the horrendous front diff mount (FDM). While plenty of posts describe issues such as torn rubber bush and the dreaded wheel hop, it took me way too long to finally throw in the town and realize that even the comp diff mount (even with a snubber) is dead terrible. So pushing 300ft-lb of torque makes it way worse, but no matter what, the FDM has always been a gummy mess and has to go.

I finally bit the bullet and bought a solid FDM from Parts Shop Max and will never go back to rubber. Even if my mounting tab breaks away from the subframe, at least I'll have a few pleasant miles without the diff having a mind of its own. Hallelujah! <rant off> Next stop redesigned FDM. PS While the Ronin Ford diff swap has a lot going for it (eg strength, stiffness, wide range of cheap alternate ratios), I prefer avoiding major surgery on a street car.

Goodbye rubber mounts, hello rigid rearend. I'll gladly wear noise canceling headphones to eliminate the eternally bouncing diff.

 

The correct answer was "Lack of Cupholder"

 

It doesn't happen often, but I wish that had been my response.
Absolutely perfect.

 

I concur. A cup holder sure would be nice.

 

I know it's expensive but I absolutely LOVE mine.

https://www.shapeways.com/product/DH...ionId=57463248

 

Sigh. Doesn't anyone drive their car in anger anymore?
Maybe I need to setup a group-buy on cupholders?
Admittedly, driving FC hard = FC on jack stands

 

Just drove my FC into work this morning, backroads are heaven at 6am at 7krpms... Just watch for Deer!!!

-M

 

S5 plastic thermostat neck
Rear Iron plate on turbo motor that come without the reinforced casting on the dowel pins.

 

S5 omp.

 

Other than the lack of a functional cup holder, the real Achilles heel of the FC are dumb owners who mod their FC's without having the smarts to do it right. That factor increases by 1,000,000X if the FC is a turbo.

As for the S5 plastic T-stat housing, agree but cast aluminum versions are available. They are a bit spendy, but it does solve the problem - see here: Aluminum Thermostat Neck/Elbow 1989 -1992 RX-7: Rotary13B1.com

Regarding the S5 OMP, I have never seen an S5 (or FD/RX8) electronic OMP part itself fail - when the system does fail, 99.9% of the time the failure is traced to the wiring harness. Age + heat + corrosion + sometimes incompetent wiring "fixes" often result in opens/shorts, which even if they are intermittent can cause havoc - often results in the ECU going into "limp home" mode, and sometimes the ECUs circuitry that drives the OMP stepper motor gets permanently damaged.

 

I love my cupholder also, we've been married 20 years!

 

The Achilles heel of an FC are the 3 piece apex seals. Mazda built a time bomb into the engine. At some point, when the mileage is high enough, the top piece will roll out.

Oh, and the damn solder joints.

 

noted for when I purchase one

 

At least Mazda saw the error in their ways and OEM seals are 2 piece now. Too bad they hadn't in '98 when I rebuilt my engine the first time. That's what killed it. Seal tried to roll out and locked it up.

Solder joints. Now that you mention it I'd agree with that too.

 

You guys are forgetting about the two cup holders in the glove box. *S4 only

 

Fixed

 

That's the joke.

However there is a guy who makes Aluminum Parts for a whole bunch of cars. He makes a cup holder for $25. I bought the warning cluster trim piece, which isn't that bad for the price.

http://lrbspeed.com/product/fc-cup-holder

 

Im curious, when you has issues with the mazdacomp front diff mount, did you also do the rear diff mounts when you installed that? or what rear diff mounts did you have in while experiencing issues with the front mazdacomp diff mount?

 

In my search for a low-flex drivetrain in my TII, I've used trial and error to run:
1) Mazdacomp in tranny, front and rear diff.
2) Mazcomp tranny, Mazcomp front, Delrin rear diff, and subframe.
3) Delrin tranny, subframe, and rear diff, Mazcomp front diff.

The more Delrin bushings I used, the more direct the drivetrain felt. However, the front diff mount flex was always noticeably irritating. Part of my issue was that my HP levels were increasing all the while . Stop and go traffic really exaggerates the bounce & SoCal has plenty of that too. The installation of a metallic/ceramic clutch to hold the torque was another contributor to shock loading the diff and exposing the weakness.