Datsun Roadster Forum-311s.org

Hey all,

I was curious as to whether anyone had put a cat on their roadster. Is it even possible? I ask because as much as I love these cars I do also care about the environment. If I'm using my Datsun for long summer road trips I don't want it to be acting like a little gas death machine.

The single best thing you can do is keep your engine in peak tune. Address any issues that keep your engine from running too rich. Unburned hydrocarbons are the most likely pollutant to come from our engines. (somthing that is not reduced with a catalytic converter) a properly tuned engines byproduct are mostly co2 and water. A catalytic converter without any sort of engine management will no t be very efficient. greatly simplified, 02 sensors provide feed back to an ecm wich in turn constantly adjust fuel trim to reduce pollutants and maximize economy. Something that 50 year old SU carburetors are simply not capable of.

Cats hate a rich mixture and will run very hot with one. I don't think it is possible to keep one in it's safe operating zone with a carb unless you add an O2 sensor along with a way to automatically adjust the mixture.

I owned a 1975 Chevy Camaro which had a two barrel carb and a cat. It had no management system and seemed to work well.

I had a carbed '75 Celica with a cat - the cat burned up in year seven...

spyder wrote:I owned a 1975 Chevy Camaro which had a two barrel carb and a cat. It had no management system and seemed to work well.

It was probably a feedback carburetor.

wassupcat wrote:Hey all,

I was curious as to whether anyone had put a cat on their roadster. Is it even possible? I ask because as much as I love these cars I do also care about the environment. If I'm using my Datsun for long summer road trips I don't want it to be acting like a little gas death machine.

yes, spriso uses one on their SR20 conversions:




Shannon's

It would be a good idea to try Wassup cat definately use some heat shielding on the floor board area and have it void of oil underneith and to check to see what your emmissions are ,if they are in specs now
the difference between carb and EFI is huge 8 to 10 + times at idle some ran 700 ppm hydrocarbons in specs, 1150 with a cam or after market carb to 60 -70 ppm for an EFI car ,you could not get them to show up on the gauge really .
removing hydrocarbon ( unburnt fuel )is the main job of the Catalitic Converter and it does some changing of carbon monoxide to dioxide
I am wanting to put one on a late 70's RV I have because it puts out more fumes than I need to breath at a stop lite
Rock Auto 's cheap one worked out good for me on a 4G6

Hi
I just finished putting one in. It cuts down on the fumes a lot. It does run hot and the floor under the driver seat gets hot.
I think it inreases my enjoyment while driving the car.

VIney

Most of our SR conversions get a CAT-- it gets rid of the hydrocarbon smell and certainly makes it so you can drive the car out and you don't smell like you have been driving a 50 year-old car anymore. We add heat shielding on the floor, and then a double layer of Dynamat and that seems to work out quite well.

Michael

vinechoy wrote:Hi
I just finished putting one in. It cuts down on the fumes a lot. It does run hot and the floor under the driver seat gets hot.
I think it inreases my enjoyment while driving the car.

VIney

On a swapped car or an R or U engined car?

Hi
It runs hot on a stroked R16 ( 2 litre now ). There are commercial muffler heat shields, but I'm thinking of making one from fibreglass mat sandwiched between aluminum sheet

VIney