ok, heres a typical external wastgate install to show what way round the wategate plumbs,

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unfortunately I cant find a good cutaway pic of a wastgate, but this pic should show what i'm talking about,



the blue valve that opens runs in a guide similar to a valve guide but quite a bit looser, boost pressure leaks past this and intp the exaust stream.

Also jumping back to the original topic AEM are now doing a setup to go pre turbo.

http://www.aemelectronics.com/wideband-air-fuel-systems-15/4-channel-wideband-uego-controller-60/

 

I see what you're saying now. By design it shouldn't leak, but the guide has large enough clearances to cause a leak.

 

yep, especially on cheaper ones, Ive not seen any with a seal yet.

 

Then why not machine a cheap one for an exhaust seal?

 

most waste gates have a air cooling fine design between the diaphram housing and valve housing containing exhaust gas..
my turbonetics gate leaks pressure from under diaphram.

BTW,
think bout this for awhile,
i would have afr sensor , NOT egt
afr sensor that reads to 3.3- 3.5 a/f
egt is a result of : cam, cam intake centre line, fuel, timing, turbine wheel, turbine housing
egt means nothing, unless it is bench marked of a know combination.

spark plugs dont lie./ nor do top shell of big end bearing

 

Wait an afr ON TOP of a wideband?
I already have a wideband an I'm looking to monitor the temp of the air/exhaust gas temp to see if it's getting to hot.

Ait would be ideal but if egt would provide that info too then I would just the egt.

And I agree the plugs don't lie but it's not exactly something you can monitor on the spot. Ex: your cruising on a 100* weather your not going to pull over and take out the plugs after you just did a quick wot.

I mean I keep my wideband connected at all times just to monitor when somethings comes up. Or maybe just a peace of mind lol

 

AFR is wideband, all the widbands Ive seen can read in either AFR or Lambda, AFR's easier to read, but lambda works for different fuels where AFR sort of dosent.

 

All widebands measure lambda, then convert to AFR for output display. AFR is air fuel ratio, this is just a ratio, not a gauge or a physical measurement in itself. AFR will vary depending on what fuel you use. A lambda output of 1 is stoichiometric, less than 1 is rich, more than 1 is lean. This applies to all fuels.

 

I thought he meant those narrowband afr gauges which in my knowledge I pretty useless.

 

nah, sorry... i must have been mumbling...

 

Narrowband o2 sensors are designed to indicate whether the engine is rich or lean, nothing else, and they have a very narrow window of operation. .5-1.5 volts I believe. They are designed so that they switch at 14.7:1, so all they are really accurate for is knowing if the engine is rich or lean. The stock computers use this to adjust constantly trying to average stoich for cruise and light throttle conditions. For WOT they run in open loop mode, which basically is just the computer using some info it has, guessing and throwing x amount of fuel at the car. The stock computer has no idea how rich or lean the car is at WOT.

From what I've heard, the new 5.0 mustangs have two widebands and the stock computer uses them to continuously adjust all four cams independently along with timing and fuel mixture, technology is a wonderful thing