4.11 Diff Gears

[BlacklistedXR]

is 4.11 diff gears okay to run on a Au2 XR8. i bought some cheap diff gears that are in good condition and am unsure whether it would be okay for road use and if it will change my fuel economy and max speed too much. i wanted a reasonable gain in acceleration and have a fast quarter mile car.
what do you guys think? will it be okay?
cheers
chris

[Casper]

I run 4.11's on my AU XR6. Love them.

[feebs]

If you are often driving at 110, this will use extra fuel, but around town it will make less of a difference.

The acceleration impact is great off the line, and made second gear a lot more usable around town.

I went from 3.23 to 3.91 and am happy with the new ratio.

[StealthAu]

If you do a lot of highway driving it might not be so great economy wise, and the top speed will still be well over the legal limit. If you already have them just fit them, give it a month and if you're not happy revert back. At most it will only take a couple of hours to fit them.

[Mechan1k]

I wanna get rid of the crappy 3.23s and go 3.7s in the ute ... I dunno how some people put up with 3.08s though. LSD would be nice as well.

It'll really help when pulling decent loads ... and help the auto out tremndously ... I guess I'd need to redial my cam as well.

[phibza_XR6]

i was thinking about putting 4.11 into my xr6 ute, and now at 100ks it sits at around 2200, wat would it jump upto with the 4.11, also its a manual

[feebs]

2200 * 4.11 / OLDRATIO = new revs

[ClassicAU]

I don't know about putting 4.11's in a manual car. I have 3.7's in mine and I find even that is too short, first gear is basically useless. Taking off at anything but snail pace usually results in wheel spin. Also, in fifth gear at 100km/h my 6 cylander revs at between 2300 and 2400rpm.
I am even considering going back to 3.45 diff gears. This is just in my limited experience with a manual. Not sure what other manual owners run in their cars.

Evan

[XR6_BABE]

Originally Posted by phibza_XR6

i was thinking about putting 4.11 into my xr6 ute, and now at 100ks it sits at around 2200, wat would it jump upto with the 4.11, also its a manual

Your revs at a 100ks would be between 2500-2600 with 4.11's.

[Mark351]

4.11's plus manual shouldn't be too short. There are members of AFF with 6 speed manual BAII/BF that have an even shorter 1st gear and are running 4.11's.

[SIKSIX]

dont XR8's run taller 1,2,3 gears?

[redef]

just got 4.11's fitted today and are great sofar. imo 4.11's in a v8 would be even better

[Sledgehammer]

Looking for a set of 4.11's for mine too...

What did you pay for yours and how much to install etc?

[redef]

mine were $900 fitted but thats live axle and an i6

[Mark351]

Originally Posted by redef

mine were $900 fitted but thats live axle and an i6

New gears or second hand?

[Sledgehammer]

thanks

[redef]

new gears as far as i know. had to brake there balls to get that price pay cash and the rest of it.

[Mark351]

Ahh, ok - I've been quoted $1100 odd with new gears, etc.

[mcflux]

4.11s are awesome for the street

On the track, if you've got a stock-ish motor (my EB's power output is probably on-par with a stock AU XR8, it made 137rwkw on a 40*C day with a 3000rpm stally), you'll get the jump on XR6Ts to the halfway mark, then they'll walk all over you after that point to the finish line. The short gears do have a negative impact on performance at highway speeds, although it's not too great an impact. This is reflected in the car feeling like it's beginning to run out of puff down the 2nd half of the track instead of continuing to charge on.

I got 14.78@91.48mph with a stally, 14.91@95.0mph without the stally (but much better on the street now).