[Supras] richness under boost

[Jeff Mohler]

Well, if you wanna tune to the bleeding edge of the safety zone, you might
want that 50-200rpm back into your math.



On Nov 6, 2007 9:07 AM, Jim Jobe <jjobe2 at supratech.org> wrote:

>
> Basic shops, yes, unfortunately.  The readings are usually 50-200 rpm
> late and hopefully taken in to account.
>
> The wideband sensor design requires exhaust pressure to be near
> 1 atmosphere.  Techedge has a decent write up about it, or used
> to.  So basically they are not going to read accurately in the
> exhaust manifold before the turbo due to the increased pressure.
> If you want to read individual cylinders on a turbo motor you're
> stuck with EGT probes and reading spark plugs.
>
> On Tue, Nov 06, 2007 at 11:52:04AM -0500, Walker, Brian (Rich. Dist)
> wrote:
> > Do the shops that 'professionally' tune engines use a clamp mount at the
> > exhaust exit for A/F readings? I do see concern for one lean cylinder
> > throwing the avg. mix readings off but I thought this was the way dyno
> > tunes were done.
> >
> > Brian
> >
> > -----Original Message-----
> > From: Jim Jobe [mailto:jjobe2 at supratech.org]
> > Sent: Tuesday, November 06, 2007 11:46 AM
> > To: Sean Cavanaugh
> > Cc: Walker, Brian (Rich. Dist); Supras at supras.com
> > Subject: Re: [Supras] richness under boost
> >
> >
> > Those that mount the sensor before the turbo, how are they accounting
> > for the new pressure differential between the air it's reading and the
> > air inside the cell?  Basically what I've read is that's how not to use
> > the sensor.
> >
> > On Tue, Nov 06, 2007 at 11:21:31AM -0500, Sean Cavanaugh wrote:
> > > Re: [Supras] richness under boostrx-7s pretty much ALWAYS have a
> > flamefront. heres a video of a pulled 13b motor running.
> > > http://www.youtube.com/watch?v=Wi8Qyr3IFRg
> > >
> > >  the heatsink adapter that Innovate makes works very well as that is
> > > what my rx-7 friends are having to use for their wideband.
> > > http://www.diyautotune.com/catalog/innovate-motorsports-hbx1-heatsink-
> > > bung-extender-p-73.html?osCsid=c6c12f9a698b80c73421e5188634b61d
> > >
> > > If it can last on an rx-7, it will last on a supra. and yes, to
> > properly tune a car with an o2 sensor, it has to be as close to engine
> > as possible. hardcore way would be to run one on each exhaust runner
> > right as it enters the manifold. Ive even seen some people fit one in
> > the manifold BEFORE the turbo in the collector area.
> > >
> > > another thing to note, the LC-1 isnt exactly the best wideband unit
> > either. friend has had to have his swapped at least 3 times (the
> > controller part, not the sensor) for issues. Most have flipped over to
> > using a TechEdge unit instead. its also way more compatible with
> > aftermarket ECUs (likeMegaSquirt) that can run in full closed loop mode.
> > >
> > > -Sean
> > >
> > >
> > > From: Walker, Brian (Rich. Dist)
> > > Sent: Tuesday, November 06, 2007 9:30 AM
> > > To: Millenia2000 at hotmail.com ; Supras at supras.com
> > > Subject: Re: [Supras] richness under boost
> > >
> > >
> > > Sean, this brings up some good info. I understand not wanting the
> > sensor in direct flame constantly as you mentioned but how will random
> > flame fronts effect the sensor? I would imagine most places in the DP
> > are going to see a flame fairly often. In fact this weekend at an event
> > I was told the car fired a large flame out of catback at one point. I
> > also recall last season when the old DP developed a hole (at the flex
> > joint, behind sensor location), flames were seen under the car many
> > times.
> > >
> > > Still seems to be reading well (same readings I always see, with no
> > input changes) Sensor has been in for ~2.5 years.
> > > Brian
> > >
> > > Date: Mon, 5 Nov 2007 18:33:46 -0000
> > > From: "Sean Cavanaugh" <Millenia2000 at hotmail.com>
> > > Subject: Re: [Supras] richness under boost
> > > To: <supras at supras.com>
> > > Message-ID: <BAY126-DAV137B6C520834B7CFAB86DFCA880 at phx.gbl>
> > > Content-Type: text/plain;       charset="us-ascii"
> > >
> > > Just buy an Innovate LC-1 for 200 bucks and install it in stock O2
> > > sensor location. Just having a wideband in the car helps out a LOT. My
> >
> > > old NA supra ran MUCH smoother just from that (used narrowband output
> > > for ECU and wideband output for tuning). Whoever told you not to use
> > > wideband O2 sensors for long periods of times must have been referring
> >
> > > to old obsolete non-heated sensors. Newer 5 wire wideband sensors are
> > > heated and have no issues (unless you install it in an RX-7 where the
> > > potential flamefront directly in the exhaust flow will melt it.)
> > >
> > > -Sean
> > > _______________________________________________
> > > Supras mailing list
> > > Supras at supras.com
> > > http://supras.com/mailman/listinfo/supras_supras.com
>
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