Ivan
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| posted on 2/10/11 at 08:19 AM |
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Individual Runners with throttle bodies or not???
What is the likely power gain or loss to be between individual throttle bodies with trumpets and similar length individual runners with trumpets but a
sealed plenum with single throttle body of same area as multiple throttle plates, which means you can optimise location of injectors?
Also, what is the optimum location for the injectors, I have always thought that they should spray onto the back of the inlet valve but don't
really know.
[Edited on 2/10/11 by Ivan]
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rusty nuts
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| posted on 2/10/11 at 08:40 AM |
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I suspect the results may vary from engine to engine and the only way to tell would be back to back dyno testing but I'm sure someone more
knowlegable will give a more definate answer. I found David Walkers book on engine management to be very helpful and IIRC he covers various injector
positioning as well as 2 sets of injectors , one being nearer the valve and the other further away with the ECU controling when each one works .
Variable trumpet length is also covered which also has some effect. My car has individual TBs and I'm well happy with the performance and I
think they sound much better than a single TB
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MikeRJ
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| posted on 2/10/11 at 09:03 AM |
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quote:
Originally posted by Ivan
Also, what is the optimum location for the injectors, I have always thought that they should spray onto the back of the inlet valve but don't
really know.
That is optimum for emissions and low speed running, but optimum power comes from having the injector further away. If you look at e.g. F1 engines
the injector is physically mounted outside the throttle body and sprays into the trumpet. You can have two sets of injectors to get the best of both
worlds.
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Guinness
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| posted on 2/10/11 at 09:16 AM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by Ivan
Also, what is the optimum location for the injectors, I have always thought that they should spray onto the back of the inlet valve but don't
really know.
That is optimum for emissions and low speed running, but optimum power comes from having the injector further away. If you look at e.g. F1 engines
the injector is physically mounted outside the throttle body and sprays into the trumpet. You can have two sets of injectors to get the best of both
worlds.
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Ivan
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| posted on 2/10/11 at 04:37 PM |
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Thanks guys - I love the fuel rail on the Ferrari.
Just thinking of options for my 383 Chevy V8 where 2 throttles will be much easier and cheaper to do than 8 and no synchronisation problems if the two
feed into one plenum.
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DIY Si
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| posted on 7/10/11 at 09:37 AM |
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Could you not run one for each bank, as most modern V engines tend to do? As you say, just the one linkage to adjust, as trying to get all 8 to open
at once will be a PITA. And it might make the plenum a little easier to make/sort out, although they won't be mirror images, so it would need
two sided versions.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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