THSCC Forums

What is the actual 2nd gear rev limit speed of a CS Miata on race tires?
I'd prefer an answer that was obtained from a data recorder rather than speedometer if possible. (related to National Championships)
Thanks

_________________
SPIN or WIN!
there's no glory for going slow.

I don't think anyone in the club owns one. I would try to hit up Rob Faulkner on the CCR website. - AB

_________________
'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

Actually data recorders have been showing up quite a lot lately, but I'll also ask on SCCA forums.

_________________
SPIN or WIN!
there's no glory for going slow.

Mike Miller is running a late model MX5 Miata in CS and doing quite well. Might want to ping him for 2nd gear speeds.

_________________
Rodney

'08 Bullitt mustang, CAM 7
Autox VP '09-'10, President '11-'12, interim President 2nd half of ‘14
proud recipient of the Bowie Grey service award '12
Now just a guy driving a mustang....

Isn't this something that a little bit of math can figure out?

_________________
In need of car.

Math is hard

_________________
02 Focus SVT
STF 9

After reading the title, I thought he was looking at a CS Miata Speed 2nd gear top speed.

I do agree, some simple math knowing the brand of tire can do the work for you, and not rely solely on GPS datalogging and corrections for it. - AB

_________________
'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

I think it's about 57 MPH on a 1999, +/- 1 MPH. I assume Chuck's trying to figure out top speed on the Nats courses per the SCCA update that just came out stating the test vehicle was banging limiter in 2nd gear on the courses. Anyone with a short 2nd gear may have to do some shifting to 3rd. Also, it will help some folks decide what tire package to run.

ep

FYI for future reference, back in my serious days when deciding on gear ratios for my formular ford, I did a lot of "time/distance/acceleration" calculations. Assuming shorter gears don't get "wasted" by more corner exit wheelspin, the quicker acceleration of shorter gearing followed by a second or two on the rev limiter can result in a shorter overall elapsed time between autocross corners than taller gears that don't reach the rev limiter. Some of the difference is due to slower acceleration and the taller geared car not actually reaching a higher speed as the rev limited shorter geared car. Keep in mind also, that even with a racing gearbox a shift to the next gear and back down again in short autocross straights can cost more time than rev limiter riding . . . even assuming no blown downshifts/braking zones.

Dick (king of the rev limiter riders )

_________________
Dick Rasmussen

FS 50 2018 Mustang GT

I had not answered previously because of the lack of trust in speedo and calculations. My speedo's pretty accurate compared to a gps. My eyesight tells me that at rev limit, the speed of my 6 speed MX5 is 56 MPH. Based on a 7100 RPM rev limit, my computer says that that I should be going 56.9 MPH. The calculation and the eye witness acount is based on running 225/45/17 tires. Using stock tires, 205/45/17 the speed is 55.6 calculated. The MSR MX5's have 5 speeds with a higher first and second. They are known to do grander clutch dumps and have a higher top speed in second.

_________________
Mike Miller
AutoX VP 2016/2017
Just a C Stock Miata DD
Mazda Speed 3 Family Car
Corvette Z06 Toy

try this:

http://www.geocities.com/z_design_studio/

I know, I know....it's a Z website, but all the fields can be changed with the gear ratios of your particular transmission, coupled with your final drive gear ratio and tire size. Seems accurate when I've used it.

$0.02

_________________
Steve Carter
1972 Datsun 240Z-- resto pics at http://picasaweb.google.com/srcartermd
2007 GPW Honda S2000-- STR 86

the 2010 MX5 has a new rev limit. I believe that it is now 7600. The press release says 500 rpm more than before. The transmition has also been revised but they didn't say if it was the gear ratios or to fix known complaints. The 2010 should have a pretty high speed in second if the raios remain the same. I'm guessing about 61 mph.

_________________
Mike Miller
AutoX VP 2016/2017
Just a C Stock Miata DD
Mazda Speed 3 Family Car
Corvette Z06 Toy

Exactly!
Thanks Eric.
Yes, I could have calculated it but then I would have had to find Miata 2nd gear ratio, rear axle ratio, tire diameter, redline. Figured it was easier to ask if someone knew the answer to one question than to research the answers to many. Howard's family Miata is M-1 flavor, but I was only looking for an idea. I expect we will go a little faster and get there sooner so looks like we'll be doing some 3rd gear shifting next week. We run TH-F and CS runs T-W so I'll be listening for their shift points while observing their runs.

We are also looking forwards to the welcome party on Monday. It will be at Speedy Bill Smith's Museum of American Speed. Bill Smith is the founder/owner of Speedway Motors, one of the earliest mail order speed parts business. After the dinner we will have complete access to the museum!

_________________
SPIN or WIN!
there's no glory for going slow.

Well, you could have calculated it based on that data and still been a little off since published redlines and the place the rev limiter kicks in aren't always the same. So it still made sense to ask.

Hope everyone from THSCC going to Nationals has a great time. It'll be the first one I've missed since 2003.


--Donnie

_________________
My Blog

Donnie, that sucks. As I understand it the builder is less than 100% engaged with the project.

_________________
Has no responsibility whatsoever.