cats or no cats

[cali+Mocasho+]

so i need a new cat and we all know that i cant use a uni-cat unless i jerry rig it. plus i wouldnt want to affect the flow by putting just 1 new cat. Anyways should i get the high flow y-pipe with cats or without? How will it sound without cats and whats the hp gain or loss with or without the cats? opinions appreciated thanks.
oh yea 1991 sho plus

 

[luigisho]

Need to pass emissions?

 

[sperold]

No performance gain with going catless. You loose a little low end torque (when catless), which is kinda important.

 

[cali+Mocasho+]

Need to pass emissions?

ahhh sadly but yes

 

[rubydist]

then you only have one answer and that is with cats.

 

[AREA 91]

Hey a high flow Y pipe with cats. You won't be sorry.

 

[luigisho]

Make sure the cats are good quality. A lot of aftermarket ones are not as efficient as oem. Is there a different standard for cars of a certain age? You're pushing 25yr mark.

 

[cali+Mocasho+]

Yea

Make sure the cats are good quality. A lot of aftermarket ones are not as efficient as oem. Is there a different standard for cars of a certain age? You're pushing 25yr mark.

yea I still need to pass emissions ;( On a previous post I know someone mentioned that I can unplug the icm or idk I'll look for it.

 

[cali+Mocasho+]

Oh and I figured having cats is better due to the back pressure. And I wouldn't want know how loud it gets.

 

[luigisho]

You pull the SPOUT plug but that won't compensate for no cats. Maybe borderline on aftermarket ones.

 

[cali+Mocasho+]

You pull the SPOUT plug but that won't compensate for no cats. Maybe borderline on aftermarket ones.

What do you mean spout? I still have stock cats. I believe the rear it bad. Just read the pulling spout fourm and noticed everyone's nox dropped when pulled. I have high HC's

 

[luigisho]

Spark output connector. Keeps the computer from adjusting timing essentially.
http://www.shoforum.com/index.php?threads/how-to-pull-the-spout-connector-with-pics.56278/

 

[LOUDSHO92]

If you get a new y-pipe you need CA cats which cost extra. We offer them for both the SHO Source and Magnaflow y-pipe: http://www.shosource.com/catalog/index.php?cPath=61_43_54_86

 

[cali+Mocasho+]

If you get a new y-pipe you need CA cats which cost extra. We offer them for both the SHO Source and Magnaflow y-pipe: http://www.shosource.com/catalog/index.php?cPath=61_43_54_86

Yea .. For Around 700 I'll wait on new y pipe for a few weeks.

 

[cali+Mocasho+]

Spark output connector. Keeps the computer from adjusting timing essentially.
http://www.shoforum.com/index.php?threads/how-to-pull-the-spout-connector-with-pics.56278/

if i pull the spout will it drop my hc (hydro carbons) thats where im failing.

 

[sperold]

Post your cars emission numbers and the total allowable numbers (from your emission test sheet), and we can give an opinion. We don't know if your test is a dyno test or a tailpipe sniff test yet.

Pulling the spout locks the timing at 10 degrees, where your emission numbers will be the best, usually.

I have passed the dyno test with not-so-great cats after a long drive and pulling the spout, so it is possible.

With the sniff test, unless your exhaust brings tears to your eyes, it will usually pass.

People who had paid to get a condition pass on the dyno for a number of years started passing when the test was changed to the sniff test.

 

[luigisho]

If you read through all the posts in that link you will see a wide variance. I think it depends on the health of the components in your particular car. Did you already fail? Couldn't hurt to try. I'd get healthy cats first and a good muffler shop can splice those in for you. I think I saw a post by sdpatt that he had mustang cats spliced into his exhaust or something thereabouts-- so it can be done.

 

[cali+Mocasho+]

Post your cars emission numbers and the total allowable numbers (from your emission test sheet), and we can give an opinion. We don't know if your test is a dyno test or a tailpipe sniff test yet.

Pulling the spout locks the timing at 10 degrees, where your emission numbers will be the best, usually.

I have passed the dyno test with not-so-great cats after a long drive and pulling the spout, so it is possible.

With the sniff test, unless your exhaust brings tears to your eyes, it will usually pass.

People who had paid to get a condition pass on the dyno for a number of years started passing when the test was changed to the sniff test.

give me a few hours and ill post my smog test numbers. thanks guys

 

[cali+Mocasho+]

If you read through all the posts in that link you will see a wide variance. I think it depends on the health of the components in your particular car. Did you already fail? Couldn't hurt to try. I'd get healthy cats first and a good muffler shop can splice those in for you. I think I saw a post by sdpatt that he had mustang cats spliced into his exhaust or something thereabouts-- so it can be done.

the car was sitting for 3 years. Heres my first test results with an open thermostat bad plugs,wires ,misfire.
15mph hc;max 99 /measured:55 co%;max:0.52 /measured at 0.08 nox: max:549/ measured:877 fail
25mph hc max 62 measured 28 co% max 0.42 measured at 0.05 nox ; max 507 measured 681 fail

after tune up and everything i can think of except cats hears my retest results...
15mph hc max 114 /measured at 147 co% max 0.73/ measured at 0.23 / nox; max 785 measured at 466 FASIL
25mph hc max 62/ measured 93 C0%:max 0.61/ measured at 0.21 nox:max 507 measured at 247 FAIL

Since the last test everything went down except my hc. Hc went up. Im pretty close i think pulling the spout will do the trick since im really close.
much help appreciated guys

 

[cali+Mocasho+]

oh yea its a dyno test