Part II: Dyno'd it....AF Ratio Problem...

[DamnYankee]

I went to LG Motorsports today with the hopes of getting different results, but they got basically the same readings.

Here's the first run again at RPM:

And these are the results from LGMotorsports (on the first graph, bottom reading is with TC unlocked, top is locked):

And another:


LG pretty much said the same thing (but for $85 instead of $25 at RPM): bad A/F ratio and it's going to cause problems. So I'm driving around babying it afraid to get into it at all.

<div class='quotetop'>QUOTE(farmtruc &#064; Jun 27 2006, 09&#58;45 AM) [snapback]56403[/snapback]</div>

For what it&#39;s worth, I never use my tail pipe a/f device because it&#39;s always a little off and isn&#39;t as consitant as the O2 bung reading.
I also found out on mine, that the dyno reads about .5 leaner than the street.
Bring it back down if you can&#39;t find a shop to dyno it and we&#39;lld double check it, but I&#39;m sure it&#39;s fine.
Also, you&#39;d be surprsed that GM doesn&#39;t allow their trucks to richen up until about 5K rpms, doh. If PE delay isn&#39;t turned off, which yours is, then most trucks will not richen up until the top of second gear.
I know the &#39;06&#39;s wont&#39; until about 4900rpms.

let me know,
allen
[/b]

I asked about doing it before the cats and they said it was such a small difference, it didn&#39;t matter. If it helps any it was a DynoJet 1 and they did the runs in 3rd gear. I know you&#39;re too thorough to miss anything Allen, so believe me, I don&#39;t think you "missed" anything. I&#39;m just not in the know enough on A/F ratios and stuff to know what to do, what to ask of them, etc.

[RedHeartbeat]

I guess that&#39;s not too bad of a price for LGM. If you made three pulls at RPM it would have cost you &#036;50.00. Does your engine ping, rattle or clatter?

What octane fuel are you running?

[DamnYankee]

<div class='quotetop'>QUOTE(RedHeartbeat &#064; Jun 27 2006, 05&#58;56 PM) [snapback]56442[/snapback]</div>

I guess that&#39;s not too bad of a price for LGM. If you made three pulls at RPM it would have cost you &#036;50.00. Does your engine ping, rattle or clatter?

What octane fuel are you running?
[/b]

Running 89 octane with no engine noise...

[RedHeartbeat]

Did you get a live tune with Allen as the co-pilot?

[DamnYankee]

<div class='quotetop'>QUOTE(RedHeartbeat &#064; Jun 27 2006, 06&#58;02 PM) [snapback]56447[/snapback]</div>

Did you get a live tune with Allen as the co-pilot?
[/b]

Sure did. He spent quite a bit of time with me.

[RedHeartbeat]

That&#39;s the best kind tune. There is nothing better. Have you made any changes to the truck since the tune?

[Motocycleguy]

Just look at the graphs there is a .5 difference between the two. Im still wondering why no one is using the wideband that goes in the bung instead of the tail pipe? I bet youll see its alittle better than you think.

[DamnYankee]

<div class='quotetop'>QUOTE(RedHeartbeat &#064; Jun 27 2006, 06&#58;45 PM) [snapback]56452[/snapback]</div>

That&#39;s the best kind tune. There is nothing better. Have you made any changes to the truck since the tune?
[/b]

Not a thing.

<div class='quotetop'>QUOTE(Tyson &#064; Jun 27 2006, 07&#58;43 PM) [snapback]56456[/snapback]</div>

Just look at the graphs there is a .5 difference between the two. Im still wondering why no one is using the wideband that goes in the bung instead of the tail pipe? I bet youll see its alittle better than you think.
[/b]

Keep in mind, I&#39;m not a pro at this so I probably don&#39;t know all of the right questions to ask. I did tell them I thought it gave more accurate results if they tested before the cats instead of after and he said the difference wasn&#39;t enough to affect anything. So I&#39;m not going to sit and argue with him - these guys build racecars, I&#39;m assuming they know what they&#39;re doing.

What I do know is two places have told me I&#39;m going to damage my engine if I get into it so I&#39;m feeling like 1.) maybe I already have and 2.) I have to pussyfoot around until I get this figured out.

[Motocycleguy]

By all means get it back to Allen and have him check it out.. Im just saying its proven that thoes sniffers are not accurate. Im using a dynojet and its up to 1 point leaner, Allen says his is .5 leaner...

Even if they say the difference only alittle, They need to do it anyway its more accurate. I think someone is just being lazy...

What are they saying your afr "Should" be? 12.5 went out the door awhile back along with flat curves... Every engine is different but 12.8-13.3 seems to be optimal.

One more thing, GO BUY A WIDEBAND&#33; I mean you have probaly all ready spent over &#036;100+ on dyno time.... You can get an AEM off ebay for &#036;250...

[DamnYankee]

<div class='quotetop'>QUOTE(Tyson &#064; Jun 27 2006, 09&#58;09 PM) [snapback]56475[/snapback]</div>

By all means get it back to Allen and have him check it out.. Im just saying its proven that thoes sniffers are not accurate. Im using a dynojet and its up to 1 point leaner, Allen says his is .5 leaner...

Even if they say the difference only alittle, They need to do it anyway its more accurate. I think someone is just being lazy...

What are they saying your afr "Should" be? 12.5 went out the door awhile back along with flat curves... Every engine is different but 12.8-13.3 seems to be optimal.

One more thing, GO BUY A WIDEBAND&#33; I mean you have probaly all ready spent over &#036;100+ on dyno time.... You can get an AEM off ebay for &#036;250...
[/b]

That&#39;s easy to say - Allen is a 5 hour drive from here. Can&#39;t just hop in the truck and go. Would if I could, but it&#39;s not that feasible at the moment.

They&#39;re saying the A/F ratio should be around 13, like you said.

And same goes for another &#036;250 part. Can&#39;t just dig it out of the couch cushion and go get it.