S simply means that the tires ORIGINALLY placed on your car, at the factory, are 'speed rated' (a MFG thing, not a carmaker or Gov't thing) to 112 mph. Thus, the PCM on your car was tickled to limit the car's speed to that.
There is no practical way to increase that. Putting H or Z rated tires on will do nothing. The PCM would have to be reprogrammed by a dealer, and common knowledge seems to be that, unless YOU are the dealer, it will not be done. Liability issues.
Live with 112 or get a different car and check the door sticker.
Sorry, but that's the way it is. My ETC has H rateds from the factory, so I'm limited to around 130. The RARE Z-rated cars will hit 150.
I ran my 2001 STS up to 120 mph the other day and it got there fairly easily , so I thought it would have a 140 mph capability . the next day when I gave it a whirl it cut out @ 130 mph . It would have done the 140 if allowed but not much more.
I've had my 95 sts pegged at the 150 mark. Your best bet is to get a vin# off of ebay from a car that was originally equipped with "z" tires. Go into a Caddy dealer, walk straight into the shop and look for the "cool" dude. Flip him a $50 and ask him to reprogram your car.
Automobile(s): White Diamond '03 DHS (with DTS floor shift)
Originally Posted by weister42
So if I give the dealer some money I can have them reprogram my PCM to have 130mph limit? My car cuts off at 112mph and I just got some Goodyear's rriple tread assurance tires are are rated H I think.
Not too likely Weister. Any trial lawyer reading this is salivating by now. I seriously doubt you'll find a dealer willing to take the liability risk for the few bucks he'd make doing it for you. Besides, were are you going to go 150 MPH around Stevens Point?