kylejohnston1

My C2 has a lwf and cup pipe. Stalling was only an occasional issue before getting my a/c fixed but it has been has been much more frequent since.

I've searched through past messages decided I will most likely try the Steve Wong chip. I also emailed Jason to see if he is still programming chips with a lwf fix.

My question is this: 91 octane chip or 93 octane chip if I go with Steve Wong?

Most of our pumps down here in the south offer 87, 89 or 93 so 93 is readily available in my region and the grade I currently use. However, it is quite warm most of the year here in Houston. Any potential downsides to going with the 93 chip over the 91 chip in a hot climate?

Jim Richards

Kyle, are you ever going to take your 964 on a trip, perhaps the West Coast or the Rockies? I think when you get into Mountain and Pacific time zones, 91 octane is more prevalent.

Makmov

Octane is really kind of a misguided rating system for fuel. The key number is really density which can only be measured by specific gravity with a hydrometer.

You can have a really high octane rating with a really low density that is ulitmately horrible fuel.

Likewise you can have a low octane fuel with high density that is better fuel than a higher rated octane rating.

There us a degree if relationship of octane and density generally speaking but they are really independant from each other.

Here in the Rockies there is no 93. There is no need for it because of the thin air.

crg53

My thought is, go with the 91 octane chip, then you are good to go wherever you please with no worries. The performance difference between the 91 and 93 will be minimal at best.

SAM DACOSTA

+1 on the 91 octane chip from Steve Wong.

Earlydays

What a coincidence - I just got a response from Steve Wong on exactly the same question.
Here's his answer:

"At full throttle past 4500 rpm, the 93 programming typically provides 3-5 more hp gain over the 91 programming. But it will depend on the knock limit of your fuel/engine combination. Since you are in Texas, and if your air temperature are high normally, where you mostly operate your car in 90+ degree temps and likely with the AC on, then you may be better to go with the 91 octane programming, while still using 93, to give you better knock margin against the hot conditions. Keeping the engine operation below the knock limits delivers better consistent performance, than if some knock is detected and the sensors dial back the car's overall performance to compensate.

Below 4500 at part throttle, the performance gains are very much the same, which is substantial. Both chips will eliminate the lag and flat response you currently are experiencing below 4000 rpm, with a significant torque and thrust boost right off the line. Customers note that the power and delivery is much like that of a V8. Hope this helps, but let me know if I can be of further assistance.

Regards,
Steve Wong"

kylejohnston1

Small world! This seems like the perfect opportunity to get a group buy going (even if there are only 2 of us).

Okay, I'm sold. Going with the 91 chip. Thanks, as always, for the excellent advice...

Kyle

mike9186

I'd jump in a group buy! So that makes three

Henry964

You can count me in too!!!

gprosser

likewise the group buy, if it can include the 95ron chip shipped to Europe :-)

Makmov

yeah I'd be in on a chip too.

mainly to get rid of that 1000-4000 flat dead space I have, but after 4000-4500 man it really pulls hard.

gprosser

agree - have only had my 964 for a month now, but quite surprised at lack of grunt under 4k - hope the chip keeps the after 4k madness though :-)

kopo

Glad I’m not alone in this dept. Not real happy with the 964’s performance thus far. It’s a real dud under 4000 rpm. I’m thinking my old 2001 Boxster S would out perform my 964.

Makmov

FWIW I just put a new O2 sensor in my car and reset the DME. It's greatly help the lower end power.

Now it is much smoother across the entire band ... it just pulls hard (2000rpm) and harder (4000rpm) and madness hard (5000 +)! It pulls hard to redline and beyond.

I did notice something with the old O2 when the check engine light came on it was stupid fast.

I know it's sampling for the AFM but I am not sure if it's leaning out or richening when that happens. I haven't quite figured it out yet. There is un-found HP somewhere there.

It might be something to look at. FWIW.

gprosser

Hi Makmov - how do you reset the DME?

What's the cost of a new O2 sensor? Plug and play?

Thanks, Gareth.