blundey
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Registered: 25th May 04
Location: Flitwick, Bedfordshire
User status: Offline
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Anyone know the set "standard" of the fuel pressure for a corsa C 1.2 ?
I thought it was a set standard something like 45psi?
Anyone know? It aint in the haynes manual.
Cheers
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miles
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Registered: 25th Mar 02
Location: plymouth Drives: Astra Sport
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Most vauxhalls are 3 bar. Measured at idle with the vacuum pipe disconnected.
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myke
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Registered: 7th Feb 01
Location: High Wycombe, Buckinghamshire
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what difference does the vacuum have on the fuel pressure?
always wondered why it was there.
must serve a purpose, but dunno how or why.
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blundey
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Registered: 25th May 04
Location: Flitwick, Bedfordshire
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whats that in PSI?
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miles
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Registered: 25th Mar 02
Location: plymouth Drives: Astra Sport
User status: Offline
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14.7 psi in a bar.
It will be stamped on the side of the FPR.
The fuel pressure @ the injectors needs to be a constant 3 bar. So without the vacuum pipe the fuel pressure would be 3 bar, however there is also going to be a vacuum inside the engine, say 0.5 bar. So if its pushing 3 bar, engine is sucking 0.5 bar you get 3.5 bar of fuel pressure. With the vacuum pipe connected the fpr knows the vacuum in engine, so adjusts accordingly, so you get, say, 2.5 bar from the reg plus the 0.5 bar = 3 bar.
Obviously the vacuum inside the engine changes with load, throttle position etc.
Its the same for turbos, but when its under boost its added pressure to the reg to overcome the boost pressure, for instance 1 bar of boost, you'd need 4 bar of fuel pressure to get 3 bar....
Hope that helps and makes sense.
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blundey
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Registered: 25th May 04
Location: Flitwick, Bedfordshire
User status: Offline
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so 44.1 psi on average....Thanks miles..corrct me if im wrong.
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myke
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Registered: 7th Feb 01
Location: High Wycombe, Buckinghamshire
User status: Offline
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always wondered that.
usefull info, cheers.
so if you didn't connect the vacuum pipe, would it just overfuel or suck in loads of unmetered air?
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miles
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Registered: 25th Mar 02
Location: plymouth Drives: Astra Sport
User status: Offline
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Thats right blundey.
If its not connected it would overfuel on an n/a car, more so at idle, over-run and low throttle positions.
On a turbo it would melt, lol.
You'd need to block the vacuum pipe though else you'd have an air leak.
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