MSD dashhawk questions

The following is from the MSD Dashhawk forum. Kenmosher is the MSD rep.

JumpingJackson
Junior Member

Join Date: Feb 2008
Posts: 4
Default
Under the mazda pid's whats the difference between AFR / AFR from sensor

Old 02-07-2008, 02:27 PM
kenmosher
Senior Member

Join Date: Feb 2007
Location: Fort Collins, CO
Posts: 1,019

One is the commanded AFR, the other is what is read back from the wide band O2 sensor ...
 
One more thing. I asked about the accuracy of the Mazda factory wideband. I was pretty sure it was accurate around stoic but as it's not really designed to read lean/rich I wasn't sure how accurate it became as the afr went down to 13, 12, 11...

Here's ken's response:
From testing of similar setups with an LC1 (on my wife's Volvo V50 ... very similar setup to yours ... turbo, 2.5L, 5 cylinder, intercooled) ... the factory WB was "spot on".

I know the Solstice GXP folks are saying it's very very close all the way down into the 11.x:1 range.

They use the same basic sensor as the aftermarket WBs do (most use one of the Bosch WB variants ... the old one being the LSU4.2 and the new one in the OEMs is the 6.2 (I think that's the number) which is more accurate for direct injection).
 
yeah the old naroww band o2 sensors basicly told you if you were rich lean or stoich. with the wideband your more accurate up and down.
 
dadasracecar said:
The following is from the MSD Dashhawk forum. Kenmosher is the MSD rep.

JumpingJackson
Junior Member

Join Date: Feb 2008
Posts: 4
Default
Under the mazda pid's whats the difference between AFR / AFR from sensor

Old 02-07-2008, 02:27 PM
kenmosher
Senior Member

Join Date: Feb 2007
Location: Fort Collins, CO
Posts: 1,019

One is the commanded AFR, the other is what is read back from the wide band O2 sensor ...
Click to expand...


Yes I read that too, but I believe Ken was just giving an educated guess. I would have said the same thing as well since the way they are labelled it make sense. But if you actually log them and look at the way they behave you'll see that the only one that acts like a commanded AFR reading is the one labelled Commanded AFR, not the 2 mazda PID's.

dadasracecar said:
One more thing. I asked about the accuracy of the Mazda factory wideband. I was pretty sure it was accurate around stoic but as it's not really designed to read lean/rich I wasn't sure how accurate it became as the afr went down to 13, 12, 11...

Here's ken's response:
From testing of similar setups with an LC1 (on my wife's Volvo V50 ... very similar setup to yours ... turbo, 2.5L, 5 cylinder, intercooled) ... the factory WB was "spot on".

I know the Solstice GXP folks are saying it's very very close all the way down into the 11.x:1 range.

They use the same basic sensor as the aftermarket WBs do (most use one of the Bosch WB variants ... the old one being the LSU4.2 and the new one in the OEMs is the 6.2 (I think that's the number) which is more accurate for direct injection).
Click to expand...

It seems that the stock WB is pretty accurate. When I compared the readings to the shop's WB that dyno'd my car, they were dead on all the way to 10:1. After that the shops WB was saturated and didn't read below 10:1.
 
Last edited:
ok, i got my replacement DH yesterday, here is a few seconds of a log graph from this afternoon.

can someone please explain what knock and retard is. please pretend your explaining to a 12 year old as that is probably my mental level on the subject. Feel free to make retard jokes all you want.

17feb08.png
 
Last edited:
meha11 said:
ok, i got my replacement DH yesterday, here is a few seconds of a log graph from this afternoon.

can someone please explain what knock and retard is. please pretend your explaining to a 12 year old as that is probably my mental level on the subject. Feel free to make retard jokes all you want.
Click to expand...

There are two reasons to retard ignition timing, boost and knock. The more boost an engine sees, the less timing advance it can handle without detonation. The computer retards ignition timing as boost increases according with its program. The engine also has a knock sensor which is essentially a filtered microphone that listens for the sound of detonation. The computer retards the ignition timing if detonation is detected to eliminate the detonation.
-enganear
 
enganear said:
There are two reasons to retard ignition timing, boost and knock. The more boost an engine sees, the less timing advance it can handle without detonation. The computer retards ignition timing as boost increases according with its program. The engine also has a knock sensor which is essentially a filtered microphone that listens for the sound of detonation. The computer retards the ignition timing if detonation is detected to eliminate the detonation.
-enganear
Click to expand...


I read this and was confused but with your explanation also I think I may understand-Thanks for the help.
http://en.wikipedia.org/wiki/Engine_knocking

so the pink line on the graph is the engine adjusting timing in the higher boost/rpm levels to ensure the combustion happens at the optimum time?

Are the units in degrees?

i may be over thinking this but if the definition is "spark knock retard" does that mean that the higher the number the less of an advance it is? IE- if the timing was advanced by 5 deg, then the retard changed to 3, would the advanced timing now be 2 deg?

Do I have this right or am I a retard?
 
I've got a quick question-
Just installed my DH today, and was taking some logs with stock bpv and forge to see if stock was leaky, mainly just an excuse to play with the DH. I accidently plugged it back into my car with out the ignition on, and lost all my mazda specific pid's. I plugged back into the computer, uploaded my saved settings, went back to car, made sure it was on, plugged in DH and still no mazda stuff. Any suggestions?
 
dkswim said:
did you post that up on the dashhawk forum? and that sounds very odd.
Click to expand...
thought this place was as good as any.


I just reflashed the unit, and will see if this work (as i'm sure it will). When i get home, i'll load up my settings.

Is there a thread dedicated to sharing settings files? I'm sure some people have got the optimum screen configs.
 
We just started carrying these. As usual very cool to see all the info. PM me if you do not have one and are interested I'll match or beat anyones price.

.
.
.
 
Is it possible to get the raw data from the data log into .txt or .xls format?

While the logger is nice, I would prefer Excel...
 
Yea, you have to visit the dashhawk forum at least once a week. I gotta hand it to them, best product ive owned in a long time with constant updates and work with people who have specific needs like us.
 
cld12pk2go said:
Is it possible to get the raw data from the data log into .txt or .xls format?

While the logger is nice, I would prefer Excel...
Click to expand...

Nevermind, the datalog files can be imported straight into Excel...They are just delimited text files.
 
cld12pk2go said:
Is it possible to get the raw data from the data log into .txt or .xls format?

While the logger is nice, I would prefer Excel...
Click to expand...

The logs are text files but you can open them in Excel just fine. I like to do that quite a bit since I'm an Excel geek too ;)

EDIT: Beat me to it!
 
Jays07MS3 said:
The logs are text files but you can open them in Excel just fine. I like to do that quite a bit since I'm an Excel geek too ;)

EDIT: Beat me to it!
Click to expand...

Haha...

Now I am off to the MSD forum to see if they can allow more parameters to be data logged in a future update. I really need 8-10 to get a good look at everything important on this turboed engine.
 
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