Tim Burgess

Well, guys, I now have a new rear end gear ratio - 41 teeth / 9 teeth = 4.56:1. It used to be 41 teeth / 11 teeth = 3.73:1 - that means it should accelerate at a more rapid rate, right????? Well, the reason for the change is due to two adjacent teeth on the pinon gear breaking off - bummer - good thing it didn't happen @ the strip. I'm planning on going with a Mosier Ford (UGH!!) 9" housing & axles, 3.70:1 ratio, a posi unit similar to a Torsen - unfortunately, Torsen only makes a posi unit for 31 spline axles, but not for the 35 spline axles, and Wilwood 4 piston discs. There are not many posi options for the GM 12 bolt, so I don't believe that it is an option. Any other recommendations for the rear end setup - that will handle 800 hp??

The diff gear broke last Sat, 1-4-03.................two weeks earlier, on 12-23-02, my 2nd gear synchro went out in the T5 - at least it lasted 160K miles - so I decided to order a Richmond 6 speed trans. Good thing it happened before the end of the month when the Summit 10% discount expired! I chose the 2.77, 1.88, 1.46, 1.18, 1.0, 0.62 ratios. It's rated @ 500 lb-ft for gears 1 - 5 & 270 lb-ft in 6th. I'd have to get the 0.84:1 OD ratio for the 500 lb-ft rating in 6th gear, but that OD ratio is too high for the 3.70:1's. The trans is supposed to be a bolt in replacement for the T5, with their supplied cross member & a new yoke for the drive shaft - so I'm planing on sending the crossmember to Steve Sphoon to see if he can make one that will work with his adjustible spherical end roded torque arm. The only speedo drive gear available with the 6 speed trans is an 8 tooth, so I'm going to have to build or buy an electronic recalibration unit, since the T5 has a 7 tooth drive gear & the dirven gear that I'd need to compensate is not available. I had looked into the Tremec TK02, which has a rating of 525 lb-ft, but it has a very steep 1st gear @ like 3.27:1 & only 4 gears to 1:1 & is only like $400 cheaper than the Richmond 6 spd. The T56 also has just 4 gears to 1:1 with 2 over drives & uses aluminum forks, which I was told were not heavy duty enough for the way I abuse - I mean enjoy - the Z.

Then, my 3-1/2" aluminum drive shaft from TPIS had something come loose inside of it - probably from driving 100+ miles with two busted pinon gear teeth - talk about a LOUD noise & lots of vibration - so I have to send that back to the mfgr to have them check it out - remove the loose beer can inside the drive shaft & rebalance it.

Any comments or suggestions???

Kingtal0n

Only 2 things to say:
you have a 5 speed TPI 305 running 11's?

and...
I've heard the richmond 6 speeds are junk. I read somwhere from somone that ordered it that it came with the WRONG gear oil and somthing else was all messed up. Ill try to find it.

Tim Burgess

Well, here's a list of the modifications required so far for the Richmond 6 spd / Moser 9" rear end swap on my '92Z:

Longer Spohn trailing arms (3/4"), new rear lug nuts (1/2"-20) for street tires (new locking lugs, too & drill out the lock key to accommodate the 2" long axle studs) & new lug nuts for strip tires, new Spohn tq arm mount for rear end (bracket on Moser 9" is 0.035" smaller & shifted toward driver's side by 1.5"), new Spohn LCA reloc brackets (Moser 9" brackets are 0.185" wider than stock brackets), new brake line plumbing for Wilwood calipers, weld bracket for brake line "T" on 9" rear end, new axle mount brackets for rear sway bar (10 bolt tubes are 2-5/8" diameter, 9" tubes are 3" diameter, & 3rd member is no longer centered on axle) (available from Spohn), new Spohn cross member for 6 spd trans with tq arm mount & drive shaft safety loop (Richmond 6 spd trans mounts @ 17 degree angle CCW viewed from rear & lower & further back than the T5), drill & tap trans housing to mount GM VSS, enlarge shifter hole in body on driver's side rear to clear 6 spd shifter - modify shifter boot??, 1-13/16" longer drive shaft with larger 1350 style turbo 400 yoke, reroute exhaust system 3" pipe over axle (interferes with 9" center section), need electronic speedo recalibrator (yet to be
built) - 6 spd available only with 8 tooth drive gear (T5 had 7 tooth drive gear), maximum number of teeth available for driven gear is only 22, so speedo will read 9% high w/o electronic correction with 3.70:1 ratio, reroute VSS & reverse light switch wires.

T5 wt = 74 lbs
Richmond 6 spd wt = 110 lbs
Delta = +36 lbs

10 bolt wt = 124 lbs
9" wt = 183 lbs
Delta = +59 lbs

Total delta = +95 lbs
(That's approx +0.1 sec in the 1/4 in my Z - bummer - hopefully it will be compensated for with the extra (5th) gear to 1:1 & the increased traction from the Detroit Locker)

Could have saved 15 lbs with an aluminum 9" center section, but it's about $150 more & not nearly as strong.

Can't wait to shift through all 6 gears & hear that Detroit Locker "clack" around the corners......

Bort62

Right on Tim.

Everything going to be okay mounting the torque arm to the 9"?

I had heard of some problems there.

And 800 HP eh.... What's the plan ?

Tim Burgess

The TQ arm will work if moved to the pass side 1.5".

800 hp from a 406 w/ Miniram & AFR heads & 200 hp nos.

89gta383

iTrader: (5)

Damn! That's $5 grand gone right there.

RU-QWIK

iTrader: (3)

Sounds to be a good combo.... Best of luck!

Hey, who is this guy?

brodyscamaro

sounds like a good combo

Tim Burgess

Thanks for posting that pict from WCG2000 - had a great time out there! I used that pict as my wallpaper for quite some time. I just painted the heritage appearence package striping on my Z in metallic gray - it looks really good - came out better than I had asticipated - I'll post a pict after I get it off of the jack stands........

383backinblack

i have a tremec TKO, and i just finished installing a moser 12 bolt. the reasons i didnt go with a 9" is the money, the ability to drop the 3rd member out really isnt a priority, its only marginally stronger than a well built 12 bolt, and its far, far less efficient, on the order of about 5% more loss.

i dont think youd need 35 spline axles, 33's should be more than adequate.....but mosers warranty will replace 33's with 35's if you break them due to excessive horsepower, and 35's with 40's within 10 years of purchase. The eaton posi should be strong enough to handle that kind of power. (the super strength 33 spline unit).

if you dont like the posi, you could always use a powertrax locker, which i have used in the past, and couldnt brake. i snapped an axle off inside it, and it didnt have a mark on it.

the tremec transmission is a great choice, get that bad larry and you will love it everyday. the 9" vs 12 bolt argument is really a matter of personal preference though.

Tim Burgess

Ya, the 12 bolt does have less parasitic loss, and it's also a bit lighter than the 9", however, there aren't many options posi wise for the 12 bolt, where there's a whole spectrum available for the 9". Also, the parasitic loss in the 9" may be reduced by using ball bearing races (no preload) in the pinon support instead of tapered roller bearings - for about $200 more.

383backinblack

thats true, that will reduce a small amount of parasitic loss, but the real cause of the inefficiency in the 9" is the gear design itself. The large (2.25") pinion spread is what eats up your power. The 12 bolt is around 1.75 i believe, and the dana 60 is like 1.5. the less pinion spread there is between the gear centerlins, the more efficient the rear end is.

Tim Burgess

Wonder what the pinon spread (gear tooth surface contact area width, correct?) is for the 10 bolt & the Dana 44?

383backinblack

hmm im not sure to tell you the truth. i would assume the 10 bolt would be even less than the 12 bolt, and the 44 would be less than the 60, but i could be wrong. if anyone finds that information id like to see it.

Tim Burgess

One other drawback of the 12 bolt - "C" clips. Even with the C clip eliminators, they don't recommend using them in road racing applications - too many Gs on them, & prone to come lose, I guess. Apparently the 10 / 12 bolt axle retainer press fit is not as snug as the bearing press fit on the 9".