.

I definitely agree there are so many small enhancements a flash could add. I have always tuned my.other cars and I would revise the maps endlessly for part throttle driving. WOT is the easiest part usually :)

If Maestro drops and has everything I want, chance are I would get it. Still keep the JB4 for sure to control most of everything, but like you have said, for small improvements I'd love a tuning solution.
 
T

themyst

Ready to race!
Location
NYC
0bLiViOuS said:
I know it's a difference of reactive versus proactive, but I'm just curious if there's evidence having it hard coded on these particular ECUs shows a difference.

I think most of the timing values are a result of IATs. I don't have any issues and my timing is usually at or higher than flash values.

I definitely agree there are so many small enhancements a flash could add. I have always tuned my.other cars and I would revise the maps endlessly for part throttle driving. WOT is the easiest part usually :)

If Maestro drops and has everything I want, chance are I would get it. Still keep the JB4 for sure to control most of everything, but like you have said, for small improvements I'd love a tuning solution.
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timing drops like a rock after wild boost swings, either during tip-in or after a shift. IAT appears to impact boost targeting. the other day when my IAT flatlined at 32, (outside ambient 16 degrees F) stock ECU was trying to target 5 psi up top lol.

Problem is the JB4 is still influenced by the stock request, regardless of if it's additive or absolute.
 
TwinDad

TwinDad

Autocross Newbie
Location
Fort Lee, NJ
themyst said:
timing drops like a rock after wild boost swings, either during tip-in or after a shift. IAT appears to impact boost targeting. the other day when my IAT flatlined at 32, (outside ambient 16 degrees F) stock ECU was trying to target 5 psi up top lol.

Problem is the JB4 is still influenced by the stock request, regardless of if it's additive or absolute.
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Not sure why you are still using additive with the known cold air issue. I switched to target and I'm hitting 8+ lbs over the ecu request at times with fantastic looking timing. I believe the timing drop at tip in or after shifts happens on tunes as well. You are switching boost levels and rpm points that the computer is going to react to. The issue would be if your timing does not recover as the rpms climb back up. Also, after seeing some of the logs from tuned cars posted here, the tune isn't doing you any favors for timing. I saw one that climbed so high and hat I would be afraid in summer months and another that had so many corrections the bottom of the graph looked like a polygraph. I think if I was going for absolute max power that I can achieve, then stacking the two would make sense. For an everyday driver that does mostly what I need it to do, the JB4 is fantastic. I haven't seen anything better out of the Cobb yet.
 
T

themyst

Ready to race!
Location
NYC
TwinDad said:
Not sure why you are still using additive with the known cold air issue. I switched to target and I'm hitting 8+ lbs over the ecu request at times with fantastic looking timing. I believe the timing drop at tip in or after shifts happens on tunes as well. You are switching boost levels and rpm points that the computer is going to react to. The issue would be if your timing does not recover as the rpms climb back up. Also, after seeing some of the logs from tuned cars posted here, the tune isn't doing you any favors for timing. I saw one that climbed so high and hat I would be afraid in summer months and another that had so many corrections the bottom of the graph looked like a polygraph. I think if I was going for absolute max power that I can achieve, then stacking the two would make sense. For an everyday driver that does mostly what I need it to do, the JB4 is fantastic. I haven't seen anything better out of the Cobb yet.
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I've logged my car numerous times both with additive and target, both won't hit target in this weather. It does get closer to target once you go deeper into the pull as EGTs rise, especially in 4th gear. I've resigned to simply cranking the additive in the cold and dropping to map 2 when it gets warm outside.

You did explain why going with a backend flash for fueling/timing would be beneficial however.

I am sure there is a barometric / IAT compensation table on the ECU side that can be modified to adjust targeting to prevent a map from being "too hot" in the summer that the early flash tunes did not account for, or did not account for properly.

I'm one who truly believes "Feelings are for your girlfriend" but try taking 8 degrees of timing away where it should be. It was dyno proven that losing that much timing resulted in 25-35 whp loss of power on a car that should be making 430-450 whp. We've had similar tuning issues on the BMW E9x N54 platform and stacking a back end flash with the JB4 was a widely accepted solution to get the best from both worlds.

Nobody here is knocking the JB4. it's a great product with amazing support, time tested across many platforms. I'm just trying to discuss ways to maximize potential on our cars!
 
G

gn4rwhals

Go Kart Champion
Location
Detroit, MI
jovian said:
What's the benifit of stacking jb4 when you have cobbs protuning ability? Maybe I'm missing something?
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Water/Meth controller with built in electronic boost control.

You can literally cut boost back without a reflash when your W/M runs out.
 
TwinDad

TwinDad

Autocross Newbie
Location
Fort Lee, NJ
themyst said:
I've logged my car numerous times both with additive and target, both won't hit target in this weather. It does get closer to target once you go deeper into the pull as EGTs rise, especially in 4th gear. I've resigned to simply cranking the additive in the cold and dropping to map 2 when it gets warm outside.

You did explain why going with a backend flash for fueling/timing would be beneficial however.

I am sure there is a barometric / IAT compensation table on the ECU side that can be modified to adjust targeting to prevent a map from being "too hot" in the summer that the early flash tunes did not account for, or did not account for properly.

I'm one who truly believes "Feelings are for your girlfriend" but try taking 8 degrees of timing away where it should be. It was dyno proven that losing that much timing resulted in 25-35 whp loss of power on a car that should be making 430-450 whp. We've had similar tuning issues on the BMW E9x N54 platform and stacking a back end flash with the JB4 was a widely accepted solution to get the best from both worlds.

Nobody here is knocking the JB4. it's a great product with amazing support, time tested across many platforms. I'm just trying to discuss ways to maximize potential on our cars!
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Gotcha. I'm not seeing that timing pull on mine, but don't have a tune to compare it to. Not any data out there for the 1.8 like there is on the 2.0. I'm hitting 16+ degrees on top
 
G

GLoBaLReBeL

Ready to race!
Location
South Bend, IN
George . . Now you're talking my language!! TCU Tune?!?! Without giving to much away, would this be the same situation as al the other TCU tunes in that once it is flashed it can now been seen by VW and voids the warranty?
 
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