Lagondaforum » Engine » Power curve V12

Peter S30	Nov 23, 2011 5:58 pm
Subject: Power curve V12 Here is a power curve of a freshly restorated V12 engine of my friend Hans (W56). Attached also is a note sheet. I see ignition advance values on it and some other details. It has the standard 2 carb setup, I still have to check the camshaft profile they were using. I had given Hans and his engine shop a copy of an article of David Hine from a Lagonda club quarterly in 2000 about cam profiles of the V12 and WO Bentley talking to him in 1968: "it´s the camshaft design, we never got it right" (or they just forgot that in the beginning they had it right...see Davids article).. The test was run with the engine with auxialliaries but out of the car. I am pushing that as soon as the engine is back in the car he should do another test on a rolling road for comparison. After that everybody who is interested would be able to compare.. I have to say the curve impresses me: peaking at 143.3 kW = 194.8 HP, when I compare to the ones found in the books peaking at 156 HP for the standard engine. This power is reached because of a better torque curve. No reason to attack engines nicely running but it may be interesting if your engine needs a complete overhaul anyway. Most of all it thrills me in combination with Davids article and what WO Bentley stated.
Attachments: powercurveV12.JPG (Filesize: 150.29 KB) pwertestV12notes.JPG (Filesize: 29.70 KB)

Peter S30

Nov 23, 2011 5:58 pm

Subject: Power curve V12

Here is a power curve of a freshly restorated V12 engine of my friend Hans (W56). Attached also is a note sheet. I see ignition advance values on it and some other details. It has the standard 2 carb setup, I still have to check the camshaft profile they were using.

I had given Hans and his engine shop a copy of an article of David Hine from a Lagonda club quarterly in 2000 about cam profiles of the V12 and WO Bentley talking to him in 1968: "it´s the camshaft design, we never got it right" (or they just forgot that in the beginning they had it right...see Davids article)..

The test was run with the engine with auxialliaries but out of the car. I am pushing that as soon as the engine is back in the car he should do another test on a rolling road for comparison. After that everybody who is interested would be able to compare..

I have to say the curve impresses me: peaking at 143.3 kW = 194.8 HP, when I compare to the ones found in the books peaking at 156 HP for the standard engine. This power is reached because of a better torque curve.

No reason to attack engines nicely running but it may be interesting if your engine needs a complete overhaul anyway. Most of all it thrills me in combination with Davids article and what WO Bentley stated.

Attachments:
powercurveV12.JPG (Filesize: 150.29 KB)
pwertestV12notes.JPG (Filesize: 29.70 KB)

Julian	Dec 16, 2011 4:38 pm
Subject: Re: Power curve V12 Hi Peter, Have a look at this test we did on a similar spec engine but with a Steel crank and rods for safety, (The std Ally rods of course would depart company in minutes at this power and revs) a slightly smaller bore than Hans's @ 76mm but our own spec cams and 4 carbs. 195KW @ 6280 (although about 160kw @ 4750 for comparrison with Hans's max) 386NM @ 2800 RPM If we try we have had engines giving 330+ BHP @ 6000+ but unlike the engine in my graph here, these are rather special engines with very much more time invested! (one of our customers in Spain drives a 300+ bhp V12 DHC !) No over heating and a Rocket ship!
Attachments: Lehr full power 4.6 litre V12 Test 2.jpg (Filesize: 175.15 KB)

Julian

Dec 16, 2011 4:38 pm

Subject: Re: Power curve V12

Hi Peter,
Have a look at this test we did on a similar spec engine but with a Steel crank and rods for safety, (The std Ally rods of course would depart company in minutes at this power and revs)
a slightly smaller bore than Hans's @ 76mm but our own spec cams and 4 carbs.

195KW @ 6280 (although about 160kw @ 4750 for comparrison with Hans's max)
386NM @ 2800 RPM

If we try we have had engines giving 330+ BHP @ 6000+ but unlike the engine in my graph here, these are rather special engines with very much more time invested!
(one of our customers in Spain drives a 300+ bhp V12 DHC !) No over heating and a Rocket ship! Happy

Attachments:
Lehr full power 4.6 litre V12 Test 2.jpg (Filesize: 175.15 KB)