Stock Narrowband O2's for tunning WOT

[SRT10KLLR]

I know it is not ideal but can someone post approximately what the A/F is at certain mv?

Something like this:

600 mv = 14 A/F
700 mv = 13 A/F
800 mv = 12 A/F
900 mv = 11 A/F

But in 50 mv increments.


I was tuned a while back ago and just recently installed a nitrous kit. I went to the track today and tested it on a 50 shot but I did not have a wideband(I let someone borrow it and never got it back). I just want to know if I am safe to continue using it until I can hook up a wideband and/or get retuned.

Attached is a log of a NA run and a nitrous run.

[WeathermanShawn]

Its a really bad idea. Sure-fire recipe for engine damage.

The experts all weighed in on this about a week ago..Check this out:http://forum.efilive.com/showthread.php?16181-Tuning-accuracy-without-AFR&highlight=No+wideband+only+narrowband

[mr.prick]

You can make a calc_pid for NBO2 mV to AFR based off WBO2. :hihi:

The one I made has a small range, 13-15 AFR.
It does match up with WBO2 too.

I certainly wouldn't use it for any adjustments tho. :doh2:

[WeathermanShawn]

SRT:

In all seriousness take a look at BlackFlags nitrous log from a day or two ago:http://forum.efilive.com/showthread.php?16195-Problem-with-my-Head-Cam-98-LS1-camaro-files-attached&p=144349&viewfull=1#post144349

He suffered engine damage on a nitrous run. You can see he went lean, but his O2's still showed >800 mv.

[SRT10KLLR]

I know it is not the greatest thing to do but I do not have access to a wideband right now. Worst case scenario if the fuel solenoid was not working at all what would 50 additional hp do to my A/F if I am at 12.3 N/A without the nitrous?

From what I have gathered it seems as the higher the mv the richer it gets. If you look at my log I went from a 840-890 range to a 900.

Almost all nitrous companies play it safe on the jet chart and are on the rich side. Heck when we sprayed a 200 shot on the 2010 Camaro it was pig rich(low 10's high 9's) with the recommended jets. We ended up going from a 46 fuel jet down to a 33 just to get it into the 11.8 A/F range.

I will definitely use a wideband when I begin upping the spray but for right now do you think I am safe?

[WeathermanShawn]

Well what I am saying is that I have seen the same 850 Mv on the narrowband equate to 11.0 or 14.0 AFR...and on the same run.

No way I am going to tell you are safe.

Would you really expect a good tuner to say its O.K. But, its your vehicle and you may have already determined its safe. I'm not really judging, I am just giving you my opinion.

I like the know my WOT AFR and a wideband is the only tool to do it with.

Good luck.

[SRT10KLLR]

Forget about being safe and just tell me in general is 900 mv richer or leaner than 800?

I should have pulled the spark plugs out to check the fuel and timing but it was freaking hot yesterday(I have a sunburn to show for it) and I was being lazy.

[joecar]

900mV at WOT NA (with no nitrous) is too lean... this is all that can be said about NBO2 mV.

Your NA log indicates:
- too lean for NA at WOT (less than 900mV and positive LTFT's),
- intake has a restriction (6 kP drop at WOT),
- MAF may be under-reporting (only 269 g/s at 5734 rpm WOT),
- something wrong with your IFR (DC only gets to 35% at 5700 rpm WOT),
- intake is pulling hot air (IAT 97°F-81°F).

Your 50 shot log indicates (see attached pic):
MAP drops even more, MAF is worse, IAT is too hot, IFR is wrong, HO2Sx1 is only 900mV (too lean for either NA or shot).

50 shot at commanded 12.3 (we have no idea what actual is, but it look like it may be leaner) will cause damage... you're not safe.

[joecar]

Forget about being safe and just tell me in general is 900 mv richer or leaner than 800?
...900mV is still too lean for NA WOT.

[SRT10KLLR]

900mV at WOT NA (with no nitrous) is too lean... this is all that can be said about NBO2 mV.

Your NA log indicates:
- too lean for NA at WOT (less than 900mV and positive LTFT's),
- intake has a restriction (6 kP drop at WOT),
- MAF may be under-reporting (only 269 g/s at 5734 rpm WOT),
- something wrong with your IFR (DC only gets to 35% at 5700 rpm WOT),
- intake is pulling hot air (IAT 97°F-81°F).

Your 50 shot log indicates (see attached pic):
MAP drops even more, MAF is worse, IAT is too hot, IFR is wrong, HO2Sx1 is only 900mV (too lean for either NA or shot).

50 shot at commanded 12.3 (we have no idea what actual is, but it look like it may be leaner) will cause damage... you're not safe.Thank you, I really appreciate it. :help2:

Here is a little more info on my setup. It is a 2003 Silverado with a low(9:1) cr 408, cam(224/231 595/595 114) and AFR 225 heads. I am running the stock air intake with just a drop in filter, stock exhaust manifolds with just gutted cats.

I always have high IAT's from waiting so long in the staging area before a run. I think the IAT sensor gets heat soaked.
My stock intake could be causing the restriction.
The tuner said my MAF was not functioning propery so he put me on a speed density tune.
I am running 60lb(72 @58PSI) injectors that is why the IDC is so low.

I noticed on my NA log that the O2 goes as low as 840 mv.


I need to get a wideband hooked up and have everything checked out. The nitrous is temporary until the turbo goes on.

What time do you want me to meet you at your house?:grin:

[rpmauto]

The narrowbands simply put "switch" they will go to 8-900mv at cruise, idle and so on. Yea 900 mv is richer than 800, but you cant tune wot with them by any means. They are constantly switching to provide the "stock" pcm the info it needs to maintain 14.7:1 afr on a "stock" engine. I would assume with the money you have in a 408, and you have efi-live that you wouldnt want to melt it down. Just put it on hold till you get a wideband.

If your tuner put you on a sd tune how come the maf is reporting data. It should be failed. (cant look at the tune on my phone)

[SRT10KLLR]

The build has been 3+ years in the making.

I looked at the tune to confirm and the MAF high/low frequency is set to 1(fail). It is still plugged in though as the IAT is in the same housing.

[joecar]

I see DTC P0103 which confirms you're running SD (i.e. in failed MAF mode).

[SRT10KLLR]

Well I did the unthinkable; I upped the shot to a 100. I went to a buddies house and we hooked up a fuel pressure gauge and wideband. Unfortunately the O2 sensor on the wideband was bad so I ended up just spraying it anyways to see if my fuel pump would be able to handle the additional hp. When the nitrous hits the pressure dips for a split second then recovers and reads normal(58 psi) for the rest of the run. The mv again were in the 900 range when spraying.

I ran it at the track with the 50 and it knocked .5 sec of my 1/4 and now the 100 knocked off a full second.

I went to a dyno to check the a/f but was out of nitrous. According to the wideband from the dyno I am in the 12.3 range NA so it looks like I am a little richer on the juice maybe a 12.1 or so.

Have to refill the bottle and try again.

Here is a log of todays N2O run and a NA run for reference.

[SRT10KLLR]

You can't see the dip on that run because it was at the track and it spun off the line. The window switch was set to activate the nitrous at 3000 rpm so when it spun it immediately started spraying.

On the run from yesterday I was on the street with street tires so I would not hit the nitrous until well into second gear so I would not spin. On this scan you can see the dip in the O2 sensors when the nitrous activates. I could see in on the fuel pressure gauge when it happened.

[WeathermanShawn]

Original OP's Question..can you use Stock NBs for Tuning WOT.

Fresh NB O2's..AFR both 12.62.

1. IAT 90F MV: 872-890

http://i1126.photobucket.com/albums/l609/weathermanshawn/WOT90FIAT.png


2. IAT 64F MV: 929-942

http://i1126.photobucket.com/albums/l609/weathermanshawn/HO2IAT64F.png

Conclusion: You can not use stock NB for Tuning WOT.

Screen-shots Added to Tuners Checklist: http://forum.efilive.com/showthread.php?16139-Mechanical-Issues-that-prevent-Good-Tuning (http://forum.efilive.com/showthread.php?16139-Mechanical-Issues-that-prevent-Good-Tuning)

[SRT10KLLR]

OK. Finally had a chance to use a wideband and it read 9.9-10.4 A/F on the juice. I did not have a smaller jet so my buddy pulled some fuel out of my tune using the PE. I went to the track and logged one run on the N2O which is named Today. The other two were from checking the A/F with the WB and after the PE was adjusted. The WB is not in the log data though.