Dyno today
Thread Starter
Instructor
Joined: Jan 2016
Posts: 145
Likes: 29
From: Pelham Alabama
Dyno today
I'm short on time and the search is not fast enough but with all the talk about AFR'S and mods I have a dyno run set up in a couple of hours because of my new found concerns with my mods. I have a 16 A8 with Borla X pipe, Halltech, and Mamo PTB so we are going to see if my car is ok on the AFR's. My guy is reputable but I would like y'alls input on a couple of things so I'm a little informed. I have half a tank of 93 and 32 oz's of Torco in the tank and its in the 60's here now and should drop a little this afternoon. What setting (sport,track) or does it matter, what gear, 4th,5th or D. This is not a drag car or even a track car at this point but I may do some after driving school next month. Just want to know where I stand with what I've done because the info on this subject with these popular mods is all over the board and I just want to be sure. Any advice would help, Thanks in advance.
Melting Slicks
Joined: Feb 2009
Posts: 2,797
Likes: 608
From: Dallas Georgia
2020 Corvette of the Year Finalist (track prepared)
C3 of Year Winner (track prepared) 2019
Mode shouldn't matter, just turn off traction control (don't be surprised if you get service axle/stabilitrac errors or warnings, they go away.)
I believe 6th gear is 1:1 with the A8 so that is the gear it should be in when pulled.
I believe 6th gear is 1:1 with the A8 so that is the gear it should be in when pulled.
Pro
Joined: Oct 2016
Posts: 578
Likes: 241
From: Hutto Texas
Six gear will overspeed the Dino.
put your car in manual mode, pulling the shifter all the way back for the rear bumper.
use the paddles to shift up to fourth gear, and run the Dino in fourth gear.
Engine coolant temp will drastically affect your power in numbers.
ideally, get to the Dino an hour and a half early electric car fully cool down.
make sure your engine coolant tip is around 150° when you begin your Dino session.
this will produce your maximum power output.
also, for your most accurate AFR readings,
have your Dino Operator remove the left front O2 sensor, and install their Wideband.
this is really important, the tailpipe sensor is not especially accurate.
please let us know how this works out, this is really important information.
my apologies for the miss spellings, I am using voice to text.
put your car in manual mode, pulling the shifter all the way back for the rear bumper.
use the paddles to shift up to fourth gear, and run the Dino in fourth gear.
Engine coolant temp will drastically affect your power in numbers.
ideally, get to the Dino an hour and a half early electric car fully cool down.
make sure your engine coolant tip is around 150° when you begin your Dino session.
this will produce your maximum power output.
also, for your most accurate AFR readings,
have your Dino Operator remove the left front O2 sensor, and install their Wideband.
this is really important, the tailpipe sensor is not especially accurate.
please let us know how this works out, this is really important information.
my apologies for the miss spellings, I am using voice to text.
Last edited by ACS55; Mar 22, 2017 at 05:58 PM.
Burning Brakes
Joined: Apr 2004
Posts: 849
Likes: 557
From: phx az
Six gear will overspeed the Dino.
put your car in manual mode, pulling the shifter all the way back for the rear bumper.
use the paddles to shift up to fourth gear, and run the Dino in fourth gear.
Engine coolant temp will drastically affect your power in numbers.
ideally, get to the Dino an hour and a half early electric car fully cool down.
make sure your engine coolant tip is around 150° when you begin your Dino session.
this will produce your maximum power output.
also, for your most accurate AFR readings,
have your Dino Operator remove the left front O2 sensor, and install their Wideband.
this is really important, the tailpipe sensor is not especially accurate.
please let us know how this works out, this is really important information.
my apologies for the miss spellings, I am using voice to text.
put your car in manual mode, pulling the shifter all the way back for the rear bumper.
use the paddles to shift up to fourth gear, and run the Dino in fourth gear.
Engine coolant temp will drastically affect your power in numbers.
ideally, get to the Dino an hour and a half early electric car fully cool down.
make sure your engine coolant tip is around 150° when you begin your Dino session.
this will produce your maximum power output.
also, for your most accurate AFR readings,
have your Dino Operator remove the left front O2 sensor, and install their Wideband.
this is really important, the tailpipe sensor is not especially accurate.
please let us know how this works out, this is really important information.
my apologies for the miss spellings, I am using voice to text.
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Drifting
Joined: Dec 2016
Posts: 1,704
Likes: 577
The tuner should know this unless this is his first C7Z06 dyno. Will you make a pull using 93 Octane 1st...because this is usually how you probably drive around, unless you will be using the octane boost upon every fill up. Anyways, thanks for sharing!
Pro
Joined: Oct 2016
Posts: 578
Likes: 241
From: Hutto Texas
It's just a dyno session, not a tune session on a dyno...at least that's how I read the OP.
In this case, they are going to pick the easy path and use the tailpipe sensor because it's easy and quick.. that's what happened to me on my previous dyno sessions and it's human nature.
What I was saying is that you should request (and pay extra if needed) for them to install a wide band (in the left front sensor bung pre-cat) to be sure and get the most accurate readings possible. I say this because your main stated reason for the dyno is to determine if you have a safe AFR or not... so why not be as accurate as possible in measuring your AFR?
I am actually installing an extra wideband O2 sensor bung on my lead pipe for a full time wide band gauge.
Last edited by ACS55; Mar 22, 2017 at 09:37 PM.
Burning Brakes
Joined: Apr 2004
Posts: 849
Likes: 557
From: phx az
Pro
Joined: Oct 2016
Posts: 578
Likes: 241
From: Hutto Texas
Are you somehow under the assumption that a catalytic converter significantly alters the oxygen content of the exhaust? Sure a cat will dampen the transient response but that isn't really what we are looking for here now is it? After all a catalytic converter is really only effective at 1.00 Lambda.
"A Catalytic Converter has 3 purposes:
1. to reduce NOx to N2 and O2 next.
2. turn carbon monoxide to CO2 (it uses o2 in this equasion)
c. turn unburned hydrocarbons to co2 and water (again using o2) .
..so while you produce a little oxygen in the cat, mostly it will consume oxygen to perform its desired function. "
And a quote from a tuners on the subject...
"I have used dual WB's on many many cars before and after the cat. Cruise and idle AFRs' will be the same in most cases. WOT will be .5 points leaner at the tailpipe on avg."
And this second quote tends to agree with the first, and they suggest that at WOT (dyno and race conditions) you will be getting a 1/2 point leaner reading at the tailpipe than before the cat.
Pro
Joined: Oct 2016
Posts: 578
Likes: 241
From: Hutto Texas
Are you somehow under the assumption that a catalytic converter significantly alters the oxygen content of the exhaust? Sure a cat will dampen the transient response but that isn't really what we are looking for here now is it? After all a catalytic converter is really only effective at 1.00 Lambda.
"A Catalytic Converter has 3 purposes:
1. to reduce NOx to N2 and O2 next.
2. turn carbon monoxide to CO2 (it uses o2 in this equasion)
c. turn unburned hydrocarbons to co2 and water (again using o2) .
..so while you produce a little oxygen in the cat, mostly it will consume oxygen to perform its desired function. "
And a quote from a tuners on the subject...
"I have used dual WB's on many many cars before and after the cat. Cruise and idle AFRs' will be the same in most cases. WOT will be .5 points leaner at the tailpipe on avg."
And this second quote tends to agree with the first, and they suggest that at WOT (dyno and race conditions) you will be getting a 1/2 point leaner reading at the tailpipe than before the cat.
Burning Brakes
Joined: Apr 2004
Posts: 849
Likes: 557
From: phx az
Here is some info I found on this topic:
"A Catalytic Converter has 3 purposes:
1. to reduce NOx to N2 and O2 next.
2. turn carbon monoxide to CO2 (it uses o2 in this equasion)
c. turn unburned hydrocarbons to co2 and water (again using o2) .
..so while you produce a little oxygen in the cat, mostly it will consume oxygen to perform its desired function. "
And a quote from a tuners on the subject...
"I have used dual WB's on many many cars before and after the cat. Cruise and idle AFRs' will be the same in most cases. WOT will be .5 points leaner at the tailpipe on avg."
And this second quote tends to agree with the first, and they suggest that at WOT (dyno and race conditions) you will be getting a 1/2 point leaner reading at the tailpipe than before the cat.
"A Catalytic Converter has 3 purposes:
1. to reduce NOx to N2 and O2 next.
2. turn carbon monoxide to CO2 (it uses o2 in this equasion)
c. turn unburned hydrocarbons to co2 and water (again using o2) .
..so while you produce a little oxygen in the cat, mostly it will consume oxygen to perform its desired function. "
And a quote from a tuners on the subject...
"I have used dual WB's on many many cars before and after the cat. Cruise and idle AFRs' will be the same in most cases. WOT will be .5 points leaner at the tailpipe on avg."
And this second quote tends to agree with the first, and they suggest that at WOT (dyno and race conditions) you will be getting a 1/2 point leaner reading at the tailpipe than before the cat.
Drifting
Joined: Feb 2014
Posts: 1,519
Likes: 145
From: Arizona
Years ago we used to dual wideband everything, I mean every car that came in got a front pre-cat O2 bung put in along with a tailpipe reading. We stopped doing that because it was within a couple tenths with or without cats. I have NEVER seen any vehicle have a significant shift like you just quoted unless it had big exhaust leaks, significant being more than 2/10ths of a point for clarification. The big difference is that I have been doing this for over 15 years now just about every single day and didn't just read about it on the internet.
Pro
Joined: Oct 2016
Posts: 578
Likes: 241
From: Hutto Texas
Years ago we used to dual wideband everything, I mean every car that came in got a front pre-cat O2 bung put in along with a tailpipe reading. We stopped doing that because it was within a couple tenths with or without cats. I have NEVER seen any vehicle have a significant shift like you just quoted unless it had big exhaust leaks, significant being more than 2/10ths of a point for clarification. The big difference is that I have been doing this for over 15 years now just about every single day and didn't just read about it on the internet.
Whether the actual difference is 2/10ths of a point, or 5/10ths of a point (on my car), I certainly do not know at this point.
I will be finding out after I get back to the Dyno next time... since I have recently installed a wideband.
So, the AFR reading will be leaner after the cat than before the cat... and the reading pre-cat will be more accurate.
But, the difference is not large enough to go through the trouble of installing a pre-cat wideband during tuning.
Got it, thanks for the clarification.. and have a
day.
Leeds.io
Joined: Sep 2003
Posts: 4,604
Likes: 409
From: White Mountains
St. Jude Donor '14-'15-'16
NCM Sinkhole Donor
At this point without hearing from Oak Mountain Body I'm left to assume the only thing that one can assume. The car leaned out and exploded on the dyno. 
Last edited by phantasms; Mar 23, 2017 at 05:31 PM.