new diff, ratios, wheel size... WTF?

[NISMOgemini]

ok the gemini has 13" rims with 70? series tires.
17' rims with 40 series tires work out to the same rolling diametre

now the gemini diff runs a 3.9 diff ratio and i am looking at a diff conversion with a 4.3 ratio. now is this a better ratio?? ie good for top end or low end??

if its gonna be to revy and way to low, i can go and put 45 series tires on to the 17' rims and it will move the "gear ratio" towards top end speed slightly instead of beaing way to low for what i want??? or would a 4.3 ratio be better than the 3.9 in the 1st place?

am i on the right track or way of and talking threw my ass?

thanx for the help
gene

[tim510]

you always talk through your arse gene


4.3 will be very torquey and u will accerate faster through the gears and your top end (top speed) will be less


if it were me i would shoot for 3.9 or 4.11 as this is a good balance...tyre profile will make little difference mate

[NISMOgemini]

ahh ok.
well this is the center thats comes with the diff....
anyone know if hilux diff centers can be bought in 3.9 or 4.11?

Originally posted by Tim510
you always talk through your arse gene

how did i guess some one was gonna say that. lol i left my self in the line of fire i guess (see sig' LOL)

[Eeyore]

lol i always wish my posts were like yours gene :D

i believe Hilux diffs do come with rations around that mark althought i cant quite recall - i think there is 4.1* and 4.2*

anyway someone will know.

[NISMOgemini]

good times.

ok
one other question

what would u pay for a compleat hilux LSD diff?

(so i can figure out if im getting it cheap or not?)

or should i buy a single spinner for next to nothign and then hunt for a better LSD ratio center and fit that to the open wheeler housing?? (or the LSD centers dont fit the single spinner housings and axels??)

[NISMOgemini]

what year hilux do all these cars with diff conversions take them from??

[Warpspeed]

In practical terms you will notice the biggest difference in top gear, the cruising RPM will obviously be higher. There will be the same change in all gears of course, but do not expect to find any great difference in first gear.

The reason being that the RPM rises faster in first, and will come up a fraction of a second earlier, hardly noticeable. But cruise RPM will be a few hundred RPM up, which you will feel, hear, and pay for in fuel.

[TurboRA28]

You can get 3.9 and 4.1 gears for the hilux diffs... But you'll probably have to purchase new, as they are very few and far between second hand.

I'm looking at buying a new set as the hilux diff (LSD) I got was 4.7 or something stupid.. I am going for the 3.9s.

[NISMOgemini]

so if i by a open wheel hylux diff for next to nothing then hunt for an apropriate center??
would that be the best way?

[TurboRA28]

Thats what I did.. I brought a 2WD hilux diff with open center and 4.7 ratio..

Then brought a brand new LSD, and soon a new gearset for it.

Being the 2WD model it is the correct width for the Celica also (1370mm)

[NISMOgemini]

what did the new diff LSD center cost u?

[isuzu_gem]

im looking at a diff in my gem the one that i can get has a ratio of 3.23-1 wil this be too low? the engine wil be peaky, power between 4500-7500 rpm so i dont think it will be too friendly on first gear i think i might be able to get a taller ratio 3.45-1 i think but it will be alot more of a pain in the ass to get anyone have any thoughts? by the way its a falcon xr6 lsd
pete