Northstar Engines and System Technical Discussion Discussion, CHanging the top-speed cut-out. in Cadillac Engine Discussion; A friend has access to a tech II and is willing to change my top speed shut off from 110 ...
A friend has access to a tech II and is willing to change my top speed shut off from 110 MPH to the most it can be. How difficult is it to do this? What all is involved? Is it just plug and play or does something need to be downloaded from GM or does it need to be tricked somehow?
While he's in there is there anything else to change to improve performance (shift points up 1 or 2 hundred RPM, fuel curve, timing?????) ?
If you have an OBD2, you're into uncharted territory my friend. Noone's managed to hack the OBD2 computer and pull the gov yet. At least not in enough numbers. You and your friend are on your own. Sorry.
It's possible to do it, but not easy. Not many people have done it. As for the dealer... In theory they possibly could, doesn't mean they will. As for the top speed limits, there's 3 available. 112, 130, 150. The Z rated option puts the 150 in. All I can offer is good luck.
It depends on what year it is and if it is an ESC or VIN Y or an ETC or VIN 9. If it is an ETC or VIN 9 you can relace the original tires with Z or W rated tires and most dealerships will reflash your OBDII to raise the top speed limiter to 150 MPH which is possible since the ETC or VIN 9 cars had the option from the factory for the Z rated tires and 150 MPH top speed limit. However, if it is an ESC or VIN Y the top speed is limited to 113 MPH. Since there was no option available from the factory for Z-rated tires and higher top speed limit, the computer cannot be reflashed to raise the limit as it only has the one speed limit figure programmed into it. This is the problem I have with my 2000 ESC. I upgraded the tires to W-rated ones, but the service manager at my local dealership says it can't be changed. He said if it was an ETC or VIN 9 no problem it could be changed very easily, but not possible with mine since there is no option to change. He also says that there is ONE WAY it could be done but would require someone to actually plug into and rewrite parts of the program of the OBD II system, and as of right now he nor I knows of anyone or anywhere that the car could be brought to do it. If anyone does figure a way to do it or knows someone who can I'd love to know about it myself. I desperatley want to do a whole list of performance mods including heads and cams from CHRFab and a tranny swap to the lower final geared 3.71 VIN 9 tranny, but unless I can get the top speed limiter raised it's not worth the money since it will end up hittin' the limiter before it reaches the end of the quarter mile. That and what's the point of having that kind of power and speed if you could never race her on the open road, you might take off on the other car but within seconds the other persons gonna be laughin' cause your dead in the water and their now flyin past you. It's happened a couple times already the way it is stock and it makes you feel pretty stupid believe me. It would feel even worse if I had a ton of money invested into performance mods.