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Discussion Starter · #1 ·
As Warr knows, I'm less than trusting when it comes to aftermarket parts, especially a tune. That said, I am interested in a tune, nonetheless. I understand the concept behind data logging and it makes a lot of sense to me.

1. Having never used any of the data logging applications, I'm under the imprecision they don't provide A/F ratios. Is that correct?

2. I'm only comfortable with a very safe tune. Do I need a wideband to make sure of that?
 

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1) Well, here's the thing. Just about any logging device can give you AFRs, but they only give you narrowband O2s, which are not reliable. What you need are wideband O2s, which require a wideband o2 sensor that you weld into your downpipe. You can then log your true AFRs with this wideband either separately or by feeding them into your logging device. I am still setting it up, but my AEM UEGO will be wired to feed into my laptop and into EvoScan while I'm logging, so I'll have my AFRs + timing + everything else except boost, which requires a MAP sensor.

2) An unsafe tune is VERY rare. I don't know what you mean by "very safe" tune other than one that is very rich with low timing. That would be stock, imo. However, any base flash is going to have conservative AFRs and timing off the bat, because that's how they're designed. A wideband won't ensure that the tune is safe - it will only show you where the AFRs sit. Tuning is a lot more than AFRs, though - it's the combination of AFRs, timing, boost, altitude, octane, temp, humidity, and load...
 

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Discussion Starter · #3 ·
1) Well, here's the thing. Just about any logging device can give you AFRs, but they only give you narrowband O2s, which are not reliable. What you need are wideband O2s, which require a wideband o2 sensor that you weld into your downpipe.
Thanks very much for the reply. I'm not comfortable with welding anything to my stock downpipe, so I gather that rules me out, given my comfort level.

2) An unsafe tune is VERY rare. I don't know what you mean by "very safe" tune other than one that is very rich with low timing.
I meant a tune that doesn't try to max-out the power/torque, running the engine very close to the margin of safety.
 

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I meant a tune that doesn't try to max-out the power/torque, running the engine very close to the margin of safety.
I don't know any tuner who tunes to that degree unless specifically requested by the customer, and that's with custom tunes. Base flashes are even more conservative, but neither type is pushed to the very edge for a daily driven Evo.
 

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Discussion Starter · #5 ·
I don't know any tuner who tunes to that degree unless specifically requested by the customer, and that's with custom tunes. Base flashes are even more conservative, but neither type is pushed to the very edge for a daily driven Evo.
As you've probably gathered, I've been following tuning threads rather attentively. Having seen many less than conservative tunes (without mentioning names) I am concerned. But, that's beside the point.

Given my priorities and concerns, it doesn't seem to make sense to flash my ECU without a wideband. Is that right? Thanks.
 

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I don't know, man. I don't know how you've seen so many "less than conservative" tunes when I have been in the scene for years and have seen VERY FEW such tunes. The vast majority are mid-to-low 11 AFRs with normal timing. That is perfectly normal for pump gas and regular boost levels. Are you sure the tunes you're seeing are aggressive? You'd have to know the timing, afrs, boost, octane, and knock levels to make that determination. You certainly can't tell by looking at AFRs, which is why just having a wideband in your case really doesn't matter. As mentioned previously, tuning is FAR MORE than just AFRs...
 
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