Note to Moderator: I intentionally chose this forum over "Steet/Strip" due to the fact this is a frequently asked question in this forum.

Performance difference between the 3.55 and 3.31
Bear with me as its a bit long. Skip to the end if you just want results.
Im also going to take this opportunity to point out how much technique affects these cars.

I was at the track and was testing my new Spidershaft (I like it! But thats a different story).
I was matched up against a stock 2007 GT Manual with 3.31 the first pass. He had never had it at the track before.
We both run stock Pirellis.

He rana 2.3 14.3 @ 102.1 on his first pass.
His second was a 2.2 14.1 @ 102.7

He saw me cut a 1.92, 1.89, 1.90 on my first three 60's. He asked for a little help and I was glad to!
After we worked on launch tactics, shift points, dealing with throttle opening rate limit on launch and shifts.
1.98 13.55 @ 103.0

Im going to use corrected numbers to compare his 3.31 car to two stock 3.55 cars.

Gene's 2007 3.55 (3700 lb) - 1.96 13.35 @ 103.5
Scott's 2005 3.55 (3650 lb) - 1.89 13.31 @ 103.7
Subject 2007 3.31 (3700 lb) - 1.98 13.45 @ 103.7

In my opinion the 3.31 car is about 0.1 slower and about the same trap speed.

 

so $500 mod is good for 0.1sec??[8D]
seriously, JMO: driving skills should be perfected first, and only then one should start throwing money at the car with mods.

 

very interesting data....

if a person doesn't go to the track, then
the right choice might be 3.31's from the
factory (for the mileage benefit).

 

I think so. Works for me.

 

Well the 3.55's were free on 2005-2006
$100 on the 2007's
$300 on 2008 Premiums (not available on Deluxe).

Is it worth it? Only you can say. To me they were worth $100.
If I was buying a 2008 I would be getting a Deluxe with 3.31.

 

Very impressive 60's, autos aren't that easy to get a good 60' with, in a manual you have more control using the clutch and throttle.

The best 60' with my auto and 4.10s on street tires is 2.2 resulting in some 13.6 passes at 105

I don't know if a lower 60' is possible though

 

Gaining about one tenth in the quarter mile from about a 7% increase in gear ratio seems to make sense.

But us 05 and 06 guys were lucky to get them for free. For the guys with 3.31s, more reason to get 4.10s!

 

Could you help me with launch tactics, shift points, dealing with throttle opening rate limit on launch and shifts? he got as good times as I did with in intake and tune, and he number were what mine where my first time at the track stock.

 

If a person raced theirs.....yes. If a daily driver who wanted a fast car that gets 27-30 mpg on the highway, then........no. It all depends on the person just like all the other possible mods.

 

PM Sent