broken diff at track ( need advise)
 

broke diff at track during an event.car ran a 7.3 in the 1/8 twice then third time rev 1000 more rpms and this is the end result. this was my third diff in 2009 and dont want to go back till i fix the problem.

diff brace
mazda speed ppf
coilovers
around 400 whp

peter Ferrell makes a cradle that helps from that happening.

http://www.pfsupercars.com/Mazda/Drivetrain/

you don't necessarily need more bracing.

you do need solid Diff bushings and you need to lose the Torsen! the spider gears are fragile. they offer an advantage on a road course as long as you are running near OEM power.

i suggest you find a S4 T2 friction plate LSD.

howard

i did get tire hop. if i do the upgrade will the case still break from tire hop.

You need to upgrade the diff. However, once you upgrade the diff, your axles will be the next week point (depending on the tires you are using). RTS3GEN (past RX7 owner) broke his diff at 359rwhp, upgraded to a Kaaz then broke an axle. He ended up going with chromoly axles.

Sell the car and call it a day. http://i86.photobucket.com/albums/k8...s/000200D5.gif

then you will let me race yours

If you win i get half. http://i86.photobucket.com/albums/k8...Car_Keys_2.jpg

Let you RACE it...:scratch:

He doesn't even drive the car himself... He built it just to see it in his parking space..:lol:

I think i will be investing in that PFS cradle..

"i did get tire hop."

you get tire hop due to the large rubber bushings that suspends your diff. i also suggest solid bushings in the front of your lower (longitudinal) links. this will eliminate any toe change.

and as Mahjik states, axles will be next on the never-ending list. welcome to the club.

hc

http://www.driveshaftshop.com/pdetail.php?pid=637

http://www.driveshaftshop.com/pdetail.php?pid=133

Stop jacking his thread. Lets stay on the topic of Phil's broken diff.

i do have upgraded super pro diff mounts and run nitto drag radials 275 40 17 . forgot to mention

sounds like a deal. but if it breaks ( oh well)

Question
 

What's the difference between Peter ferrel's brace as proposed abived compared to Banzai's diff brace? If theyare not for the same application can they be used together?

Just thought I would ask since there is a big price difference.
Thankx guys!

Andrew Kanho

both are worth what they cost.

the PFS brace supports the diff case whereas the Banzai delivers additional help to the PPF by helping resist the pinion bearing walking up and down on the ring gear.

in your case, since you have the diff bushings you might just start w the Banzai brace which i run.

your problem is probably the Torsen. it does not work for drag racing.

howard

If you can, switch from the drag radials to a bias ply street slick, such as the MT ET Streets. Not only will you hook harder, but the soft sidewall will absorb alot of the drivetrain shock that is being transmitted to your diff. Also be sure you are preloading the drivetrain before a launch. Also as mentioned earlier, a S4 T2 clutch type LSD ( Or Kaaz if you can afford it) will help, as the torsen gears tend to push apart... but that isnt entirely the problem. Under heavy loading your differential is torqued to where the pinion flange is wanting to rotate upwards, and the PPF mounting points are the only thing holding it back.. eventually snapping it as yours did. Good bushings and bracing (such as the PFS unit) will help. You will also want to invest in upgraded axles as well. Or you can go a bit more radical as some of us have done and upgrade to a cobra 8.8 rear end. This isnt quite as "plug and play", but is also a valid solution and will offer you a much greater variety of gears if you would ever choose to do so.

Exactly.


Everything rxmfn7 said above is right on the money. The soft sidewall helps a lot, preloading, Kaaz, PFS Brace and uploading axles or cobra 8.8.

He summed it up pretty well. Great post.

Anthony

you guys gave me some great info. thanks everyone. i was trying to figure if the torson broke the case or the case broke the torson. it makes sense because the teeth on the torson were not stripped. so the case broke first.

Get a Kaaz 2 way. It survives my 8k rev limiter drops on slicks with ease.

another reason for me to continue staying away from drag launches...

While drag launches are obviously the biggest killer, a hard 1-2 or even 2-3 shift has been known to break diffs also. Especially if wheelhop is introduced.

alot of good info came from this thread.

More horsepower always leads to weaker drive line components, eventually something will fail. But you have tools to help prevent it. I'd go with solid differential bushings, cryo'd axles, Differential brace and Differential girdle. I made the girdle and brace in the past. Search some of my posts and ypu'll see the girdle. I made 5 girdles, three for my cars and sold two. aicrotary2- Pm me and I can send you some pictures of what I made.



later