Cadillac CTS-V Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
21 Posts
Discussion Starter #1 (Edited)
Anyone ever have this issue or hear about it? Really weird. Engine surges badly on coastdown when stabilitrac/traction control is engaged. Turn it off and it goes away instantly?! Started doing this out of nowhere. Obviously I could just turn it off every time I drive but I’d rather diagnose it and fix it.
 

·
Premium Member
Joined
·
3,562 Posts
It's out of my league, but is the car modded with a new tune?
 

·
Registered
Joined
·
1,226 Posts
It's most likely a mismatch of tire sizes.
 

·
Registered
Joined
·
21 Posts
Discussion Starter #5
Yes the car is modded and tuned. Close to 800 wheel. Never had an issue with the tune. This started out of nowhere just recently. 26” front and 28” rear tires.
Stiff steering, hard brake pedal, TCS going on and off in my logs and making the timing spike and drop which is causing the surge. Everything points to the BCM doing weird shit. You can’t tune the BCM but does anyone know a way to alleviate this issue assuming the BCM isn’t bad that is. And other than changing the wheel / tire combo because that’s not an option. The car is primarily a drag car.
 

·
Registered
Joined
·
1,226 Posts
Start reading threads in the google search below. Everyone that runs a 28" rear tire deals with this. The allowable mismatch in tire size is really small. Just get in a habit of turning traction control off when you get in the car. I run a 27" (225/50/18) front and a 28" (305/45/17) rear and it's still not close enough.

 

·
Registered
Joined
·
21 Posts
Discussion Starter #7
Thanks guys. I’ll see if I can get things working properly and post an update of what I find and learn about this.
 
1 - 8 of 8 Posts
Top