Ducati Monster Forum

powered by:

March 28, 2024, 04:32:19 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Welcome to the DMF
 
   Home   Help Search Login Register  



Pages: [1]   Go Down
  Print  
Author Topic: Top speed fuel consumption? How to calculate?  (Read 2201 times)
stopintime
Hero Member
*****
Offline Offline

Posts: 8910


S2R 800 '07


« on: September 09, 2021, 12:22:27 PM »

Every annual Alps/Italy ride I get a few opportunities to floor it for 10-15-20 minutes. Autobahn and AutoStrada.

Track days almost double my consumption, but pushing air with 100% throttle opening is another thing. I have a feeling based on how fast I go from normal fuel levels to yellow light. My guess is somewhere around 4 liters pr 10km (~ a gallon per 6 miles?)

Anyone know the answer? Or how much per injection? How many injections per time unit?
Logged

237,000 km/sixteen years - loving it
Dirty Duc
I'd rather be an anti-
Hero Member
*****
Offline Offline

Posts: 2183


I'm a hooliCAN, not a hooliCAN'T!


WWW
« Reply #1 on: September 10, 2021, 06:13:04 AM »

Injections per time unit? 1 per rpm. Iirc, most Ducatis have injectors that range from 150-195cc/min. That's a max that you can bump a little by raising fuel pressure.

It's considered that the tune should try never to exceed 90% duty cycle in most applications.

I wouldn't think as bad as 6, but you could easily be looking at 20-25 miles per gallon (not sure how that works out to liters per 10km)
Logged

stopintime
Hero Member
*****
Offline Offline

Posts: 8910


S2R 800 '07


« Reply #2 on: September 10, 2021, 10:08:05 AM »

Ok - thanks a lot.

Assuming flat out means full injector capasity, so 175cc x 60 x 2 cyl = 21 liter / hour
Flat out (never 100% flat out for long) 200km/h
.... is 10 liter / 100km

Which is the same as my track day consumption and not nearly enough  Huh?

Dirty Duc: how sure are you about those cc per injector numbers?
Logged

237,000 km/sixteen years - loving it
stopintime
Hero Member
*****
Offline Offline

Posts: 8910


S2R 800 '07


« Reply #3 on: September 12, 2021, 12:16:49 PM »

Krista at CaCW told me I'm on my own on this - trial and testing.

Logged

237,000 km/sixteen years - loving it
koko64
Post Whore
******
Offline Offline

Posts: 15649


« Reply #4 on: September 13, 2021, 01:06:48 AM »

With my NC30 race bike, I had a calibrated stick with a saw cut on it that corresponded to 5 litres of fuel in the tank when lowered into the fuel cap. The bike used 3 litres of fuel for 5-6 laps of the tight Broadford track. The stick went with bike when I sold it  Wink

Sounds like direction you're headed Grin
Logged

2015 Scrambler 800
2004 GSXR 750
Dirty Duc
I'd rather be an anti-
Hero Member
*****
Offline Offline

Posts: 2183


I'm a hooliCAN, not a hooliCAN'T!


WWW
« Reply #5 on: September 13, 2021, 01:29:26 PM »

Ok - thanks a lot.

Assuming flat out means full injector capasity, so 175cc x 60 x 2 cyl = 21 liter / hour
Flat out (never 100% flat out for long) 200km/h
.... is 10 liter / 100km

Which is the same as my track day consumption and not nearly enough  Huh?

Dirty Duc: how sure are you about those cc per injector numbers?
It's been 8 years since I researched it. So...

I was way off. CA-cycleworks says IWP 043 Brown band is for an S2R800. Here's specs for that injector according to https://www.thunder-max.com/techdocs/fuelinjectorspecs.pdf

Flow .................................................. Fully open
At 3 bar ..........................329 cc/min – 3.75g/s
At 4 bar ..........................377 cc/min – 4.30g/s
At 5 bar ..........................421 cc/min – 4.80g/s
Logged

Dirty Duc
I'd rather be an anti-
Hero Member
*****
Offline Offline

Posts: 2183


I'm a hooliCAN, not a hooliCAN'T!


WWW
« Reply #6 on: September 13, 2021, 01:40:08 PM »

Also, "matched set"  Roll Eyes

I use a service like mrinjector.us for the stonking big LSR injectors. He flow tests them, cleans them ultrasonically, replaces any consumables like rubber o-rings and such, flow tests them, and mails them back with a before and after report and a couple of hard candies for not much $US. When they come back they are on advertised spec and match. Significantly cheaper than buying a new set every year, and methanol is hard on everything. They have always cleaned back up so far.
Logged

koko64
Post Whore
******
Offline Offline

Posts: 15649


« Reply #7 on: September 13, 2021, 05:51:49 PM »

Really handy specs.👍
Logged

2015 Scrambler 800
2004 GSXR 750
stopintime
Hero Member
*****
Offline Offline

Posts: 8910


S2R 800 '07


« Reply #8 on: September 14, 2021, 12:31:58 AM »

Since I really don't know; the injectors inject only during one stroke? Only while the intake valve is open? If so, it won't make the calculations easier.... 

Does a fuel map have numbers for this?
Logged

237,000 km/sixteen years - loving it
ungeheuer
ɹǝʌO d∩ uıɐןɐɹʇsn∀
Local Moderator
Post Whore
*****
Offline Offline

Posts: 20602


Often wrong. Never in doubt.


WWW
« Reply #9 on: September 16, 2021, 08:18:52 AM »

You bunch of freakin' nerds  laughingdp




 popcorn
Logged

Ducati 1100S Monster Ducati 1260ST Multistrada + Moto Guzzi Griso 1200SE


Previously: Ducati1200SMultistradaDucatiMonster696DucatiSD900MotoMorini31/2
Dirty Duc
I'd rather be an anti-
Hero Member
*****
Offline Offline

Posts: 2183


I'm a hooliCAN, not a hooliCAN'T!


WWW
« Reply #10 on: September 16, 2021, 08:28:46 AM »

I'm not sure how it's set up in a stock-ish bike, but it makes sense that each injector only fires once per cycle. I think one can adjust the injectors individually using guzzidiag or some other software.

I don't think the injections are particularly timed to the valve opening events, that tech has emerged in cars based on stringent emissions, but was not particularly common in the aughts.

The fuel map has numbers, but they are probably nonsense for a practical calculation. The map numbers are likely some percentage of a constant expressed in a number from 0-255 (0-100%). Some tuning software might translate that for you, but I have no experience with that.
Logged

stopintime
Hero Member
*****
Offline Offline

Posts: 8910


S2R 800 '07


« Reply #11 on: September 16, 2021, 10:30:12 AM »

There are vehicles with 'live' consumption info. Previously based on a vacum instrument, but calculated now (I assume).

I can't remember what Stu/other guru told us, but amount of fuel can be injection duration and/or 'continuous' amount. I would guess duration.

If full flow is known and I apply it x degrees/%, then the correct answer can be calculated.


You bunch of freakin' nerds  laughingdp


 popcorn

What?
Logged

237,000 km/sixteen years - loving it
ungeheuer
ɹǝʌO d∩ uıɐןɐɹʇsn∀
Local Moderator
Post Whore
*****
Offline Offline

Posts: 20602


Often wrong. Never in doubt.


WWW
« Reply #12 on: September 16, 2021, 11:42:18 AM »

What?
Precisely Cheesy
Logged

Ducati 1100S Monster Ducati 1260ST Multistrada + Moto Guzzi Griso 1200SE


Previously: Ducati1200SMultistradaDucatiMonster696DucatiSD900MotoMorini31/2
ducpainter
The Often Hated
Flounder-Administrator
Post Whore
*****
Offline Offline

Posts: 78189


DILLIGAF


« Reply #13 on: September 16, 2021, 01:48:57 PM »

How many what's?
Logged

"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent.”


Pages: [1]   Go Up
  Print  
 
Jump to:  


Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!
SimplePortal 2.1.1