dschmink

Ah, then I would definitely get the 4.10s, blkonblkgt. The 3.73s will be a good change for you, but you'll be wondering what if...
I had thought about doing 3.73's as I thought that changing the gear ratios in our manuals would lower top speed, however that is completely wrong.
Our overdrive ratio is a low enough number that top speed is not 125 as some would say.
I can personally vouch for going 145 and another has said their GPS pegged em at 170+.
Another person in the know said our cars with 4.10s are capable of 180.
With that being said, if you've opened up your car on your 3.27s you know how long it can take just to get above 100.
With the 4.10s I had a buddy stopwatch me to 120. Took me ~13.6 seconds give or take a few tenths to human error.
Go with the 4.10s and never look back. Trust me, you wont ever regret it.
Just pm me a a year later and tell me if the smile has left your face yet.

Gene K

If you dont live at high altitude 3.73 is ideal for a street car on real street tires in my opinion.
I have 4.10 and on the factory Pirellis I can spin them anywhere I go full throttle from idle to 6000+ rpm in 1st.
Its just more gear than you can use on the street with real street tires.
Thats from someone who went a 1.85 60ft on factory Pirellis with the 3.55.
The 3.55 Pirelli combo can bog (even with 5500 rpm launch) at the track sometimes if its really sticky.
I personally think 3.73 would be the ideal replacement for the 3.31s if you dont plan to run Drag Radials at the track.

As to the tune I would download the software from SCT to handle managing the tunes on your X2.
Then have Bamachips email you a 93 Octane Race Tune (dont worry its fully streetable) for $50.
Then have Brenspeed email you a 93 Octane Tunefor $50.
If your still curious try a VMP Tuning 93 Octane Performance Tune for $50.

The Demolet CAI is fine. Their will be more difference between a good and bad tune than CAI.

AmericanSpeed went 12.87 @ 107.0 with nothing other than a VMP Perf Tune and K&N CAI (Which most will say is inferior to your Demolet). Stock gears, stock tires.

I went 12.94 @ 107.7with nothing other than a BamaChips Race Tune and JLTII CAI. Stock gears, stock tires.
That was in 'Mineshaft' air. My sig is a run with worse air but better traction.

With 3.73 you should be slightly quicker under average conditions but may have to use 4th in Mineshaft air (I was trapping in 3rd at 6500-6600 rpm).

Fuel Mileage:
Stock 17/27
CAI/Tune 18/29
Spydershaft 19/30
4.10 gears 20/27

blkonblkgt

right on gents. GENE K I'm in Albuquerque elevation is somewhere in the 4K or so. I emailed Brenspeed about a tune and will be calling them tomorrow so that they can set me up with a new one. Unfortunately, they don't sell 93 octane out here. I'll have to settle for a 91 octane tune. Should still make a difference no? as for the gears....gonna have to think about it a bit. I do travel in my car sometimes and not sure how it would do on a long distance trip with 4.10s

dschmink as for the gears what can you tell me abouthighway and 4.10 and or 3.73. Will I see a big difference in fuel consumption? Say cruising at about 80-85on the interstate...what kind of RPMs would I be looking at with each gear setup.

Thanks again for all your help guys.

JC
2008 GT Premium Black
5 Speed Manual

Gene K

In Albuquerque you might prefer the 4.10s for performance on the street.
However it would definately impact mpg at that speed.
I get 27 mpg at 70 mph indicated (66.5 dataport).
Im sure 85 indicated would give you a major hit on that.

At 80 mph actual from dataport (Speedo is a little optimistic at 84 mph)
4.10 = 2834 rpm
3.73 = 2578 rpm

Those are calculated but output from my dataport confirms the rpm on the 4.10s
Considering the altitude you could easily trap in 3rd with 3.73 if you run at the strip.

PS I was thinking Albuquerque was closer to 5280 ft?

dschmink

That sounds about right for the speed he was asking for. I cruise at 60, 65 tops if traffic is moving fast mostly because I don't want to hear my exhaust on the few hour long drives I do. But, as I said, driving on the highway with my gears I average 28-30 mpg using manual calculation. In the city doing a 2nd-4th-5th shift scheme I avg 22-24. If you have to cruise at 80 get the 3.73s. You'll see some difference and it'll let you cruise at higher speeds but can't throw you in the seat like some 4.10s can.