Originally posted by Tim:
What I'd like to know is what some of the turbo/supercharged SVT's have been able to hit in top speed runs. If there's still plenty of rpm left in that gear and if you've got the tires to grip and power to push back against all of that air, I'd imagine they should be pulling a higher top speed than 143mph.

I'd like to see one trap that

Tim



A little more explanation is in order here.

Modern cars usually have more than one governor. The is a top speed limiter unless the car is equipped with tires that are speed rated high enough to handle the cars true top speed. I had thought that the speed limiter on the non SVT Contours was 118 MPH, but my memory could be faulty.

There is usually a rev limiter, often more than one. It is set at a speed that the factory feels they can live with without having too many warranty high rev problems such as thrown rods and the like. Often there is an even lower rev limiter when the trans is in neutral. For example, the Lincoln LS is rev limited to 3000 RPM in neutral.

When there is no speed limiter, top speed is self limited by the ability of the car to overcome everything that tends to limit it. These things include wieght, air drag, tire rolling restitance, wheel bearing resistance, parasitic drag in the transmission and axles, etc.

As you may guess, the biggest limiting factor is horsepower. Just because an engine can rev to 7000 RPM or higher in lower gears, doesn't mean that it can reach those revs in top gear. Sometimes you can gain top speed with lower gearing because the gearsets are just too tall to keep the engine in it's best working range.

If you add significant horsepower such as adding forced induction or additional displacement (3.0 conversion) you will add top speed. Just remember that it is not directly proportional. You need very big gains in horsepower to make much of a dent in top speed. Don't expect to see 180 MPH even with a blower combined with a 3.0 conversion. Even 160 MPH will require an awful lot of work.

Jim Johnson 98 SVT 03 Escape Limited