what diff ratio

[sideshow]

hey too all

my 2wd hilux has very good off the mark power but after 80 or 100 its sort of drops abit

it has a 4.3 diff ratio if i go by whats on the compliance plate

so the car weights about 1250 to 1300
has a crown 1uz with auto tranny from crown

has a 4.3 diff and at 120 kph it does 3200 rpm
i run 16 inch rims with 50 series tyres

i can get a 3.45 diff ratio from an 85 model hilux if it will fit im goin to try it

just wondering what people out there thing a good ratio would be

i was thinking of 3.7 but i thought 3.45 aint to much diff and since i can try them

on the dyno the thing revs to fast and doesnt allow the engione to build up power or torque

 

[hi-lex]

mines got 3.7 an its a 98 2wd but im runin 235/75 15 wheels, dunno what 110km revs are as dont have tacho yet but seems to be perfect gearing, awsome off the mark (read: lights up 1st and 2nd) and doesnt seem to be reving much at 110

 

[sideshow]

so with my 16 in rims and 50 series tyres mine will be bit more revvy than yrs if i get a 3.7

so i guess a 3.45 should be good

the 3.45 is in a 85 hilux with a 1gg twin turbo

he said of mark its bit doughy but once u get over 100 it just pulls to 220

so i guess if i put it in the 1uz hilux i should have the torque off the mark and up top too

 

[hi-lex]

yeah my speedo is exactly 10% out from original 14in wheels so it needs 4.1/1 to correct it so I guess 3.45 would work out about right with smaller wheels, for a multi valve motor it does seem to have lots of low down torque which you usually dont get, my old 3rz 4cyl had that prob, no power, no power then bang like a turbo coming on boost then rev limiter time, very undrivable unless thrashed, auto didnt help much, also driven a BA falcon which was a lot like that too but from what Ive read seems inherant with multi valve engines as they have too much port flow ,also why they are more suited to forced induction I guess.

 

[sideshow]

if your speedo is electronic not cable i sell speedo signal adjusters

 

[madmont]

Try this calculator
http://www.thedirtforum.com/gearcalc.htm

 

[hi-lex]

mines cable , like your site btw

 

[Muzza_NZ]

3.9 hilux diff

Lads,
I'm running the standard 3.9 in my hilux, and at 100km/hr its doing about 2500rpm. I'm using a W58 supra gearbox. If you want a 3.7 diff, they were most common in automatic hiaces (in NZ anyway) just need to replace the LSD centre (make sure you blue it beforehand or it will whine)

I've attached a gearbox calculator that I made up a while ago FYI

Muzz

 

[fugly]

I have a Chrysler Centura fitted with a crown 1uz & auto, diff is a borg warner with 3.7 to 1. Tyre's are 225/60/15 (about 25"tall). Car weight is about 1300kg
To hook up the speedo i removed the original transducer from the gearbox & had a cable made to suit,speedo seem's to be accurate,what a fluke.
As far as ratio's go,my car definitly needs at least 4.1 maybe even 4.5,as over the quarter mile i'm only just getting into 3rd gear (reving to 7000rpm through gears).
Run's a 14.3@104mph measured using a g-tech
Either there is something wrong with my motor or i'm used to my old 265, cause i feel that my 1uz doesn't have much torque down low, that's another reason i want lower gears.

It does depend what you want to do with your car, acceleration or cruize as to what ratio you settle on. The good thing about having an over drive is you can get away with having lower gears & still cruize at reasonable rpm, also helps that the 1uz loves to rev.

 

[krayn]

Fugly, What has been done to your 1uz motor. is it standard with extractors ect.

 

[fugly]

Krayn, yes, it's a standard 1990 crown engine, custom extractors, Autronic computer, MSD ignition.

Check out photo's in Personal Car Pictures section.

 

[fugly]

Krayn, i just though of it, there's also video of my girlfriend doing a burnout, in the Video section.