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Better transmission mounts for 1/4 mile? Long read
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08-17-2007, 09:08 PM | #1 |
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Better transmission mounts for 1/4 mile? Long read
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Well after 3 days at the track trying to figure out why i was running so slow, worrying there was something wrong with my car, good news! theres just something wrong with me (well not really) anyway, stock i was consistently running ~13.5x @ ~105 i had almost a dozen slips of this after procede, i lost all consistency i was LUCKY if i got a 13.5 (first time @ track w/ procede last week, been 3 times since) most of the time 13.5 + out of 12 passes so far ive had 1 13.2 and one 13.4 the rest are 13.5+. i would miss third gear, reather i should say i DIDNT miss third gear maybe every 3 runs, its been horrible, and again this is all when i had very consistent runs stock (i missed a gear maybe twice out of the dozens of runs i made) also the way i shift at the track is obviously a lot different from the way i do on the street (0 problems on the street) or even on a road course now granted its a lot hotter now, thats no reason for my times to suck that much a few tenths sure, but not this so i was talking to another bimmer owner about my problem and he mentioned transmission mounts, said he got some better ones and it made his shift more solid, he also literally said "with the stock mounts the torque makes the transmission twist and the synchros not line up as good" this made me very skeptical because even though i know little about transmission mounts, i know it would have 0 affect on the interior of the transmission like that, so im very skeptical, what DID make sense after thinking about it though is the linkage, it seems very possible that the increased torque would affect that before this i had already started paying close attention to my shifts and logging them, i found in stock form i was ranging from .3-.5 per shift (rpm drop to where it climbs again) this was very consistently under .5, in the logs even the spot where i slip the clutch a little while engaging was consistent put back the 1.47 map, and it goes to hell again, cant get under .5 seconds, and third gear is hell to get into again :/ the point of this thread: who knows lots about transmission mounts, could it have a big affect while shifting quickly? im very skeptical that this is the reason, but since i have narrowed the problem down to shifting, and since it only comes on with increased torque, i figured there is a legitimate chance and to those who have read about my wonderful endevour going into 4th, the shifting problem was not caused by that and of course anything else anyone can think about that would affect shifting under more power, hate to be arrogant (ok no i dont, i love it) by i am NOT a noob at shifting so dont say its something like that, though maybe its just something i need to get used to the gates being in a little different position while shifting quickly like this |
08-17-2007, 09:18 PM | #2 |
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Sorry, I have no idea about the tranny mounts. However, after months of hearing about PROcede 335is with 6MTs having trouble launching (while PROcede 335i's like mine with the 6AT not having as much trouble launching)...how are your launches? Do you have major wheel/tire slippage or are you hooking up ok?
btw -- which track did you go to for the 13.5x+ sec. @ 105mph times?
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08-17-2007, 09:25 PM | #3 |
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The trans. mounts are actually pretty tough from the ones i've seen on BMW's. Diff. mounts are a different story unless you have an M car. I would think that is where the "twist" is coming from.. Take a look at one next time you see your car in the air and you will see what I mean.
makes me more curious to run my steptronic now...
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08-17-2007, 09:28 PM | #4 | |
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and no, no trouble launching (well no more than should be expected), 2.0-2.1 60 foots, i haven't gotten launching 100% down because ive been preoccupied with worrying about shifting, if i was having trouble launching though i would have mentioned that, its definably shifting (and a tenth or so from the heat) that accounts for it edit: sorry the mph's were 104s, i was thinking of the one 13.5 i ran w/ procede, that was a 105 |
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08-17-2007, 09:29 PM | #5 | |
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08-17-2007, 10:18 PM | #6 |
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The mounts themself will have little affect on the speed of the shift, particularly with an AT. With a MT, you could run into some problems with the shift gate. I am not sure what the mounts are made of, but if there are just rubber, then it's certainly something that may need to be replaced. Also have to worry about the engine mounts too if thats the case.
I have used polyurethane mounts and solid metal mounts in my Nova. I wouldn't consider the latter for the BMW because of the bad drivetrain vibration you will get. I always run the combination of solid motor mounts and urethane transmission mounts. You don't want to change the transmission mounts without changing the motor mounts (particuarly if they are rubber), because as the engine twists, if there is no flex at the transmission because of stronger mounts, then engine mounts quickly tear. Change the motor mounts > then change transmission. Last edited by musc; 08-17-2007 at 11:09 PM.. |
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08-17-2007, 10:42 PM | #7 |
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533,
Did you remove your CDV? Are you using a shorter shift knob? Are you power shifting? Are you using stock tires? All of these will affect 1/4 mile time.
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08-17-2007, 10:48 PM | #8 | |
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as for the rest, yes i have done CDV removal, yes i have a shorter knob, yes i am using stock tires, i dont "power shift" per se, but i do shift much quicker at the track than i do normally (which is the type of shifting ive been talking about) im not comparing my times with someone else though, im comparing them to my own, i lose 1-3 tenths per shift (so x3) after i load the 1.47 map this in line with the hotter temps very well accounts for my unimproved time (combined with the extreme constancy to extreme unconsitancy) its something to do with the tranny and shift gates, i know that much, just trying to figure out whats causing it oh and before someone gets on my ass for knocking the procede, this is in NO WAY me saying the procede is causing problems, procede is awesome |
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08-17-2007, 10:56 PM | #9 |
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There are several companies that have stiffer transmission mounts that work out well for the older BMWs but I haven't seen the stock trans mounts or if they look like the old ones. According to the picture on ETK it does look like BMW is still using the same style.
If so then a set of Rogue Engineering Transmission mounts will be a great mod for the manual transmission owners. Benefits include precise feel of the shift gates because the transmission doesn't twist as much. Inexpensive too.. only $45.00. Again I have to confirm if the Rogue TMs can replace the stock ones. |
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08-17-2007, 10:59 PM | #10 | |
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08-17-2007, 11:06 PM | #11 | |
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So you're theory about the transmission twisting due to increase torque is highly plausible. Only way to test it is to actually buy the mounts and install them to see how it feels. I haven't read of any E90 335i with them yet. This is a highly popular modification for E36, E46, and E39 M5s with a manual transmission. http://www.rogueengineering.com/Merc...tegory_Code=TM |
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08-17-2007, 11:10 PM | #12 | |
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the "sure why not" does not inspire much confidence though <_< |
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08-17-2007, 11:11 PM | #13 | |
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08-17-2007, 11:13 PM | #14 | |
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I just havent heard of anyone with a 335i manual having to install aftermarket transmission mounts and giving a review. |
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08-17-2007, 11:15 PM | #15 |
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i dont mind vibration through the transmission, i actually would like some more feedback from this car, i know its "more refined" but i liked my cheap ass car where i could feel every little thing
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08-17-2007, 11:16 PM | #16 | |
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The Rogue Engineering Transmission mounts are of a cylindrical shape with are higher durometer rating rubber so it is stiffer than factory. You don't want to put solid transmission mounts. |
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08-17-2007, 11:17 PM | #17 | |
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Other companies sell transmission mounts with a metal top reinforcement. With those kits you have to torque them down properly or else there will be an increase of NVH. |
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08-17-2007, 11:19 PM | #19 | |
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When I get to the office tomorrow I'll try to take pics of the Rogue instructions if I still have them in stock. |
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08-17-2007, 11:22 PM | #21 | |
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http://m3.madrussian.net/diy_re_tranny_mnt.shtml |
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08-17-2007, 11:33 PM | #22 | |
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looks like |
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