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Title: fd gear ratios and mph/1000
Post by: beast20vt on February 21, 2007, 04:20:46 PM

can someone tell me what the mph/1000 in each gear are for an fd?
there are 2 different final drives as far as ive read???so can you tell me the standard ones and the rz ratio\'s too.not fussed about auto ratios.

thanks rich

Title: fd gear ratios and mph/1000
Post by: strange_days_uk on February 21, 2007, 04:24:47 PM

did you used to be on the fccuk forum ?

Title: fd gear ratios and mph/1000
Post by: beast20vt on February 21, 2007, 05:16:03 PM

yes and still am although i havnt had my 20vt fiat coupe for about 3 years now.
before anyone slates me i never slagged any rx7\'s off in my time on the fiat coupe forum and from another post on here that ive just got through the search my coupe ran better than 16\'s to the 1/4 mile lol.was a good car,just fwd which is always going to limit it although someone has now got one into the 11\'s and theres a fair few in 12\'s.my best was 13.795 with about 250bhp

Title: fd gear ratios and mph/1000
Post by: Evil Twin on February 21, 2007, 08:06:55 PM

The ratios for the Standard Japanese box are as follows:

1st 3:483
2nd 2.015
3rd 1:391
4th 1.0
5th 0.719
Final drive 4.10

The 92 RZ box are as follows:

1st - 4th Same as standard
5th 0.762
Final Drive 4.30

To calculate it out you need the following equations

Drive ratio= Final drive ratio x Gear ratio

MPH= Engine RPM x Tyre diameter / Drive ratio x 336

Hope this helps

Title: fd gear ratios and mph/1000
Post by: beast20vt on February 21, 2007, 08:45:47 PM

thanks twin that will do nicely:Thumbs-up

assuming its measured off the rear tyre size?probably being dumb but thought best to act(hold head in embaressment)

Title: fd gear ratios and mph/1000
Post by: 20B_boy on February 21, 2007, 09:13:08 PM

On a stock box/final drive but with 18" rims - I get a GPS indicated 91mph at 4K rpm per the dashboard tach fwiw (not a lot :P)...

Title: fd gear ratios and mph/1000
Post by: Evil Twin on February 21, 2007, 09:31:12 PM

Hi Rich

You\'ve got it, the power transmitting ones.

I found this calculator online. Just plumb in your specifications and it works out a table of gears vs engine RPM and the resulting speed. I believe it\'s American so read Axle ratio as Final drive ratio.

http://www.f-body.org/gears/

It even works the tyre diameter out from the tyre size (eg 225/50 16 for a standard car), so no getting wet and muddy.

Hope this clears things up for you.

Title: fd gear ratios and mph/1000
Post by: 20B_boy on February 21, 2007, 09:40:01 PM

Think its being a bit generous with my wheel diameter - 207mph at 8100 seems a tad enthusiastic! :D

Title: fd gear ratios and mph/1000
Post by: Evil Twin on February 21, 2007, 09:50:09 PM

The gearing will get you there, question is do you have the power to get there? ;-)

Title: fd gear ratios and mph/1000
Post by: shaunwil on February 21, 2007, 10:32:15 PM

Makes interesting reading for the 1/4 mile. Wonder which is easier to watch, rpm or mph.

I know my best terminal last year was 114mph, but i was in top gear. Maybe i was changing too early !

Shaun

Title: fd gear ratios and mph/1000
Post by: stylus350 on February 21, 2007, 10:43:26 PM

Quote from: shaunwilMakes interesting reading for the 1/4 mile. Wonder which is easier to watch, rpm or mph.

I know my best terminal last year was 114mph, but i was in top gear. Maybe i was changing too early !

Shaun

Should have been in fourth i would have thought.

Title: fd gear ratios and mph/1000
Post by: shaunwil on February 21, 2007, 10:49:19 PM

Possibly, haven\'t done much drag racing :p

It was a 13.25 so maybe too many gear changes !

Shaun

Mazda Rotary Club

General => General Technical => Topic started by: beast20vt on February 21, 2007, 04:20:46 PM