Folks, the situation is: I have a 2001 996S with a stock chip and 50mm termis. The bike (before the refurb) had the infamous stumble somewhere between 3000-5000 rpm. Gaining a few ponies is welcome, but I mostly want to be rid of the fuelling issue. I have a PC3 that I do not have a custom map for. I do know the FIM chip UM231 is perfect for my bike. Sadly I cannot find the chip (or a clone) for love or money. I would be grateful if anyone could offer: a) A source for a FIM UM231. I know FIM no longer exists. But I am hoping there is one of these chips out there somewhere that someone is happy to part with or allow me to clone for my bike. OR b) Confirmation that a custom power commander map, created by a decent tuner, will resolve the infamous mid rpm stumble. Cheers, Sam
The trick with the FIM eprom was the deletion of the 2nd injector on each throttle, ie just run one injector per cylinder. It also had the ability to fuel each cylinder separately which was the FIM's party trick. This could be achieved using a PC to correct the fuelling for the single injector. Back in the day, I know a few people used a "Senna" eprom which as far as I know was a 916 eprom for 50mm pipes. No PC, just fitted the eprom and set up the base fuelling as per a normal injection setup. I didn't have my dyno back then, but they seemed to run pretty well. No idea how they were actually fuelling though.
Not sure I am willing to chance a 'foreign' chip in my S model. I expect the dual injector + SPS cam needs or deserves a matched fuel + ignition map.
It'll certainly do no harm. The root issue with the S was the twin injectors and the overlap of the T1 cams. All 996 suffer to a degree and good setup helps reduce it, but the dual injectors aren't sequential like the SPS. They fire together and at low rpm the injector duration is too short giving poor spray patterns.... They almost 'dribble'. The T1's accentuate this and there's your stumble. Never pinned it down but it seems to coincide with the crossover point of power and torque curves.... FIM solved this by disabling one injector on each throttle, and in simple terms, doubling the duration on the injector timing. It works well all the way through the rev range simply because the injectors are firing for longer and giving a good strong spray pattern. When dynos were few and far between looking at injector timings showed that the 916 50mm EPROMs were firing their single injector for around double that of the twin setup in 996 was proof enough to give it a try and it worked pretty well. Chris will be able to do a bespoke EPROM for sure. Pretty sure he's done some single injector mod'd bikes. May even have a file to burn the EPROM without needing the bike.
I wish I could do that. But the bike (and I) leave for Italy in a couple of days. Don’t feel too sorry for me. I’m sure I’ll find a decent tuner over there eventually.
Hi Sam, I have a 2001 996s and had the same issues that you are having, I went down the PC3 route and had the bike mapped on a dyno, resulting in a 128ps at the back wheel and more importantly the poor running at 3-5trpm was eliminated. I also have a PC5 which has been modified by Smaltmoto specifically on this model but time worked against me last year as I had to do a full motor rebuild due to gearbox output shaft bearing failure... im not sure If I can send the Pc3 file, as that would be a good start position for you, but I think a bit of time on the dyno for individual mapping would be advantageous
Hi Sam, I have a 2001 996s and had the same issues that you are having, I went down the PC3 route and had the bike mapped on a dyno, resulting in a 128ps at the back wheel and more importantly the poor running at 3-5trpm was eliminated. I also have a PC5 which has been modified by Smaltmoto specifically on this model but time worked against me last year as I had to do a full motor rebuild due to gearbox output shaft bearing failure... im not sure If I can send the Pc3 file, as that would be a good start position for you, but I think a bit of time on the dyno for individual mapping would be advantageous
I would be interested in seeing your PC3 map and grateful if you could share it with me. Even if just for reference. If you’re in the US and you’re running a different exhaust or air filter I know my bike will require map tweaking.
Hi Sam, im actually in Russia, but bike in Germany ..... im at work behind a VPN so that maybe why im showing as USA etc.. I have 50 mm termi cans and BMC panel filters plus quickshifter, so shoul dbe compatible with yours. im home at the end of Jan so I can download the file and ping it you across via cloud storage link I was hoping to convert the file to PC5 and try that out in the near future as well...
Hi guys, just came across this old thread. My 996 S has exactly the same problem but only when the bike is hot (>80 Degree water temp). I tried a different eprom but no luck. As I want to stick with both injectors the PC seems the way to go. @Nathanhu hopefully you are still active. Would you mind to share your file again? I have Pretty much the same setup- As you bike in Germany - where did you dyno the bike? Cheers Thorsten
@Goddi8 Hi Thorsten, i had have sadly sold my 996 now, but i think i have a back up file from the PC3 map, and ill try and dig it out for you. i have my bike mapped by Ducati Melle, near Osnabruck if that helps
@Nathanhu thanks! Osnabruck is quite far from where I live but I will give it a shot if there is no other solution.
