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Transmission remap - Let's do it ourselves
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06-15-2015, 01:04 PM | #155 |
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This has been done in Europe. There is a blog site that explains much of the process (but I can't find it right now). As you might have guessed, the challenge is still in the software side of things. Mechanically, it is relatively easy. Unless, you insist on a BMW transmission.
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06-15-2015, 02:57 PM | #156 | |
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06-15-2015, 03:49 PM | #157 | |
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http://www.tremec.com/anexos/File/TREMEC_TR-6060.pdf
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06-15-2015, 05:33 PM | #158 | |
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06-15-2015, 07:07 PM | #159 | |
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The gear ratios are vastly different though. 1 2 3 4 5 6 Tremec: 2.26 1.58 1.19 1.00 0.71 0.5 6hp28: 4.17 2.34 1.52 1.14 0.87 0.69 In 6th gear that would drop rpm from 2100 to 1521. While that would be perfect for mpg, maybe that's a little bit too low? And what a long 1st gear - it would actually be usable! Let's cut that that SW crap and get to good old mechanical work! Just kidding... |
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06-15-2015, 08:21 PM | #160 |
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Yeah there are a couple different ratio options but theyre all pretty different. You can get a 0.68 6th gear it looks like, but 1st and 2nd are wildly different. If this was a project car and not my daily I would seriously consider that. But, its definitely not in the 5 year plan. FWIW I dont think freeway cruise at 1300-1500 would be an issue in this car. Another daily of mine makes less than half the tq and cruises just fine at the same RPM the d currently does, dont have to downshift for anything but the steepest of hills.
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06-15-2015, 10:09 PM | #161 | |
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Man it'd be nice to get rid of the slushbox, have a 1st gear we can actually use, etc..... |
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06-17-2015, 08:16 PM | #165 |
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Looking for a parameter that indicates shifting status, with the hope it would give a clue to map selection. Doing considerable logging with Testo, just driving under a variety of conditions, I monitored a mystery parameter called "SA". It looks like a logical 'switch'. It's value correlates to both static and transitional states in D and DS. Looks like there are a couple of states I never encountered during my drives, based on the 'blanks' in the patterns. Not sure what to do with this other than share it as something interesting ... maybe it will come in handy later?
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06-18-2015, 07:13 AM | #166 |
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Thanks DWR. It makes it much easier to follow and envision now. By looking at the map for downshift 6>5 I can tell, that this is not the D XE map. At 50mph the downshift at 30% throttle needs to be around 50mph. And the upshift 5>6 is probably a bit lower so they are overlapping.
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06-18-2015, 09:00 AM | #167 |
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The upshift speed is always going to be higher than the downshift speed for a given throttle %, if it wasn't you would get locked in a perpetual downshift/upshift situation when you hit a cell between the two curves. It looks to me like the downshift at 30% is pretty close to 50mph.
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06-18-2015, 12:46 PM | #169 | |
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06-18-2015, 02:02 PM | #170 | |
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06-18-2015, 02:04 PM | #171 |
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That is an excellent hint 3lli0t! Thank you very much. I'll check it out. So far I wasn't very fond of NCS-Dummy and would rather use NCS-Expert. But that might change now .
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06-18-2015, 03:48 PM | #172 |
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At the risk of asking a stupid question, where is all this leading? I assume that by dissecting the software files the intent is to create our own transmission software flash. Correct? To the technologically sophisticated folks who have dedicated countless hours to the noble endeavor how far away are we from the end goal (assuming I have summed it up correctly)?
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06-18-2015, 03:53 PM | #173 |
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I would love to see the low throttle upshift dropped by several MPH in that range. You can hit 6th at about 42 mph with manual shifting, I see no reason that in D you shouldnt get the same situation at throttle % from 0-15 or even 0-20. The 6>5 would have to be dropped to about 38 in that range in order to make it reasonable though. I sometimes wonder if part of the reason the shifts seem too late at low throttle is because the transmission would just be shifting too much at low speeds if you cram that many gears into just 40 MPH and lower, so they knowingly sacrificed some mileage to avoid the confused transmission experience that many people complained about with the 6 and 8 speed autos when they first came out
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06-18-2015, 08:49 PM | #174 | |
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We are also trying to change the lock up behavior of the clutch especially in first and second gear in order to get rid of the slushy behavior. That is a little further out since we haven't found the maps yet and don't quite understand yet how they work. |
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06-18-2015, 09:01 PM | #175 | |
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Have you tried the A7610591 yet? |
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