Thumper3322

So...found out about the gearing from Mazdee's

It is basically making our cars into the R3 gearing ratio of 4.777. They say it should fit. Cost of the part is $672 and labour eee...$500. So there ya have it. I gotta go drive the R3 to see if it's really worth the swap.

I thought we might be able to get it a little more aggressive than this, but that seems like it.

Side note...they will do a clutch and flywheel install for $275.

rotarygreg

i dont think that the r3 comparison is apt. the new rx8s have a different transmission with different ratios (which are all slightly wider than ours). that tranny and the final they have will result in something very close to what we (in 04-08 rx8s) already have anyways. popping this final drive in with our transmission will result in something even tighter than the r3(which in my opinion pulls just the same as our cars) ratios over all. just my .2

01Racing

The cost of part will be less than $672.00............................

ZmFnZm

This is sounding better and better, all we have to do now is worry about the speedometer readings, and make sure that they don't get F'd up.

rx8thunder

Good to know. I've been thinking about this one for a while. Who is going to be the "Ginny pig"

rx8thunder

There are a few devices around that can deal with this I believe. I haven't fully investigated them though....

Thumper3322

What do you mean by tighter?? U think it will or will not pull better than the r3 when done, which u think is the same anyway?

Why can you get us a deal on it Al?? That's what they quoted me.

I don't know is it?!?! I'm curious as hell about it, but almost need more info about it and how much difference it is really gonna make for that kinda cost.

Thumper3322

Ya good question!! There should be a discount for the first 8 being done by them

Ya just don't look at your speedo and go with the flow of traffic

rotarygreg

marc, i mean tighter/lower gearing which is the reason for doing this. What im saying is that our cars (04-08 6spd) with the R3 final drive installed should have tighter/lower gearing than a stock R3 because the r3s transmission has wider gears than our transmissions do.

https://www.rx8club.com/series-ii-technical-trouble-shooting-160/2009-rx-8-transmission-gear-chart-discussion-135710/

check out the numbers in that thread and it should be more clear. see how there is very little difference between series 1 and the r3 in any given gear? but what im saying is if you put that final drive in a series 1 it should be a much bigger difference so test driving an r3 is gonna feel very close (if not exactly the same from when i drove an r3) to our cars stock. pop in that final and it should pull through each gear quicker for sure. thats really the problem i have with this, i feel like the car pulls through fist gear too fast and you have to shift so soon. our trannies being as week as they are, every shift (when you are really pushing the car) is potential havock for the tranny. i think this will mean you have to shift noticebly sooner, and you will have to shift hard if you are neck and neck with a stock 8 to keep the advantage you have, thus the big reason i dont like this mod.

Thumper3322

huh...interesting!

rotarygreg

okay, so i just rechecked the ratios and it seems the OP of that thread has updated the ratios since i looked at them before. now it looks like the r3 tranny ratios are almost the same as ours, so then driving one would be a good comparios. Insert foot in mouth. lol. but honestly, look at the differences there, your 0-100km/h time will go to **** as the end of second lands just before that (at 97km/hr). that doesnt really matter so much i guess. anyways, when i drove the r3 i didnt think there was much difference in accel at all, maybe those big heavy 19s taking away any good that final drive gives it. anyways, im sure someone in the GTA is gonna do this sooner or later, so we'll just have to wait and see i guess.

Kafka

The 19" is LIGHTER than the stock 18, supposedly...??

rotarygreg

really my muscle test says otherwise IIRC. swapped a set of winters onto the r3 we had a few months back and i happened to have my rx8 wheels there for comparison. although i might be thinking of the 40th AE wheels...did winters on that one the next day. who sells 2 rx8s in the winter?

rx8thunder

Hmmm... I drove and R3 and with all of my mods, mine felt faster -- even the sales guy commented on that. So I can't get an apples to apples comparison by driving one and it's a lot of money to spend on something that may not produce much of a difference.

Al seems to really believe in it but community reaction to 4.777 is very mixed it seems

rotarygreg

i thought i saw a thread somewhere where some guy actually did this and posted his personal reaction to it...search that out. he liked it, but he also had a ton of other mods too so....

Kafka

Thunder OF COURSE your car is faster after all these mod...I would be freaking pissed if thats not the case lol

Greg:
the R3-specific, 19-inch forged rims, which are couple of pounds lighter than the 18-inch versions on all non-R3 RX-8s.

Autoweek review

Not sure if its true though...

01Racing

Even though the spec on the gear ratios in the transmission look close, when you get up into 3rd 4th and 5th gears .5 difference is HUGE! They wider ratios in the new 6spd definately take a lot of the advantage of the gear change away. If you went to a drag strip the 60ft time with the 4.77 in the 2004-2008 6spd gear box would be dramatically reduced, which would have a big impact on 1/4 mile times. You can't compare a 2009 R3 with 4.77's with the 2004-2008 RX-8 that was changed to 4.77. Its apples and oranges. If you take a page from basic hot-rodding 101, the 2nd change to a performance car is usually shifter or rear gear. The 1st is always wheels and tires.

prospectjtaz

iTrader: (1)

Al, sent you a PM, give me a call, at Scar Mazda right now.

rx8thunder

Al, you should change your moniker to "4.77RaceDude"

01Racing

Lol, after 30 years of doing this ****, you learn after spending thousands of your own dollars on what is good bang for the buck! Changing gear ratios has been around since the 1920's to go faster. The only thing with imports in the past has been the cost and limitation of parts. If I could get gears for the race car as cheap as domestics, I would have different gear sets for each track we run. Right now a gear change for the RX7 runs about $2500.00usd!

rx8thunder

Was thinking that I could experience what 4.777 would be like by putting my wife's mx5 tires on my 8. From what I understand, I would need to get to a diameter of 24.1" to replicate what a 4.777 diff would do.

So I have two options, use her regular tires with a diameter of 24.3 inches (205x17x45) or use her winter tires, which have a diameter of 24.1 inches (205x16x50).

Will this work Al?

rx8thunder

ok, I did some math to try and quantify the difference between the 04 and the 09 with 4.777 diff. As you can see by the attached, I increased the effective gear ratio by a common factor across the board.

If we assume that the added leverage from the diff could be translated into butt dyno terms (perceived, not real), HP/Torque would grow by about 15%.

A little more food for discussion. Hope my math is correct

rx8thunder

As an update, I put MX5 wheels on my 8. They are 24.3 inches in diameter which equates to about a 4.73 diff. So these wheels effectively give me the kind of performance differnce I should expect from a 4.77 diff.

On a side note, the car looked ridiculous with these wheels on it

Making this change made a noticeable difference to the car. Here the differences as I experienced them...

* Car had more usable tourque. Comes off the line faster and easier. Easier to drive around town as a result.

* Revs up much more quickly which means I am in the power zone much more quickly and more often. As I have stated previously, I like this car above 4k and this change makes it very easy for me to play there all day long.

Having said that, being below 4k now is not such a chore because there is more torque to give it a kick in the pants...

* Just feels more peppy overall -- that extra bit of usable power reduces the motivation to go FI (which is a very positive thing in my books)

* I've hear the comment that the 4.77 makes you shift more and I suppose that is true but for me, I never really noticed it. In other words, amount to shifting is not an issue in my books.

So net net, I'm going for it! With any luck, the 4.778 diff will go in without any real problems so costs don't get out of control. I think I will get Mazdees to do the work as they come highly recommended from Al.

rotarygreg

great little reveiw here. not to belittle what youve done or anything, but how much do those mx5 wheels weight? IIRC they are pretty light compared to the rx8 wheels. that will also make a difference in your butt dyno, but still, most of what you felt was likely more of the "gear" change than the weight change. just wanted to point out the weight thing really. are you planning to do anything about the speedometer/odometer after the gear change? if so, have you looked into the cost of said modification?

I'd also like to point out that im not completely against this. it seems like im the only one fighting this. lol. at first i was, but im coming into it more and more, i just want to point things out as they come up you know. subjective is the word im looking for. Im sort of against any mods that are hard to change back and i really am not a fan of the speedo/odometer readings being thrown off.

rx8thunder

^ Thanks for bringing up the weight thing because I had the same concern. Al reassured me that the vast majority of what I was feeling was due to gear change and not wheel weight. I am accepting his opinion at face value -- you better be right Al

In terms of speedo, I heard that it may not be affected, only wheel diameter screws it up. To verify, I will travel along side another 8 and see oif speed is off. If it is, I will find a solution, like the Yellow Box or something else. Not too worried about that....