Ok, so looks like the 7" rear swap needs to happen. The one I have is assembled with a 4.10 r&p. I'm on the stock 4.30 now, and it's very short in 1 & 2, a bit short in 3, fine in 4 and 5 but I wouldn't mind spinning a bit less on the highway.

For you guys who have swapped your rear/r&p, what ratio did you put in, and are you happy with it?

I need to decide if I'm going 4.10 (free and easy) or 3.90 (not free and more work).

 

I'm loving the 4.10, seems like a good compromise without going too tall. I noticed it right away, 1st is a bit more tame, however I can still light it up. anything taller at my power level would be a waste. Highway cruise is a lot better, right where it needs to be.

 

where do i get a new speedo gear?

 

Dealer.

 

I went with a 4.10 for the Torsen in my '92. I can still spin the tires (T1S) in first gear, they break loose at around 4,000RPM. This isn't a big change- only 4.6%. I did not change the speedo gear, and according to my GPS receiver my speedo is now less inaccurate than it was before.

 

according to the 3 police speed signs I've passed since the swap, my speedo is dead on

 

sounds like you guys are happy with the 4.10s. I was afraid that it wasn't enough of a difference to be meaningful. I would like to make 1&2 more useful and also calm the motor down on the interstate.

another thought I had was 410s w/ an rx7 5th gear in the miata tranny. i have the tools and help available to do it, but not the time or motivation.

 

i hear that I dont even wanna finish wiring my knocksense and EBC, let alone rewire the LC-1 whenever is shows up.

 

do cheap and easy, worry about the rest later... you'd rather be driving anyway

 

since I'm probably getting my gearbox rebuilt, would it be worth swapping in the rx7 5th gear? (4.1 diff)

 

If you do any interstate driving, hell yes.

 

Like I said, 4.30 to 4.10 is a very small change. You're not really going to notice it unless you're keeping notes. At 70 MPH and assuming a 22.6" tire we're talking about a reduction of 170 RPM (3643 to 3473).

 

went with 205/50x16 on the back ... about an 1.5" (6%) more diameter, and that all important slammed look

No noticeable performance difference, but yeah my speedo is closer to true now - very important for when you're passing police cars :gay:

 

Mark just posted on m.net that the mazdaspeed/comp dropped the price on the 3.63 over $100 (now just over $300) - and somebody said that they bought the set two weeks ago for under $300. So you might just keep an eye on that after driving around with the 4.10. I went for it- especially since the R trans has an even shorter 1st gear than the Miata. I know there's one guy driving around with the 3.63 and the 5speed and he loves it (kmag?). Granted you're gonna lose some time on a standing start acceleration with that setup... but my guess is you'll be shopping a 6 speed soon anyway.

 

Can I get a link on this ****? I was thinking about getting a 3.63 for my sister's msm, then taking her 3.90 and running that in my 5 speed...I have a 4.30 now and I doubt I'll be happy with that on the track or highway.

How much HP is enough to "be fun" with a 3.63 or a 3.90 in a 5-speed?

Sorry to resurrect.

 

I don't think I'd be happy with a 3.90 in my car. The 4.10 seems perfect. An rx7 5th gear would probably make it even better.

 

too wide?

 

I loved my car with 4.3 at 200whp. Maybe its just me. I'm gonna be using the ~4 from the rx7 diff swap with my 6speed once it goes in. My speedo will be off, but not by much.

 

i bet those gears didn't last long from shift to shift.

 

Whats the problem with accelerating quickly?