To high AFR
03-24-2007, 12:01 PM
#16
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Nathan, the mods were done by JZM or Autofarm (Sadler) can't remember, but I think it was Autofarm. The car had serious modifications done to it and was featured on the cover of 911 & Porsche mag back then. The car that Miles has now.
03-24-2007, 12:24 PM
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Sorry for OT.
I bought that magazine from '98-'05, should have seen that article but I do not remember. I will see if I can find it now. I seem to have two missing June & July I think, I suppose it was in one of those...
I bought that magazine from '98-'05, should have seen that article but I do not remember. I will see if I can find it now. I seem to have two missing June & July I think, I suppose it was in one of those...
Last edited by nathanUK '81 930 G50; 03-24-2007 at 01:45 PM.
03-24-2007, 04:12 PM
#19
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Originally Posted by PorschePhD
Normally about 13-13.5. The other thing you have to do is unhook the air injection at the same time. Otherwise the CO will not be accurate at idle. You really should not need this standard if you have a good AFR gauge. What is it? There is a possiablity it is not calibrated. You should base line it to something else that is a "known" good unit.
If you are too close to time at the track to do any tuning/checking simply fillup with some 100 octane. 12.6 on 100 is fine!
If you are too close to time at the track to do any tuning/checking simply fillup with some 100 octane. 12.6 on 100 is fine!
I guess I could run Shell V-power at the track (99 octane), but I am concerned about the heat, don't want to ruin my headers.
Drew, how long have you had your car, are you sure a previous owner hasn't done a wur mod? Your numbers are very good.
I have a friend who has I complete workshop and he can do magic.
Thinking about doing the WUR mod myself, if something goes wrong we will fix it I think.
03-24-2007, 04:25 PM
#20
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You will be fine with 99 octane.
Keep in mind that the 02s will start to become lazy the older they get. I replace mine on the dyno about every 6 months. Also my unit will self calibrate every time it is turned on. I use the Zeitronic as well on in car installs but do not recall if it self calibrates on every power up. I will have to look.
It seems strange the mods you have that the system would be that lean. That is why I brought the accuracy question up.
Keep in mind that the 02s will start to become lazy the older they get. I replace mine on the dyno about every 6 months. Also my unit will self calibrate every time it is turned on. I use the Zeitronic as well on in car installs but do not recall if it self calibrates on every power up. I will have to look.
It seems strange the mods you have that the system would be that lean. That is why I brought the accuracy question up.
03-24-2007, 04:28 PM
#21
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Originally Posted by Jean
I Still have a copy. I will try to scan it one of these days, or I will tell you the issue date. It is teh 4WD speed yellow 964 on the cover.
Oh let me tell you...that car was nice! If it hadn't been on the other side of the world I would have probably bought it. Jean, post up some of the pics! Boy that car was nice.
03-24-2007, 07:04 PM
#22
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Originally Posted by PorschePhD
You will be fine with 99 octane.
Keep in mind that the 02s will start to become lazy the older they get. I replace mine on the dyno about every 6 months. Also my unit will self calibrate every time it is turned on. I use the Zeitronic as well on in car installs but do not recall if it self calibrates on every power up. I will have to look.
It seems strange the mods you have that the system would be that lean. That is why I brought the accuracy question up.
Keep in mind that the 02s will start to become lazy the older they get. I replace mine on the dyno about every 6 months. Also my unit will self calibrate every time it is turned on. I use the Zeitronic as well on in car installs but do not recall if it self calibrates on every power up. I will have to look.
It seems strange the mods you have that the system would be that lean. That is why I brought the accuracy question up.
It is at times like this I am a happy owner of a 1.500+ entry "blog" of all the work I have done on my car.
According to my Zeitronix unit, I had this AFR on full boost
- April 4th 2005, around 11.8 (stock turbo, o2 sensor in muffler /w cat)
- April 8th 2005, around 12.2 (stock turbo, o2 sensor in muffler no cat)
- August 18 2005, 11.6 - 12.0 (HF turbo, o2 sensor in muffler no cat)
- March 25 2006, 12.6 - 12.8 (HR turbo, 02 sensor i u-bend no cat)
- March 20 2007, 12.2 - 12.8 (HF tubo , o2 sensor i u-bend no cat)
It doesn't seems to be the HF turbo.
Does the temperature make a difference, it was cold in march last year, and it's about 40F now ?
Could it be that my AFR values started to drift after moving the wideband o2 sensor to the u-bend (had it in the muffler before)?
Or perhaps it got lazy as Stephen put it?
Perhaps I don't have a problem..
03-24-2007, 07:38 PM
#23
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Hmm, that is interesting. I wouldn't think the placement to the U bend would matter much as long as you have some distance from the turbo. At least 8 inches or so. Is it possible the 02 got damaged(dropped, contaminated etc) when it was moved?
There are other variables. A free flowing muffler or system will yield more HP and generally a leaner mixture. The temps also play a big part, HOWEVER in colder weather the air is generally more dense hence more 02 and the car will run leaner.
There are other variables. A free flowing muffler or system will yield more HP and generally a leaner mixture. The temps also play a big part, HOWEVER in colder weather the air is generally more dense hence more 02 and the car will run leaner.
03-24-2007, 07:54 PM
#24
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Originally Posted by PorschePhD
Hmm, that is interesting. I wouldn't think the placement to the U bend would matter much as long as you have some distance from the turbo. At least 8 inches or so. Is it possible the 02 got damaged(dropped, contaminated etc) when it was moved?
There are other variables. A free flowing muffler or system will yield more HP and generally a leaner mixture. The temps also play a big part, HOWEVER in colder weather the air is generally more dense hence more 02 and the car will run leaner.
There are other variables. A free flowing muffler or system will yield more HP and generally a leaner mixture. The temps also play a big part, HOWEVER in colder weather the air is generally more dense hence more 02 and the car will run leaner.
I have been pretty careful with the o2 sensor, but I will clean it and also see in what way the promised 50F for tomorrow will influence my AFR reading (compared to 40F).
03-24-2007, 08:21 PM
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I didn't think you could calibrate a sensor that was fitted in an exhaust pipe unless the motor hadn't been run for at least a week. This is why Motec & Innovate have to be forced to be calibrated by the user ?
I have a pic I can post of Jeans old car (now belongs to Miles) that I took at a Porsche Club GB event. I will post it when Jean does.
I have a pic I can post of Jeans old car (now belongs to Miles) that I took at a Porsche Club GB event. I will post it when Jean does.
