Dh a/f accuracy.

[laloosh]

im begginning to question the accuracy of this thing. the 1/4 mile feature on it et wise seems to be spot on as im always in the high 12s low 13s and thats what i ran at the track. Tonight i've actually hit my best of a 12.72 @ 116.2. neway what irks me about this thing is that the a/f ratio varies greatly depending on how you log it. let me show you what i mean. All three charts have a green line at 12.0 a/f ratio

here are the three runs.
4th gear pull

3rd through 5th

and finally the 1/4 pass with a/f

how is it possible for me to be sub 12s mid to high 11s ont he 4th gear pull from down low. Then be in the high 12 even low 13 range for the other pulls. The passes were made within 5-10 min of each other.

 

[Bravnik]

The DH AFR is right on the money with my car. When I did my Dyno runs, I checked my DH against the AFR of the dyno. They were almost identical.

I would suggest you go do a dyno run with an AFR and then check your DH against what the Dyno says. For $50 you will get your answer. Maybe the DH is bad or maybe you have so much done now that your confusing the s*** out of the factory ECU and its trying to compensate thus screwing your AFRs?

When I go WOT, my AFRs drops smoothly to the mid 9s and stay there will I shift or let off. I don't get any spikes and its consistant and always around the same number.

 

[driver311]

Exactly why I say the DH is off. The sniffer on the dyno will show about .5-1 full point leaner than it actually is. When I dyno srts or my car for that, if the aem uego(which is PROVEN to be VERY ACCURATE) says 12to1 then the dyno will usually show around 12.5-13.0. Usually around .5 off. Ive seen it over and over again. I dont believe the dh to be entirely accurate. Consistant maybe but accurate no. The only way to tell would be to test it against a uego or lm1. Both very accurate widebands. If I had a dashhawk to try I would be glad to test the theory.

WHO HAS ONE THEY CAN PART WITH FOR ABOUT A WEEK?????????????????

 

[dadasracecar]

This is from the MSD Mod in the DH forum, "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)."

Also, the AEM UEGO is not as accurate or as fast as the LC1 according to a wideband shootout that was posted somewhere on this board.

 

[driver311]

This is from the MSD Mod in the DH forum, "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)."

Also, the AEM UEGO is not as accurate or as fast as the LC1 according to a wideband shootout that was posted somewhere on this board.

You mean lm1? LOL and yes I know I have gone over that shootout many many times. Some one send me there dashhawk to compare these bitches.

 

[laloosh]

The DH AFR is right on the money with my car. When I did my Dyno runs, I checked my DH against the AFR of the dyno. They were almost identical.

I would suggest you go do a dyno run with an AFR and then check your DH against what the Dyno says. For $50 you will get your answer. Maybe the DH is bad or maybe you have so much done now that your confusing the s*** out of the factory ECU and its trying to compensate thus screwing your AFRs?

When I go WOT, my AFRs drops smoothly to the mid 9s and stay there will I shift or let off. I don't get any spikes and its consistant and always around the same number.

into the mid 9s? i think ure logging COMMAND afr instead of actual

 

[laloosh]

driver ill part with mine for a week. The problem is that my car runs fine if i do a pull downlow. however rowing through the gears it gets lean. how is that even possible? why would the car be 1-1.5 point leanser going through the gears?

 

[chrisyng]

driver311: You state that you are seeing a diffrence between the Dyno wideband and AEM unit.. is the where is the AEM unit installed and where dno unit installed? Chances are the AEM is in the downpipe while the dyno unit is mounted in the tailpipe.. you are going to see a diffrence from the 2 diffrent locations already.. exhaust temps are also higher in the downpipe than tailpipe which will account for diffrent readings..

Laloosh: Do a simple test.. Log commanded AFR as well as Actual AFR's on the dashhawk and do your runs again... if your Actual AFR's follow your commanded afr's, chances are your scaling could have screwed up with your past datalogs showing leaner than it actually was...

 

[Bravnik]

into the mid 9s? i think ure logging COMMAND afr instead of actual

Sorry Laloosh, I had the DH before most people on this board. A lot got theirs after my recommondation. I know exactly what to log PID wise.

Also I have 3 Dyno runs at the same AFR's of low to mid 9's. I also seen plenty of stock Dyno runs in the 8's on the same dyno I ran on.

Here is one of my dyno runs:




The DH reports only what the ECU sees. There is no way the ECU is wrong unless the WB sensor is wrong. Which if it was your car would be running like s*** and you would probably have CEL's all over the place. So Meh.

 

[Bravnik]

Exactly why I say the DH is off. The sniffer on the dyno will show about .5-1 full point leaner than it actually is. When I dyno srts or my car for that, if the aem uego(which is PROVEN to be VERY ACCURATE) says 12to1 then the dyno will usually show around 12.5-13.0. Usually around .5 off. Ive seen it over and over again. I dont believe the dh to be entirely accurate. Consistant maybe but accurate no. The only way to tell would be to test it against a uego or lm1. Both very accurate widebands. If I had a dashhawk to try I would be glad to test the theory.

WHO HAS ONE THEY CAN PART WITH FOR ABOUT A WEEK?????????????????

Oh and Driver. I really don't think you need to worry then if your Dyno shows your in the 9s AFR wise then (headshake seeing that by your experience its actually lower (cool) than what the Dyno shows.

The highest AFR I saw on the day we ran (there were about 5-6 MS3's) was one that had 3.5 TMIC, TBE, CPE Standback at 18PSI with Forge BPV. He was at like 10.5 AFR.

 

[driver311]

driver ill part with mine for a week. The problem is that my car runs fine if i do a pull downlow. however rowing through the gears it gets lean. how is that even possible? why would the car be 1-1.5 point leanser going through the gears?

Mines the exact opposite and thats really weird. Mine is richer when going through the gears. Ill go test it again to verify.

 

[Darksun280]

into the mid 9s? i think ure logging COMMAND afr instead of actual

I told you the same thing loosh. When i did the Bc and bcd as first mods the dash hawk had my a/fs touch 9s. I lowered the boost then it went back to 10's like the car knew it was being ****** with. it wasn't the commanded PID either I triple checked it. Lets just blame it on the weather an put this one to rest.

 

[Darksun280]

his A/f sensor is probably on it's way out. Oh Noes!!!!!

 

[laloosh]

this thing is off, theres no way in hell its chaning that much btwn doing a one gear pull and rowing through the gears

 

[chrisyng]

this thing is off, theres no way in hell its chaning that much btwn doing a one gear pull and rowing through the gears

sigh. like I said.. log commanded AFR along with actual AFR and do the tests again.. If the DH readings are really that far off, then you will see a significant diffrence between the commanded vs actual ...

 

[laloosh]

sigh. like I said.. log commanded AFR along with actual AFR and do the tests again.. If the DH readings are really that far off, then you will see a significant diffrence between the commanded vs actual ...

sigh i did a bunch of times. Commanded a/f ratio dip into the 9.2-9.4 range. Actual is nowhere near that, it stays close to about 3500 after that it not even close to each other

 

[mrlilguy157]

Sorry Laloosh, I had the DH before most people on this board. A lot got theirs after my recommondation. I know exactly what to log PID wise.

Also I have 3 Dyno runs at the same AFR's of low to mid 9's. I also seen plenty of stock Dyno runs in the 8's on the same dyno I ran on.

Here is one of my dyno runs:




The DH reports only what the ECU sees. There is no way the ECU is wrong unless the WB sensor is wrong. Which if it was your car would be running like s*** and you would probably have CEL's all over the place. So Meh.

please don't host images there....

pop ups galore!

 

[kingpinMS3]

please don't host images there....

pop ups galore!

use firefox, homie. it'll take care of that.

 

[Bravnik]

pop-ups? I never get any pop-up when I got to imageshack.

 

[laloosh]

dadaracecar just experienced the same exact thing. So either these cars run lean as **** rowing through the gears, or the DH readings are messed up