4.777 Diff
 

Hey Guys, as many of you know, I've been thinking hard about changing diff gearing from 4.44 to 4.77. Been a tough decision actually.

Pros:
-Car feels quicker off the line, "peppier" if you will
-Perceived as having more torque
-Easier and more enjoyable to drive around town

Cons:
-More shifting
-Lose some of the magic of third gear - magic is now spread between 3rd and 4th
-Go through RPMs so quickly, lose some of perception that it has a 9k redline (seems more like 6k because you hit it so fast)

So here's where we are at...
-I am in the process of trying to work a deal with a local shop to put new diff gearing in a used back end they have in stock so we could make the swap with my back end. If after a month, I don't decide to keep it, I will put my back end on and sell the other with the 4.77 gear in it.

Still working through the details. Hope to finalize deal points this week. If all goes well, will picking up diff from you shortly Al.

let us know how you like it.

how much are you getting charged to put it in?

shouldn't be more than a few hours, i guess, right?

Still working out pricing and logistics. Will let you know. I will also provide a very detailed review if I go ahead with this.

Good luck and wish you can have it done in time for the June HPDE day!

It will be interesting with yours thunder since you have so many other things done. I would think it would be more everyday driving manageable doing it to a stock 8 i.e. no new fly-wheel and suck. I'm thinking I might do it next year and not bother with any other mods that make my car rev faster like the flywheel.

If you have it done before the track day, you will be smokin everyone...well except me of course :-p

We're a go!!! Will keep you apprised of progress. First step is to ship new diff to tranny place for install into used RX8 back end.

Thumper, I had my clutch changed over the weekend and noticed an issue with my SPEC lightweight flywheel (only a year old), so I put back the OEM flywheel. I'm thinking seriously about just keeping the OEM flywheel on with the new diff becaiuse I think it might be the ideal combo, faster off the line/ easier to drive and a tad slower to redline (vs light flywheel).

junk...

i'm really interested in the 4.77 as well. keep us updated!!

^ to clarify, you mean the flywheel? Are you using OEM or a different brand?

i'm referring to your pictures. what you have pictured is your pressure plate and NOT your flywheel. flywheel is bolted to the block and has a ring gear around it.

my drive train is totally stock. the stock clutch and flywheel have never been changed on mine (86k miles). and it still has plenty of life left. i plan on getting the final drive out of an 09 R3, which is also 4.77. but instead of cracking my OE drive open and redoing the gear, i'd much rather swap out units and sell mine to an S2000 owner.

Ah good call Thunder! that will definitely be interesting as that's what I'm thinkin next year. Hope you have it done before track day.

hey, i was there for this and yes, those pics are of his pressure plate, but oddly enough the flywheel has the exact same damage and looks just like that, so i can see how it may have been mixed up when the pics were being edited. The spec lightweight flywheel is alluminum with a steel replaceable surface for the firction disc to wear on and this is the part that has the same damage as the pressure plate pictured. In fact, the spec pressure plate looked like it used the exact same peice for its part that contacts the friction disc and both share the same manufactured flaw that lead to this crack/disaster.

also, just to fill you in, the final he is getting is the same one that would go inf an 09 R3, and he is having it installed in a spare diff and putting that in the car. instead of splitting his diff open. Have you priced out buying the entire diff like you are suggesting? it will be a few $$$.

Here are all of the pics in case I mixed them up :) Thanks Greg, for your added perspective...

Damn... I wouldn't think it was really easy to tear something like that. Maybe you do too many 9k launches there,bud :)

^ LOL, no, not my style :)

Update: Expecting to have it installed late next week, so should be good to go for June 5th track event :)

ok, well, i won't ever buy that crap. note to self! those hot spots are huge man! are you sure you know how to drive stick? hehe, jk ;)

i get slightly over wholesale cost at any dealership around my way (i work for a dealership). so it wouldn't be as bad as retail. i'd love to find a wrecked R3 diff, but that's near impossible at this point. we'll see in the next few months if any pop up.

Greg works at a dealership as well. Kind of curious, what would a new R3 back end cost?

I would suggest you PM Al for that...

Have you bothered contacting the manufacturer of said flywheel to say wtf? If I recall correctly you haven't had that in the car for too long...

^ yeah dude, you know it! Yet to hear back tho...

From my untrained eye it looks like an installation issue...................

Well to the trained eye who installed it, I'm going to say its a manufactur's defect in the parts.

Both the flywheel and pressure plate have a thin spot on the backside of the wear surface which heated up from normal use and cracked.

I dont know if anyone else here has done as many clutch jobs as I have on sports cars, but the heat marks on the flywheel and pressure plate actually look kinda normal.

Sports cars like Scotts get driven....usually hard and any car with an aftermarket clutch disc and pressure plate usually has to be slipped more than an OEM one to get going in 1st gear. Slipping causes heat, cant be avoided. Heat marks are caused by heat.

This is my first experience with Spec clutches, I have a Spec clutch kit for a 500whp 3rd Gen RX-7 which I'm seriously considering not installing now.

^^yea, definately not installed wrong. incorrect installation of a clutch would be noticed right away upon driving it.

that product is just a POS. i've done tons of clutches in my time and that is definately one of the worst ones i've seen. those hot spots are normal you say? like i said before, my car has 86k on the original clutch. i daily drive it HARD, been to several track days, and do the occasional donuts/drifting ;) still doesn't look anywhere near to that. i have barely any hot spots!

Joe, you are a real pleasure to deal with and have my complete confidence.

Original clutch as in OEM clutch and flywheel?

Most clutches I have changed are aftermarket with lightweight flywheels, the lightweight flywheel pretty much forces you rev the engine higher to initially get the car going or it will bog out.

Taking off from an set of lights with a lightweight flywheel involves revving to 1500-2000rpm where as an OEM flywheel you can just tap the throttle and take off at 900-1000rpm.

When your spinning that flwheel at almost double the speed and trying to move a 3200lbs car, its going to get warm. City driving kills clutches and wears out flywheels.