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10-09-2017, 10:04 PM | #23 | |
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subframe bushings alone should be good, just know that it isn't a common route. the subframe and diff bushings work together to buffer NVH and soften the ride a bit. if you just do sub bushings and leave the diff bushings oem, you're going to transfer 100% of the shared load that was previously distributed among all of the bushings back there. understand what i mean? you might get more differential deflection since it is the only thing that can flex. i personally would go all the way with the bushings (solid sub, derlin diff) or don't do it. i get slight diff whine from about 55mph to about 83ish mph. if i cruise at about 85 (not ideal), it fades away. windows down i can't hear it. windows up with radio on helps, but you can hear it when the radio is at lower volumes. for me personally, if its not too hot, i have both windows down. if you're one of those "auto" climate control guys that rolls around with their windows all the way up, you might be annoyed. i still have oem dct software. when i mention clunk, i'm talking about when downshifting while coming to a stop and the car lurches a little bit because now it is mechanically slowing down in addition to brake force and it combines and now you're stopping even faster.... that sort of thing. if you're in 2nd gear and on it pretty good, then let off the throttle, then get back on it, its a little harsh (oem or not). this driveshaft combined with the bushings sharpens that. its crisp- more immediate. i feel like it doesn't make anything new, it just magnifies what is already there.
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10-09-2017, 11:01 PM | #24 |
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Solid subframe bushings are one of the best mods I've done. Makes the M3 feel like a newer chassis.
Now the bad news - M Factory carbon drive shafts are on back order for 2-3 months. I asked if that was a real time frame or is it delayed indefinitely (due to the legal issues YCW were having with the carbon tube supplier), no reply yet. |
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10-09-2017, 11:07 PM | #25 | |
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Couple more questions for ya: It seems a majority of the sound (whine), if not all, is due to your diff and subframe (solid) bushings, correct? If so, I am leaning towards retaining my OE (new) bushings coupled with the CF propshaft. Do you think there will be any issue with using this CF propshaft with the OE (new) bushings? Are the OE bushings robust enough to deal with the more direct force of the CF propshaft? TIA |
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10-09-2017, 11:26 PM | #26 | |
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i think you'll be fine with oem bushings and the carbon shaft. just not if you're supercharged or track your car a bunch. i take it you have seen my subframe undercar video?
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10-09-2017, 11:27 PM | #27 |
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Solid subframe bushings add zero NVH. And CF driveshaft actually flexes more than steel and is less harsh on drivetrain components.
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10-09-2017, 11:59 PM | #28 | ||
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Quote:
Last edited by buddalun; 10-10-2017 at 12:04 AM.. |
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10-10-2017, 12:13 AM | #29 | |
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For max performance, aluminum subframe and either delrin or aluminum diff is probably your best bet. But for keeping NVH to a minimum while still vastly improving rear end stability, aluminum subframe and PowerFlex purple is the ticket. |
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10-10-2017, 01:33 AM | #30 | |
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10-10-2017, 05:24 AM | #31 | |
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AA Gen 2 Lvl 2 w/Meth; MagnaFlow catless x-pipe; Dinan Underdrive Pulley; VAC Coated Bearings; ARP Rod Bolts; Oil Diverter Valve; Dinan Strut Braces; Dinan Rear Toe Links; ECS Rear Trailing Arms; MCS 2-Way NR w/700F-1000R; GC Camber Plates; AKG 75D MM & 95A TM; CAE Shifter; Titan T-S5; StopTech ST60 380mm/ST40 355mm; MFactory DS; Zebulon Splitter; Zebulon 330 Rear Wing; Gutted w/Piper Motorsports Custom Cage; OMP WRC-R Seats
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10-10-2017, 05:32 AM | #32 |
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10-10-2017, 01:48 PM | #33 | |
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I would say for me it is maybe 10-15% more than stock at most. All I can say is that I almost never hear it except for a brief moment in very rare scenarios with the radio off and the car in the gear/speed combo. With the delrin bushings it was the opposite: it was pretty much there nonstop (and louder) except on rare occasion. PowerFlex Purple was a godsend for me; bummer you aren't getting the same mileage out of it. Edit: I should also add that I have the diff damper installed that MRF was testing on my car. However, it didn't seem to make a tremendous difference with the delrin bushings so I assumed it wasn't doing a whole lot with the PowerFlex Purple, but I could be wrong. Maybe it's the combo that is really working the magic. |
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10-10-2017, 02:09 PM | #34 |
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I recently installed akg red 75d poly subframe bushings and 95a black poly diff bushings. There is whine from 65-75 mph. It's not bad but you can hear it. It's diff speed dependent so a dct may differ from my 6mt. I like the improvement in rear end feel from the subframe bushings. I did the diff bushings because a few people have broken diff bolts or damaged their diffs or even their subframe. I would not go any harder than 95A for the diff. Powerflex purple is softer. I did drive a solid subframe solid diff car but it was a convertible and the top was down so I heard other sounds.
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10-10-2017, 06:20 PM | #35 |
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I may have to try the diff damper...I wouldn't trade the improved feel for zero whine but if I could have my cake and eat it too I'd be psyched.
I'm one of the victims of the broken diff bolt. |
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10-10-2017, 07:34 PM | #36 | |
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i put three 3"x8" cuts of dynamat like material on the subframe tubes and i think it helped a tiny bit in dulling the sound, but it is definitely still there. i don't expect it to completely go away, but if i can reduce it, i'd be stoked. i'm going to see malek on the 19th for some work.
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07-23-2018, 01:28 PM | #37 |
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I hate to bump an old thread but it looks like the driveshaft was removed from the MFactory website. Did they discontinue it? Any news? Does another company make a carbon fiber driveshaft that uses the factory guibo? Thanks for the help!
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07-23-2018, 04:40 PM | #39 |
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07-23-2018, 09:00 PM | #40 |
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07-24-2018, 06:21 PM | #41 |
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I can only wish that it becomes true. Been waiting quite a while to hear some upcoming news from them.
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07-25-2018, 09:47 PM | #44 |
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What about this option?
https://store.vacmotorsports.com/mob...e92-p3692.aspx |
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