turbocharged 928 (32v) just dynoed...(first dyno)
.. here's Shane's Helmut.
10-03-2005, 03:23 PM
#47
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that's exactly what I dyno'd before the turbosystem. I can always check to see what my first '86.5 did back in 1998, but Dynojet didn't offer the sniffer back then, & w/o AF readings, they're of no use to me. 
10-03-2005, 06:24 PM
#49
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PS: Those runs I did above were in third gear. I believe most of the other 5sp's that ran that day used 4th gear as it is closer to 1:1. But as I will be adding a supercharger, I didn't want to overspeed the dyno when I go back for a follow up dyno, so I used third.
10-04-2005, 01:29 AM
#51
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Hey Mark,
Great numbers!
You and I need to talk up this "donor" car thing, as I am definitely interested. Was thinking SC boost, but you've got my attention now.
Really enjoyed dropping in and visiting with you at Elite... just wish I had had more time. Quite impressive resources you have there at your disposal to make this thing top notch.
Let me know if you would care to have a tag along for the drag runs on Wednesday. Give me a shout.
Best Regards,
Bill
Great numbers!
You and I need to talk up this "donor" car thing, as I am definitely interested. Was thinking SC boost, but you've got my attention now.
Really enjoyed dropping in and visiting with you at Elite... just wish I had had more time. Quite impressive resources you have there at your disposal to make this thing top notch.
Let me know if you would care to have a tag along for the drag runs on Wednesday. Give me a shout.
Best Regards,
Bill
10-04-2005, 02:58 AM
#52
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FWIW...
Don't forget that the only way that one can get a useful A/F measurement on a cat equipped car is to measure BEFORE the cats.
I have seen (more than once) Dynojet "operators" try to convince people that they can log A/F ratios with a tailpipe WBO2 on cat conv equipped cars.
While you will get a reading, the oxygen level (and therefore the A/F ratio) will not be accurate because of the basic function of the cat and the fact that the fuel level will have been corrected by the pre-cat O2 sensor feedback loop to the ECU.
If you are running cats, and looking at post-cat (tailpipe sensor) A/F readings to tune, you are guaranteed not to get the best out of your engine, and stand a really good chance of burning it down if you are running forced induction.
Greg
Don't forget that the only way that one can get a useful A/F measurement on a cat equipped car is to measure BEFORE the cats.
I have seen (more than once) Dynojet "operators" try to convince people that they can log A/F ratios with a tailpipe WBO2 on cat conv equipped cars.
While you will get a reading, the oxygen level (and therefore the A/F ratio) will not be accurate because of the basic function of the cat and the fact that the fuel level will have been corrected by the pre-cat O2 sensor feedback loop to the ECU.
If you are running cats, and looking at post-cat (tailpipe sensor) A/F readings to tune, you are guaranteed not to get the best out of your engine, and stand a really good chance of burning it down if you are running forced induction.
Greg
10-04-2005, 10:21 AM
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pretty damn low, but still not the lowest part of the car. Luckily, for the last month, have not scraped it or the new exhaust once, only the swaybar (Sorry Dave). 
10-04-2005, 01:47 PM
#55
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Originally Posted by 2V4V
FWIW...
Don't forget that the only way that one can get a useful A/F measurement on a cat equipped car is to measure BEFORE the cats.
Don't forget that the only way that one can get a useful A/F measurement on a cat equipped car is to measure BEFORE the cats.
...and with out the airpump hooked up if you have the cat bypass in.
10-04-2005, 02:09 PM
#56
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Originally Posted by 2V4V
FWIW...
Don't forget that the only way that one can get a useful A/F measurement on a cat equipped car is to measure BEFORE the cats.
I have seen (more than once) Dynojet "operators" try to convince people that they can log A/F ratios with a tailpipe WBO2 on cat conv equipped cars.
While you will get a reading, the oxygen level (and therefore the A/F ratio) will not be accurate because of the basic function of the cat and the fact that the fuel level will have been corrected by the pre-cat O2 sensor feedback loop to the ECU.
If you are running cats, and looking at post-cat (tailpipe sensor) A/F readings to tune, you are guaranteed not to get the best out of your engine, and stand a really good chance of burning it down if you are running forced induction.
Greg
Don't forget that the only way that one can get a useful A/F measurement on a cat equipped car is to measure BEFORE the cats.
I have seen (more than once) Dynojet "operators" try to convince people that they can log A/F ratios with a tailpipe WBO2 on cat conv equipped cars.
While you will get a reading, the oxygen level (and therefore the A/F ratio) will not be accurate because of the basic function of the cat and the fact that the fuel level will have been corrected by the pre-cat O2 sensor feedback loop to the ECU.
If you are running cats, and looking at post-cat (tailpipe sensor) A/F readings to tune, you are guaranteed not to get the best out of your engine, and stand a really good chance of burning it down if you are running forced induction.
Greg
Your statement makes sense, so I'm not trying to argue. But I've seen multiple cars with custom wideband sensors installed, match the dyno readings from the tailpipe.
10-04-2005, 02:15 PM
#57
I have thought about this question too..as you would think that the readings after cat would be more lean than before the cats. So...any error in measurement would force you to go richer by adding more fuel..not the opposite...
I am just guessing here, but I figure the cats need a certain residence time (ie time for exhaust to react with catalyst in Cat..and get converted). The factory probaby designs the cat size and length based on normal driving conditions and normal revs... of course the dyno is at WOT...so the exhaust passes too fast for the complete reaction....
More of a statistical thing as car do not see wot very often in normal usage...therefor the car companys can design it this way..
Just a SWAG...though..
any other thoughts..?
Later,
Tom
midlman@rennlist.net
89GT
I am just guessing here, but I figure the cats need a certain residence time (ie time for exhaust to react with catalyst in Cat..and get converted). The factory probaby designs the cat size and length based on normal driving conditions and normal revs... of course the dyno is at WOT...so the exhaust passes too fast for the complete reaction....
More of a statistical thing as car do not see wot very often in normal usage...therefor the car companys can design it this way..
Just a SWAG...though..
any other thoughts..?
Later,
Tom
midlman@rennlist.net
89GT
