(2023) Let’s say Moser can’t supply me with axles
07-18-23, 08:13 PM
#1
Damn, it did start!
Thread Starter
(2023) Let’s say Moser can’t supply me with axles
A few weeks ago I reached out to Moser using the GSLSE axle parts numbers. I received a bit of a email version of a blank stare
” Please send us a detailed diagram of your shaft and we can get with the Shop Supervisor to see if we can make them.”Seems they should have record of a product they have produced in the past.
anyway.
I’m rebuilding my rear end. Really my kids GSLSE shredded the ring and pinion so I sold him mine (family discount) and will be rebuilding his. I have a 3.939 on the way instead of the 4.0x which I guess is a bit tougher? Also I think my speedometer ma be just a hair more accurate with the 205/50s. Looking at a Kaaz or Giken LSD.
Where am I going here?
Let’s say I find my self north of 400hp with street tires . Will I be disadvantaged with the Mazda axles? I’m not building a drag car. But I would like to be able to let loose on the track on occasion.
” Please send us a detailed diagram of your shaft and we can get with the Shop Supervisor to see if we can make them.”Seems they should have record of a product they have produced in the past.
anyway.
I’m rebuilding my rear end. Really my kids GSLSE shredded the ring and pinion so I sold him mine (family discount) and will be rebuilding his. I have a 3.939 on the way instead of the 4.0x which I guess is a bit tougher? Also I think my speedometer ma be just a hair more accurate with the 205/50s. Looking at a Kaaz or Giken LSD.
Where am I going here?
Let’s say I find my self north of 400hp with street tires . Will I be disadvantaged with the Mazda axles? I’m not building a drag car. But I would like to be able to let loose on the track on occasion.
07-18-23, 08:31 PM
#2
I just did some Googling and came up with this.
https://www.rx7.org/jes/axles.html. This is another link, Torsen Diff from that document with first gen axel info. It's pretty old but could be good. I don't know.
"Custom long axles for an '84/'85 Rx-7 housing with a Miata Torsen installed. These will allow full spline engagement and do not use axles spacers used by factory axles.
David Lane has thoroughly Beta tested the SE bolt pattern. I have assembled but not driven the non-SE bolt pattern. The SE axles were more difficult to reproduce in the wheel mounting area, but the problems were solved. Both of us discovered a length problem. Dave after bolting the axle retainers on and then finding the axles no longer turned. 8-0 I found it during a test fit. When I inserted the 2nd axle I heard a clank about the same time it reached the proper position. It was more obvious to me because I hadn't installed the axle bearings yet.
You can order axles direct from Moser Engineering @ 260-726-6689 for $295/pr. Reference the following invoice numbers so they know what to build. MAKE SURE YOU SPECIFY the length of the axle should be REDUCED from 13mm to 11mm longer than stock. If you forget, you will have to have a local shop cut 2 mm off each axle before installing...
293953 for SE axles
292383 for non-SE axles
Warning for those that haven't built such a rear end yet: If you are going to use the Miata pumpkin, instead of installing the parts in the Rx-7 pumpkin, you will have to cut off the Miata torque mount to clear the Watts link. Picture of modified pumpkin is here. Also the pinion flange from the Miata is larger than the Rx-7. If you have to make a custom drive line anyway it won't matter."
https://www.rx7.org/jes/axles.html. This is another link, Torsen Diff from that document with first gen axel info. It's pretty old but could be good. I don't know.
"Custom long axles for an '84/'85 Rx-7 housing with a Miata Torsen installed. These will allow full spline engagement and do not use axles spacers used by factory axles.
David Lane has thoroughly Beta tested the SE bolt pattern. I have assembled but not driven the non-SE bolt pattern. The SE axles were more difficult to reproduce in the wheel mounting area, but the problems were solved. Both of us discovered a length problem. Dave after bolting the axle retainers on and then finding the axles no longer turned. 8-0 I found it during a test fit. When I inserted the 2nd axle I heard a clank about the same time it reached the proper position. It was more obvious to me because I hadn't installed the axle bearings yet.
You can order axles direct from Moser Engineering @ 260-726-6689 for $295/pr. Reference the following invoice numbers so they know what to build. MAKE SURE YOU SPECIFY the length of the axle should be REDUCED from 13mm to 11mm longer than stock. If you forget, you will have to have a local shop cut 2 mm off each axle before installing...
293953 for SE axles
292383 for non-SE axles
Warning for those that haven't built such a rear end yet: If you are going to use the Miata pumpkin, instead of installing the parts in the Rx-7 pumpkin, you will have to cut off the Miata torque mount to clear the Watts link. Picture of modified pumpkin is here. Also the pinion flange from the Miata is larger than the Rx-7. If you have to make a custom drive line anyway it won't matter."
Last edited by KansasCityREPU; 07-18-23 at 08:34 PM.
07-18-23, 11:56 PM
#3
Damn, it did start!
Thread Starter
Thank you for your response KansasCityREPU, Some fair points. First concern is the Miata torsen may be rated up to 300hp. I’ve seen as low as 200 and as high as 400. For the price I’m seeing used torsen going for, I might as well get a new Kaaz and not worry.
David Lane’s write up is a core part of my inspiration. These are the numbers I reached out to Moser with. I was responded with soap opera levels of amnesia. While I didn’t expect an off the shelf, I did think they would have some history reference.
speaking of research…
Moser claims a 30% improvement over “stock”. The rule of thumb for FB axles seems to be an “it depends” but informally “about 300” . The question at that point is what is the first failure point? Ring and pinion? The LSD? Back to the 30%. If nothing else changes in the rear end assembly, could it really handle 90 more horsepower? Seems unlikely. When diffs break, what is the most common failure. My only experience is a ring and pinion on a GSLSE.
David Lane’s write up is a core part of my inspiration. These are the numbers I reached out to Moser with. I was responded with soap opera levels of amnesia. While I didn’t expect an off the shelf, I did think they would have some history reference.
speaking of research…
Moser claims a 30% improvement over “stock”. The rule of thumb for FB axles seems to be an “it depends” but informally “about 300” . The question at that point is what is the first failure point? Ring and pinion? The LSD? Back to the 30%. If nothing else changes in the rear end assembly, could it really handle 90 more horsepower? Seems unlikely. When diffs break, what is the most common failure. My only experience is a ring and pinion on a GSLSE.
07-19-23, 05:54 AM
#4
Old [Sch|F]ool
A lot of people with Moser axles find they are weaker than their stock axles.
Really the weak point in the Mazda rearend is not the axles, it is the rearend flexing, which causes the axles to fail. Rallycrossing with about 270hp, I never had a ring and pinion or diff failure, but damaged a lot of housings and this led to axle failures. I started to brace the housings, and I broke an axle very shortly after I broke one of the braces off... coincidence?
Really the weak point in the Mazda rearend is not the axles, it is the rearend flexing, which causes the axles to fail. Rallycrossing with about 270hp, I never had a ring and pinion or diff failure, but damaged a lot of housings and this led to axle failures. I started to brace the housings, and I broke an axle very shortly after I broke one of the braces off... coincidence?
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Frogman (08-07-23)
07-19-23, 10:49 AM
#5
Damn, it did start!
Thread Starter
Peejay, could you elaborate on the bracing? All searching leads to FD only.
Thank you
Thank you
07-20-23, 06:06 AM
#6
Senior Member
I ended up just going Ford 8.8, I know someone drag racing on one with 31 spline axles with no issues, he has 1200hp
07-20-23, 06:44 AM
#7
Damn, it did start!
Thread Starter
Ah, I believe I had seen a picture of the truss framing before. Thank you for the reminder. I assume four braces one at each quadrant of the pumpkin?
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07-20-23, 08:00 AM
#8
Senior Member
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Richard Miller (07-20-23)
07-20-23, 01:21 PM
#9
I would blame Moser's amnesia on workforce turnover along with bad records keeping. The first time these axles were made was close to 20-30 years ago and I doubt they made very many of them. You may need to supply an axle so they can copy it If that is the route you want to go.
Visually Moser axles look different than stock axles (beefier) and In my experience the axle bearing retainers fit tighter on the Moser axles. With stock axles, you won't likely know their history unless you are the original owner of the car. And even then, a stock axle out of a car made in the 80s is an OLD part.
In road racing I have seen stock GSL and Moser GLS/SE axles fail. I don't think it is HP related but rather the side loading stresses imposed by sticky racing tires. Throw in some curb/rumble strip hoping and they can fail eventually. There is no doubt that the paper mache rear axle housing contributes to this.
I don't think I have ever seen a ring/pinion fail.
Visually Moser axles look different than stock axles (beefier) and In my experience the axle bearing retainers fit tighter on the Moser axles. With stock axles, you won't likely know their history unless you are the original owner of the car. And even then, a stock axle out of a car made in the 80s is an OLD part.
In road racing I have seen stock GSL and Moser GLS/SE axles fail. I don't think it is HP related but rather the side loading stresses imposed by sticky racing tires. Throw in some curb/rumble strip hoping and they can fail eventually. There is no doubt that the paper mache rear axle housing contributes to this.
I don't think I have ever seen a ring/pinion fail.
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Richard Miller (08-07-23)
08-07-23, 03:56 PM
#11
Old [Sch|F]ool
This housing replaced one that I'd split up the middle.
This happened immediately after I broke the left side of that brace off when my jack slipped.
Coincidence? I dunno.
Last edited by peejay; 08-07-23 at 03:59 PM.
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Richard Miller (11-09-23)
08-07-23, 06:27 PM
#12
[QUOTE=peejay;12571015]
This housing replaced one that I'd split up the middle.
/QUOTE]
Damn Peejay you are hard on ****!
I did manage to bend the rear end housing in my race car (drive shaft failure) but it was repairable. Guess I am not trying hard enough
This housing replaced one that I'd split up the middle.
/QUOTE]
Damn Peejay you are hard on ****!
I did manage to bend the rear end housing in my race car (drive shaft failure) but it was repairable. Guess I am not trying hard enough
08-08-23, 09:30 AM
#13
There's an active drift build in the build threads section and he's using axles from Panic specifically for 84-85 FBs.
08-08-23, 11:16 AM
#14
Damn, it did start!
Thread Starter
The Panic axles are more than I would like to spend. but not out of reach.
08-08-23, 03:20 PM
#15
The General RE
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