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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Twin injection benefits?
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Sat, 17 September 2005 12:48
 
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| spirokeet wrote on Sat, 17 September 2005 22:41 |
Quite a few motorbikes run 2 injectors per cylinder
Taken from Motor Cyclist article about the Honda CBR 600 RR:
There's one in the normal place downstream of the throttle plate that operates alone below 5500 rpm. Above that speed, a second injector, located above the bellmouth, comes into play, providing the fuel necessary for high-rpm power.
Race bikes have used this setup for years.
I remember reading somewhere that the second injector also provides the cylinder with fuel in a more combustion friendly manner, something about the size of the fuel droplets after being sucked down through the bellmouths.
Why bother though?
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bikes are difference as they actually have revs 
at idle and low rpm (ie 5500) they don't use as much fuel... but to get to 14000rpm, they have a much smaller window of injection in which to play with...
ie at 6000rpm, one engine cycle is 20ms.
at 14000rpm, each cycle is 8.6ms....
you need much bgger squirters to be able to get the fuel in during that time period.. not so many ppl even think about how much timethere si to inject, but for high revving motors (i consider 8000 to be about the start of that), you have to consider how long you have to play with...
also... for the higher rpm bikes the second injector is before the TB, like in most decent race car setups, so the fuel has time to atomise better before it gets to cylinder, and has better distribution.... safr to have a small injector below the TB so that you don't get fuel pooling etc from the big injector at idle...
on a car to be road driven?? why bother indeed 
but if you are aiming for 400 ponies from something under 2L, chances are your idle will suffer if you have just a big set of squirters..
as i said, it's just a 20V... even 300cc injectors are probably a bit too big
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| | Subject | Poster | Date |
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Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 05:31 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 05:57 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 06:03 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 06:05 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 06:07 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 06:10 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 06:12 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 06:14 |
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Re: Twin injection benefits?
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thechuckster | Sat, 17 September 2005 06:23 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 06:34 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 07:20 |
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Re: Twin injection benefits?
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clubagreenie | Sat, 17 September 2005 06:47 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 07:14 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 07:19 |
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Re: Twin injection benefits?
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gearb0x | Sat, 17 September 2005 07:37 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 08:01 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 08:04 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 08:10 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 11:45 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 11:49 |
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Re: Twin injection benefits?
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Yian | Sat, 17 September 2005 12:04 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 12:10 |
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Re: Twin injection benefits?
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gianttomato | Sat, 17 September 2005 12:17 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 12:33 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 12:50 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 12:52 |
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Re: Twin injection benefits?
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spirokeet | Sat, 17 September 2005 13:00 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 13:03 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 13:00 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 13:05 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 13:09 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 13:15 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 13:19 |
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Re: Twin injection benefits?
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STR8 2.8 | Sat, 17 September 2005 14:13 |
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Re: Twin injection benefits?
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emmac | Sat, 17 September 2005 12:49 |
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Re: Twin injection benefits?
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river | Sat, 17 September 2005 08:41 |
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Re: Twin injection benefits?
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kingmick | Sat, 17 September 2005 10:00 |
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Re: Twin injection benefits?
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spirokeet | Sat, 17 September 2005 12:41 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 12:48 |
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Re: Twin injection benefits?
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Yian | Sat, 17 September 2005 13:08 |
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Re: Twin injection benefits?
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Dorio86 | Sat, 17 September 2005 13:17 |
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Re: Twin injection benefits?
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Yian | Sat, 17 September 2005 13:21 |
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Re: Twin injection benefits?
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oldcorollas | Sat, 17 September 2005 13:26 |
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Re: Twin injection benefits?
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thechuckster | Sat, 17 September 2005 13:49 |
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Re: Twin injection benefits?
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spirokeet | Sat, 17 September 2005 13:09 |
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Re: Twin injection benefits?
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spirokeet | Sat, 17 September 2005 14:19 |
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Re: Twin injection benefits?
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ed_ma61 | Sat, 17 September 2005 15:10 |
