allegretto

Well, that's cool. You're now back to stock w/ the intake.

They can lean it out but you still want it to run in a range. What is the fuel:air right now that is too rich?

You can blow it up real good running too lean.

robbonds

looks like under 12 - but the graph is tough to read..both after dynos showed it running rich..confirmed by 2 seperate dynos - both dyno jets

allegretto

Under 12 would not be rich. It would be HYPER-rich.

Stoch for 93 Oct is about 14.2 as I reacall. Perhaps some Dyno Monkeys want to help me out. You want it to run a little rich, but under 12 is probably too much for any application. Sounds like that chip is not smart enough yet.

fast1

Rather than merely looking at the maximum torque, I find it much more instructive to look at a plot of the torque curve from around 2000 RPM to red line. The C6 puts out around 400 lb-ft of torque and weighs about the same as a 997S with a maximum torque output of 295 lb-ft. If you check out the March '05 issue of R&T, it shows 1/4 times of 12.3 for the 3300 lb 997S and 12.8 for the 3290 lb C6. So why does the slightly heavier 997S have better performance than a C6? The different gearing of the cars plays a role, and of course the great distribution of torque for the 997S over the power RPM range is also decisive.

allegretto

Those magazine results make no sense some times though.

I love my car but I doubt it would turn low 12's. Simply doesn't feel that strong.

Tina K

Try a back to back run with Sport Chrono off, then turned on?

No this is not a dumb blonde suggestion, a friend of ours working for PCNA in Atlanta absolutely insists that the ignition timing curve is modified to be more aggressive using SC, this in spite of my pointing out no such information recorded elsewhere. Maybe peak HP & TQ are not affected, but instead an improvement over the entire RPM range? I would love to see SC on/off comparison dyno readouts along the RPM range, even if it proves me wrong!

robbonds

tried to engage sport button after first pull - you cant - because front tires arent moving you get an abs/psm deactivated light - pressing sport at this point doesnt work...

is it possible that the chip needs more time to find the proper map? The car defintely running very rich

mdrums

Rob, thanks for the post and being thruthful about your findings. I find on other websites from performance boats to cars that people will do mods and tell everyone how well they worked (when they do not work) because they are embarrassed they made the wrong decision.

Anyway, your findings I guess prove that Porsche really did engineer a great stock car and it will take some major changes to improve on the performance. However I wonder how any changes will affect the everyday driving.

Thanks again and keep us posted!
Mike

allegretto

He's correct! I can tell by driving it. Where do you think the extra kick comes from?

allegretto

Aye here!

You're a brave lad and hopefully your wasted money will prevent others here from the come-on.

In fact, we should take up a collection for Rob, he took a "bullet" for us.

On second thought, considering the Day; Rob, how Christian of you.

Eggplant Cab

Well, the mod mentality is from the 90s where performance gains were decent with $5k of mods thru motronic mods etc.
Even chip tuners for BMW like Dinan admitted that power gains are slim for the new engines because the manufacturers have stepped up in optimizing programming.
Cognitive dissonance is probably the more likely explanation for the percieved power gains through mods. The Sports Chrono thing I can't say. When I had a 997S with SC to evaluate, I didn't think much of it. If the sports chrono is a programmable throttle response improvement thru out the rev range, I guess the chip tuners could incorporate that into a chip.
However I think the sport mode does affect PASM and the shocks for sure. And those visceral cues give a perceived kick in the butt which gives the illusion of more power. Maybe it's Porsche marketing magic at work?

1AS

The C6 ZO6 loses time due to wheel spin. To get top times in a 997, you have to kick the crap out of the rear suspension and tolerate wheel hop without lifting. People who have driven a ZO6 back-to-back with an Enzo feel the ZO6 is faster up to about 90 (that's from a Bondurant instructor when they were doing ZO6 demos for dealers- a client brought an Enzo by)
Dinan, of BMW tuning fame spoke freely on the subject of aftermarket maps, indicating very little was to be gained after the fatory was done (specific to normally aspirated, not turbo'ed, cars). He found maximally 5 hp when enormous fans were used, and none without the fans.
If you want to keep believing the car has more hp, you must now postulate that at true highway speeds, the engine is getting more air than it could on the dyno. This implies the reflash could not demonstrate its value on the dyno, as it was air-limited. That may be wishful thinking, but if it works for you..... AS

gpjli2

Just a different throttle map, faster tip in. ie 1/4 throttle sport =1/2 throttle normal.

allegretto

Oh, no doubt. I don't think it makes more HP, just a more agressive throttle curve.

The_Phantom

What does that mean?