How do you tune an ECU without knock control

Thu Oct 4 00:35:28 GMT 2001

Factory cars, especially turbo, came equipped with knock sensors to make
them idiot proof.  You can put all the octane labels in the fuel filler, in
the manual etc, but you will still have people putting low octane into these
cars.

Rather than damaging engines and having to repair/replace under warr, they
use knock sensors.

On the tuning side.  I have been using a knock microphone for tuning
recently.  It plugs onto the engine block near where the knock sensor would
be, and you can here any PROBLEMATIC knock.
Take note.  A knock sensor it tuned to also only listen for loud knock.  If
they weren't the ign retard system would be overworked due to all the other
engine noise that is going on, that is within the same frequencies.

With the knock mic on, you can here the air-con gas flowing through the
system when you turn it on, it's quite amazing.

Anyhow, my final point.  We have recently tuned a 732hp(@wheels) 2.2 Litre
Nissan SR20Turbo engine using the knock mic, and Motec.  This thing lights
up 5th gear at over 140Mph...

Jeff
-----Original Message-----
From: owner-diy_efi at diy-efi.org [mailto:owner-diy_efi at diy-efi.org]On
Behalf Of Jason Mauldin
Sent: Thursday, 4 October 2001 2:36 AM
To: diy_efi at diy-efi.org
Subject: Re: How do you tune an ECU without knock control

I'm new to the list (signed on today), so I may be
stating comments that have already been stated or
discussed.

At anyrate, I autocross and dragrace a Turbo
Mitsubishi car.  The stock ECU has a knock sensor and
keeps a running sum of the knock that it hears.  At
around a knock sum of 6-8 during any acceleration
moment it will start to retard the ignition.
Generally the owners who monitor the knock sum value
from the ECU acheive the most power up to the point
that the ECU retards timing.  In other words, keep
increasing the boost or ignition timing until the ECU
sees enough knock to start caring about it, then turn
it back just a bit.

However, I believe the assumption is that your knock
is caused by pressure and not the buildup of carbon.
As you stated, that's another problem that should be
addressed in a different manner.

Since you mentioned Autospeed, they also did a article
on making a device so that you can "hear" the knock
through a set of ear phones.  This could be a possible
way of tuning.  Here is the article:
http://www.autospeed.com/A_0353/page1.html

If you do a search on autospeed, a lot of articles
come up about tuning for knock.

Again, I hope I am not way off base with what you were
looking for.
Jason

--- Hugh Keir <hugh at sol.co.uk> wrote:
> A series of articles by Autospeed
> http://www.autospeed.com/ based on Tim
> White's Bachelor of Engineering thesis entitled 'The
> Effect of Spark-Knock
> on the Performance of a Modern Spark-Ignition
> Engine' suggested to me that
> maximum power is achieved around the onset of
> spark-knock.
>
> I have also read other articles that suggest power
> is still increasing at
> the onset of spark knock, never mind that your
> engine may be detonating
> through carbon buildup / other overheating malodies.
>
> Motec and Autronic are generaly classed as highly
> competent systems by most
> commentators, yet they have no integrated means of
> displaying / reading
> knock.
>
> This begs the question for a DIY-er with no access
> to an engine dyno, how do
> you tune the ignition advance without risking
> blowing up your engine.
>
>
> ----- Original Message -----
> From: "James Ballenger" <vtjballeng at yifan.net>
> To: <diy_efi at diy-efi.org>
> Sent: Saturday, March 10, 2001 6:59 PM
> Subject: RE: AUTRONIC SM2 ECU.
>
>
> > I have been looking into their unit recently and
> it is truly a kick ass
> > piece.  I currently have a Haltech E6S-8 and am
> running into output
> channel
> > problems, I only have 5 and want 10 or so.  I have
> been talking to Ray
> Hall
> > and the unit is a friggin Motec that costs less
> than my Haltech.  I
> strongly
> > suspect we will be running the SMC next year and I
> am looking into them
> for
> > some friends projects as well.
> >
> > If there is a system to judge it by, I started to
> do the same, it only
> > stands next to the Motec M48 except at a
> significant discount.  I tried to
> > compare it to some units like my Haltech or SDS
> which are both in the same
> > price range and it blows them out of the water.
> >
> > Sorry to rave about this one, but I am pumped up
> to get one next year for
> > our team.  At which point I should be able to
> provide much more tuning
> > information and specifics.  I have gotten a lot of
> details about the
> system
> > from Ray, so you may be able to direct some
> questions at me now if you
> want
> > to.
> >
> > James Ballenger
> >
> > >-----Original Message-----
> > >From: owner-diy_efi at diy-efi.org
> [mailto:owner-diy_efi at diy-efi.org]On
> > >Behalf Of clayb
> > >Sent: Saturday, March 10, 2001 10:55 AM
> > >To: diy_efi at diy-efi.org
> > >Subject: Re:AUTRONIC SM2 ECU.
> > >
> > >
> > >> It seems to be very comprehensive in it's
> capabilities and
> > >similar to =
> > >> Motec, but are there any technical things like
> accuracy of spark =
> > >> delivery, fuel delivery, anything else? that
> can be used to
> > >judge this =
> > >> system against others.
> > >
> > >I don't know the exact pulse width resolution,
> but I'm sure
> > >Ray Hall can
> > >give you the specs. I use the SMC, similar to the
> SM2, but missing a
> > >couple inputs and outputs for traction control,
> idle air, and
> > >some other
> > >niceties.
> > >
> > >It has no problem controlling large injectors (96
> lb/hr) at idle. I'm
> > >able to make small corrections in fuel delivery.
> Ignition is similarly
> > >accurate. I understand they're also coming out
> with a knock
> > >sensing unit
> > >that will interface with their ECU, and do the
> usual individual spark
> > >and fuel adjustment. I believe it will also
> reduce the turbo boost, if
> > >necessary.
> > >
> > >- Clay
> >
>
>---------------------------------------------------------------
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> > >To unsubscribe from diy_efi, send "unsubscribe
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> > >
> > >
> >
> >
>
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