dondpipe cat off. tune??
Thread Starter
Intermediate
Joined: Sep 2007
Posts: 49
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dondpipe cat off. tune??
a doubt. by putting downpipe and X Pipe.
I plan to put the simulators for the O2 sensor and not tune.
Is it necessary to tune?
Or is it just optional to get some more CVs?
I mean, won't removing the CAT affect the proper functioning of the engine if I don't tune?
I guess I won't have any problems and the air-gas mixture will continue to be good.
But I prefer to ask.
I plan to put the simulators for the O2 sensor and not tune.
Is it necessary to tune?
Or is it just optional to get some more CVs?
I mean, won't removing the CAT affect the proper functioning of the engine if I don't tune?
I guess I won't have any problems and the air-gas mixture will continue to be good.
But I prefer to ask.
Race Director
Joined: Apr 2000
Posts: 15,344
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From: Texas
Sims are for the rear O2 sensors only.
The front o2 sensors will still control fueling.
If you're removing all four of the o2 sensors, you'll need to tune it to run Open Loop.
Without cats, you'll pick up marginal power and have the pleasure of smelling like a fuel truck due to the fumes.
The front o2 sensors will still control fueling.
If you're removing all four of the o2 sensors, you'll need to tune it to run Open Loop.
Without cats, you'll pick up marginal power and have the pleasure of smelling like a fuel truck due to the fumes.
Thread Starter
Intermediate
Joined: Sep 2007
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Yes, my idea is to leave the front O2s, and put the simulators in the rear ones.
I don't care much about the smell.
My intention is a louder sound. and be able to regulate it with the rear silencer.
Approximately how many HP are gained with the downpipe and the xpipe without catalysts? and without making a tune?
I don't care much about the smell.
My intention is a louder sound. and be able to regulate it with the rear silencer.
Approximately how many HP are gained with the downpipe and the xpipe without catalysts? and without making a tune?
Melting Slicks
Joined: Nov 2007
Posts: 2,280
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From: Pittsburgh PA
St. Jude Donor '10-'11-'12-'13-'14
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
Yes, my idea is to leave the front O2s, and put the simulators in the rear ones.
I don't care much about the smell.
My intention is a louder sound. and be able to regulate it with the rear silencer.
Approximately how many HP are gained with the downpipe and the xpipe without catalysts? and without making a tune?
I don't care much about the smell.
My intention is a louder sound. and be able to regulate it with the rear silencer.
Approximately how many HP are gained with the downpipe and the xpipe without catalysts? and without making a tune?
If you want loud, remove the mufflers and run pipes like those made by AFE.
As for power....<10. Nothing noticeable. If you want power, you need to combine it with tuning and if you want more, then you need full length headers.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
Short of the OEMs or a shop building an engine, your hp will be at the wheels. An A8 is generally going to be in the 380-390 range on a DynoJet. A little less on a Mustang dyno since they measure differently.
Thread Starter
Intermediate
Joined: Sep 2007
Posts: 49
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Safety Car
Joined: Jul 2019
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From: nashville TN
You will care when you take the car somewhere and everyone smells you as you walk by them. Also, if it's in a garage, it'll really stink during initial startup since the car runs a bit rich (think of it as a choke on a carb'ed car). It's amazing how the smell hangs on your clothes.
If you want loud, remove the mufflers and run pipes like those made by AFE.
As for power....<10. Nothing noticeable. If you want power, you need to combine it with tuning and if you want more, then you need full length headers.
If you want loud, remove the mufflers and run pipes like those made by AFE.
As for power....<10. Nothing noticeable. If you want power, you need to combine it with tuning and if you want more, then you need full length headers.
Team Owner
Joined: Jul 2004
Posts: 28,432
Likes: 3,285
From: Hartford WI
You will care when you take the car somewhere and everyone smells you as you walk by them. Also, if it's in a garage, it'll really stink during initial startup since the car runs a bit rich (think of it as a choke on a carb'ed car). It's amazing how the smell hangs on your clothes.
Does it matter what they smell as you walk by? Also, when I start up the car, my garage door is already opened and I drive out. In my case, the windows are always up but IDK how much smell there is if you pull out quickly. I open the door, get in the car, fire it up and away I go. I don't hang around and the tailpipe is pretty close to the open garage door. I suppose it would matter to my dogs but I don't know if I smell anything much.
Team Owner
Joined: Jul 2004
Posts: 28,432
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From: Hartford WI
My car warms up on the road. It starts cold and gets driven. It's fuel injected so I don't know about a warm up cycle. At the end of the driveway you can drive off and since we live in a neighborhood, you can't romp on it.
Race Director
Joined: Apr 2000
Posts: 15,344
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From: Texas
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
I also see you say "after the car is warmed up". The smell is worse at startup. I will also surmise yours is tuned. The OP has asked about not tuning the car.
Team Owner
Joined: Jul 2004
Posts: 28,432
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From: Hartford WI
Why does anyone idle for a few minutes? Is that a necessary thing or an old habit? Can you just dump it in gear, back it out and go on your merry way? Obviously, because of where most of us live, we cannot stand on the pedal but we have to drive civilly so that should be enough of a warm up unless your driveway ends at the start of the quarter mile track.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
I don't follow. When you startup, it is in open loop, right? Doesn't that mean it goes off preprogrammed tables and ignores whatever the O2 sensor says till it gets to light off temp or did I get it wrong? Are the cats working at startup even or doesn't it work after it hits light off temp?
Does it matter what they smell as you walk by? Also, when I start up the car, my garage door is already opened and I drive out. In my case, the windows are always up but IDK how much smell there is if you pull out quickly. I open the door, get in the car, fire it up and away I go. I don't hang around and the tailpipe is pretty close to the open garage door. I suppose it would matter to my dogs but I don't know if I smell anything much.
Does it matter what they smell as you walk by? Also, when I start up the car, my garage door is already opened and I drive out. In my case, the windows are always up but IDK how much smell there is if you pull out quickly. I open the door, get in the car, fire it up and away I go. I don't hang around and the tailpipe is pretty close to the open garage door. I suppose it would matter to my dogs but I don't know if I smell anything much.
The one saving grace is that a stock cam will be much better than a cam with a lot of duration.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
Why does anyone idle for a few minutes? Is that a necessary thing or an old habit? Can you just dump it in gear, back it out and go on your merry way? Obviously, because of where most of us live, we cannot stand on the pedal but we have to drive civilly so that should be enough of a warm up unless your driveway ends at the start of the quarter mile track.
Burning Brakes
Joined: Mar 2022
Posts: 1,220
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From: Phoenix, Arizona
At the risk of being a bit off topic, in the "old days" I thought I recall automatics having less HP at the rear wheels due to driveline loss compared to manuals? Is that no longer the case with modern automatic transmissions or is it something not talked about?
Team Owner
Joined: Jul 2004
Posts: 28,432
Likes: 3,285
From: Hartford WI
True. I guess what I meant was that the O2 sensor should have no effect on the engine being rich since it is all a programmed course of action. Probably for protective reasons.
Team Owner
Joined: Jul 2004
Posts: 28,432
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From: Hartford WI
I dunno....maybe you need to dash inside to grab something you forgot? Perhaps it's 20* out so you start the car so it's marginally comfortable in the cabin before departing? Perhaps it's 115* outside and you want to start it and let the AC cool things off for a moment before getting in?
In my case, I'm in the pits and getting strapped into the car while letting the oil and coolant come up to temp before going out for a 30 minute track session
In my case, I'm in the pits and getting strapped into the car while letting the oil and coolant come up to temp before going out for a 30 minute track session
That I can see.