What gauges out there are the best in terms of accuracy, ergonomics and aesthetically pleasing? I've used the Autometer Phantom and Cyberdyne but found that the lights weren't bright enough in the day time. I'm now using a custom one I bought on Ebay and am quite pleased with its low profile, easy mounting and optional brightness control switch. He has another one for sale:http://cgi.ebay.com/ebaymotors/aw-cg...635586&r=0&t=0

 

Any A/F guage based off LEDS is just a pretty light show.

The only good A/F guage is a volt metter hooked up to your o2 sensor.

You are better off buying an EGT guage-

 

dont waste your money on an A/F Ratio gauge. if you want to look cool with lights dancing around, go for it...but it means nothing if you still have your original 02 sensor.

get an EGT gauge. it will tell you a whole lot more.

 

I use the Haltech Haltuner A/F meter. It is a good indication of what your car is doing and is alot easier to glance at super quick when up it than having to look closer at an actual gauge reading.

 

I agree that an EGT gauge is a must but it will not react fast enough as an air/fuel ratio gauge. By the way, what is the maximum temperature I should read on the EGT when at full throttle? Currently I'm reading around 1700F - 1850F on a Westach EGT at full throttle running @ 18 psi.

 

Where is the EGT probe located? Before or after the turbo?
What gear did you do the test in?

crispeed
87TII
9.20@150MPH

 

The only A/F ratio monitor that's worth a damm is a wide band!
I happen to trust the Uego the most. There's a lot of cheaper alternatives outhere but in any case any wide band is much better than a LED light show!

crispeed
87TII
9.20@150mph

 

agree with crispeed there, unless you have a wideband set up you'd be better off hanging out the back of your car with your nose next to the tip and sniffing the gas yourself

 

I have the Greddy A/F guage w/ 4-wire 02 sensor. I like, and it gives a good reading. Obviously it's not going to be nearly as precise, nor will it measure A/F in low load situations. It still gives a good indication for high load though, so I would not call it worthless. I don't know maybe it is

 

Like I said, I use the Haltuner as an indicator and gives a good general idea of what the car is doing.

I leave the tuning of the car to HITman with his M&W Uego setup

 

The probe is after the turbo.




But the wide band gauge would have to be used with a wide band oxygen sensor, wouldn't it? Sounds bloody expensive. What if you used a wide band setup when tuning the vehicle then after everyhting is nicely tuned just use a regular, no frills A/F gauge, in conjunction with an EGT gauge just to monitor how the car is running.

 

I was in 3rd gear but didn't hold it for long because I thought the temp was kinda high. Above 1700F.

 

An A/F gauge is essentially a voltmeter that is hooked up to your O2 sensor. A voltmeter will give the actual voltage but the sensor display a specific LED within a voltage range. The typical 10 LED gauge breaks the voltage into .1V increments. This guy sell a 5 LED gauge which only displays the five LED's on the scale. Check it out.
http://www.dawesdevices.com/airfuelmeter.html
The guy on Ebay has a 8 LED version.
http://cgi.ebay.com/ebaymotors/aw-cg...635586&r=0&t=0

 

JoeD,
I agree an EGT is a must but I read an interesting article on the response time of the EGT as opposed to the Air?Fuel ratio gauge.


Date: Tue, 13 Jan 1998 17:25:36 -0800
From: David Lane

Paul Yaw made the point that A/F meters are not very accurate as they get farther from the 14.7 ratio. He said: "IT IS NOT ACCURATE FOR FULL THROTTLE MIXTURE!" Paul recommends getting an exhaust temperature gauge.

Paul's advice is accurate, but I think he is missing a point of practicality. Most of us using A/F meters only want to know how the mixture is doing on a relative basis. In other words, if you are seeing, say, 9 of 10 leds lit up under moderate acceleration, and the lights fade away, one by one, as the revs climb, you know instantly that you have a problem. In another situation, if you raise boost, and your mixture shows (again relatively) leaner, you know that you need to provide more fuel. It would be nice to know absolute values, but as Paul said, that is an expensive proposition

The problem with an EGT gauge (I have a fancy HKS one) is that there is a little delay in its response. Thus, if you do a 3rd gear run to redline, you will see how hot the exhaust gas got. This will tell you something. However, it will not be fast enough to show that you experienced a lean condition as the engine passed through 5 to 6 thousand RPM. Also, if you do your test run in 2nd gear, it could easly occur too fast for the EGT gauge to ever register the max temp through the pipe.

Here is a practical example. The other day I was talking to some people at a tire store for about 10 minutes. This was enough time for the under-hood temps to soar. I left the tire store and hit the throttle hard to merge with a busy street. The A/F gauge took a dive by 2nd gear and I heard detonation. The EGT gauge showed normal because it hadn't had time to register in 2nd. My guess is that the ECU was reading the hot under-hood temperature when I left the parking lot, and leaned the car out. The A/F meter told me instantly that something was wrong. The EGT gauge did not. A minute later, the A/F meter said everything was fine, and it was.

I have had the EGT gauge for two years, and I was never able to tune my system with it. The day I installed the A/F meter I saw an obvious pattern of the car leaning out as the revs climbed. It only took a minute or two to make corrections. Finely, the A/F meter is easy to install and relatively cheap. The EGT gauge is expensive and requires the insertion of a probe in the exhaust manifold.

I got this from http://www.scuderiaciriani.com/rx7/AF_meter.html

 

see this link for why a lot of A/F gauges are useless at WOT

http://www.autospeed.com/A_0618/page1.html

 

If it's at 1700 in the downpipe and you let off early then you were smart!
That's way to hot. Shoot for 1400 degrees to begin with!
Just to give you an idea my car runs at 1600 to 1650 deg. Farenheit max(measured before the turbo in the exhaust manifold) all the way to 9000 rpm in 5th gear with the A/F ratio in the 10's. If I leaned it out to about 11.8:1 A/F ratio it would run 1800 to 1900 deg.F!
There are also instances where running too rich can cause the EGT's to rise due to misfire and also running the timing too retarded would cause the fuel to continue burning all the way into the exhaust manifold but that's an entire subject with a lot of different factors involved that can cause that.

crispeed
87TII
9.20@150mph

 

What you said makes sense. Maybe I should run the sensor before the turbo and try a short run again. It's strange though, the car seems to be running quite rich. AT WOT some black smoke come out the exhaust and after a short run 2' - 3' high flames shoot out the exhaust pipes. People often flag me down to say the car is catching on fire. the previous owner once did a long run on I75 and when he back off the throttle to slow down he left 2 trails of fire on the asphalt (similar to the DeLorean on Back to the Future). My theory, maybe at WOT it could be running lean but when you back off the throttle it gets really rich and the extreme heat could be igniting the fuel?