OK, someone out there tell me what the "Boost Gauge" is telling me as I drive. It goes from -10 to +10 what is happening at each end of the scale.

Wow, this is gonna be interesting.

Basically to the best of my knowlege, it is directly related to your supercharger, and is telling you how much air charge your engine is getting. To the most basic degree, you will probably get a very elaborate answer.Very soon...

I think there is a decent explaination here Recent question about boost

Please..post if you have more questions, I'm thinking back to when I asked the same things. (note..it is inversly connect to fuel gauge)

-10 to 0 is the engine is sucking the air in, or vaccum pretty much.

0 Is even pressure, not sucking air, not boosting air, just ambient pressure.

0 to +10 Is boost, air being compressed or forced into the cylinders.

Pretty simple.....and basic

Well that'* the way I thought it should be, but in reading some other threads I got confused and started thinking I must be understanding it backwards. From the other thread shown one of the respondents talked about going to a 3.4 pulley. The boost increase by running the SC faster must be noticable.

What is the standard size pulley? How much performance increase do you see by changing to this size of pulley? And what other changes need to be made to take advantage of the mod (shorter belt, computer reprogram, exhaust, etc)? Are there any noticable drwbacks to going to the 3.4" pulley?

Thanks for the feedback.

The standard size pulley on the */C is 3.8 I believe. You can go down to a 3.4, but you'll need stuff like a cold air intake, high flow muffler, PCM would be good but not required, 180* Thermostat, and more than likely a smaller belt due to the pulley size change. Picking up a good scan tool too will help you a lot with changing pulleys. Mainly so you can scan for Knock Retard (KR), which when the knock sensor picks up a knock, it retards the timing back to a safe level, thus robbing performance.

For a performance increase, you won't want to go back to stock if you have a choice

Generally with a 3.4 pulley I'd imagine (not too sure) about a 20-25 hp increase, about 60 lbs torque. That'* with the supporting mods done first, like the intake, exhaust, etc.

As far as drawbacks, I haven't found any

I have a 3.4 and can speak from experience. The standard size on your series 2 motor is a 3.8" pulley.
How much performance increase is dependent upon other mods etc. However a rough estimate I think I heard was around 20hp. (Not positive on this though)
Other changes you would need would be one heat range cooler spark plugs and open up the air intake. It is also suggested that you change the catalytic with a high flow..but wasn't necessary in my case. (I am doing it now though)
Computer does not "have" to be reprogrammed. I am keeping my original one to keep the transmission saving parameters (this limits power at the low speeds to a certain degree)
Shorter belt or oversizing another pulley would also be needed.
Drawbacks:
More power, equals more pedal pressing
GF or wife will be constantly telling you to slow down.

Colder plugs, I knew I forgot about something.....

Forgot a draw back too:



3 Blocks after I pullied my car, got a 65 in a 50 zone........

I have a FWI , 180 STAT ,will have cooler plugs and I am looking to go 3.5 pulley ,this seems to be pretty safe for what little mods we have.I am also told you can keep stock belt.I keep telling myself im done spending on cars but these guys on here inadvertantly suck you in.But I love it.