early 90's MX5's, wanting to purchase one of these fantastic little sports
cars having wanting one for a long time. But there's a problem I'm not sure
about. Every MX5 I've tested had a reasonably quick launch & handled like a
dream, but were all somewhat flat performers in third & fourth gear. My
current car is a Mazda Familia Astina 1990 with the same BD6 1600 DOHC engine
with the usual cosmetic differences (it's definitely not a BP 1.8 DOHC) but is
considerably faster through all the gear ranges, especially in third and
fourth & even top where it pulls like a train. I read that the BD6 in the MX5
produces 86Kw (116 Hp) while the stock BD6 in my Astina was quoted by the
second-hand dealer as producing 96Kw (130 Hp) with a claim that it was an
ex-factory high compression version. But I haven't been able to find any hard
info to verify this claim. Does anyone know about a high compression ratio
variant of the BD6 DOHC engine & whether there's an early 90's MX5 model
variant that has it? Want a clean classic stock 1600 MX5 sports car with it's
handling bonus & rear drive but want the power of my Astina too. (As far as I
know the Astina weighs the same as an MX5 at a little over 1,000 Kg). Any help
and advice related to the considerable performance variation between these
stock BD6 1600 DOHC engines is very welcome. Cheers. Mark.
From jifjif@gmail.com Fri Apr 27 17:28:04 2007
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Date: Mon, 17 Oct 2005 11:59:04 +1300
From: ~Jeff~ <jifjif@gmail.com>
To: MX5List <mx5list@mx5club.org.nz>
Subject: Re: Lack of Power in MX5 with BD6 engine
In-Reply-To: <003201c5d29c$03de5240$c92c58db@MARK>
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AFAIK all the 1600 (B6?) engines were 9.5:1 compression. Other than
that your front wheel drive may have a bit less drivetrain loss
compared to rear wheel drive - but that's only <5 hp at the top end.
It's not too hard to tweak things to gain some hp/torque - advance the
timing, remove the clogged catalytic converter, uncork the intake and
exhaust etc.
It's possible that your Astina engine has had these done already! Or
it has some other hot bits surreptitiously installed in the engine, or
cam overlap or other factory tolerances are aligned in your favour
hence the difference.
Hey, you could always swap them over

On 10/17/05, Mark O'Sullivan <mark.os@xtra.co.nz> wrote:
[...]