[Supras] richness under boost

Tue Nov 6 11:32:21 CST 2007

also remember, air/fuel ratio should be the same, no matter what the 
pressure of the exhaust mixture is. if you blow a balloon up, is it going to 
have more or less carbon dioxide because you blew it up slowly, or fast? 
(Excluding the light headed part :-p )

-Sean

--------------------------------------------------
From: "Walker, Brian (Rich. Dist)" <Brian.Walker2 at VDOT.Virginia.gov>
Sent: Tuesday, November 06, 2007 12:17 PM
To: "Jim Jobe" <jjobe2 at supratech.org>
Cc: "Sean Cavanaugh" <millenia2000 at hotmail.com>; <Supras at supras.com>
Subject: Re: [Supras] richness under boost

> Seems like too close to the turbine could cause faulty readings too if
> there's an ideal pressure condition. I'd imagine with the high
> turbulence before flow straightens out, you might see some funny
> pressure variations/voids in that area.
>
> Brian
>
> -----Original Message-----
> From: Jim Jobe [mailto:jjobe2 at supratech.org]
> Sent: Tuesday, November 06, 2007 12:07 PM
> To: Walker, Brian (Rich. Dist)
> Cc: Sean Cavanaugh; Supras at supras.com
> Subject: Re: [Supras] richness under boost
>
>
> 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-heatsin
>> > k- 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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