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Re: Diff ratios

Posted: 06 Sep 2017 12:11
by TijmenvdS
RPM vs KM/H gaan altyd die selfde bly ongeag watter diffs gechange is of tires omdat RPM op die enjin gemeet word en Spoed op die ratkas so daai verhouding sal nie verander met tire of diff change nie. Verskillende modelle is sekerlik anders gekalibreer afhangende van standaard diff ratios. :mytwocents:

Re: Diff ratios

Posted: 06 Sep 2017 13:00
by SJC
kyk hier: https://tiresize.com/gear-ratio-calculator/

PS> n groot wiel en n klein wiel gaan mos nie dieselfde spoed draai om selfde afstand af te le nie, so dit sal mos n effek he op die spoed wat die enjin draai om sekere spoed te handhaaf? :think:

Re: Diff ratios

Posted: 06 Sep 2017 13:12
by davidvdm
SJC yes jy is reg as dit kom by GPS spoed, maar op die dash se speedo gaan dit altyd die selle "lyk" want hy is uitgewerk op die rat verhouding van alles in die drivetrain. Hy kan nie sien as jy groter wiele op sit nie. So hy wys maar altyd die selle spoed teenoor revs. GPS is die manier om die verskil te check. Toe ek gaan van 29" na 33" bande op die Sani, toe gaan my speedo van amper 10km/h meer as GPS, na 12km/h onder GPS spoed.

Sal graag wil sien wat hy nou weer doen as ek 35" bande gaan.

Maar kyk my spreadsheet en kyk hoe verander die crawl spoed soos bande size verander. As dit by crawl kom, sou ek daarvan hou om 29" bande te hê, maar self met die 35" bande is ek op 26 meter/minuut. Ek het glad nog nie gekyk wat is my highway spoed teenoor revs nie, dit pla my net nie op die stadium nie.

Re: Diff ratios

Posted: 06 Sep 2017 17:33
by Peter Connan
When somebody clearly states "True speed" I am going to assume GPS speed...

:mytwocents:

Re: Diff ratios

Posted: 06 Sep 2017 22:08
by davidvdm
Yip agree.... Hope I'm not the one being confusing :doh:

So this discussion got me back onto my spread sheet as I was now curious to see what my RPM on the Sani will be, once I am done and with my drivetrain and tyres.

Here is the update for those who may just be interested. I bashed this together while cooking supper, so please let me know if there are any errors in my calculations. Also remember that if you use this, you will need to input the second TC with a ratio of 1 (unless you have a second TC of course). I added some colour, to try and show where the cells in the second and third calculation box, gets it's information from.

I'm leaving it up to you to input your gearbox and TC ratios :wink: , and I also have no idea what your engine torque is, so I'm just leaving my old TD27 Sani/Hardbody figures in there.

Have fun :blonde:
Gear ratio calcs Rev1.xlsx
(15.54 KiB) Downloaded 270 times

Re: Diff ratios

Posted: 11 Jul 2020 22:33
by NoPressure
Reviving an old post.
I read that Wilkie swapped his TB45 4.1 to 4.3 ratios. Does anybody know the part number(s) for the genuine nissan crown wheel and pinion?

I did send him a pm, but the guy I want to buy it from only has one left - and it is a very good price. (not a scam job) Thus it won't sit on the shelf long.

The guy sent me a photo with nr 3100 J7460

Re: Diff ratios

Posted: 12 Jul 2020 07:31
by Tinus lotz
Die 4.5 het h260 diff agter sover ek weet kry mens met 4.11 vir hulle maar ek mag verkeerd wees dis hoekom manne h233 diwwe ruil om rasios te kan doen ek het nou van 3.5 na 4.66 toe gegaan

Re: Diff ratios

Posted: 12 Jul 2020 12:47
by NoPressure
Dankie Tinus

Dit lyk my die handrat 4.8 het met n h260 en 4.375 ratios gekom. Dus soek ek daai part nommer om seker te maak ek kry die regte part. Het Errol eers H233B toe gegaan? Ek soek maar OEM parte - ek weet nie of Nissan self 4.6 ratios gemaak het nie? :think:

Re: Diff ratios

Posted: 29 Aug 2022 19:59
by SJC
Het 4.2 SGL (manual) GQ, 4.1 diff ratios in?

Ek het onlangs vanaf 31" na 33" bande gegaan en moet sê kom nie regtig n verskil agter op voertuig se ry vermoe nie.
Vir my ry hy lekker met die 33's...
(Dan moet ek ook by sê dat voertuig se punte was vervang en timing gestel net voor ek die bande geruil het... )

Re: Diff ratios

Posted: 30 Aug 2022 06:41
by Peter Connan
Behoort 4.1 te he ja.

Die TB42 het seker die mees liniere wringkrag-lewering van al die Patrol enjins, dus het bandgrote-veranderinge minder effek op hom as op enige van die ander enjins.