what diff ratio to run in 3.8 v6 4runner 5 speed with 31''

[madjimmy]

my commo v6 revs hi when on the hiway, it has 4.556:1 ratio diffs and uses a bit of fuel . i need to drop the revs as i do 700 hiway ks per week. any help cheers jimmy

[Weiner]

4.3, should be cheap from any wreckers

[madjimmy]

a mate of mine has a 253 hilux with 32" ,4.3 diffs still abit heavy on fuel. what would 3.9 4.1 be like??? cheers jimmy

[Weiner]

Whats yours reving at, at 100?

[madjimmy]

not sure no taco but revs hard great pickup. need to find a pulse wire to get taco to work??? .

[berad]

3.9 is a bit low, 4.3's should be fine, if anything id go 4.11's at the lowest.

[Timmeh]

I have a hilux with vs v6 engine 4.5 diffs, goes good but probably could be a little lower, have a mate with vr v6 4.1 diffs and he uses more fuel than i do so i would say that they are starting to get a little low. I would probably say that 4.3 would be as low as i would go.

[Zooknut]

I have a 3.8 also in my lux running 4.3's and have it on running on gas. it works out to be 20lts per 100k's on gas so for 400k's is about $38-40 to refuel. I looked at changing diff ratio's but thought the best gain would be to put in the auto box from the holden in for a few reasons.
1. the box is better matched for the power output of the holden engine.
2. the hilux 5th gear is .85:1 and the holden overdrive is .70:1 = lots lower revs on the highway 15% VS 30%.
My lux revs at 2000 RPM for 80kph and close to 3000 for 100kph. The original holden with 3.06 diffs and 0.70 overdrive revved at about 1100 for 110kph so I would suggest the gearbox would be the best option. If you need to lower the revs further then lookmat diff ratio's but if all this is done then you will most likely have to put in transfer case gears to regain any decent low range. I hope this helps with your problem. Regards, Nick.

[smaddock]

When I had a VS V6 auto, I had stock gears for a while (3.08's) and it pulled 1900rpm at 100kph. Ended up going 3.9's and it revved at 2400rpm at 100. Fuel usage barely changed, as in I didn't notice any difference, lower ratio got it off the line easier, hence less throttle needed which probably counteracted the higher revs at 100.

As nick said, if you go lowering your diff ratios too much you'll probably need to look at transfer case gears to get some low range gearing back.

[madjimmy]

thanks for everyone who had tru advice , i will start by trying 4.3 ratio and see if i can save some fuel+ money.


cheers jimmy

[omlet]

I have a 92 4wd lux with a 22r that i'm about to swap for a worked 253. currently at 100 kmh in 5th gear, it sits on 3000 rpm. the car has 4.88 diff gears but i am going for the 3.5 gears. it should crop the revs down to about 2000 at the same speed. There is a place called SA race and transmission that sell the diff gears and i got a quote from them for 600 a pair. marks 4wd apaptors also do them for 5 bucks less. i hope the revs are still in a good power range and should help the fuel economy compared to if i left it. there's always 4th gear anyways haha

[madjimmy]

thanks omlet i,ll track tham down.

I hope you get your transplant going ,my mate ronny had a 79 lux 253 with 32" bfg, 4.3 diffs 5 speed for a shooting rig. full rego and it was a rocket with heaps i mean heaps of power just no good on fuel . cheers jimmy.

[madjimmy]

now
i have the tacko in the v6 is sitting at 3grand at 100ks .

if i put 4.3 diffs in and 32''s what revs should i be doing????