A speed limiter... on an LS?

[NateRW21]

so the speedo would be off less at low speeds, and off by more at high speeds.

That's exactly correct; you look at the precentage bigger or smaller a tire is and your speedo will be off in accordance to that; if your tires are 6% larger, at 100mph you'll actually be doing 106mph... at 200mph, 212mph. So on and so forth.

But the car doesn't know it's going faster unless you tell it (or adjust axle ratios on most other cars... won't work on this one since speed is taken by rotation of the tires as opposed to rotation of the output shaft on a trans)

 

[02V8Sport]

Entirely not true. There are two types of limiters, and most modern cars have both... a rev limiter (so idiots don't over rev their car) and a speed limiter. The two are totally separate from each other. If this were not the case, mustang owners who's car comes from the factory with a 3.03 (or something along those lines) ratio and bump up to a 4.10 would effectively have their speed limited dropped down by around 1000 RPMs (because your RPMs at speed in overdrive would increase by nearly 1000 RPM's. There for bringing on the "RPM induced speed limiter" a full 1000 RPM early... which would be something along the lines of what... 75-80mph??)

My 98 F-150 is factory limited to 94mph... before I changed my axle ratio's I was running 33" tires (factory are about 28-29), I assure you... my limiter was still at 94mph. But remember that I am still turning my axles and tires at the same rate... there for because the tires have a larger circumference... the radar said around 105ish. Your statement kind of contrdicted itself.

As for the first part, a friend of mine's mustang is a prime example... as I explained to you his exact case. His car had something like 2.98 gears in it, he installed 3.73's, then later 4.10's; top speed unaffected. It goes by the speed of the vehicle, not the RPM's in top gear.

got ya. I never hit top speed in the LS, but in my turbo 240sx I was limited to 165mph by the 7400 RPM rev limiter in 5th gear. Guess its different for different makes of vehicles.

 

[Fla02LS]

133 mph sounds about right. I posted before that i hit about 135 one night. Could have been 133 but it didnt feel like i hit a limiter, the car felt like it had more to give and was surprisingly stable at that speed. My old T/A shook and felt like it was going to disintigrate at those speeds. I am sure the accuracy of the speedo dial can have a small margin of error but like i said it didnt feel like i hit any sort of limiter. Regardless 135+ mph is pretty insane to test. Dont see myself trying to test the top speed again anytime soon.

 

[NateRW21]

got ya. I never hit top speed in the LS, but in my turbo 240sx I was limited to 165mph by the 7400 RPM rev limiter in 5th gear. Guess its different for different makes of vehicles.

I know what you mean on this one... when I was stationed in German, I had an 80's Porsche... it topped out at 172mph (taken from GPS) in 5th gear at the 6200 RPM limiter.

Cars like those didn't really have a speed limiter; it's just that's as fast as it could go from the factory without chancing grenade-ing the engine or trans.

 

[97stscaddy]

and the search engine.

The search engine here sucks.

97 - Did you have the pedal to the floor both times?

Yup.

Come to think of it though, I wasn't really paying that close attention to the tachometer until I had already let of the gas.
What speed should 4th gear top out at? Cuz it didn't sound like it was wound up to the rev limiter, but there was a lot of wind noise. The engines sound may have gotten drowned out, and I just couldn't tell that it was time to shift up.

This would indicate that his car is not producing the factory spec power and therefore could not overcome the wind resistance above 120 mph.

It felt like it hit a wall when it stopped accelerating. It was sudden, no doubt in my mind it would go faster had it not done what it did. I thought something was wrong with the car for a second because it just went from pushing me into the seat to steady pace in a split second.

BTW this is NOT something I'm gonna to go out and try again any time soon. State police are out big time (full staff) this weekend and all next week. There are several local police crackdowns taking place as well.