New 4" cold air intake! I'm going to paint it black, it's a little too shiny
New 4" cold air intake! I'm going to paint it black, it's a little too shiny
A chrome snoot is HOT!!! go fiddle with the trunk lid............
Too late! It's black now. What does the trunk lid need?
I got new tires, see what I found when I cut apart the old ones
I had a great weekend of racing. The car felt great and performed nearly flawlessly. I got Fastest Time of Day on both days and was 3rd and 4th in PAX, both my best PAX results with this car. Video of the fun
I wasn't expecting to have another video up so soon but after making the last one, a tuner friend looked at the logs and told me to not drive the car again until I fix whatever is causing lean spikes in the AFR readings. A lot of discussion later and I was no closer to a solution or cause of the problem, only that I had a BIG problem. Today I think I solved the problem, see the video to find out how CLICK HERE FOR VIDEO
Great troubleshooting, good luck.
I swear this guy could be your brother.
I had two events in one day and got some good, bad and ugly video footage out of it.
After I posted that video, I remembered that I now have a way of overlaying data on the video, check out the short clip
loosecannon said:I wasn't expecting to have another video up so soon but after making the last one, a tuner friend looked at the logs and told me to not drive the car again until I fix whatever is causing lean spikes in the AFR readings. A lot of discussion later and I was no closer to a solution or cause of the problem, only that I had a BIG problem. Today I think I solved the problem, see the video to find out how CLICK HERE FOR VIDEO
About that sensor locations.... While your friend, in concept, is right, in reality, by the time the O2 gave you odd readings, the turbos would be well beyond damage. In other words, your original location is fine. It's also fine for mixing, since the turbo does a great job mixing any biased flow going into it.
In reply to alfadriver :
But for diagnosing tuning problems or whatever, don't you want accurate AFR readings?
loosecannon said:In reply to alfadriver :
But for diagnosing tuning problems or whatever, don't you want accurate AFR readings?
IMHO, it's 1) not that big of a deal, and 2) it's not hot enough to really matter. The turbo takes about 200F out of the exhaust temp, and unless you are melting turbines, you are probably in the 1700-1800F temp at worst. So the sensor is seeing 1500-1600F, which isn't that big of a deal. We run them closed loop hotter than that. But the turbine does wonders with the exhaust temp.
(the temp loss I'm noting is with a catalyst- so there's a good chance that the turbo will loose a lot more temp in your situation, as it can be a lot more efficient with much less back pressure)
Besides, mixing with the fresh air is a far bigger risk to an incorrect a/f reading than the heat will be, as you have found out.
All I know is that I know next to nothing about how to analyze my engine datalogs but the guy that does told me that my afr readings are erratic and I should move the sensor farther away from the turbo. I did that and now the afr readings are better. I still don't know what is causing my stumbling issue. Sometimes it does it and sometimes it doesn't. I have checked for boost leaks, relocated my crankcase vent, gapped the plugs, replaced both fuel filters, checked my fuel cell vent, replaced the battery, replaced power wires, did a compression test, checked grounds and replaced maf sensor and both cam sensors. I have a test n tune Saturday, hope it runs well.
In reply to loosecannon :
Are you logging when it stumbles? Do you see an a/f excursion that corresponds to the lag?
In reply to alfadriver :
Yes, but there's nothing obvious on the logs. I can't tell from the logs where it is stumbling. I am going to use video from my runs to determine the exact moment of stumbling then I can look at the log and see what is happening.
Can you screen shot the datalog when it stumbles?
Or can you upload a datalog file that shows stumbling?
In reply to loosecannon :
Do you have any logs you can share? Not via pictures, but the raw data. I'll be happy to look at it.
One thing that may help- if your device has a single analog input for it- put a switch on the steering wheel that you push when you feel the stumble. We use that trick all the time with CC switches.
I watched a video of a run where I was datalogging and the afr goes to 8 or 9 when it's stumbling. I am starting to think it is a tune problem because it only does it when I mash the throttle too quickly. Here's the video, you can't really hear the stumble but I can feel it. The video
Too rich for a stumble is a decent problem to have. for the most part, you need to turn some transient fuel down....
But I'd still like to see that data on my own graphing tool. The stumble will be pretty obvious in the rpm trace.
In reply to alfadriver :
Where can I email a data log to?
In reply to loosecannon :
Alfa73 at Comcast dot net
Going on the back garage wall above the 'X' brace....do grass tufts make for dodgy handling???
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