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Jun 28, 2016 11:02 am
Jun 28, 2016 11:02 am
Subject: Re: V12 4 carburetter: SU D4s v D5s
Hi Julian,
Many thanks for your reply. Just located my SU Carb. Workshop Manual. Their listing shows the D5 is 1 5/8" throttle diameter, whereas the D4 is 1 3/8". A D4L is also listed, which is 1 1/2", but I assume it's the D4 on factory 4-carb. set-ups.
So; the D4 is a fair bit smaller than the D5, not the other way round. Does what you say still hold true? Will petrol consumption be materially different between 4 D4s and 4 D5s?
Interestingly, the manual states "Max. Capacity in B.H.P." For the D4: 55, and D5: 75. Unfortunately, no explanation or guidance is given. That indicates max bhp for a 2 carb V12 is 150 (oh dear), and for a 4 D4 version 220, which I think matches Lagonda's claimed output. Perhaps I can look forward to 300bhp!
Laurence
Hi Julian,
Many thanks for your reply. Just located my SU Carb. Workshop Manual. Their listing shows the D5 is 1 5/8" throttle diameter, whereas the D4 is 1 3/8". A D4L is also listed, which is 1 1/2", but I assume it's the D4 on factory 4-carb. set-ups.
So; the D4 is a fair bit smaller than the D5, not the other way round. Does what you say still hold true? Will petrol consumption be materially different between 4 D4s and 4 D5s?
Interestingly, the manual states "Max. Capacity in B.H.P." For the D4: 55, and D5: 75. Unfortunately, no explanation or guidance is given. That indicates max bhp for a 2 carb V12 is 150 (oh dear), and for a 4 D4 version 220, which I think matches Lagonda's claimed output. Perhaps I can look forward to 300bhp!
Laurence