ed_crouch
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| posted on 3/2/04 at 11:58 AM |
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Custom individual throttle bodies
I would like to do some sork on developing individual throttle bodies alongside work on an engine management system (i need to do SOMETHING with my
2.1 in Avionic Systems Engineering, or it was a waste!!). Does anyone know of any good sources of info on the design of throttle bodies. I am after a
starter for ten to get the design work going.
Anyone got any info... Please???
Cheers
Ed.
P.S. if you're interested, check out
http://www.wings-and-wheels.net
for information on how i'm getting on with it...
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timf
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| posted on 3/2/04 at 12:00 PM |
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http://www.jenvey.co.uk/
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JoelP
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| posted on 3/2/04 at 07:56 PM |
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http://www.locostbuilders.co.uk/viewthread.php?tid=8100
dunno if you've seen this thread but that seems a good start if you havent! there are some mentions of throttle bodies in it.
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paulbeyer
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| posted on 3/2/04 at 10:49 PM |
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I understand down draught and side draught carburettors and seem to have got to grips with standard fuel injection systems but what exactly are
throttle bodies and what are the pro's and con's?
7 out of 10 people suffer with hemorrhoids. Does that mean the other 3 enjoy them?
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James
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| posted on 4/2/04 at 12:47 AM |
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quote:
Originally posted by paulbeyer
I understand down draught and side draught carburettors and seem to have got to grips with standard fuel injection systems but what exactly are
throttle bodies and what are the pro's and con's?
I'm glad you asked that Paul.
I was going to ask earlier but thought everyone knew so didn't like to ask!
...wouldn't want to look an idiot...
Doh! 
James
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James
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| posted on 4/2/04 at 12:47 AM |
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quote:
Originally posted by paulbeyer
I understand down draught and side draught carburettors and seem to have got to grips with standard fuel injection systems but what exactly are
throttle bodies and what are the pro's and con's?
I'm glad you asked that Paul.
I was going to ask earlier but thought everyone knew so didn't like to ask!
...wouldn't want to look an idiot...
Doh!
James
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Metal Hippy
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| posted on 4/2/04 at 01:35 AM |
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I'm tempted by the thought of throttle bodies post sva....
They'd reduce the height of the Beemer engine a fair bit...
Anyone here able to make me a new engine management system?
Cock off or cock on. You choose.
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sgraber
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| posted on 4/2/04 at 02:11 AM |
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This is a good read
http://home.earthlink.net/~jcgebhart/msindex.html
Steve
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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JoelP
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| posted on 4/2/04 at 09:11 AM |
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as far as i know, throttle bodies are like having a separate injector for each cylinder. thirsty work...
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zetec
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| posted on 4/2/04 at 09:31 AM |
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If you can get your head around carbs then throttle bodies are childs play! The ones I got from Jenvey are a straight tube, one for each inlet port
(as per twin webers) with a throttle butterfly and a hole for an eletronic fuel injector to poke thru. Thats it! The clever bit is designing the
length of the inlet tract, how far back you mount the injector and the ECU program which opens the injector. I will add I had nothing to do with any
of this, I just bolted mine on. It must take hours on a dyno to get all these variables just right. As an example a mild tune zetec can gain or loose
20-30BHP if the inlet tract from air filter to inlet valve is too short, hard to believe but true. As said jenvey site is a good read.
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Stu16v
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| posted on 4/2/04 at 07:58 PM |
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Throttle bodies can be made out of an old pair of carburettors, or alternatively a lot of big bike engine now run ideally sized ones. After all,
it's only a tube with a butterfly in it! The injectors dont even have to be mounted there, and in actual fact it isnt necessarily the best place
to fit them. Some suitably machined adapters for injectors welded onto the inlet manifold which point them at the back of the inlet valves is as good
as anything. Add an ECU, and a way of measuring engine load and you are not far away....
Dont just build it.....make it!
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racer56
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| posted on 4/2/04 at 11:37 PM |
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Attempt at explaining what a throttle body does.
For electronic fuel injected petrol engines, the powertrain control module (PCM) controls the amount of fuel injected per firing event. All the driver
controls is the amount of air entering the engine. To do this there is (as already described) a tube with a butterfly in it. The butterfly controls
the air, and the driver controls the butterfly with his (or her) right foot.
Some form or air metering is needed (Mass air flow (MAF) or manifold air pressure (MAP)) and a "lookup table" that the PCM uses to figure
out what air fuel ratio has been calibrated and therefore how much fuel to inject. Hopefully at that point the whole lot is encouraged to go bang and
the engine moves on by 180 degrees. Good luck with building your own system. Personally I would go for a twin weber set up, and spend some time on
the rolling road. Sounds better and (my opinion) looks better.
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paulbeyer
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| posted on 4/2/04 at 11:44 PM |
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quote:
Originally posted by JoelP
as far as i know, throttle bodies are like having a separate injector for each cylinder. thirsty work...
I am using a 4AGE with standard injection system. That uses separate injectors for each cylinder. They deliver the fuel direct into the cylider head
so what is the advantage of using throttle bodies to what is in all intents and purposes doing the same thing.
James I don't mind asking questions if I don't understand something, that's how I learn, who cares if others think I'm an
idiot?
7 out of 10 people suffer with hemorrhoids. Does that mean the other 3 enjoy them?
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