4by4 - judging by what you are saying, I take it to mean that the O2 sensor loop is not able to compensate for the richness for some reason? Assuming that your dyno run is reasonably accurate, and that Scott's is too, there has to be some reason for the significant difference. It would be great if you could continue dialogue with Scott on this to determine the reason for the gap.

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1980 Honda CBX
2004 Suzuki SV1000
2006 Subaru Legacy
2002 Honda Insight

I'll let Scott confirm, but I think the O2 sensors are "out of the loop" so to say under WOT. They are only used for closed-loop optimization. What I don't know is whether the closed-loop fuel adjustments (long term fuel trims) affect open-loop operation at all. My impression and limited testing is no.

The graphs posted, to my limited knowledge, do look like the AFRs are too rich. I actually have the same problem on my 986 (stock OE program). From what I have gathered, dropping from stoichiometric down to around 13:1 is what to expect for WOT, 12:1 is even OK (but no extra power), and below that loses power. Mine is as low as 11:1 or 10:1. There was a tuner (Upsolute) that allegedly would tailor your fuel maps if you provided them with AFR graphs. The company looks sort of defunct, though. I also had GIAC on mine. The AFRs were a little leaner than the stock program.

It would be great if Scott can comment on the whether the LTFTs (closed loop) have any impact on WOT fuel maps and if he could do any AFR adjustments. I'm sure Scott is a busy guy and provides a decent "generic" program. I would be interested, for example, if there was a "premium" programming option where, for some reasonable surcharge, he could adjust the fuel trims. I'm sure Scott knows where the AFRs should be on these cars and maybe this can be offered as part of the generic package or offered as a premium option.

Hello All,

Yes the O2 are open at WOT.

I would not consider these flashes generic yet they are not custom tuned for every dyno run. What you have to keep in mind is that wheel or roller dyno's are not very accurate. You could take one car and run it on 5 different dynos before and after for any given mod or stock and yield 5 completely different results. Porsche does not use any roller dyno's for this reason. Even if you ran a car today and then again on a later date after a mod the chances are it would be off.

I will give an example , in another post on this site an individual ran his car before and after on 2 different dynos. Both yielded completely different results, in fact one dyno yielded 2 different results under different modes. Why? The software and the mod was the same, the Software does not change nor did the TB or Plenum in size or shape. This was the same car in mechanics, so what was different? The dynos or the runs in which human interaction or other variables could be applied.

This region Australia has been supplied with the same software and parts yet I have seen several completely different dyno runs. Once again the software is the same and so are the parts so why the diverse runs in the same area? I basically answered this in the first part, however lets continue.

Back to the fuel. Yes I can make a leaner file and one could run it on a dyno and show HP increases etc. for that specific car. This file should be able to be used on all the cars in the same area or region. Porsche only makes a NA, EU2, EU4, Japan file for these cars and they are Global. Did you know that all WP0 beginning VIN's use a NA file and all WP0ZZZ typically use a EU4 file? Now a VERY few WP0ZZZ Vin cars use the EU2 and only Japan uses this file in which is for idling emissions. China does use WP0 Vins with an EU4 file and then again they may not the next year.

Take a Mod or lets say change or repair to a car. We would not only have the dyno variables yet now compound it with the alteration. Was it actually installed correctly? Perhaps a hose left off or not capped off? Maybe even another one disconnected by mistake etc. When both of these are put together it compounds even more. Cars with different mods are also thrown into the loop in which will change it all once again.

Now we all know that all USA cars will use just one file for a given year and it is a NA for North America. This file is used in high elevations like CO and lower octane states like CA and also in Sea level states like SC. All of these cars or even the same car that could be run under perfectly matched testing would yield different results in all of these areas period. Why, Ca uses 91 Octane when all Porsche maps are set for 93. Sc has 93 octane and is close to Sea level in which the air is more dense and better yet perhaps warmer than some other states like CO. CO has it own problem in general and that Is altitude. The higher the altitude the thinner the air or less oxygen to burn.

Porsche does not give different charts for any of these areas or regions globally. Why? Because the engine was tested under controlled conditions and posted by Porsche and the few maps will all yield the same results by them.

This was only meant to be a quick educational post on maps etc.


Best,
Scott Slauson

Scott, thanks for the reply and info on the regional programs.

I mis-spoke in referring to your files as generic as you do consider fundamental mods, octane, and such. What I meant was that it is not "custom"-tuned for a specific car. As a point for other readers, GIAC and Revo are "truly" generic. GIAC has a single program--no customization or adjustment other than the built-in adaptability. Revo has two "stages" and some fudge-factors which adjust timing and fuel, but I felt this was only due to an extreme lack of adaptability with their software (much worse than GIAC). Theirs just felt hard-coded.

Back on topic: Scott is absolutely correct in talking about the repeatability and comparison of dynos. Even with the same dyno program, on the same dyno, on the same day, with the same operator, you can easily get 5HP difference due to fan placement, different gearing, dyno smoothing, engine temperature differences (wait 5 minutes), etc. You really need to establish a repeatable and statistically significant difference in order to say "A" or "B".

I need to contact you offline, Scott, since mine is not a Cayman, and I don't want to take this further off-topic. I would like to get the Softronic tune, apply it, dyno it, and if my AFRs are still off, know that you would be willing to do some tweaking to the AFRs (possibly with some service fee since I know your time is not free). I believe Scott is the most qualified out there to make these kinds of tunings and adjustments.

Thanks!