Er...
I was referring to the fugly bracket. If you remember at earlier posts, I did use it in my FB but didnt like the peg leg at the canyon.

 

Er... Okay then.

I go through trannies because of the weak-suck bearings failing. Usually manifest themselves as a horrible vibration in 5th gear, but this latest one sounds like there's so much endplay in the layshaft that its front gear is grinding against the input shaft's synchro splines. Horrible grank-grank-grank noises under load in all but 4th, and it turns into a screeching grind under heavy throttle. It's quite awesome

Anyway I *think* the bearings are failing because of brass from the synchros circulating in the fluid. The magnets don't pick up brass, and after every rallycross event when I change the fluid it looks like nail polish coming out. (Whee.) None of my trannies has ever had synchro problems, though.

 

But you don't *have* to grind it off... it doesn't hurt the function. Maybe it does with a G-Force Engineering style 3-link, I dunno.

Heck, I kinda like it, it might be useful. I've been thinking about using really soft springs on the ends and a third spring in the middle, so the vertical springing gets decoupled from the roll resistance. Kind of going in the opposite direction of a sway bar, while not as extreme as a Z-bar. I like the 200-pound springs for their resistance to bottoming out, but they raise the rear roll stiffness far too much...

That part of my floor is all hacked up *anyway* so throwing a small turret in there won't be too difficult in the process of closing things up

 

True that but I like the innocent look, not the looks that kill.

 

Nail polish ouch. Try going with a t2 tranny than. They're near bullet proof. Good up to 500 horses too.

 

T2 trannies have a huge 1-2 drop and a waaaay tall 5th gear. Yucky.

Besides, for the cost of the swap (custom driveshaft for $480, Turbo-sized lightweight flywheel for maybe $350, clutch for $150ish) I could buy *nine* bearing kits for a smoothcase. And the only racers I've seen using T2 trannies took forever to shift at high RPM, like literally you think their engine shut down because it's taking over a second to crowbar the thing into the next gear.

Sure you could pro-shift the T2 trannies to get around the balky synchros problem, but then again, if synchro effluent is what's killing the bearings, the smoothcase can be pro-shifted too...

 

woot was just reading some old stuff and thought i would bring it up again

 

ok. here's what I will add to that.

96 KIA 4x4 sportage = 4.78

I just picked up a free FB tranny with miata internals from my bros mazdacomp duece. The bad thing: I more ******* item to add to my busy schedule. Why cant I get good things when Im not busy.

 

so let me see if i got this right the 4.44 will fit a SE lsd but the 4.77 wont. But in order to use the 4.77 we have to use the kia pumpkin? Am i close or fucked

 

Now if your trying to slap on the entire KIA/B2600 front diffy on FB, it will only work on the S3 as they have big axles. On the other hand, they are open diffy.

So if you want a LSD, you can use just the 4.44 and 4.78's Ring and Pinion as they have same diameter and pinion shaft lenght as the pre-86 RX-7 including RX-3 SP (wont work on non-SP) and RX-2.

 

With all this pinion and ring gear swapping in and out of different diff carriers !
Who is taking the time to check / adjust the pinion height in the diff carrier before it's assembled ??
This would explain the whinging , etc !

 

Ok guys here's a great tip on how to find the gear ratio on any car without taking anything apart. Lets use the Kia Sportage 4x4 FRONT diff. as an example

First jack the front end so both front wheels are off the ground. Make a mark on one of the front tires/wheels at the 12'oclock position- I use white paint/white- out. Then make another mark on the front diff. output flange or driveshaft. Next, rotate the wheel that you marked exactly one revolution and while doing this count the number of revolutions from the mark you made on the diff flange/driveshaft. If the number of revolutions of the driveshaft is a little less than 4.5 turns then you know you have the 4.44gears. If you count a little more than 4 3/4 turns then you know you have the 4.77gears. There you go, it's that simple and you can use this method on any car to find out the gear ratio of the ring and pinion. Now go to the junkyard and have some fun.

Note: obvious if you wanted to know the rear ratio you would use the rear wheels and rear driveshaft/flange with the same steps as mentioned above.


Cheers,

Jarrett

 

I'm digging up this old post so that I can add to it for people in the future that want to do this kia r&p swap. I want to add this info:
I purchased a front diff from my loal junky from a 97 sportage. The gear ratio was 4.4. Pinion gear 10 teeth, ring gear 44 teeth.
I am going back tomorrow to get a front diff from a 95 sportage if they have one. I'll update the thread accordingly. Maybe we can actually find out what year sportages have the 4.7 gear and what years have the 4.4..............

 

So I went back to the junky and got a front dif from a 2002 sportage and guess what, this mother ****** is a ******* 4.44 too. I can't believe this ****. I'm done with this search. I'm just going to put in the 4.44 gears and call it a day. I don't know why every kia I came across had the 4.44 but I is just not meant to be for me to have a 4.78 gear in my RX-7. Maybe God is telling me that is too much gear?

 

Wacky tells us that the 96=4.78, and in earlier post others mention different years.

This thread certainly needs to be archived. Good job all.

 

Dont know if anyone posted this , but the 96-00 Kia Sportage front diff has the 4.7 gears ill double check on that....

 

so just to make sure im only wanting to use the 4.78 kia's ring and pinon in my factory mazdas 3rd member this is possible correct? . also will my smaller 79-82 drive shaft flange bolt on the kia's pinon?

 

 

I should add, I added this gearset to my B2200, it also bolted right in. I did have to change the driveshaft flange, the B2200 is larger I guess. Recently found out that the B2200, B2600, and Turbo RX7 use the same size U-joints, so maybe the B2200 has the same size flange on the 3rd member as a Turbo II car?

I also added a LSD unit from an 86 n/a RX7, it bolted in, however the B2200 axles (and I assume FB axles are the same) use the center pin for the spider to push the axles against, and the FC LSD was straight through, so I welded some hardened washers on the end of the axles, and they push against the other axles now.

Original B2200 rear axle was 3.909, I am using a non-turbo RX7 transmission, and at 60MPH, I was turning 2000RPM, and I could hit 60MPH in 2nd gear. Now with the 4.77's, I am turning 2800RPM at 60MPH, and way more power in other gears since I am not way over geared. I pulled a 2200lb 10ft tent trailer at 60MPH in 5th gear this year, worked good.

 

Wanted to dust this thread off and add my experience.. I Finally got mine in over the weekend, but had to take the grinder to the inner flange of the axle housing where the bump-out for the ring gear is welded to the main axle housing. The carrier adjusters were hanging up at that spot. A little grinding inside the axle housing at the seam and it popped right in and sits nice and flush. Probably only had to remove like 2.0mm.

 

It has to go STRAIGHT in... that edge is what locates the pumpkin in the housing. If it's at all crooked it won't go in. They're usually a right bitch to get in.

It's part of the reason why I installed studs in my rearend housings. Makes installation a bit easier.

 

The machined boss on the KIA housing is very helpful if you have a 3rd link. It gives you a nice flat accurate surface to mount your angle finder when you are setting pinion angle.

 

Nice! I never thought of that.

I ended up making a Watts brace that went over the pumpkin to the other side and bolted in to that hole. Worked great.

 

It's fairly easy to ID the correct years of KIA Sportage diffs, the correct front diff looks very similar to the cast-iron 3rd member in the 7, the wrong years have less ribbing and IIRC, are also aluminum. That 3rd member also drops into NA FC housings, I've done it. HOWEVER the FC 3rd members are long pinion, therefore either a longer drive-shaft must be made OR have a pro-welder/machinist cut the gear end off the FC long pinion and weld the 4.77 pinion onto the long pinion shaft. SIDENOTE: I've been told by Subaru and Nissan guys that they have long pinion gears too.... there may be further interchange with their gear sets for the FC guys...

 

Any pics of that Watts brace?