Derek,
I'm sure the factory ratings were "optimistic", however they were also rated
differently than your rolling road test. Factory numbers were obtained
without any engine accessories on an engine dyno. The same engine on a rolling
road would be somewhere in the neighborhood of 15-20% less powerful due to the
parasitic losses of the driveline, engine accessories and silencers.
Rick
Follow My Nasty Boy Build: http://tinyurl.com/yj52fwo
--- On Thu, 5/31/12, Derek Job <derek.c.job at gmail.com> wrote:
From: Derek Job <derek.c.job at gmail.com>
Subject: [Healeys] BHP - the real figures.
To: "Forum" <Healeys at autox.team.net>
Date: Thursday, May 31, 2012, 11:37 AM
In preparation for my first competitive outing I took the car to a
specialist with a rolling road to give it the once over generally and set
everything for optimum performance. He is a well known guy in motor sport
circles having prepared various Pro-rally teams cars as well as a lot of
exotic classics including Miuras and Ferrari 250s. One of the reasons he
got the rally prep jobs was because they were impressed that had the most
accurately calibrated dyno, which translates to one that produces real, but
lower figures than most of the others.
My car has a BJ8 engine, twin HD8s, DWR8 'fast road cam, polished and
ported iron head, six branch manifold, itg fast flow filter. Compression
came in at 195 pretty much across the board and he thought the comp ratio
would be around 10.5 : 1. Maximum ignition advance was 31 degrees initially
but when we optimised the performance i think it was advanced a tiny bit
further. I will check it's exact current setting when I get chance
The result.
Maximum power is 160 bhp at 5500 revs.
Max torque is 158 ft/lbs at 3100 revs and stays flat until 4700.
Torque is 140ft lbs at 1700 so there is a very broad and useable power
band.
I think we can safely say a stock BJ8 never produced 150 bhp!
He told me that whenever he tests classic cars there is always a very
large difference between reality and the bhp figures stated at the time.
Derek
www.healeysix.net
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