Why might I want a turbo boost gauge?

Its just for fun...

Nothing..................BOOST ! Yay

You can also tell when its kicking in and how much.

You don't. The only gages you *really* need are a speedo and a gas gage.

The speedometer is the LEAST necessary gauge! Road, weather, traffic and the condition of your car should determine your velocity - ie. your brain. I suppose a boost gauge - once you were familiar with your car COULD indicate trouble with with the system if you began seeing atypical response.

Carl

1 Lucky Texan

Rob Munach wrote:

Actually one of the best uses for the boost gauge is as an ECONOMY gage. Keep that needle out of boost and you'll get better gas mileage. There used to be some cars that had vacuum/economy gauges to help one keep from using too much gas.

Having said all that, it's darn near impossible to not use and enjoy the thrust from the turbo on the WRX!

--------------------------------------------------------------- Alan Peterman al at scn.rain.com Tigard, OR As I grow older, the days seem longer and the years seem shorter.

Well it usually feels safe for me to drive 70mph on a 55mph interstate, but I can still get a ticket. If you aren't going to worry about your wallet or your license to drive I guess a speedo is not required. FWIW, my old GPz550 race bike had NO gages after a bad endo-ing wreck. I raced it many times like that.

I prefer idiot lights for these functions as I don't have to constantly scan them to determine if there is a problem. A bright light on my dash is much more obvious to me then a pegged gage. A few seconds w/o oil pressure is all it takes to trash your bearings. If you don't happen to be looking at the gage at that moment then you are outta luck! Actually, I would prefer a gage and a flashing strobe idiot light.

4 to 5 psi over the factory 14.5 psi I see in my WRX would be very bad without some seriously high octane gas. It's interesting to see how much less boost my car makes at higher elevations, 14.5psi at 2000' but only about 12.5 at 7000'.

I don't think it would be safe to drive in fog staring at ANY dashboard instrumentation. If you can't see vehicles in front of you or the road, only ZERO is a safe speed and I don't need a speedo to determine that.

Carl

1 Lucky Texan

JaySee wrote:

What about using the tach and the gear you're in? 3rd gear, 4000 rpm is ALWAYS the same speed.

On my motorcycle, I seldom look at the speedometer. I know by engine RPM and gear exactly how fast I'm going.

Yeah 4-5 psi could probably be a little over the top, however much fun it might be on the odd occasion. I've been thinking about why your boost tends to taper off at higher elevations and I think I might have the answer, What probably happens is at higher altitudes the ambiant air pressure is a lot less, this would tend to suggest that the amount of pressure required to open the waste gate is less because there is less atmospheric pressure on the back of the diaphragm. Because it takes less pressure to open the waste gate it will open alot earlier preventing you from getting to full boost. If this is indeed the reason why you get less boost and you wish to fix it, a boost controller is relativly inexpensive and easy to intall.

Nice idea but the waste gate only needs about 5 psi to actuate. The ECU via a solenoid valve prevents the waste gate opening untill higher boost pressures. The ECU mesures air intake and boost pressures and it probably determines what boost pressure the engine should run at. Why does the ECU reduce boost at higher altitude? I would guess that it is to be engine safe.

I was wondering whether the ECU had anything to do with the wastegate, seems like a logical thing to do. Would I be right in assuming that in older versions the wastegate is actuated directly from the compressor outlet?, or is it always maintained by the ECU?

If you are looking at any performance mods that involved boost, you need it

Early turbo cars probably used some sort of pressure regulator to control boost. My 91 legacy uses ECU control the boost and the late 80's rx turbos also used a primative ECU.