Re: Petrol or Unleaded?

["David Middlewick" <dave@gorseclose.freeserve.co.uk>]

Ewan
Have you tried a Ford spark delay unit in your vacuum advance line as fitted
to some Escorts and Sierras as this may reduce your pinking when opening the
throttle with a warm engine?

My GTX has K-Jetronic injection and a DX code engine.

I am set up at 6 deg BTDC. I have run on unleaded for approximately 2000
miles with no pinking. On my second tank of unleaded I got nervous about the
set-up and reset to 3 deg BTDC and the engine ran poorly with a lot of
vibration. So I returned to 6 deg BTDC and was happy again. But I got
concerned again for no good reason and got 4 star at the next fill up. Now
it might be my imagination but power appeared to be down with the 4 star
compared to unleaded at 6 deg BTDC! So since I have used unleaded at 6 deg
BTDC. As you say all engines are different but unless 4 star has been
downgraded prior to its departure I cant figure it out. When I was using 4
star all the time I tried advancing the timing a few degrees but got pinking
under load.

I have noted that where the distributor vacuum advance unit connects to the
rear of inlet manifold the vacuum has a lot less suck than the other vacuum
connectors do. I notice that most change in the advance is from the
mechanical advance when using the strobe disconnecting and connecting the
vacuum advance makes little difference.  The distributor vacuum advance unit
is airtight i.e. not leaking.  This minimal vacuum advance may explain my
lack of pinking.

What is your understanding of how the k-star ignition module works and why
change the coil and ignition leads?

Adding knock sensors in my opinion is properly the best way to use low
octane fuel to the best.

Dave

-----Original Message-----
From: Ewan Hopkins <ewan.hopkins@virgin.net>
To: David Middlewick <dave@gorseclose.freeserve.co.uk>
Date: 12 May 1999 11:05
Subject: Re: Petrol or Unleaded?


>David,
>I'm looking at putting together a system for my car which would effectively
>do the same as the k-star ignition module, i.e. modify the ignition timing
>and it would be considerably cheaper - I reckon it would be somewhere
around
>£50 to put together the module itself and the rest of the bits should be
off
>the shelf and not expensive - coil, ignition leads, some wire  My own setup
>would be with knock sensors as I have a 2L audi engine which originally had
>CIS motronic with dual knock sensors but I have stuck with my original
k-jet
>setup and I have problems with pinking when its hot.  It would be easy
>enough, though to set it up for the straight k-jet as you should have.   If
>you are interested and aren't in a desperate hurry let me know and I'll
keep
>you posted.  I'd be looking to get it going sometime in the summer.
>In the meantime, one suggestion wold be to set your timing manually, by ear
>so to speak.  If your timing is currently at the factory setting, i.e.
>+6deg, run the tank almost dry & fill-up with unleaded and listen for any
>pinking - it'll be most obvious if you go out for a reasonable run to
>warm-up the engine then let it idle until the fan comes on  a few times.
>It'll pink most at 1/2 - 3/4 throttle when accelerating from standstill.
If
>it does pink then retard the timing by loosening the distributor clamp nut
>at the base of the distributor and turn the distributor anti-clockwise (i
>think) a millimeter or so. It would be wise to mark the position of the
>clamp in relation to the block and then the position of the distributor in
>relation to the the clamp before you start, so that you can return to
>original settings if you want!  Go through this process until the pinking
>stops and that should be you.  If your timing is a 0deg. then you do the
>reverse process, until it just starts pinking and then knock it back a
>touch.  I did this and then had the timing checked - my setup was OK at
>+2deg but pinked like hell at the factory +6deg.  Every engine is
different,
>even within a batch that are nominally identical - the recommended 0deg
>setting for the 1.8 8v with unleaded is a catch-all which plays safe.
>
>HTH,
>
>Ewan Hopkins
>'85 Storm 2.0
>'86 GT 1.8
>----- Original Message -----
>From: David Middlewick <dave@gorseclose.freeserve.co.uk>
>To: Andrew Holmes <aholmes@chubb.com>
>Cc: Gary Meakin <gary@basstudio.demon.co.uk>; <scirocco-l@scirocco.org>
>Sent: Tuesday, May 11, 1999 8:18 PM
>Subject: Re: Petrol or Unleaded?
>
>
>>
>> Andrew Holmes <aholmes@chubb.com> Wrote:
>>
>>
>> >There is also something called a K-star out there which can be used on
>all
>> VW's
>> >with Bosch K-tronic with allows you to use normal unleaded without
>> retarding the
>> >timing and therefore without losing power. I've read good things about
it
>> and
>> >will be having it fitted to mine shortly (Its a kind of piggyback ECU).
>> >If this intrigues you go to www.tsr-performance.com for further details.
>>
>>
>> Hi Andrew
>>
>> Thank you for the link lot of good stuff but the prices. I will stick
with
>> standard timing and hope for the best.
>> Dave
>>
>>
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>
>


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