Rear end gear swap changes emissions???

[KrisHorton]

Dropped by the dealership today to pick up my GT from the body shop (all better now!) and thought I'd ask about ordering up some rear end gears. I talked to the service manager about it. She looked at me as though I was insane for wanting to do something like that to a brand new car. She checked if they could do it and got a firm "no" because it supposedly messes with the emissions. Is this true? If so, how badly does it affect the emissions. I'd really like to go to 4.10's but don't want to risk failing the CA emissions tests.

Thanks for any insight,
Kris Horton

 

[Mossberg]

Has nothing to do with emmisions except that your car will be at a higher rpm which increases carbons out of the exhaust pipe. It's really no huge difference at all depending on how you drive.

 

[knight_rider69]

I swapped my stock rear for 4.10s, the only thing is you have to have your spedo recalibrated. Right now I'm about 10-15 OVER every time. It's a bit of a pain not knowing exactly how fast you're going. They told me a predator can recalibrate it, has anyone done this? Is it easy??

 

[mpentico]

Since smog testing takes place at idle, new gears will not change the emissions.

You will need to re-calibrate your speedo!

I have my 4.10's on order, and should have them installed in a couple of weeks.

I run with an Xcalibrator. You can hook it to your home computer and change the gear ratio by simply selecting the new ratio, downloading the modified program to the xcal, then uploading it to the car.

The Xcal2 is even easier.... connect it to the cars computer and select the new gear ratio, and hit enter.

From what I understand, the Predator is similar.

Now go get them gears!!!!

 

[YELLOW42RCODE]

I also have 4.10's in my GT . I used the SCT Excaliber 2 to correct the speedo. I would ask the servive writer what she is smoking

Fred

 

[1ba96gt]

Never take a dealerships service departments info on performance parts. They are some exceptions, like I work at high performance shop that runs out of a dealership, but thats the abnormal. Most service people now days are R&R people, remove broken piece and replace with new one.

 

[KrisHorton]

What kind of shop would you recommend I take my car to to have them installed? I don't know of any local speed shops here.

Kris

 

[Alec]

Since smog testing takes place at idle, new gears will not change the emissions.

Some areas maybe, but they strap your car to the rollers in Houston Texas

 

[mpentico]

Some areas maybe, but they strap your car to the rollers in Houston Texas

Dang that is bad.... when I was living in Texas, all I needed was $20 to the right mechanic and presto.... instant inspection sticker!
(And I had some really bad cars)

Well here in NC they just test at idle. Thanks for the update....

 

[Alec]

Dang that is bad.... when I was living in Texas, all I needed was $20 to the right mechanic and presto.... instant inspection sticker!
(And I had some really bad cars)

Well here in NC they just test at idle. Thanks for the update....

Oh, you can still get a $$$ticker if you look around.
Anyhoo, California does idle, OBD and acceleration simulation mode (Dyno) testing. Check with the vendor to see if the gears are C.A.R.B certified. I don't think you'll have problem passing

 

[tdaily2]

you should not have a problem. i would not have the dlr put it in