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Nov 23, 2011 5:58 pm
Peter S30 Offline
Member
Registered since: Nov 27, 2007
Location: Germany


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: "itīs 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.

Thumbnails of attached images:

Filename: powercurveV12.JPG
Filetype: File Type Information for: jpg jpg
Downloads: 841
Filesize: 150.29 KB
Image size: 1000 x 725 Pixels

Filename: pwertestV12notes.JPG
Filetype: File Type Information for: jpg jpg
Downloads: 844
Filesize: 29.70 KB
Image size: 1000 x 725 Pixels

 

Dec 16, 2011 4:38 pm
Julian Offline
Member
Registered since: Dec 04, 2007
Location: Belgium


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

Thumbnails of attached images:

Filename: Lehr full power 4.6 litre V12 Test 2.jpg
Filetype: File Type Information for: jpg jpg
Downloads: 816
Filesize: 175.15 KB
Image size: 948 x 887 Pixels


Julian Messent
This post has been edited 8 times. Last edit on Dec 16, 2011 5:14 pm by Julian.  

Dec 16, 2011 5:17 pm
Julian Offline
Member
Registered since: Dec 04, 2007
Location: Belgium


Subject: Re: Power curve V12
PS.
The owner of the above engine has now had it uprated to over 330 and it's "probably" the fastest pre-war V12 Lagonda in the universe! So Far! Crazy

Julian
Julian Messent
 

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