11-12-2017, 11:50 AM | #1 |
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JB+ Made My Car Slower? Shift Delay
Hello everyone!
I got a JB+ (along with a BMS intake) a few months ago and since install I noticed a nice mid range power boost during daily driving, however I am a little disappointed in the shift delay problems that some others have noticed on WOT. I went to the drag strip before doing the tune and intake install and I was really impressed with the times. With my stock 340i xDrive the best time I managed was a 12.863 @108.56 mph 1/4 mile. I then went a few weeks after installing the tune and intake (tune was at default 3 o'clock position). I was expecting to be under 12.5 but the best time I managed was 13.078 @105.67 mph. I did 5 or 6 runs and I was never able to get back into the 12s as before when I was stock which is disappointing since I never went into the 13s when I was stock. Both these runs were done on the same track. Weather was slightly cooler on the tuned run day but track was a little damp due to a slight drizzle. No other changes have been done to the car other than the tune and intake I mentioned. I always use Top Tier 93 octane gas from Costco. I have a feeling that the shift delay is hurting the times. Is there anything that can be done to fix this issue? I am considering upgrading to a JB4 in the spring but I want to make sure that will not have the same issue. Is there anyone who went from JB+ to JB4 and saw an improvement in shifts? I turned the dial back to the 12 o'clock position and I still feel the same shift delay.
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11-12-2017, 03:47 PM | #2 |
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If you are going slower with more boost then likely its an octane issue or just weather difference. I would not expect JB4 to help but it would let you log so you can better determine what is slowing the car down.
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11-14-2017, 10:21 AM | #3 | |
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One point Terry made to me personally - every car is different. Some tolerate more or less timing differently with added boost. My car super sensitive to octane... the best gas yields tiny gains in timing - but any improvement allows me to run higher boost than stock.
Costco is not "top tier gas" lol.... And yes Top Tier gas makes a big difference. Put some VShell in there OR put 1 gallon of E85 with your "Costco Top Tier Gas".. Dont put more than 1 gallon - your trims / afr may rise without you knowing.. Timing is key to make power with added boost. If timing is retarding - all the extra boost wont make a difference - this is probably whats occuring due to your "Costco Top Tier Gas". Of course weather plays a role but varies most by season not by day or week honestly. For example, I can now run 3 PSI additive now that the weather is cold out... but during the summer with my VShell 93 the best I could run and maintain sufficient timing was 2 PSI. (I have 440 with MPPSK which already has roughly 2 -3 PSI above stock thus the very conservative boost targets). My suggestion is first get some good premium gas and see how it drives... If its still falls flat, back it off... keep backing it off until you see gains. The benefit of the JB4 is you can see all the metrics needed to properly tune to the situation (ie bad gas, hot weather, etc. etc.). PS - I have no shifting issues honestly - may or maynot be because of the JB4 Quote:
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11-14-2017, 03:51 PM | #4 | |
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It's every bit as good as Chevron and Shell, as many people have logged and verified this on many platforms. I highly doubt it's his gas considering it was used on both runs. All these additive based "boost controllers" honestly don't work well on the B58. I've had two of the top name brands and both produced significantly slower shift speeds although added power was there. The torque intervention with the 8AT is quiet aggressive. Their are too many mixed reviews about shift delays and shift speeds to believe the Jb4 is immune from it unless you significantly taper the boost at redline. I've specifically asked even Terry about this with no answer given...and there are more than a few JB4 owners complaining of it and some say they don't notice. |
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11-15-2017, 10:26 AM | #5 | |
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No matter what as you add boost you need timing.. and timing is dependent on many factors with Octane / Fuel quality being the most important. I would suggest trying a different brand of gas to prove or disprove that theory. Also try adding some Boostane when going to the track.
I cant speak of the shifting outside I have no issues at all on the JB4. And yes, the JB4 could cut throttle at a more precise time vs the JB+ that has no knowledge of the TQ index, RPM, etc. etc. So, it may be as you said. But getting back to your issue of slower times, the JB4 will tell you what you need to know no matter whats. Its a worthy purchase if your looking to squeeze reliable, enjoyable performance out of the platform. One point to make, most people I know who are running JB4 on a relatively stock car can easily push 3psi on 91 octane and easily push 4 or 5 PSI on 93 (and some cars 6 psi) all while maintaining positive timing. Based on this, you should be able to max out the JB+ and see improved performance - again, leads me to believe your too much boost for your octane (everything else being equal). Quote:
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11-15-2017, 11:35 AM | #6 | |
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Invaluable tool if you are trying to dial things in. Mike |
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11-15-2017, 04:56 PM | #7 |
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I would go with a JB4 for the datalogging feature ... It will save you a lot of time and headache
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11-16-2017, 12:51 PM | #8 |
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Yep - and how I found 2psi Additive on Map 6 yielded best performance during the summer ; and now 3psi Additive on Map 6 yields the best performance..
without it.. I would have been pulling my hair |
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11-18-2017, 08:37 PM | #9 |
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12-10-2017, 05:28 PM | #10 |
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What you are fighting is a boost spike on during WOT shifts on the 8AT. Only real cure is to get off the throttle slighty when shifting. Turning down the boost might fix it at shifts, but you lose all the power during the rest of the band.
It's the DME saving your transmission from blowing up due to an over-torque condition. |
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12-18-2017, 12:56 PM | #11 | |
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12-20-2017, 03:56 PM | #12 |
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It's probably worth noting that when you have something like a JB+ which is simply a boost scalar, drivability is not always going to be favored. A true tune will add the power with the drivability. It's why at a minimum we recommend the JB4.
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12-21-2017, 07:17 PM | #13 |
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So it looks like JB4 is the way to go in terms of better drivability and data logging. Does anyone have experiences going from JB+ to JB4? I'm assuming map 2 or map 3 is good to use on an essentially stock car with just a BMS intake on 93 octane.
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12-21-2017, 07:20 PM | #14 |
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I wouldn't assume JB4 is the route to go in terms of drivability...just about EVERY piggyback regardless of trickery has some sort of drivability downside especially with the 8AT. With that said the JB4 has the most available control to help tailor it to how aggressive you want it.
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12-21-2017, 07:24 PM | #15 | |
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12-22-2017, 07:20 PM | #16 | |
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12-28-2017, 05:44 PM | #17 |
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I'm sure you have but fact remains numerous people experience and complain about shift delays with piggybacks on the 8AT. This goes for Dinan, AA, JB+, JB4, etc.
Regarding the JB4 you can find complaints here and on N54Tech that dive into a big more details. You can also ask each one of these manufactures and they will also mention why it is...I know because I have and I've tried almost every major piggyback with my own $$. What the JB4 has going for it is you can manipulate the boost thresholds to drop near redline and this helps mitigate the torque intervention of the 8AT. That is probably the most positive aspect of the JB4. The AA Active-8 on the other hand makes more power but the shifts at redline are slower than my wife's CX5, especially on the colder nights (it runs almost 7psi of boost over OEM). The Dinan Sport wasn't as bad when only running the default 3psi setting. I'm not sure if the Dinan Stg1 is any better but that seems to have mixed reviews as well. I'm not trying to bash all piggybacks but in my opinion they leave a lot to be desired on the F30 B58 platform especially with the 8AT. This is going to be a platform and engine that benefits immensely from flash tuning. |
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12-29-2017, 12:50 PM | #18 | |
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Generally in my experience the JB4 shifting is fine under hard acceleration... it doesnt like around town driving.. especially if your coming to a stop sign and then give it some gas...
In sport manual mode its perfect under 99% conditions. Quote:
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12-29-2017, 01:01 PM | #19 |
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What boost leaks? Everything is locked down tight.
Car feeling laggier is normal? Is it actually faster, but feels laggier, or is it simply slower in low RPM's and a little faster in high RPM's? |
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12-29-2017, 07:30 PM | #20 | |
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01-02-2018, 05:35 PM | #21 | |
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Development always moves forward, especially with the JB4. What it has going for it that the other tuning solutions you mentioned don't are that the JB4 can datalog to evaluate problems like this, and has plenty of settings and mapping strategies to allow you to tune around whatever issues may come up. If more people capture JB4 logs of their shifting issue and post them to the BMS support forum I'm sure they can help you sort it out. The B58 JB4 cars I've driven all shifted as good as stock if not better. Mike |
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01-03-2018, 02:55 PM | #22 | |
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I will however have to disagree with another one of your statements as it seems too much of a sales pitch...yes it's possible with the right settings and climate for it to shift as good as stock. It will NEVER shift better though as it has zero positive impact or change on the TCU. The TCU on the 8AT will only delay shift times with the higher than normal load values. You can ask Terry this himself and he will tell you the same thing... I don't mean to argue with your comments my point is just about every vendor I've spoke too says what they need to sell a piggyback. If you speak to AA, Dinan, Burger, etc. they are all aware of the B58 and especially the 8AT limitations. I'm not trying to sound like a transmission snob but having owned the M3 7sp DCT and various DSG's the 8AT in stock form is pretty darn good in comparison...with a piggyback on more aggressive settings that benefit goes away quickly. For some that might not matter and other it's very noticeable. My reason for even bringing it to light and much of this info wasn't around 6-8 months ago when I started researching piggybacks. It was only threads of "OMG look at this awesome dyno run I did" |
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