Why do gears break on the stock transmissions? - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


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

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 09-15-2009, 12:52 AM   #21
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,362
Total Cats: 1,323
Default

My 6-speed use to grind almost every 1-2 and 2-3. Switched to MT-90 and they were gone within 3k miles. Just jumped to Amsoil/GM Synchromesh and they've stayed gone.

BTW - 3 trannies in 16k miles isn't ridiculous. I broke my 5 after 6k. thesnowboarder broke his at under 200whp after 1500 miles.

Last edited by Savington; 09-15-2009 at 01:06 AM.
Savington is online now   Reply With Quote
Old 09-15-2009, 01:38 AM   #22
:(
iTrader: (7)
 
Join Date: Jul 2006
Location: nowhere
Posts: 8,281
Total Cats: 2
Default

Quote:
Originally Posted by bbundy View Post
I have broken 6 of the 5 speeds. Driving style has very little to do with it. 300+ ft-lbs of torque and R-compound tires kills them in a short amount of time. Iíve broken 2nd twice, 3rd, twice and the gear that drives the secondary shaft and all gears but 4th twice. Gears stripped clean off.

I think I will try and find a cheap 6 speed until I can save the money for the Quafe. I still hate the gearing on the 6 speed. The problem I am having is I keep on getting 5 speeds for $75 or less and I havenít found a 6 speed for less than $700.

Bob
you said 220 whp and then you come on this post and say 300 ftlbs lol stop contridicting yourself. Yes the 6 speed will hold up alot better. But the gearing isnt ideal obviusly. If you have the no how and tools etc the quafie is a better deal.
magnamx-5 is offline   Reply With Quote
Old 09-15-2009, 08:43 AM   #23
Junior Member
iTrader: (4)
 
Join Date: Jan 2009
Location: Fife, Scotland
Posts: 296
Total Cats: 4
Default

I've been to the drag strip once with this car, so hard launches have very little to do with it. I drive my car hard, but I'm certainly not hashy with the gears. I drove this car for a year N/A and never had any problems. I've also been driving manual cars for over 7 years and never broke a box before.

It seems that the boxes plain can't handle the power. That, or maybe its Flatshift...
GrahamC is offline   Reply With Quote
Old 09-15-2009, 09:22 AM   #24
Senior Member
iTrader: (1)
 
Join Date: Sep 2007
Location: Trenton, NJ
Posts: 1,125
Total Cats: 0
Default

Quote:
Originally Posted by GrahamC View Post

It seems that the boxes plain can't handle the power.
That must be it. That's why my 275hp/263tq car has 20k of turboing on it and Paul's 311hp car has probably like 25k on it and both haven't blown a trans yet. And we ain't driving grandma around town either.
ArtieParty is offline   Reply With Quote
Old 09-15-2009, 10:07 AM   #25
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by ArtieParty View Post
That must be it. That's why my 275hp/263tq car has 20k of turboing on it and Paul's 311hp car has probably like 25k on it and both haven't blown a trans yet. And we ain't driving grandma around town either.
Deduct 10-12% for using dynojet garbage.
hustler is offline   Reply With Quote
Old 09-15-2009, 10:20 AM   #26
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,662
Total Cats: 1,560
Default

Quote:
Originally Posted by magnamx-5 View Post
you said 220 whp and then you come on this post and say 300 ftlbs lol stop contridicting yourself.
Hey, buddy, those were two different guys. GrahamC with 220 and bbundy with 300.
sixshooter is offline   Reply With Quote
Old 09-15-2009, 10:35 AM   #27
Senior Member
iTrader: (6)
 
tyson87's Avatar
 
Join Date: Aug 2008
Location: West Palm Beach, FL
Posts: 1,023
Total Cats: 1
Default

let me ask,
is there a difference in strength between the na and nb 5spd?
tyson87 is offline   Reply With Quote
Old 09-15-2009, 10:40 AM   #28
Senior Member
iTrader: (1)
 
Join Date: Sep 2007
Location: Trenton, NJ
Posts: 1,125
Total Cats: 0
Default

Quote:
Originally Posted by hustler View Post
Deduct 10-12% for using dynojet garbage.
You're just upset cause your car sux. You should've invested in a IM with larger TB first.
ArtieParty is offline   Reply With Quote
Old 09-15-2009, 10:52 AM   #29
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by ArtieParty View Post
You're just upset cause your car sux. You should've invested in a IM with larger TB first.
Why do you have to act like a ------ around me all the time? Friendship annulled.
hustler is offline   Reply With Quote
Old 09-15-2009, 01:25 PM   #30
Elite Member
 
Join Date: Jul 2005
Location: Anacortes, WA
Posts: 2,476
Total Cats: 114
Default

Quote:
Originally Posted by magnamx-5 View Post
you said 220 whp and then you come on this post and say 300 ftlbs lol stop contridicting yourself. Yes the 6 speed will hold up alot better. But the gearing isnt ideal obviusly. If you have the no how and tools etc the quafie is a better deal.
356hp and 321 ft-lbs on a dyno dynamics dyno at sea level with just 17 lbs of boost. I haven’t finished my last two track days with a transmission in tact.

I was making it through about 4 track days previously before upgrading the ECU and a few other things which upped the output a small amount.

Bob
bbundy is offline   Reply With Quote
Old 09-15-2009, 02:14 PM   #31
:(
iTrader: (7)
 
Join Date: Jul 2006
Location: nowhere
Posts: 8,281
Total Cats: 2
Default

ah my mistake i got cross posted bundy you are well past the know dangerzone for a stock five speed and need to consider doing something about it seriusly. No one has held much hope of more than 250 lb/ft through a stock tranny for any amount of time or abuse. For a long time. Either the FM gearset or the 6 speed would pay dividends for you.
magnamx-5 is offline   Reply With Quote
Old 09-15-2009, 02:20 PM   #32
Elite Member
iTrader: (8)
 
Join Date: Aug 2007
Location: Bellingham, Wa
Posts: 2,732
Total Cats: 3
Default

Man you guys have me worried for my tranny and i bet i'm not even at 200whp yet.

What is the gearing like with a 6sp and a 3.63? I dont know how to do the math.
wayne_curr is offline   Reply With Quote
Old 09-15-2009, 02:28 PM   #33
Elite Member
iTrader: (12)
 
Join Date: May 2007
Location: Austin, TX
Posts: 1,923
Total Cats: 0
Default

Quote:
Originally Posted by wayne_curr View Post
What is the gearing like with a 6sp and a 3.63? I dont know how to do the math.
If you make it down to Corksport this weekend you can take my car out for a drive. Should give you a better feel than looking at a chart.
JayL is offline   Reply With Quote
Old 09-15-2009, 02:30 PM   #34
Elite Member
iTrader: (8)
 
Join Date: Aug 2007
Location: Bellingham, Wa
Posts: 2,732
Total Cats: 3
Default

Quote:
Originally Posted by JayL View Post
If you make it down to Corksport this weekend you can take my car out for a drive. Should give you a better feel than looking at a chart.
As badly as I want to go to that, I cant make it :(

Edit:
Here it is, quoting savington from an m.net thread:

6-speed with 3.636 final
34.6 in 1st
57.3 in 2nd
79 in 3rd
103.4 in 4th
129.9 in 5th
154.1 in 6th (2952rpm @ 65mph, 3406rpm @ 75mph)

The idea of going from a 5sp with 4.3 to that is giving me a semi. I definitely know what i'm saving for this winter.

Last edited by wayne_curr; 09-15-2009 at 02:45 PM.
wayne_curr is offline   Reply With Quote
Old 09-15-2009, 08:05 PM   #35
Junior Member
iTrader: (4)
 
Join Date: Jan 2009
Location: Fife, Scotland
Posts: 296
Total Cats: 4
Default

6 speed box....... crossing the quartermile in 5th gear FTL.

Having said that, if it proves to be a durable solution then I'm all for it. Especially if it gives me a bit lower RPM when cruising on the motorway.
GrahamC is offline   Reply With Quote
Old 09-15-2009, 08:59 PM   #36
Elite Member
iTrader: (13)
 
Join Date: Nov 2006
Location: Tigard, Oregon
Posts: 3,908
Total Cats: 0
Default

Here's the FM gear ratio calculator. Factors in tire size, 5 or 6 spd tranny, desired max rpms and has ratio's for the quaife gear sets too. Damn helpful tool.

Flyin' Miata : Technical info : Gearing calculator

I'd do a queef 5 speed gearset if it didn't cost as much as my entire car. I'm looking for a cheap 6 spd to go with the 3.63s I just got.
cueball1 is offline   Reply With Quote
Old 09-15-2009, 11:24 PM   #37
Junior Member
 
Join Date: Sep 2008
Posts: 267
Total Cats: 0
Default

Quote:
Originally Posted by Savington View Post
My 6-speed use to grind almost every 1-2 and 2-3. Switched to MT-90 and they were gone within 3k miles. Just jumped to Amsoil/GM Synchromesh and they've stayed gone.


If the grinds went away after 3K, why did you change again?


So what oils are everyone else using? I had planned to change that out soon after I got it running, but I don't know what oil is best for tranny longevity.


I am a firm believer in updating tranny oils, with VWs you can't help but crunch every aggressive shift into 2nd, but with MT90, I can downshift into 1st while rolling (no synchro on that gear, that might be on all manuals).
fahrvergnugen is offline   Reply With Quote
Old 09-16-2009, 02:32 PM   #38
Elite Member
 
Join Date: Jul 2005
Location: Anacortes, WA
Posts: 2,476
Total Cats: 114
Default

Quote:
Originally Posted by cueball1 View Post
Here's the FM gear ratio calculator. Factors in tire size, 5 or 6 spd tranny, desired max rpms and has ratio's for the quaife gear sets too. Damn helpful tool.

Flyin' Miata : Technical info : Gearing calculator

I'd do a queef 5 speed gearset if it didn't cost as much as my entire car. I'm looking for a cheap 6 spd to go with the 3.63s I just got.
Yea for a really high hp car a Quafe 5 wide ratio 5 speed with a 4.10 is what I want. The 6 speed really needs a 3.308 to not have silly 1st second and 3rd gears if there was a good easy solution for getting 3.308 in the diff I wouldnít hesitate to go that route. The 3.636 is not quite there for the 6 speed still kind of silly 1st second and 3rd. A stock 5 speed with a 3.909 has really good gears but is pretty useless if it breaks every time you take it to the track.

Bob
bbundy is offline   Reply With Quote
Old 09-16-2009, 03:35 PM   #39
Elite Member
iTrader: (15)
 
Join Date: Dec 2007
Location: San Antonio, Texas
Posts: 4,889
Total Cats: 28
Default

Quote:
Originally Posted by wayne_curr View Post
The idea of going from a 5sp with 4.3 to that is giving me a semi. I definitely know what i'm saving for this winter.
That is what I did. 5-speed 4.30 to a 6-speed 3.63. Absolutely no regrets. 1st is still too short, but no sillier than it was with the 5-speed 4.30. Plus, I am not as concerned about destroying the transmission with 300 rwhp. 6th is really nice on the highway.

I have a spare 6-speed I may be selling off here in a couple of weeks if anyone is interested. I'm checking with the local crowd first to see if any of my Miata buddies want it. If not, I'll post it in the classifieds.
ZX-Tex is offline   Reply With Quote
Old 09-16-2009, 11:48 PM   #40
Newb
 
Join Date: May 2009
Location: Currently in Bielsko-Biala Poland
Posts: 12
Total Cats: 0
Default

Weight of the car also has a significant impact on the stress the transmission receives. That said, I'm not sure that even removing a couple hundred pounds off a miata is going to improve the life of the 5 speed that much...
Dangasaur is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 57 07-19-2017 05:11 PM
WTB MP62 (Hotside) (NB2) Rick02R WTB 3 01-03-2016 08:18 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Going back to stock. Need some 1.6 parts. Trent WTB 2 10-01-2015 01:15 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 01:39 AM.