A question about the stock ECU - Ducati.ms

Hazzbin · May 4th, 2011, 9:23 am

I'm riding an '08 Hyper with a FatDuc, and am happy with the ridability and low RPM throttle response. I intend on keeping the original mufflers but am interested in installing one of the MWR air filters. Above 4K RPM will the stock ECU still provide adequate fuel with the larger inlet and airflow, or do I need to bite the bullet and buy an ECU? If so, would the correct one be the slipon ECU? Thanks.

minusone · May 4th, 2011, 5:35 pm

I have on 09 S with opened airbox and filter, fatduc and have removed the cat, but standard cans

Fueling is AOK and feels better than my stock multistrada S

moperfserv · May 4th, 2011, 10:45 pm

Unlike with carbs, changing the inlet restriction does not result in big changes to fuel.

The increase in total system airflow will be small and the effect on AFR will be inversely small.

The real question is; is the fueling, or has it ever been, correct.

Doug

Once again, the Grinch!

1badduck · May 5th, 2011, 12:10 am

Quote:

Originally Posted by moperfserv

Unlike with carbs, changing the inlet restriction does not result in big changes to fuel.

The increase in total system airflow will be small and the effect on AFR will be inversely small.

The real question is; is the fueling, or has it ever been, correct.

Doug

Once again, the Grinch!

I'm no expert, but my butt dyno totally disagrees w/ this. I had the larger fuel tank put on and w/ that comes air box removal and K&N air filters and I could feel a difference in the power - there was more - so there must be more air getting in.

I have cored exhausts and don't have any ecu mods and it seems to run fine, but it could be running lean - dunno - have 800 miles on it like this and no blowy uppy.

would like to remove cat but nervous that would put me into too lean territory.

moperfserv · May 5th, 2011, 8:01 am

Alright, the nisunderstanding here is about the term 'big changes.

Yes, eliminating inlet restrictions, plus coring the muffler, does result in a detectable difference in power. Attributing all of the difference to inlet mods may be a little myopic.

But, the point was (and poorly made) that with a carb, a small change in inlet restriction will result in a large change in fuel flow, while a small change (f'rinstance 5%) will result in a proportional change in fueling. The injection system continues to deliver exactly the same amount of fuel while the total system airflow went up 5% resulting in a 5% shift in AFR. That is a change from 12.6:1 to 13.23:1 and that will only run better.

With a carb it could go to 15:1 with the same change.

Hope that clears it up.

Doug

1badduck · May 5th, 2011, 2:59 pm

for the record - i cored the exhausts first, and that didn't make any difference i could feel...then a few weeks later had the intake changed and that made a difference i could feel.

I hope you're right that the a/f doesn't change so much that you need a new tune.

I wonder if taking out the cat would be ok or if that would require a re-tune...my guess is the cats are where most of the exhaust blockage occurs.

DemonTweaks · May 5th, 2011, 6:14 pm

Within certain limits the CPU make sure it's where it should be. That's why there is an lambda sond... (O2 sensor) But the range is only so wide with the OEM one, hence the DP CPUs.
That's not the case with carbs and why it's not so noticeable with a dirty airfilter for instance on an FI bike.
Removing the cat is one my future too but I'll get a pipe (or fab my own) that have a bung for the sensor.

1badduck · May 5th, 2011, 11:11 pm

if you took the cat out and still had the stock o2 sensor, wouldn't that cause problems? Like it would read to rich or something?

I want to take my cat out but don't want to spend the cash on an ecu or tune.

DemonTweaks · May 6th, 2011, 10:52 am

Quote:

Originally Posted by 1badduck

if you took the cat out and still had the stock o2 sensor, wouldn't that cause problems? Like it would read to rich or something?

I want to take my cat out but don't want to spend the cash on an ecu or tune.

If anything it would run lean, since the cat is restrictive. That is theoretical though, modern cats have really little restriction and there is not much performance gain from removing it. They are pretty heavy though...

If your not willing to spend the money to actually make more power (cuz' that's why you want to pull it right?) just leave it alone. All you gain is some weightloss and noise.
Contrary to popular belief noise doesn't make the bike quicker...

1badduck · May 6th, 2011, 11:00 am

Quote:

Originally Posted by DemonTweaks

If anything it would run lean, since the cat is restrictive. That is theoretical though, modern cats have really little restriction and there is not much performance gain from removing it. They are pretty heavy though...

If your not willing to spend the money to actually make more power (cuz' that's why you want to pull it right?) just leave it alone. All you gain is some weightloss and noise.
Contrary to popular belief noise doesn't make the bike quicker...

well, I thought rich b/c the cat wouldn't be there taking out whatever crap it is supposed to take out, so the 02 sensor would read it as malfunctioning or something - again, just my crazy assumptions here...I'm confident they could be totally wrong!

As for the cat - not too concerned about more power, but would like to lose the weight, better sound and let the bike breath more - i think the cat keeps in a lot of heat.