IainB
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| posted on 29/12/06 at 11:48 PM |
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One for the EFI guys
Whats the advantage of having injectors before the trumpets?
Enjoy...
Linky
Iain
http://s43.photobucket.com/albums/e365/IainB1986/
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macnab
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| posted on 30/12/06 at 12:02 AM |
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maybe so the fuel has more turbulance to mix with air properly. Looks like a fire hazard to me...
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macnab
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| posted on 30/12/06 at 12:20 AM |
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so normally would it be like that when the cars racing?? seems a huge amount of wasted fuel..?
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gazza285
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| posted on 30/12/06 at 12:38 AM |
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Wasted? It's all going down the hole .
All engines do this to a degree, it's just the amount of fuel that is different.
Looks fairly rich though, you'ld expect the headers to be white hot, not cherry red.
DO NOT PUT ON KNOB OR BOLLOCKS!
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macnab
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| posted on 30/12/06 at 12:40 AM |
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very interesting.
though all that petrol getting past the rings would thin the oil I suspect. Like when a cylinders dead and its been run like that then the oils aways
like water...
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macnab
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| posted on 30/12/06 at 12:42 AM |
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quote:
Originally posted by gazza285
Wasted? It's all going down the hole.
It may be going down the hole but I bet it'll be coming out the other end unburnt...
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macnab
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| posted on 30/12/06 at 12:47 AM |
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a bit like when I pump the buggys throttle and the start it at the gas station, BOOOMM!!! fireball XL5!! makes them jump he he
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macnab
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| posted on 30/12/06 at 01:00 AM |
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can't be much fun in the car then.
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martyn_16v
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| posted on 30/12/06 at 09:27 AM |
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Having the injectors way up there allows the fuel to atomise completely and mix more fully with the air before it gets to the cylinder, giving a more
even charge to burn. Doing this on a road car is probably actually worse than having the injectors down by the inlet valve though. On a road engine
there's generally time for the fuel/air to mix well enough, it's only really on race engines where the air is coming in at much larger
speeds/in a shorter window where you may get a benefit from moving the injectors away from the inlet valve. At slow engine speeds and when starting
from cold you could find that the fuel actually has enough time to drop out of suspension and condense on the port walls if the injectors are too far
from the inlet valve. Add to this the fact that for most of the time a road engine has it's throttle at least partially shut, having the
injectors spray at a closed butterfly doesn't make for good running. A partway solution for highly tuned road engines is to have two sets of
staged injectors, one set in the 'normal' place near the inlet valves, and a second set further up the inlet tract that are staged to only
come on at high load (i.e. open throttle), the second set can be sized to either work in parallel with the primary injectors, or be big enough to take
over fuelling completely when in use (providing you use an ecu capable of doing this of course) 
[Edited on 30/12/06 by martyn_16v]
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oliwb
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| posted on 30/12/06 at 01:21 PM |
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7L - 10Km! Eeeek I make that to be - almost 4mpg!
If your not living life on the edge you're taking up too much room!
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MikeRJ
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| posted on 30/12/06 at 02:45 PM |
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The fuel hanging around in front of the trumpets is called "stand off" and is almost inevitable on a race tuned engine, even a road engine
running a hot cam can suffer from it.
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