got my posi 3.73

[whitdog54]

Re: got my posi 3.73

what RPM's would a M5 be at with 3.73's without a tune?

well ssms said 3.73s in an auto were around 2500, so in an m5 prob around 2700ish, not positive though

im going from 3.23 to 3.42 with a posi. i have an m5. will i need to do any tuning? i have no idea what im doing when it comes to that.

you will need a tune, your RPMs and Speedo will be off.

[XmatttttthewX]

Re: got my posi 3.73

how would i go about doing that? anyone here know of anywhere in central massachusetts that does it?

[Bonemaro]

Re: got my posi 3.73

your RPMs and Speedo will be off.

The speedo with be off for sure, but the RPM shouldn't be effected. Engine speed isn't changing, just tire rotational speed.

[bwkmaro]

Re: got my posi 3.73

going from a 3.42 to a 3.73 it is off by about 1 mph per 10 mph so if your doing 50 mph it will e off by 5 mph and as for accualy tuning u dont need it just a speed sensor recalibration with hp tuners its a 2 second fix and if you dont do it your abs will trip.

[bigbrian442]

Re: got my posi 3.73

going from a 3.42 to a 3.73 it is off by about 1 mph per 10 mph so if your doing 50 mph it will e off by 5 mph and as for accualy tuning u dont need it just a speed sensor recalibration with hp tuners its a 2 second fix and if you dont do it your abs will trip.

HPtuners does not change or help anything with your ABS. Changing your gears will not effect your ABS. The ABS picks up its input from the carrier on 3 channel, or the axles on 4 channel.

[bwkmaro]

Re: got my posi 3.73

got mixed up there but getting the kinks worked out have to get one new axle shaft mines bent my friend is gunna give me one free so its all good i have a knocking thats very annoying but am in love especially wit all the snow we have been getting here

[Mark42]

Re: got my posi 3.73

I can tell you that the 3.73's are really going to wake the car up. I had 3.73's, and an Eaton Truetrac installed a few weeks ago, then had the PCM tuned by PCMforless.com. The car is 100% more fun to drive than when it had the 3.08's.

Now at 70 mph the engine is turning 2500 rpm. Thats about as high as you want to go for a car used on the highway a lot. Under light throttle, the car will shift into 4th as low as 40 mph. That helps the fuel economy in around town driving.

BTW, I lost about 1 full MPG going from 3.08 to 3.73. Now I average 24.5 mpg.

[bwkmaro]

Re: got my posi 3.73

ok well this is the wierd part im getting about 1 more mpg i think its cause i usually travel at 65-70mph and my cars sweet spot is 70-75 but i usually dont go that fast so now my sweet spot has moved down into my normal driving range. just makes then oh so much sweeter. also my car even with 3.42s it would shift into 4th around 40 now it does it at about 37

[Watazz]

Re: got my posi 3.73

Posi is fun. I ment from 3.42 open to 3.42 posi and i still noticed a difference. Just watch what you are buying cause i got mine off of a 2000 z28 and it needs a little service.

[bwkmaro]

Re: got my posi 3.73

mine was brand new from a friend that is a camaro guru

[Watazz]

Re: got my posi 3.73

Then i guess you are all set. Enjoy.

[Bonemaro]

Re: got my posi 3.73

Got my 3.73 LSD going it today. Hope all goes well.

[bwkmaro]

Re: got my posi 3.73

sweet good luck man

[ssms5411]

Re: got my posi 3.73

Good luck with it, just remember if you have a auto , make sure you get the PCM flashed for the new gears before you get on it or it will shift alot sooner and not fell as well with a flashed PCM. If a auto just watch your speed since it will be off. But I think you'll like the 3.73's I know I did once installed.

[Bonemaro]

Re: got my posi 3.73

Ok, I'm bad. 3.73 LSD is install and running great. Can't wait to get through the break in period. :excited: Mine is a manual though, so no shift issues. Just have to get other Ye Ol' HPTuner and get the ratio corrected.

Question though. My cruise control isn't working now. Is this because the car "thinks" the rear tires are moving faster than the front tires and the ABS system is disabling it?