Join Date: Jan 2005
Location: Very Southern Maryland
Top speed allowed by the cars programming is almost always not driven by engine size, but by the tires that come stock on the car. Now, bigger engines almost always get better tires, and with those better tires, a higher limiter, but its the tires rated speed that drives the limiter.
Now, the stock tires for the 2008 SE Plus charger, those are the Goodyear Integrity, 215/65R17
Load Index 98 = 1653lbs (750kg) per tire
Speed Rating “T” = 118mph (190kph) 98T SL
So, given the tires rated speed of 118, and the factorys usual penchant for keeping the limiter a couple mph below the rated, the limit should be in the 115mph range.
Now, the "normal" RT comes with tires that are rated at 130mph, ands it limiter is set at I believe 128mph. Daytonas, they get 149mpg rated, and I think a 145 or so limiter. The SRTs tires are rated to 186, which is about 13-15mph over the speed the car caould possibly achieve, and so, the car has no limiter, since the tires are more capable than the car.
"For a mechanic, you seem to do an excessive amount of thinking."
―C-3PO, to R2-D2