4.77 gear for 1.8 miata?

[pitbull113]

I can get a good deal on a 4.77 ring and pinion for my '94 miata and was wondering if it's too much gear. The car isn't done yet so I have no idea what rpms I'll be turning with the 4.1 so I have no info to help make this decision.I mostly run at daytona,sebring and roebling. Thanks in advance.

[RacerBowie]

Would almost certainly be too much gear for Daytona and Roebling. Don't know about Sebring.

Clarification: While you won't run out of 5th gear at Roebling, a short final drive makes you shift more, and in more awkward places there. I slowed down by over a second when I tried my 4.88 there, versus my 4.30 in my 1.6 Miata. I think a 4.1 would be GREAT at Roebling.

[pitbull113]

Would almost certainly be too much gear for Daytona and Roebling. Don't know about Sebring.

Clarification: While you won't run out of 5th gear at Roebling, a short final drive makes you shift more, and in more awkward places there. I slowed down by over a second when I tried my 4.88 there, versus my 4.30 in my 1.6 Miata. I think a 4.1 would be GREAT at Roebling.Thanks for the info, I guess I will stick with the 4.1 for now.

[mazdagt3]

Would almost certainly be too much gear for Daytona and Roebling. Don't know about Sebring.

Clarification: While you won't run out of 5th gear at Roebling, a short final drive makes you shift more, and in more awkward places there. I slowed down by over a second when I tried my 4.88 there, versus my 4.30 in my 1.6 Miata. I think a 4.1 would be GREAT at Roebling.

agreed... the 4:77 (s2000?????) and/or 4:88 are way too much for a 1.8. my car uses a 4:30 that's good at MOST tracks.

the biggest thing you need to consider is just how much extra gear you need out of a given corner. for example my 4:30 works fine for exiting most corners. i never find myself shifting in awkward places yet some tracks i could use a BIT steeper gear but in only one corner or two. is the change worth it? to go to a 4:44 would make sense but to jump to a 4:88 is a day and night difference.

most guys who used to run rotarys make the assumption that you use as steep of a gear as possible, since you'll be revving the ever living daylights out of the motor. not in a 1.8 miata.

suggestion. try a 4:30. since last year of using the 4:10 i've noticed a big difference and since it's an oem ratio in the 99+ cars, you can get center sections all ready set up with the torsen limited slip.

check our link and we'll see what we can do for you.

[pitbull113]

agreed... the 4:77 (s2000?????) and/or 4:88 are way too much for a 1.8. my car uses a 4:30 that's good at MOST tracks.

the biggest thing you need to consider is just how much extra gear you need out of a given corner. for example my 4:30 works fine for exiting most corners. i never find myself shifting in awkward places yet some tracks i could use a BIT steeper gear but in only one corner or two. is the change worth it? to go to a 4:44 would make sense but to jump to a 4:88 is a day and night difference.

most guys who used to run rotarys make the assumption that you use as steep of a gear as possible, since you'll be revving the ever living daylights out of the motor. not in a 1.8 miata.

suggestion. try a 4:30. since last year of using the 4:10 i've noticed a big difference and since it's an oem ratio in the 99+ cars, you can get center sections all ready set up with the torsen limited slip.

check our link and we'll see what we can do for you.Thanks 4.3 was my other choice.

[ITABoy]

agreed... the 4:77 (s2000?????) and/or 4:88 are way too much for a 1.8. my car uses a 4:30 that's good at MOST tracks.

<snip>

suggestion. try a 4:30. since last year of using the 4:10 i've noticed a big difference and since it's an oem ratio in the 99+ cars, you can get center sections all ready set up with the torsen limited slip.

I too was wondering about this approach. I think it is a good possibility, but I have one reservation. I've never race a Torsion, but I've heard it said that if one pounds a curb and loses traction on an inside rear tire, then the Torsion will break lock and not recover until the torque on that wheel drops. Any experience or opinion on that question?

[madrabbit15]

After racing a 1.8 SM for two years I can say with much certainty that a 4.1 is not optimal on any of our tracks here in the SE. You want at aleast a 4.3 on any of the tracks we race in the SE I would think. You would want to go to a 4.77 at RA as it is straight drag race out of turn 7. Maybe even the same at VIR because of Oak Tree.

I agree with Bowie that with Roeblings long sweeping corners where you have to be smooth, you probably want a taller gear, but I still think that 4.1 is a little too tall. I have raced against a similarly prepped 1.8 with a 4.3 and the difference was noticable.

[pitbull113]

Thanks for all the input guys. I guess I'm searching for a 4.3 r&p.

[TStiles]

Bringing this back from the dead :

I currently have a 4.1 Torsen in my 95 ITA Miata , running a Stahl header that makes good HP up top , but gives up some TQ down low ... We're adding a MSPNP and Louie R is tuning this week help that.

My primary tracks are TWS 2.9 CCW , MSRH CW , MSRH CW

The 4.1 is terrible @ MSRH CW

The 4.1 is less terrible @ MSRH CCW

The 4.1 is less than perfect @ TWS 2.9 CCW

I've heard many conflicting opinions about which gear , but we all agree the 4.1 is less than optimal

Any other thoughts ?

[red986s]

I bought my 1.6 with a 4.10 and hated it! I was always above or below my power band in the corners and I ALWAYS got my butt kicked on the start. I switched to a 4.77 (Kia Sportage R&P), Megasquirt, and upgraded the header. It completely transformed the car!

Granted, it's a 1.6 and the MiDiv tracks I race are shorter and more technical. I shift a lot more but I've learned to adjust. My times have really improved and I'm getting podium finishes.

Don't forget there's a 4.44 R&P out there to.

[iambhooper]

Have I read everything correctly... if I have a 1.6 and want to change from the 4.3 to a 4.44, I can find a R&P from a 1st gen Rx7? I usually find myself at VIR or CMS, I think the 4.44 should help keep the rpms up in the slow corners.

Thanks in advance!

[Matt93SE]

The 1.6 diff is a smaller ring gear diameter- you'll need to use the 1.8 housing. At that point, lots of stuff will just bolt right in.
http://www.miataturbo.net/diy-turbo-discussion-14/diy-faq-all-your-answers-one-big-post-4288/#13

[iambhooper]

But would that be IT legal?

[Dano77]

Nope, Not IT compliant. In IT the 1.6 car is stuck with its stock diff housing, in SM the 1.6 is allowed to upgrade to the 94-97 later 1.8 housing which uses first gen RX7 gears. The same gears are used in the RX8, the Honda S2000 and the Kia Sportage as well.

[iambhooper]

So then im stuck with either the 4.3 or 4.1?

[Marcus Miller]

There are (were) 4.8's available for the 1.6 rearend. When I ran my 1.6 in ITA, I had an Ekerich diff with them in it. I picked it up off Bowie, and I think it went with the car when I sold it.

[iambhooper]

There are (were) 4.8's available for the 1.6 rearend. When I ran my 1.6 in ITA, I had an Ekerich diff with them in it. I picked it up off Bowie, and I think it went with the car when I sold it.

duh.. why didn't I think of Ekerich? Paging Steve'o... hello,we need to chat.

[Andy Bettencourt]

I'd go with a 4.44 if Steve can customize something for you.

[seckerich]

Somebody rub my bottle!! :D I will do a longer post later when I get back from CMP. Still have plenty of stuff for the 1.6 diff. 4.44 is perfect unless you want to twist it to Bowie levels. I still want to see someone fit a RX8 gear in any Miata. I need to do a cross reference spec sheet and post it.

[iambhooper]

You still got my digits? Give me a call next week or so (preferably day time, Melinda doesnt need to know about this) and we can talk. Ive got some time, but it works best for me to plan and budget.