The boost is about the same @ ~ 20 psi. Here is the before (top) and after (bottom). There is one data point @ 21.80 in the before, but that is an anamoly.

 

I run a stock filter and airbox. The only thing that was changed between the runs is the TP. That is it. If I swap back to the HFC and the AFRs return to "normal", would that make the case that it is the test pipe.

BTW, the testpipe is a resonated 3 inch one. Would that make a difference?

 

im not surprised!

 

Surprised by what? Please explain

 

Do a free air cal (with sensor in air)
nevermind


The only thing you change was the test pipe?

Maybe the test pipe change the path of exhaust or something or you had a leak before you installed it

 

if you have a cat, youre going to get leaner readings than without one..... youre reading unmolested air with the test pipe...

with the cat youre obviously reading air that has gone through a brick that is designed to filter emissions!

we see that all the time on the dyno...

cb

 

surely he doesn't have the wb02 AFTER the cat...

 

I have the wideband installed in the downpipe. So this should no be an issue.

 

The only change was the TP. Even if I had a leak when I had a HFC, the wideband is installed in the middle of the downpipe and I do not see how a leak @ the cat would contaminate the wideband results.

 

actually a leak can skew the numbers pretty badly if it's anywhere near the WB02 sensor, they are very sensitive.

 

never mind. missed a post above.

 

That is the only logical explanation. It is entirely possible that I had an exhaust leak right after I installed the TBE with the HFC. Here is why I think so:

1. I noticed that when I would try and richen the fuel map in the 3500-4500 rpm rpm the car would still run lean. It was not as responsive as it should have been to fuel changes. This continued to happen even after I turned off lean spool. The car was more responsive to fuel changes on the high end of the rpm, however. This tells me that the exhaust leak was not large enough to contaminate the AFR when the exhaust gases are moving at a fast rate, but it was large enough to contaminate the results on the low end.

2. When I isantalled the TBE w/HFC, I re-used the same worn out gaskets, since I did not have any new one. When I installed the TP, Iused brand new gaskets that came with it.

3. When I removed the HFC, I noticed some soot residue on the heat shield above the HFC. That is a telltale sign of a leak.

That is the best explanation that I have so far.

 

I would say that nails it on the head then. Just chalk it up to an exhaust leak and start tuning now that you have everything working nicely and found the cause of this issue.

Another quick question: Did you notice your idle AFRs any leaner with the HFC than with the test pipe? When I used to have a leak at my downpipe a long time ago, it would show up as lean idle AFR, but as you mentioned, with higher velocities and volumes of exhaust gases at WOT, it wasn't much of a difference. That was also a quick indicator for me of an exhaust leak.


Eric

 

Bingo...Back when I was working on making the boost pills deal, I noticed when I started the car that it would run lean at idle when the car is cold or when the car is strated and then it would settle down. That NEVER happened before. This was when I was tuning the timing and fuel and it was right after I flashed the car with the JDM RS mivec map. I thought it was the JDM RS mivec map, so I flashed the car back to the stock mivec map, but it kept on happening.

I made nothing of it, but in retrospect, it all makes sense.

 

ok sorry lol...

was a quick response...

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leaks can cause massive fluctuations as stated here...

even the smallest of leaks..

i had three widebands on my 2.3 at one point... and could see variance from just the smallest leaks

cb