sports exhaust

[martin]

okay mother nature owes me one...

took my car to an exhaust shop and while looking around they couldnt understand why i had o2 sensors on the exhaust...

10 minutes later i agree on getting a 2 1/4 inch pipe put on with a muffler in the centre of the car then a hotdog then a tip

then they tell me that if i dont get a cat they can get fined a shitlaod cause my car is sposed to have one cause its got all the sensors and shit

anwyay get to that point and then when hes putting the fuckin pipe on he goes, aww im gonna rip off that second "heat" (sic) sensor cause you dont need it anyways

by this point im gettin the shits but its too late to do anything about it, anyways its all welded up, start her up and she coughs a little then revs out okay driving it home and it does feel like it pulls a bit more up top but seems a little less tourquy in the 'fun' spot of the engine say around 2.5-4k revs

quesion is what should i do? get the sensor put back in and have it tuned?

or have a whinge to the exhaust shop, problem there is i know fuckall of what to tell them

i wish i had dyno readouts for before and after, it doesnt feel much faster but it powers more from 4.5k upwards for sure

[QldRobbo]

Did you get extractor put on with your sports exhaust aswell? or do you have extractors? a 4-into-1 system (from personal experience) can cause you to lose a little grunt in the lower end, but gain a lot at top end. This might be your problem, and not any sensors.

[martin]

nah

i have some extractors 4-2-1 motovators but they are too small for the 1.8dohc that i go so i just left the stock headers

i rekon its to do with the efi but i could be wrong

[Ben Wight]

If you have extractors, why are they too small? Do they not bolt onto the head?

This sensor you mention, what did it look like and exactly where was it? Does it look like an oxy sensor of some sort?

[martin]

it was right after where the catalytic converter SHOULD have been on my original exhaust

the wire came out of the bottom of the passanger floor pan

and it had a little ceramic head on it, i am pretty sure it is an oxy sensor i think the exhaust guy thort i had absolutely no idea what it was. (exhaust guys dont like being told stuff)

the port sizes on a g161 and a g180w would be different would they not? and also i think the extractors hit the crossmember

and he was probly just too lazy to put them on

thanks ben

[yellowTE]

i had an exhaust put on my vn commodore that was a little too large for a stock engine and it lost a helluva lot of grunt around 2500rpm it sometimes bogged down and kept a steady speed for about 2secs b4 taking off again.

maybe 2 1/4 was too free flowing and you're not getting enough backpressure in the lower rev range.

just a thought anyway.