Just for everyone's info that doesn't know this, the HHR's come with different final drive gear ratios. "Sleeper" kindly shared this information with me. Check your build sheet and see what it lists for your particular car. My car has the steeper FX2 3.91 ratio gearing, meaning that it accelerates better, but gets worse mileage. That now explains why my mileage is a lot lower than some folks list here. Worth checking before gnashing your teeth about your car's mileage. God Bless, Marc

Just for everyone's info that doesn't know this, the HHR's come with different final drive gear ratios. "Sleeper" kindly shared this information with me. Check your build sheet and see what it lists for your particular car. My car has the steeper FX2 3.91 ratio gearing, meaning that it accelerates better, but gets worse mileage. That now explains why my mileage is a lot lower than some folks list here. Worth checking before gnashing your teeth about your car's mileage. God Bless, Marc

I'll have to check that out when I get a chance. I seem to have the same issue. The MPG is not respectable.

:thumb:

I've got the FX2 3.91 ratio and am getting 29-30 mpg combined..... accelerates quite well I might add. ;)

I always thought the 3.91 was auto, and the other ratio was for the 5spd.

That's very possible....... I've got the automatic also.

After 2006, the auto's also came with a 3.31 I believe (not totally sure of that ratio exactly).

4.17 here with the manual.

After 2006, the auto's also came with a 3.31 I believe (not totally sure of that ratio exactly).

4.17 here with the manual.

The RPO code will tell all but all good info. Too bad no one got on this post earlier.

After 2006, the auto's also came with a 3.31 I believe (not totally sure of that ratio exactly).

4.17 here with the manual.

Where exactly does one find this info? I've got the 2.4L 5spd 1LT just like Solman...safe to assume 4.17?

Where exactly does one find this info? I've got the 2.4L 5spd 1LT just like Solman...safe to assume 4.17?

The ratio's are based on the tranny, not the motor. For 2006, this was the specs:

Type: F23 5-speed manual
Gear ratios: (:1):
First: 3.58
Second: 2.02
Third: 1.35
Fourth: 0.98
Fifth: 0.69
Reverse: 3.31
Final drive ratio: 4.17:1


Transmissions
Type: Hydra-Matic 4T45-E 4-speed automatic
Gear ratios: (:1):
First: 2.95
Second: 1.62
Third: 1.00
Fourth: 0.68
Fifth: –
Reverse: 2.14
Final drive ratio: 3.91:1

I never could find data on the 2.2 auto, but here are the performance numbers for the 06's.

2.4/Auto
0-60=8.37
1/4=16.35
1/4 MPH=85.2

2.4/5 Speed
0-60=7.9
1/4=16.2
1/4 MPH=87.2

2.2/5 Speed
0-60=8.51
1/4=16.63
1/4 MPH=84.95

Mine is the 2.2 BTW.

My RPO lists my SS auto as : FR9 Ratio - Transaxle Final Driver 3.29

I seem to (after 3 tanks of gas) get around 25/26 MPG with my daily drive.

Sorry Sol, thought yours was also the 2.4L

One thing to remember though, a lower gear ratio doesn't always equal better fuel economy. There are a lot of factors involved including driving style and conditions. As an example, I have a Trailblazer with 4.10 gears, and on long trips at 72 mph, I get 22 mpg. My dad has a Trailblazer with 3.42 gears, and at that speed, it struggles to get 21 mpg. My engine seems to be in the sweet spot at that speed and RPM, while his struggles at that speed.

My SS 5 speed has a 4.05 final drive ration BTW. On the way up north this past weekend driving mostly freeway at 80-85, we averaged 28 mpg. On the way back on mostly 2 lanes at 60, the avg was 31.4.

One thing to remember though, a lower gear ratio doesn't always equal better fuel economy. There are a lot of factors involved including driving style and conditions. As an example, I have a Trailblazer with 4.10 gears, and on long trips at 72 mph, I get 22 mpg. My dad has a Trailblazer with 3.42 gears, and at that speed, it struggles to get 21 mpg. My engine seems to be in the sweet spot at that speed and RPM, while his struggles at that speed.

My SS 5 speed has a 4.05 final drive ration BTW. On the way up north this past weekend driving mostly freeway at 80-85, we averaged 28 mpg. On the way back on mostly 2 lanes at 60, the avg was 31.4.

That is true, and a given BUT depending on Drive train, and conditions such as flat land vs hills, Ethenol mixed gas or straight fuel, there are going to be differences.

With a Manual car, you can keep the RPMS down and skip gears with drastically helps gas milage.

A stock tuned Auto matic has it's quirks and most times will not upshift unless its north of 3k rpms. Thats where the fuel gets wasted the most. :nuts:

I've got the FX2 3.91 ratio and am getting 29-30 mpg combined..... accelerates quite well I might add. ;)

Same here, & great mileage

If someone is NOT getting great mileage, I think it would be prudent to explore why not ....

Don't forget...tire size will affect this also...so be careful comparing different vehicles with similar gears...

I believe the original poster got it backwards. Lower final drive ratio gives higher, "stiffer" gears and lower RPMs, and hence better mileage. I also believe that the final drive ratio on the manual non-SS was lowered in more recent HHRs to improve mileage.

don't forget that its not just final drive ratio but the ratio of the gears themselves as well as the tire size.

Same here, & great mileage

If someone is NOT getting great mileage, I think it would be prudent to explore why not ....

I don't seem to get great mileage. 06 2.4L, 5spd.

computer fives an Avg speed of 35-40 mph, fuel mileage usually around 23 MPG.
I don't drive it like I stole it. When trying really hard to get the best mileage I can (slow accel, little braking, set cruise as often as possible) , I can't ever seem to top 27-28. highway speeds @ 55-65 mph.

That said, its not terrible. Better than the Honda Accord it replaced, surprisingly... But I thought I'd be able to squeeze 30 out of it, like some forum members seem to.

I don't seem to get great mileage. 06 2.4L, 5spd.

computer fives an Avg speed of 35-40 mph, fuel mileage usually around 23 MPG.
I don't drive it like I stole it. When trying really hard to get the best mileage I can (slow accel, little braking, set cruise as often as possible) , I can't ever seem to top 27-28. highway speeds @ 55-65 mph.

That said, its not terrible. Better than the Honda Accord it replaced, surprisingly... But I thought I'd be able to squeeze 30 out of it, like some forum members seem to.

Try using different brands of gas, I know when I use Shell 93, I get less mpg..

True. I've been using 87 octane... Totally Forgot about that. i'm currently getting 28.5 on it though. Being REALLY gentle...

Speaking of final drive ratios and transmissions and all that good stuff........ I believe my final drive ratio is 4.05 and the transmission is a MU3/F35/LSD saab designed chevy built 5 speed....now I was readin' where there are actually 2 transmission that are in the SS and identical except for the drive ratio.....If I read correctly my transmission is a MU3/F35/MC2........ it's got me confused and my head hurts.

both 5spd hhr ss have 4.05 finals, the auto does not.

I hear Jaxon..... but is the MU or MC? I guess only Chevy would know.
(this all came 'bout when I was researching the transmission mounts that are used in the Balt SS and the HHR SS)

they are the rpo codes, m3u is for the 5spd, mc2 is the non lsd. that's if I'm correct, but basically that's a good explination.