I am installing the 4.57 gears and I understand I will need a calibrator to adjust my speed. I see that Rick's sells the Yellow Box for $90 and on the S2K marketplace there is a Modifry's Yellow Jacket Speedometer Calibrator for $48.

Q1: What's the difference between the two?
Q2: Which one will I need to suite my needs?
Q3: What other options for speed calibrators do I have?

Thanks!

 

either one will suit you. just buy Modifry's--it's cheaper. Those are basically your 2 main/best options, short of building something yourself to modify the signal

 

More people have the yellow box. I have the yellow jacket. You can easily return to stock by making on t-connection. Modifrys has dials instead of dip switches. You can just do the calculations and keep your stock error.

 

wow.. i feel stupid. can you speak in "newb" terminology because that made no sense to me.

 

I have Modifry's yellow jacket as well. It's a snap to install. I love that you don't have to power-cycle it to pickup changes. The yellow box needs to be power-cycled, which is a pain when trying to calibrate.

 

Wich is the easiest to install,and less apparent,or intrusive???

 

damn, i wish i knew about the yellow jacket before i ordered the yellow box. sounds like it's easier to use and its also cheaper.

 

The yellow jacket is smaller than the box. To install the box I think you need to clip into the speed sensor outside the car and then push the wires through the firewall into the engine bay. The jacket installs inside the the kick panel inside the car. To adjust the settings the jacket has little dials with numbers while the box has 1/0 dip switches which are kind of confusing. You easily return the jacket to stock by reconnecting one wire. If you have no GPS you can calibrate the jacket by calculating the correct setting by the new gear ratio you have, you keep your original speedo error though.

 

Not correct. Both boxes can be install exactly the same way. They do the same thing, only the yellow box can adjust either shorter or longer gears (+ or -) and the Yellow jacket can only adjust for shorter gears.

 

What Jeff says is true but only the Yellow Jacket can be adjusted on the fly without needing to shut the car off for each calibration attempt.