Questions (fuel octane rating & advancing timing)

Archives of Posts to the NZ MX5 List back in 2001
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zorruno
Black is the new black.
Black is the new black.
Posts: 601
Joined: Thu Apr 13, 2006 11:20 pm
Location: An Eastern Beach

Questions (fuel octane rating & advancing timing)

Post by zorruno » Thu Aug 23, 2001 11:53 am

as per Jeffs comments, there is no real point running a higher octane fuel
on an 1989-97 model. It will run fine on 91 unleaded.

If however you increase the timing settings from the factory default 10
degrees BTDC, you may like to (or need to) run a higher octane fuel to
prevent engine 'pinking' or pre-detonation (this is probably not technically
the correct term, but hey - I'm not a mechanic). Advancing the timing can
be an easy way to gain a little bit of extra power. Hopefully someone will
photograph/write this procedure for the website one day...

Most people report that advancing the timing to 14 degrees still allows the
use of 91 octane without problems. Mine is at around 16 deg and I find that
I have to use 96. Others (Gary M?) have used an 18 degree setting in the
past and I assume 96 octane?

If you have an M2 model (1998+) I believe the factory ECU takes care of the
timing advance by checking for the onset of engine 'pink' and then backing
off a bit. If you run higher octane in these, the timing advances or
retards as necessary.

cheers
zorruno


[...]
(z)

Keith Cook

Questions (fuel octane rating & advancing timing)

Post by Keith Cook » Thu Aug 23, 2001 2:25 pm

I had a 1990 626 GT and always ran 96 in it although the local franchise told me there was an "antiknock" device there if I wanted to use 91. Being new to these little beasts I kinda assumed they would incorporate the same technology. No?

zorruno
Black is the new black.
Black is the new black.
Posts: 601
Joined: Thu Apr 13, 2006 11:20 pm
Location: An Eastern Beach

Questions (fuel octane rating & advancing timing)

Post by zorruno » Thu Aug 23, 2001 3:17 pm

no. sorry, no antiknock device in an 89-97 MX-5. You have to retrofit an
aftermarket ECU with knock sensor (e.g. LINK) to get this.

BTW - I had an 89 MX6. Same engine as your GT. 2.0L DOHC

I had a 1990 626 GT and always ran 96 in it although the local franchise
told me there was an "antiknock" device there if I wanted to use 91. Being
new to these little beasts I kinda assumed they would incorporate the same
technology. No?
(z)

peter
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 125
Joined: Thu May 18, 2006 10:02 pm
Location: Auckland

Questions (fuel octane rating & advancing timing)

Post by peter » Thu Aug 23, 2001 3:25 pm

anti-knock device?

got one fitted to the front door. It's called a doorbell.

got one in the car = 4-cell Maglite torch. yous knocka my car, I knocka yous back.

Peter
DRGN1

Keith Cook

Questions (fuel octane rating & advancing timing)

Post by Keith Cook » Thu Aug 23, 2001 5:39 pm

A GT mill? WOW!!!

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