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Location:
Yowie Bay, Sydney
Registered:
June 2002
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external wastegate/oxygen sensor effects?
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Sun, 23 November 2003 11:38
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fitted T04E to my 1g
the external wastegate is open to atmosphere
therefore the gasses not going past the oxygen sensor
anyone know if this has any effect on the mixtures?
i'm thinkin not as it still has a strong smple of the exhaust gases from what goes thru the turbo
needing some helpful input....
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Location:
Brisbane
Registered:
October 2002
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Re: external wastegate/oxygen sensor effects?
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Sun, 23 November 2003 12:05
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as far as i'm aware u need all the gases going past the o2 sensor, even if 90% r going past it'll only read 90% od whats happening and may run it way too rich
u may have to run the WG back into the exh.
but tell us how it goes with the T04 
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Location:
Yowie Bay, Sydney
Registered:
June 2002
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Re: external wastegate/oxygen sensor effects?
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Sun, 23 November 2003 12:11
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well too rich cant hurt, as it has 100% of the gases up until it makes 15psi, maybe its a good thing....
yeh it goes great, blew an engine last week, found alot of aluminium paste (old turbo housings) in the sump
but goes even better on a good engine which i just finished putting in today, also removed the TVIS system
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: external wastegate/oxygen sensor effects?
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Sun, 23 November 2003 12:34
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the oxygen sensor is only used for cruise, since it can only tell if it is one side or the other of stoich. so either above 14.7 or below 14.7AFR.
even if you had a wideband sensor, and half the exhaust was being diverted pre-turbo, the composition of the exhaust gases will be the same... the only way that the wastegate and turbo gases willbe different is if air goes back thru the wastegate, and since it only opens under pressure, this is pretty unlikely..
so basically, unless you have an aftermarket ECU that auto-tunes based on an AFR table, using feedback from a wideband sensor, you have nothing to worry about. even then, i would say you would have nothing to worry about.
since the narrowband O2 sensor is only used for cruise auto-tuning (to stoich for economy), it should be fine with the external wastegate.
Cya, Stewart
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Location:
Yowie Bay, Sydney
Registered:
June 2002
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Re: external wastegate/oxygen sensor effects?
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Sun, 23 November 2003 19:51
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thats the sort of answer i wanted to hear
i thought it went somethin like that, just wanted to see what others knew
so do u know how the std. ecu uses it? ie, full time or just cruise??
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Location:
Montrose, VIC
Registered:
May 2002
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Re: external wastegate/oxygen sensor effects?
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Sun, 23 November 2003 22:27
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The standard ECU doesn't use the sensor full time.
As for bypassing gas, have a think about what a typical wide band sensor on a dyno looks like - the (heated) sensor is placed in a piece of small pipe that is shoved up the exhaust - only a few % of gases would pass through this...
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Location:
Wollongong
Registered:
May 2002
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Re: external wastegate/oxygen sensor effects?
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Mon, 24 November 2003 00:03
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I would have thought that it didn't matter if all of the gases passed the sensor or not, because it measures the instantaneous ratio of air to fuel, not quantity of one or the other (correct me if I'm wrong). Whether 200cfm or 150cfm of exhaust gas passes the sensor shouldn't make any difference, as the ratio of air to fuel over that volume would still be the same.
Have I totally missed something here, cos it's seems rather simple ?
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: external wastegate/oxygen sensor effects?
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Mon, 24 November 2003 00:17
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i think ill just back up what others have said,
its not like the oxygen sensor in the stock setup measures exhaust flow, it just measures oxygen content as a percentage,
think about an air temp sensor probe in the inlet, all of the air going in is going to be the same temperature,
its more a question of whether the oxygen content will differ in the wastegate pipe or the turbo dump pipe,
just dont mount it it in the wastegate pipe, as then it will only read when you are at max boost.
put it post turbo and it shoud be fine id say
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Location:
Perth
Registered:
October 2003
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Re: external wastegate/oxygen sensor effects?
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Mon, 24 November 2003 04:20
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I made a set of twin dumps for the 1JZ, and as said previously exhaust gas flow is not an issue, therefore my sensor is mounted in only one of the dumps, meaning it gets ratio off 3 cylinders. I suppose this could cause problems with readings if one or more dodgy cylinders were operating in that 3 feeding the O2 sensor, giving bung ratios. Any thoughts on this issue?
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