drbobvs

I doubt you'd feel any difference from 3.31-3.55. If you're going to spend the $$, just go with the 3.73.

Bluestar

+1....

wmtheflash

+1. You won't notice much of a difference from 3.31 to 3.55. As far as gas is concerned, yes, you will lose 2 mpg. Gas is about $3.25 here for premium, a 2 mpg drop is like paying $3.49 instead.

Modifications like an aluminum driveshaft will help your MPG while you accelerate, but will do nothing for you when traveling at a constant speed. A tune will help theoretically, but in my case it seems to have made little difference. I'm still 2 mpg less than I was completely stock.

I'm seriously considering a driveshaft, but the price on these is about $500, which is pretty expensive for a driveshaft. Also, I keep reading about vibration problems, especially with the automatic. It seems that Spyder has had good luck with automatics (http://www.leonardracingproducts.com/drive.php). I'm still hoping that technology will give us a solution like a lighter two piece shaft...

Anyway, don't forget you'll need adjustable lower control arms or an adjustable upper control arm to correct pinion angle after the driveshaft.

Mikes_BLK_GT

Based on a thread I read in the handling forum I'm leaning towards adjustable LCA's. Spyder is the shaft I had in mind but hadn't heard of any vibration issue's.All good info for me to consider while planning my mods

mustangman02232

you know you would only loose like 2 mpg by going to 4.10s from what your currently getting right? i really dont see the point in putting anything less in in a SOHC car like this unless you plan on driving 100+ mph for a commute, 80 and below you will be fine

06GT4RAD

If you are that concerned about the MPG then i would suggest you stay with what you have. Going to 3.55 is not worth the cost first of all and the improvement is not going to be enough to justify the cost.

Moosestang. I would suggest you break those new gears in properly before racing and banging gears.
Hopefully your gear installer knows enough to tell you the proper procedure but in case he doesn't take a look here.




[/align]All new ring & pinion sets require a brief break-in period in order to ensure long life and quiet operation. The following break-in procedure is recommended before applying a heavy load and/or constant usage.[/align][/align]


1. Insure that the axle has been filled to the correct level with
proper hypoid lubricant before driving the vehicle.
The oil rating must be GL5 or higher.

2. Bring the axle to normal operating temperature by driving the
vehicle (unloaded) for approximately 15 to 20 miles. Do not
run full throttle accelerations or create any shock loads.

3. Let the axle assembly cool completely.

4. For the next 500 miles of operation, drive gently, without any
heavy loads.

5. If trailer towing is intended, an additional cycle of 200 to 300
miles of break-in is required without the trailer. This is important!
To properly break-in a new gear set, a minimum of 500 miles of
driving is essential before towing.[/font]


Then after the 500 Mile Break In i would change the fluid out and put Redline 75w140 [font=arial]

Richard

07SCGT

I'm not sure that I completely agree with the 500 mile statement and changing the oil in the rear end housing. I'm looking in my manual now and it says nothing about a 500 mile braek in period for new cars. Maybe FORD knows something that we don't. Also I opted to not get the aftermarket FRPP gears since all I could find were the Motive manufactured ones, and I have heard horror stories from a lot of people about gear whine and clunking going on just after 20-30 miles. Avoid those -"M" FRPP gears, there Motives. I had just about 25 miles on my gears when I pulled alongside a VIPER, and smoked it through end of 2nd gear. That was about 300 miles ago and I still don't have any"sounds" or clunking.

07SCGT

Here's a link that has been floating on a couple other posts regarding break in. I have pretty much done the same to all the cars I have ever owned. My last car I had through college a 1984 Honda CRX had 186,000 miles when I donated it, it was still running, (before you flame me, yes I know I was young and dumb). I have wised up in my older years...LOL).

http://www.mototuneusa.com/break_in_secrets.htm

06GT4RAD

Well although the owners manual does not say anything specifically about the gears break in it does tell you to take it easy on the car for it's break in procedure and this is one of the reasons why. You can take the info i give or not, but just about every gear manufacture out has this break in procedure. So I am sure they know what they are doing since they make the gears. Go check their websites.

Richard

moosestang

Well I'm not sure how i'm going to drive 15-20 miles and then let it cool down completely. I have a 50 mile drive to get back home. Luckily none of those miles are on an interstate so i can take it easy. Maybe the installer will break it in on the dyno.