Gear Ratio Calculator

[Duncan]

Does anyone have a gear ratio calculator handy? I need to do some rev vs speed calculations. Even better if it's prefilled with 32/33 GTR ratios

[SSHatch]

Clicky Here!!

Thats the best one I have found to use so far.

Fairly easy to use and also very detailed in the info its spits out for you.

[Beer Baron]

not bad.

[djr81]

Gear ratios for the R32 GT-R on stock wheels are (in km/h per 1000 rpm for each gear):

8.9, 14.8, 21.9, 28.5, 40.

[Duncan]

thanks guys.

ss hatch thats a good one. this is the 32 gtr results

-----------------------------------

....GearCalc.v2.0.0.1..Copyright.©2001,.Peter.Ogden

....Gear.Ratio,.Speed.and.RPM.Calculator

....Gear.set:.Manually.entered.values

....Gear........1........2........3........4........5......Final

....Ratios:...3.214....1.925....1.302....1.000....0.752....4.111

....RPM.Limit:..........8100

[email protected]:....7500

....Tyre.Size:..........225/60.x.16

....Tyre.Diameter:......676.40.mm

....Tyre.Circumference:.2124.97.mm

....Gear...Km/h.per.1000.RPM..Km/[email protected]/[email protected]

....--------------------------------------------------------

......1.........9.65................72..............78

......2........16.11...............121.............131

......3........23.82...............179.............193

......4........31.01...............233.............251

......5........41.24...............309.............334

....

....Km/h.............RPM.(in.Gears)

....-------------------------------------------------

...............1........2........3........4........5........

....-------------------------------------------------

......10.....1036......621......420......322......242

......20.....2073.....1241......840......645......485

......30.....3109.....1862.....1259......967......727

......40.....4145.....2483.....1679.....1290......970

......50.....5182.....3103.....2099.....1612.....1212

......60.....6218.....3724.....2519.....1935.....1455

......70.....7254.....4345.....2939.....2257.....1697

......80..............4966.....3358.....2579.....1940

......90..............5586.....3778.....2902.....2182

.....100..............6207.....4198.....3224.....2425

.....110..............6828.....4618.....3547.....2667

.....120..............7448.....5038.....3869.....2910

.....130..............8069.....5458.....4192.....3152

.....140.......................5877.....4514.....3395

.....150.......................6297.....4837.....3637

.....160.......................6717.....5159.....3880

.....170.......................7137.....5481.....4122

.....180.......................7557.....5804.....4364

.....190.......................7976.....6126.....4607

.....200................................6449.....4849

.....210................................6771.....5092

.....220................................7094.....5334

.....230................................7416.....5577

.....240................................7738.....5819

.....250................................8061.....6062

.....260.........................................6304

.....270.........................................6547

.....280.........................................6789

.....290.........................................7032

.....300.........................................7274

.....310.........................................7517

.....320.........................................7759

.....330.........................................8002

....

....Gear.Change..RPM.drop.(change.@7500)..RPM.drop.(change.@8100)

....-------------------------------------------------------------

......1.->.2.........-3008.(to.4492)..........-3249.(to.4851)

......2.->.3.........-2427.(to.5073)..........-2621.(to.5479)

......3.->.4.........-1740.(to.5760)..........-1879.(to.6221)

......4.->.5.........-1860.(to.5640)..........-2009.(to.6091)

[SSHatch]

Glad I could be of assistance.

I have used that a fair bit to help guys work out gear, wheel and tyre combinations for race use.

As you can see it predicts exactly where in the rev range it will drop to so you can alter your gearing to keep the engine singing at the sweet spot instead of dropping down too low in the revs.

With enough data you can set up a car with different combinations for circuit work without actually having to try out all the wheel tyre diff ratio combinations first hand.

Also helps out for drag racers as it shows that you don't necessarily have to hold it redline for each gear change depending on the ratios in your box. Sometimes it works out to be quicker to short shift one or two gears.

[Shaun O]

Awesome, just posting here for bookmarkage and damn usefulness, especially that program

Today, I was talking to a friend about choosing the right turbo&cams to suit an 8k rpm redline but he suggested that you may not even need such a high redline, if you can just pull down a gear and still be on full boost and in peak power

He had a excel graph of his gear ratios but this is way better, will pass it on as well..

Will have to play around with combinations of the GTS4 diff/gbox and GTR diff/gbox.

Basically going to be building a 4wd Rb30DET into a GTS4 next year, but unsure of whether going to use the GTS4 or GTR diff/gbox (or combination)

Does anyone have the ratios of the GTS4 diff and gearbox? I did a quick google but didn't get anything, will take another look after dinner

Edit: looks like the GTS-4 and GTR gearboxes are the same ratios (im talking R32 here btw ) but the diff ratio on the GTR is 4.111 and GTS-4 is 4.375 -- correct?

[2rismo]

Does that software have a value for converter slip?

[Shaun O]

No it doesn't.

And I'm an idiot -_- why would the diff ratio affect the RPM on the upshift zzzz

Anyone know if the GTR gearbox has any strength difference to the GTS-4 one?

[Duncan]

what is converter slip? clutches don't slip and no real race car would run an auto?

[KB240RB]

Majority of the drag cars in the US run Autos.

[SSHatch]

Like he said...

No real race car runs an auto...

[Swiper the Fox]

Like he said...

No real race car runs an auto...

X 3

[KB240RB]

Guess i gotta disagree. So many Supras here in the states run a Powerglide or TH400 doing sub 9 second passes. Not to mention 90% of the Domestics run the Powerglide or TH400 doing 7's. Not sure how these dont qualify as "real race cars"?

[SSHatch]

hmmmm...

Lets try this again...

Like he said, no real >>insert sarcastic tonehere with tongue in cheek whilst having a go at lazy drag racers with auto boxes who cant be bothered or are too slow to change gears for themselves and anyway most "real" race cars go around corners and change up and down gears<< race car runs an auto...

Paul, whats the 9 sec twoogle run in the way of gear selecting device???

[Duncan]

indeed. good translation

Pauls drag car has 3 proper pedals.