Suspension, Brakes, Drivetrain discuss the wondrous effects of boost and your miata...
Sponsored by:
Sponsored by:

Motor mounts and shifting

Thread Tools
 
Search this Thread
 
Old 03-31-2011, 03:07 AM
  #1  
Elite Member
Thread Starter
iTrader: (6)
 
kenzo42's Avatar
 
Join Date: Sep 2007
Location: CA
Posts: 2,016
Total Cats: 13
Default Motor mounts and shifting

This probably has a very simple explanation, but I don't know squat about transmissions. I'll probably feel stupid after hearing the answer...

Question: why is it that stiffer motor mounts make shifting smoother? Is the bellhousing flexing? Doesn't seem like it can flex, but who knows.

I ask b/c I was considering the FM DP brace.
kenzo42 is offline  
Old 03-31-2011, 03:24 AM
  #2  
Former Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,099
Default

The entire drivetrain is attached to the car at 4 points - two motor mounts and two diff mounts. Stiffen them up and the drivetrain rocks in the chassis less, which moves the shifter around less and makes shifting easier.
Savington is offline  
Old 03-31-2011, 10:09 AM
  #3  
Elite Member
iTrader: (8)
 
shlammed's Avatar
 
Join Date: Dec 2008
Location: Kingston, Ontario
Posts: 2,910
Total Cats: 51
Default

could explain why i could never snap 3rd with my worn out engine mounts.
shlammed is offline  
Old 03-31-2011, 10:31 AM
  #4  
Elite Member
iTrader: (12)
 
Doppelgänger's Avatar
 
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,850
Total Cats: 71
Default

"BradC" on here got his hands on this Carbing transmission brace, which I would imagine would be quite nice to have and reduce almost all drivetrain rock and reduce wear on the engine/diff. mounts as well.



They're discontinued and are as rare as hens teeth. He said something about having a similar part made but nothing ever came of that. I would love to get my hands on such a device.
Doppelgänger is offline  
Old 03-31-2011, 11:01 AM
  #5  
Elite Member
iTrader: (2)
 
BenR's Avatar
 
Join Date: Jun 2006
Location: ABQ, NM
Posts: 1,838
Total Cats: -7
Default

I'd love one of those, I'd make one, but I can't weld AL. Would probably be easy to make.
BenR is offline  
Old 03-31-2011, 01:02 PM
  #6  
Senior Member
iTrader: (6)
 
wittyworks's Avatar
 
Join Date: May 2009
Location: San Francisco
Posts: 983
Total Cats: 23
Default

Does anyone have any more information on that carbing trans brace? I could definitely look into making a run of those if people are interested.
wittyworks is offline  
Old 03-31-2011, 01:06 PM
  #7  
Elite Member
iTrader: (9)
 
TurboTim's Avatar
 
Join Date: Jun 2006
Location: Chesterfield, NJ
Posts: 6,892
Total Cats: 399
Default

better solution to guaranteed snapping 3rd is to attach the seat to the drivetrain instead of the chassis. That way when the motor mounts wear out you can still SNAP THAT BITCH yeah baby horray!!
TurboTim is offline  
Old 03-31-2011, 01:09 PM
  #8  
Senior Member
iTrader: (6)
 
wittyworks's Avatar
 
Join Date: May 2009
Location: San Francisco
Posts: 983
Total Cats: 23
Default

Looked up the carbing brace, couldnt find nearly any info on it. But I did also find this trans brace idea.

http://www.miata.net/products/hot/images/rsp301-027.jpg

I'll start a thread on the idea of making these soon and see what happens.
wittyworks is offline  
Old 03-31-2011, 01:10 PM
  #9  
Senior Member
iTrader: (6)
 
wittyworks's Avatar
 
Join Date: May 2009
Location: San Francisco
Posts: 983
Total Cats: 23
Default

Originally Posted by TurboTim
better solution to guaranteed snapping 3rd is to attach the seat to the drivetrain instead of the chassis. That way when the motor mounts wear out you can still SNAP THAT BITCH yeah baby horray!!
I wish there was a "like" button on here, a la facebook, but instead I'll just do it this way.

LIKE!!
wittyworks is offline  
Old 03-31-2011, 02:31 PM
  #10  
Elite Member
 
JasonC SBB's Avatar
 
Join Date: Jul 2005
Posts: 6,420
Total Cats: 84
Default

Can anyone say "NVH"?

(LOL, disclaimer, my miata is a street car)
JasonC SBB is offline  
Old 03-31-2011, 03:33 PM
  #11  
Elite Member
iTrader: (12)
 
Sean's Avatar
 
Join Date: Nov 2009
Location: Harpers Ferry WV
Posts: 1,516
Total Cats: 20
Default

That would be so easy to make out of steel and it still would not weigh that much.
Sean is offline  
Old 04-01-2011, 12:48 PM
  #12  
Junior Member
 
GDSpeed's Avatar
 
Join Date: Apr 2010
Location: DC Area, VA
Posts: 71
Total Cats: 2
Default

Originally Posted by JasonC SBB
Can anyone say "NVH"?

(LOL, disclaimer, my miata is a street car)
I have Mazda Comp engine mounts and ES poly diff mounts in my car - made shifting a whole lot more positive but the added NVH was surprisingly minimal. The car buzzes and shakes a bit more at idle but in all its pretty negligible.
GDSpeed is offline  
Old 04-01-2011, 02:26 PM
  #13  
Junior Member
iTrader: (8)
 
kaisersoze's Avatar
 
Join Date: Jul 2008
Location: Portland, OR
Posts: 401
Total Cats: 9
Default

Moss used to have a similar brace but doesnt appear like it is available anymore. the picture is still up though and gives a better idea of how it mounts. Looks like it would be pretty simple for someone to make. It's basically like the Racing beat control arm brace but it also bolts to the transmission.
http://www.miatamania.com/Shop/ViewP...05&SortOrder=1
kaisersoze is offline  
Old 04-01-2011, 04:19 PM
  #14  
Elite Member
iTrader: (12)
 
JayL's Avatar
 
Join Date: May 2007
Location: Austin, TX
Posts: 1,881
Total Cats: 2
Default

I want to say that in the past a few people that ran those transmission braces ended up having ppf issues.
JayL is offline  
Old 04-01-2011, 07:47 PM
  #15  
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,085
Total Cats: 375
Default

one day I' going to install this:

It makes a difference in how much the trans moves around.
hustler is offline  
Old 04-02-2011, 09:00 AM
  #16  
Elite Member
iTrader: (2)
 
Oscar's Avatar
 
Join Date: Jan 2007
Location: Bolton, UK
Posts: 3,022
Total Cats: 120
Default

Originally Posted by Doppelgänger
"BradC" on here got his hands on this Carbing transmission brace, which I would imagine would be quite nice to have and reduce almost all drivetrain rock and reduce wear on the engine/diff. mounts as well.



They're discontinued and are as rare as hens teeth. He said something about having a similar part made but nothing ever came of that. I would love to get my hands on such a device.
I have one installed and I love it. Got it for $50 locally. I want to swap the rubber bushings for something stiffer tho.
Oscar is offline  
Old 05-12-2011, 07:50 AM
  #17  
Elite Member
iTrader: (12)
 
Doppelgänger's Avatar
 
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,850
Total Cats: 71
Default

Bringing this thread back-

Hussie, I have that diff. brace. It'll do more for you than your pozi hooker NSA friends. Get it.


I was skimming through pics on CR and saw this gay engine bay. But it has a rather interesting "torque brace". Looks like it has a nice rubber mount in it as well.

Doppelgänger is offline  
Old 05-17-2011, 06:49 PM
  #18  
Elite Member
 
bbundy's Avatar
 
Join Date: Jul 2005
Location: Anacortes, WA
Posts: 2,478
Total Cats: 144
Default

Originally Posted by GDSpeed
I have Mazda Comp engine mounts and ES poly diff mounts in my car - made shifting a whole lot more positive but the added NVH was surprisingly minimal. The car buzzes and shakes a bit more at idle but in all its pretty negligible.
I have the same combo in my car and the car vibrates like crazy at 3500 to 3700 RPM under light load. Loud vibration in the cabin. It is kind of annoying to drive on the street it just goes nuts as you pass through that RPM range with the drive shaft ingaged.

I also took the mass damper off the drive shaft and have an unsprung 4 puck clutch with a 7 lb flywheel though with lots of overrun buzz though by taking the sprung disk out.

Based on other peoples comments I didn’t expect the diff mounts to be as bad as what I am exeriancing but maybe it is other things with my setup that are contributing.

The soft AWR engine mounts were unbearable with this combo and I went back to Mazda comps.

Bob
bbundy is offline  
Old 05-17-2011, 06:54 PM
  #19  
I'm Miserable!
 
Techsalvager's Avatar
 
Join Date: Jun 2009
Location: albany, ga
Posts: 1,866
Total Cats: 0
Default

MMR engine mounts rock my world between 1k rpm to 2k rpm on the tach. Everything vibrates, if something isn't bolted down, you gonna lose it.
Techsalvager is offline  
Old 05-17-2011, 11:48 PM
  #20  
Elite Member
iTrader: (13)
 
falcon's Avatar
 
Join Date: Dec 2009
Posts: 2,499
Total Cats: 16
Default

I had my MMR engine mounts in the car for about 10 minutes. After busting knuckles putting them in for an hour I promptly pulled them out. I did like the combo of one MMR and one stock mount. I also had MMR diff mounts in my old car and didn't mind them. I NEVER missed gears with that set up.
falcon is offline  


Quick Reply: Motor mounts and shifting



All times are GMT -4. The time now is 11:23 PM.