Twin O2 sensor question

[xxalexx at ix.netcom.com]

I have seeen some Turbo Bentleys from HongKong that have
a CAT  TC   but is in  cat.  
Alex
> Hello EFI,
> 
> I am about to remove the 2 cats from my Supra twin turbo (1994) to
> alleviate any restriction, but I have a question. Currently, there is
> an O2 sender just after the 2 turbos join at a common outlet point,
> then a pre cat, then a bit of plain pipe, with what *appears* to be a
> second 02 sender, and about 2 feet further back, a second, main cat.
> 
> Out of curiosity I removed the second 02 sensor, and it appears to be
> a simple straight stick, about 3 sixteenths inch diameter, where it
> enters the exhaust stream. Is it an 02 sensor, or some sort of
> temperature probe? The car is a Jap import, hence Japanese spec,
> slightly different to US and Europe spec Supras, in that the turbos
> are smaller, have ceramic turbine wheels, and the air flow is measured
> by a vane type AFM, but uses a MAP sensor.
> 
> If I remove both cats, and make up a plain pipe section to replace
> them, and re fit both (what I assume to be...) 02 sensors, how will
> the ECU react??? I assume it will be happy, as it seem,s a common
> enough mod. But why 2 02 sensors in the first place?
> 
> Thanks, I'd better ask before cutting .... :-)
> 
> -- 
> 
> Best Regards,
>  Chris                          
> 
> mailto:chris at formula3.demon.co.uk
> 
> http://www.formula3.demon.co.uk
> 
> Performance car sales at http://www.formula3.demon.co.uk/forsale.htm
> 
> 
> 
>