gauge question - Boost Forum

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gauge question
Friday, April 08, 2005 10:02 AM
http://www.nopionline.com/nopistore/dsp_large_pic.cfm?vpic=L9812690.jpg

I don't know how to insert the picture but that's the link to the pic. How does this gauge work? And no stupid answers!!! I don't see how it would read below Zero unless the BOV went off and the suction created by the motor would cause it to go below Zero. Is this called "Vacuum"?

thanx

Re: gauge question
Friday, April 08, 2005 10:12 AM
wow... alright I don't know exactly where to start so bear with me

basically, a turbo isn't always spooled and making boost, therefore the engine is pulling in air with its vacuum like normal... so the guage should read around 12-14 in. hg in the vacuum range during idle and light driving. Then when you punch it, your turbo spools and the guage will jump to the boost section and show the appropriate boost in PSI







Re: gauge question
Friday, April 08, 2005 10:46 AM
Thank you I understand perfectly now. So the only gauges "needed" when turbo'ing your car are Vacuum/Boost and air/fuel ratio. So when you want to "run'em" you can turn your fuel pressure up so the gauge reads rich in order to run safely at high boost. Then the gauge would read "Stoich" (between lean and rich) since more air is being mixed with the fuel wouldn't it?
Re: gauge question
Friday, April 08, 2005 11:53 AM
That little AF gauge isn't what you need. You'd need a wideband kit.

Also, an oil pressure gauge is almost a must... and a lot of ppl like you run EGT gauges.

Boost and airfuel gauge all you need for boost? Not bloody likely!

-Chris-



-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
Re: gauge question
Friday, April 08, 2005 7:19 PM
Quote:

base 2200
Today 1:46 PM

Thank you I understand perfectly now. So the only gauges "needed" when turbo'ing your car are Vacuum/Boost and air/fuel ratio. So when you want to "run'em" you can turn your fuel pressure up so the gauge reads rich in order to run safely at high boost. Then the gauge would read "Stoich" (between lean and rich) since more air is being mixed with the fuel wouldn't it?



um... if this confuses you, don't touch your car.

This is a very simple matter and since you dont understand, I wouldn't suggest bolting a turbo on anytime soon.

Consult the boost forum FAQ for questions regarding this stuff. There's a lot of helpful links to websites to help you understand how to turbo charge a n/a engine.









Re: gauge question
Friday, April 08, 2005 7:51 PM
Don't be like that!! After all it was a question and you don't learn anything unless you ask them. Okay... So you need these gauges...oil pressure, water temp, boos/vacuum, and fuel pressure. You could also get an air/fuel ratio gauge just for added security. I understand the whole concept of boost/vacuum now but the only thing I needed to know was which guages to buy and which things to monitor in order to have a safely boosted car and adjust settings when needed. It's not going to be boosted for a while because I am still learning but I do get the whole idea now.
Re: gauge question
Friday, April 08, 2005 9:47 PM
Quote:

base 2200
Yesterday 10:51 PM

Don't be like that!! After all it was a question and you don't learn anything unless you ask them. Okay... So you need these gauges...oil pressure, water temp, boos/vacuum, and fuel pressure. You could also get an air/fuel ratio gauge just for added security. I understand the whole concept of boost/vacuum now but the only thing I needed to know was which guages to buy and which things to monitor in order to have a safely boosted car and adjust settings when needed. It's not going to be boosted for a while because I am still learning but I do get the whole idea now.


I'm not flaming man.

If you need to know which gauges you need to buy, but you dont know how they work or what they are monitoring, then you need to do more research and need to understand how turbo works, why it works, and what you're risking by bolting one on.


There's a bunch of great websites out there, here's a few that I got

How turbos work
Turbocharger selection
How to read compressor maps

here's a basic run down of the gauges and what they would do and why they're important:

Oil press.
Oil is the life blood of your engine and turbo. It keeps everything lubricated and helps to cool the bottom end. You want to monitor the pressure to make sure everything is flowing properly and lubricant is getting where it needs to. If your oil press fluctuates, it's an early warning sign to failure. Not really essential on stock engines, but when you go turbo or other high performance, you want to make sure your investment stays healthy and strong.

Water temp.
J-bodies come with a water temp guage in the cluster, so you dont really have to worry about this. But it is important to keep track of the coolant temp to make sure your car doesn't overheat. Turbos do generate heat, and if not checked can hurt other engine components.

Fuel press.
Fuel pressure is important because fuel is one third of the formula needed for combustion. If your fuel is incorrect, a lean condition could occur (too much air, not enough fuel) in which case pre-ignition (aka detonation or ping)occurs. This is something you want to AVOID AT ALL COSTS. Detonation is VERY harmful to your engine, and WILL destroy it very quickly.

Boost/ vac.
Boost/ vacuum is important because this lets you know if your engine is breathing right. It'll help to make sure everything is air tight before running the car (a good vacuum reading). Also, it helps to keep track of how much boost you're making in order to keep the car below your desired boost range, it also helps to know if you're spiking, and to make sure you dont have any leaks.

Air/ fuel ratio
Air fuel is VERY important. This monitors the crucial mix of air and fuel in your combustion chamber. When a car is tuned, this is one of the most important factors for good power and reliability. A normal narrow band air fuel gauge will not be enough, although most people have them in the car for peace of mind. However, if you were to do some tuning yourself, or just for added safety, a wideband is much more practical however very expensive. Usually laptop computers are also needed in order to make sense of the data that they collect and monitor.

Exhaust Gas Temp. (EGT)
EGT gauges are important to also monitor the air/fuel mix. Higher temperatures hint towards a lean condition, while cooler temps mean you're running too rich. Lean is much worse than rich, as I said previously it is the leading cause of detonation, but rich is also bad because you dont want to wash down the cylinders causing abrasions from the rings.

This is just the beginning... there's a lot more to know. This is only the monitoring part. Individual components, and what they do should be researched on your part. Different style turbos, internal and external wastegates, bar and plate vs pipe and fin intercoolers, boost controllers, turbo timers, etc etc all help your car get more power and be more reliable. I suggest reading up on them in the FAQ and visit any websites you can find on the subject.

Also, have a plan when turbo charging your car. Don't just slap one on there... do some calculations, know what your engine is capable of... and don't push your limits. Have a budget, and a target.




Re: gauge question
Friday, April 08, 2005 10:20 PM
All i can say is that Gauge is amazing.. i have that exact boost gauge and all Stewart warner gauges in my car (except the knock gauge) but i love them i would say go with them for all your gauges.



Re: gauge question
Friday, April 08, 2005 10:42 PM
I know how the other gauges work but the Vacuum side of the Boost/Vacuum gauge confused me. It all makes sense now though. So EGT, Oil pressure, Boost/vacuum, and Fuel pressure gauges are essential for a turbo setup. The EGT gauge is basically the same as the Air/fuel ratio gauge but which one do you use or would you suggest both?
Thanks
Re: gauge question
Saturday, April 09, 2005 12:18 AM
both

they work independently, but to be a tuner you want to cover your ass from as many angles as possible

having two seperate gauges that confirm the same thing is a bit more reassuring then just going off of one or the other. When in doubt, have as many variables covered so you'll be able to work out and prevent any problems you come across.






Re: gauge question
Saturday, April 09, 2005 9:08 AM
That's exactly what I was thinking.

Re: gauge question
Saturday, April 09, 2005 9:18 AM
why dont you just buy a wideband O2 sensor. That is a TRUE Lamba reading....Do not buy the a/f ratio guage that runs off of the stock O2 sensor, the needle of these gauges sweep back and forth and dont give you an accurate reading....if you have a wideband i dont see why you would need an EGT gauge....check this out.....
.
http://www.coximport.com/aem/uego.html

that is a little expensive... all you need is the sensor and gauge... 250 dollars should cover it.....
Re: gauge question
Saturday, April 09, 2005 9:27 AM
At idle the gauge would be at one temp and when you give it gas the temp rises so that's why the gauge sweeps back and forth. You would read where the needle is at it's highest when it stops climbing and if it goes too high then you need to richen the fuel a bit so the temp isn't so high and you get the desired EGT reading.
Re: gauge question
Sunday, April 10, 2005 8:45 PM
that gauge is fine if you're making 40 psi.

some gauges will go up to 30, or 15 .. more accurate imo

14.82 @ 97 mph
Re: gauge question
Sunday, April 10, 2005 10:16 PM
yeah... huh!!! I just noticed that. It would make alot more sense if the gauge went from 30 hg to 30 psi or even 25 hg to 25 psi but that gauge probably had the turbocharged V8 dragster in mind haha lol!!! There are other gauges out there though.
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