Air/FUel guage usefulness

[70]

....(snip)


Widebands on Dynos read post cat exhaust, not the most reliable either.... unless you are running no cats.

Not necessarily...It depends on where you put the sensor, and if you have a bung for it pre-cat. As is the case on my car.

The bung is in the downpipe from the turbo before the first cat. It reads, post-turbo exhaust, not post-cat.

I see what you are getting at, but it's not true in all cases...

 

[Keith@FP]

If you're at a dyno shop and they try to put the wideband after the cat, leave and take your money with you. It's basically useless there and they're either clueless or they're hoping you are.

We always, always mount widebands before the cat. Many of our turbo kits actually come with an extra bung just because of this. On cars with standalone ECUs that have this option, you can take the car out of closed loop operation and put the wideband in place of the factory front sensor, but cars with the stock ECU (like Chris' car) need to have a new bung welded in.

There's a lot of confusion about how to read EGTs, actually.

Keith

 

[syntrix]

If you're at a dyno shop and they try to put the wideband after the cat, leave and take your money with you.

....

There's a lot of confusion about how to read EGTs, actually.

Keith

Agreed on the wideband in the tailpipe, then run! However this is more common than you might expect!

The operating temp of the Bosh Wideband is something like 1550 degrees.... don't remember the exact amount, but if you go over that spec, then you can get false readings on an O2. This applies to narrow AND wide.

Ugh, we could have headaches for days discussing egt's probes, ambient, placement, etc etc etc

 

[AFaceInTheCrowd]

i'm gonna try to get my egt sensor (when i get the guage) mounted in the manifold. i heard it's best there.

 

[syntrix]

Where did you hear that?

 

[Keith@FP]

Well, if you put it in the collector it is the best place.

Keith

 

[WeldingHank]

after the turbo reads ABOUT 200 deg. cooler. i would say the best place is in the manifold off of the runner for the cylinder that runs the leanest. usually the #4. in the manifold you will get more consistent temps.

 

[syntrix]

Agreed with Keith, but I just hate it when people say "I hear that x is the best for y".