zetec
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| posted on 6/3/04 at 06:30 AM |
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Mine is running 3.25bar, about 50PSI, which seems to be the norm. If you need more fuel fit a bigger injector, 10mins with the spanner and 5mins on
laptop.
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Mix
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| posted on 6/3/04 at 08:41 AM |
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Quote from Browser
Eh? When I read about common rail diesels when they first came out the Citroen system was running at 1350 bar and I'd imagine pressures have
probably gone UP not down
I think you've got the decimal point in the wrong place !! Thats 19,845 psi or about seven times the safe working pressure of a commercial gas
bottle.
Hardy things these Citroens
Mick
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NS Dev
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| posted on 27/3/04 at 10:22 AM |
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Haven't read all the posts but as a throttle body user (Jenvey) and knowing quite a bit about engine management, the reason we use throttle
bodies is that we can get the fuel delivery exactly as the engine needs it all the time. Carbs are always a compromise, jetting can NEVER be right
throughout the complete rev range/load range (due to the fact that we can only alter "slope" with a carb), with injection it can be. The
individual runners are used so that we can pulse-tune the inlet length to give supercharge at our chosen revs, which will depend on the overall inlet
length.
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britishtrident
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| posted on 27/3/04 at 10:53 AM |
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quote:
Originally posted by NS Dev
Haven't read all the posts but as a throttle body user (Jenvey) and knowing quite a bit about engine management, the reason we use throttle
bodies is that we can get the fuel delivery exactly as the engine needs it all the time. Carbs are always a compromise, jetting can NEVER be right
throughout the complete rev range/load range (due to the fact that we can only alter "slope" with a carb), with injection it can be. The
individual runners are used so that we can pulse-tune the inlet length to give supercharge at our chosen revs, which will depend on the overall inlet
length.
All right on the button also better atomisation and mixing also play a big part especially at off cam low rpm.
Throttle bodies also have less gubbins (such as the aux venturi on DCOEs) in the way of the airflow .
Having said all that a decent plenum EFI system could be made almost as efficiently --- And in the USA throttle body injection still has a
following. Of course without one choke per cylinder you don't get the glorious induction noise.
[Edited on 27/3/04 by britishtrident]
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guff
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| posted on 27/3/04 at 12:51 PM |
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ok I am confused, I dont know that much, or have any experience with engines, but can anyone answer these q's:?
1. what exactly does the plenum chamber do in an inj system?
2. are tb's just an injection system without the plenum?!
3. what would be cheaper: pinto+webers, or pinto injection (modified plenm a la mark allinson..)?
4. what software do you need to fidde with the ecu?
5. think thats it...
cheers gareth
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kingr
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| posted on 27/3/04 at 04:51 PM |
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quote:
Originally posted by guff
1. what exactly does the plenum chamber do in an inj system?
2. are tb's just an injection system without the plenum?!
3. what would be cheaper: pinto+webers, or pinto injection (modified plenm a la mark allinson..)?
4. what software do you need to fidde with the ecu?
OK, here goes :
1) A plenum chamber is simply a large box between the air filter and the carbs which gives an area of less tubulent air than is typically directly
after the air filter. The gains produced are likely to be fairly small though.
2) Typically if someone says "throttle body" (singular) they mean the single large butterfly controling the ammount of air into a
typically factory injected engine. If someone says "throttle bodies" it means a similar thing, but one per cylinder, and with provision
for a fuel injector on the device itself (such as what's available from Jenvey, Alpha, Omex and so on). There's no reason that you
couldn't put a plenum onto aftermarket throttle bodies, but typically people don't due to space restrictions.
3) I would say pinto and webbers would be the cheaper option - Webbers aren't that expensive, whereas the cost of injectors and an ecu (assuming
you don't need an engineering work done to make the throttle bodies themselves) would probably be more. Both will need a spot of tuning on a
rolling road.
4) What software you need will depend on what ECU you have - factory ECUs don't readily allow any modification, so you have to use an
aftermarket ECU, either from the likes of Omex, Alpha, Motec and so on, or building one yourself by taking the megasquirt route (see previous posts
for more info).
Hope that answers your questions satisfactorily.
Kingr
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