3rd Gear?

[Bogie]

Is the following correct?

The NA runs a 3.91 final gear ratio.
The RL runs a 3.73 final gear ratio.

The NA and RL automatic gear box match gear ratios.

The NA and RL manual gear box match gear ratios EXCEPT for 3rd gear. The RL runs 1.51 in 3rd . The NA runs 1.37 in third.

Hence, the title of this thread; 3rd gear. Interesting how they are all matched up except for third gear on the manual.

Can anyone verify? Be careful surfing the net for verification, as you may come across conflicting answers. So I'm looking for more verification than simply a website.

[uranium-238]

Originally Posted by Bogie

ISo I'm looking for more verification than simply a website.

Well if that's the case I cant help unless I tear into my tranny and start counting teeth...

That being said, the only other source I have that's not the internet is Forza Motorsport 2 for Xbox 360, were 3rd gear is in fact 1.51.

[RedSkyMan]

I did find this.

[Bogie]

Originally Posted by RedSkyMan

I did find this.

At the risk of hijacking my own thread....I note the spec limit on torque is 260 lb-ft. So, if that's the spec, how the hell is GM going to be able to offer a tune to 310 lb-ft and keep the transmission within spec?

[cerberus]

IIRC it's not a difference today between models, but rather a change to the AR5 in 2007 I think it was. Early Kappas, folks felt the distance between 2nd and 3rd was too wide. Chase down the AR5 changelog to find mention of it.

Powertrain docs for the trans are here : http://media.gm.com/us/powertrain/en...2008/08car.htm

[cerberus]

Originally Posted by Bogie

At the risk of hijacking my own thread....I note the spec limit on torque is 260 lb-ft. So, if that's the spec, how the hell is GM going to be able to offer a tune to 310 lb-ft and keep the transmission within spec?

Eh, there's specs and there's engineers safe specs.


Again, 2007 changes, there were changes to handle the additional power, but I don't recall the rated torque number changing between years.

1ST AND 3RD GEARS STRENGTHENED WITH SHOT PEENING PROCESS
The 1st and 3rd gearsets on the Solstice and Sky, and the Hummer H3, are strengthened by a shot peening process during gear manufacturing. The increase in torque from the new high-performance 2.0L I4 turbocharged engine in the Solstice GXP
and the Sky Red Line, as well as in the new 3.7L I5 in the H3 required the stronger gears.

[Bogie]

Originally Posted by cerberus

IIRC it's not a difference today between models, but rather a change to the AR5 in 2007 I think it was. Early Kappas, folks felt the distance between 2nd and 3rd was too wide. Chase down the AR5 changelog to find mention of it.

Powertrain docs for the trans are here : GM Media Online: English

OK, if I read it correctly, the 2006 Solstice and 2007 Solstice/SKY NA manual have a 1.37 3rd gear. Beginning in 2008, all manual kappas have a 1.51 third gear.

Thanks for the good source; straight from GM.

Edit: Oh, and I think the tables are incorrect for the 2007 Solstice since it does not distinguish a difference between NA and GXP, identifying both as 1.37. The Saturn table identifies 1.37 for NA and 1.51 for RL. It seems if the RL is 1.51 for 2007 then so too would be the GXP.

[cerberus]

One thing to remember is model year vs build year. The first Sky model year ran more across than one build year, starting in early calender year 2006.

2007 build year was 1.51. 2006 build year was 1.37. 2007 model year Skys were a mix depending on which build year they were produced in.

[RedSkyMan]

Originally Posted by Bogie

At the risk of hijacking my own thread....I note the spec limit on torque is 260 lb-ft. So, if that's the spec, how the hell is GM going to be able to offer a tune to 310 lb-ft and keep the transmission within spec?

I asked that same question when I talked to Chuck Mallett about getting the LS2 conversion and he assured me It would not be a problem. He did say they upgrade to a six speed Tremec Transmission with any package bigger then mine.