pull octane plug for emissions?

Phillio99

Registered User
Do I want to pull the octane plug for the emissions test and does anyone else have some helpful hints to passing this test?
Thanks,
Phil
 
Pulling the octane plug retards the timing 4 degrees, so I doubt it would have much impact on the emissions testing.

David
 
As long as your cats are good timing is good. Less timing can hurt you in the test.

Other advice would be change your oil(fuel in dirty oil is recycled through the pcv and can raise CO readings a lot).

Let the car sit and idle for 5 minutes or so before the test, and hold the rpm around 2,000 for a minute right before, this will ensure the cats are hot and doing their job.
 
Has anyone passed emissions with no cats? I've heard of it happening. I need to re-test in March. I might need to find a hookup.;)
 
You cut your cats off? :rolleyes: :rolleyes: :rolleyes:

Hope the loss in torque is what you were after. The manifolds on these cars are the real restriction. A good set of headers and high flow cats are the best thing you probably could have done.
 
I read here you can port your stock exhaust manifold out and they are just as good as those expensive headers.
 
90coug said:
I read here you can port your stock exhaust manifold out and they are just as good as those expensive headers.
You are correct. Just ask Dave D. I have ported manifolds and downtubes with Flowmaster from the resonator back. 1/4 mile dyno says it made more power.;) The stock resonator and the cats (in that order) are the real restriction with these cars.
 
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RBH Racing said:
You cut your cats off? :rolleyes: :rolleyes: :rolleyes:

Hope the loss in torque is what you were after. The manifolds on these cars are the real restriction. A good set of headers and high flow cats are the best thing you probably could have done.
You might want to read this.....

http://www.sccoa.com/articles/cwexhaust.php

Would you actually LOSE any torque by removing the cats... or just shift the torque a bit in the RPM band? I could be wrong there, but even so... these cars have enough torque that if you did actually LOSE a couple lb/ft it would not be the end of the world. The biggest thing is relieving backpressure which will free up some HP. From what I understand about the perceived torque "loss" is that you lose it down low and gain it back (and then some) higher up.

Fact is.. the stock resonator and cats are worthless and that is explained in the article I linked.

As far as passing emissions without cats... It is possible I guess. IF everything else is in top condition and the car is tuned just right. The tune required to pass emissions without cats would likely NOT be the best tune for power and may not even be a safe tune to run without worries of going lean. Someone please correct me if I am way off here, but this is the way I have always understood it. BUT, please give some supporting facts if I am wrong cuz I would like to know what IS right. And by all means, if I am RIGHT, please jump in and say so as well, cuz I am not positive on this. Just going off what I have heard from other sources.

There is one other thing to consider too if thinking about getting emissions testing done without cats. It is possible you could end up with a fine for removing them if you showed up without cats. Maybe you could say the car was like that when ya got it and they would just tell you to get cats installed before it is considered legal. We don't have testing here so I have no 1st hand experience... anyone else?


Tracy
 
XR7inWI said:
You might want to read this.....

http://www.sccoa.com/articles/cwexhaust.php

Would you actually LOSE any torque by removing the cats... or just shift the torque a bit in the RPM band? I could be wrong there, but even so... these cars have enough torque that if you did actually LOSE a couple lb/ft it would not be the end of the world. The biggest thing is relieving backpressure which will free up some HP. From what I understand about the perceived torque "loss" is that you lose it down low and gain it back (and then some) higher up.

Fact is.. the stock resonator and cats are worthless and that is explained in the article I linked.

As far as passing emissions without cats... It is possible I guess. IF everything else is in top condition and the car is tuned just right. The tune required to pass emissions without cats would likely NOT be the best tune for power and may not even be a safe tune to run without worries of going lean. Someone please correct me if I am way off here, but this is the way I have always understood it. BUT, please give some supporting facts if I am wrong cuz I would like to know what IS right. And by all means, if I am RIGHT, please jump in and say so as well, cuz I am not positive on this. Just going off what I have heard from other sources.

There is one other thing to consider too if thinking about getting emissions testing done without cats. It is possible you could end up with a fine for removing them if you showed up without cats. Maybe you could say the car was like that when ya got it and they would just tell you to get cats installed before it is considered legal. We don't have testing here so I have no 1st hand experience... anyone else?


Tracy
I don't think I'll need to worry about them not seeing the cats because they are too lazy to look under the car. They will just fail you and have you do a retest to renew your registration. If that's the case then I can bolt my stock cats back in since it's just clamped together.
 
oh yeah:rolleyes: any real racer knows you would much rather have less tq down low and another hp or 2 up high.:rolleyes:

Do What you want with your car man, this forum so far loves to come up with snotty little answers to counter what they don't want to hear. I hope it passes inspection and that it's worth it to you to feel like your car is faster while you rev it harder and faster to achieve the same result.

As for supporting facts do some research on "valve overlap" and the effects of it. Maybe even something called "scavenging" especially on a boosted engine.

One thing that I can believe though is that porting the exhaust manifolds may serve as well as headers on these engines more because of the flow characteristics than the actual rate.
That's assuming it's still on the same cam and head combo it came with.

Jeremy your better off just running some good cats and making improvements else where. It's not worth going through this every year, unless your really going to turn this thing into a 75/25 race/street.

just my .02 like anyone elses.....
 
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RBH Racing said:
oh yeah:rolleyes: any real racer knows you would much rather have less tq down low and another hp or 2 up high.:rolleyes:

Do What you want with your car man, this forum so far loves to come up with snotty little answers to counter what they don't want to hear. I hope it passes inspection and that it's worth it to you to feel like your car is faster while you rev it harder and faster to achieve the same result.

As for supporting facts do some research on "valve overlap" and the effects of it. Maybe even something called "scavenging" especially on a boosted engine.

One thing that I can believe though is that porting the exhaust manifolds may serve as well as headers on these engines more because of the flow characteristics than the actual rate.
That's assuming it's still on the same cam and head combo it came with.

Maybe you haven't been around here long enough to know if you don't do something about the stock cats then you will pop your headgaskets on these engines. I highly doubt there is that much of a difference between downtubes and high flow cats." Hope the loss in torque is what you were after" seems a little snotty to me don't you think? Don't come on here spouting off all of your "racing knowledge". Most people in this club base their responses myself included on their experience with SCs. Why don't you go tell some drag racers with open headers to throw some cats on their exhaust to help them perform a little better. :D My decision to get rid of them is only temporary anyway since I blew my head gaskets and they took an antifreeze bath,nor was the decision performance based at all. Like I said, the 1/4 mile dyno doesn't lie and I noticed no difference.
 
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Jeremy_K said:
Why don't you go tell some drag racers with open headers to throw some cats on their exhaust to help them perform a little better. :D

better yet, tell em to put some mufflers on so we dont have to hear that junk ;)
 
Blown 91 Bird said:
better yet, tell em to put some mufflers on so we dont have to hear that junk ;)
LOL That's funny!:D We don't want them harming the environment either. Just think of all that nasty ozone depleting exhaust gas. Oh my word!:eek:
 
RBH Racing said:
oh yeah:rolleyes: any real racer knows you would much rather have less tq down low and another hp or 2 up high.:rolleyes:

Do What you want with your car man, this forum so far loves to come up with snotty little answers to counter what they don't want to hear. I hope it passes inspection and that it's worth it to you to feel like your car is faster while you rev it harder and faster to achieve the same result.

As for supporting facts do some research on "valve overlap" and the effects of it. Maybe even something called "scavenging" especially on a boosted engine.

One thing that I can believe though is that porting the exhaust manifolds may serve as well as headers on these engines more because of the flow characteristics than the actual rate.
That's assuming it's still on the same cam and head combo it came with.

Jeremy your better off just running some good cats and making improvements else where. It's not worth going through this every year, unless your really going to turn this thing into a 75/25 race/street.

just my .02 like anyone elses.....


OK Professor. If you say so.:rolleyes:
 
Yeah and the prof. has also heard great tales of catalytic converters blowing head gaskets. I guess I need to be a member of this forum for a while for my head gaskets to blow. couldn't be the underdrive pulleys and constant 6500 rpm or depleted materials....Nah Ford designed them for all that, it's the cats they forgot about! Not to say that these engines don't have some serious issues with head gaskets.

Mine has all original exhaust with a measured exhaust pressure well below what is considered normal even.

As for the crowd or class of drag racers I am guessing you are refering to... Maybe we should check their center angle and lobe seperation in comparison to duration, not to mention their engines are built and designed to be run at rpm's far beyond ours.

this isn't "all my racer knowledge", I just hate to see people spend money, time, and energy trying to fix something based on what someone else blames their problems on. Especially if the problem was caused by them.

I'm not here to fight or make comparisons. If we could let's just drop it and go back to trying to help people and possibly even enjoy this forum.
 
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