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Author Topic: Straight pipes. Back to Topics
Damon77

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Florida

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Message Posted: Apr 11, 2013 1:21:11 PM

I recently added straight pipes to my 2004 ford ranger and was wondering if itll hurt gas mileage even more? Its a 3.0L v6.For those that dont know straight pipes are deleting the muffler. Its not that loud for the police to bother me at all. Its quite mellow.
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OceanArcher
Champion Author Mississippi

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Message Posted: Apr 15, 2013 7:59:09 AM

Hmmmm --

If Houckster's figures are correct, you could probably gain 15 HP or so just by cleaning out yer trunk! Damn lot cheaper than paying a fine for running on the street without a CAT ....
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WEPSMAN
Champion Author South Dakota

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Message Posted: Apr 15, 2013 7:52:06 AM

Not going to make much difference if still running through the catylic converter.
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MertieMan
Champion Author Lexington

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Message Posted: Apr 14, 2013 7:42:51 AM

I suppose by straight pipes, you mean coming off of the headers on both sides of the engine all the way to the rear end, am I correct?
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Banjoe
Champion Author Winnipeg

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Message Posted: Apr 14, 2013 7:16:43 AM

Damon77 - I think you've confused the group with your reference to straight pipes as we don't know exactly what you've done.

Exactly what portion of your exhaust system have you 'straightened' out?
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priver
All-Star Author Alberta

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Message Posted: Apr 13, 2013 5:56:31 AM

it should help, I would also install a K+N filter cheap add on and it pays for itself as the filter is washable.
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oilpan4
Champion Author Virginia

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Message Posted: Apr 13, 2013 1:00:04 AM

"Removing the cat will set off a diagnostic trouble code and light up the Check Engine light".

Not if you take the after the converter oxygen sensor out, screw a spark plug non fouler into the sensor hole then screw the sensor back in to the non fouler.
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giwan
Champion Author Michigan

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Message Posted: Apr 13, 2013 12:57:46 AM

You may not pass emissions as the straight pipes may allow the exhaust gases to exit to quickly. This does not give the catalytic converter enough time to deal with them.
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Clunk49
Rookie Author Nashville

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Message Posted: Apr 12, 2013 7:58:12 PM

Later OBDII compliant vehicles have an O2 sensor AFTER the catalytic converter to watch the efficiency of the system. Removing the cat will set off a diagnostic trouble code and light up the Check Engine light.

Removing the muffler won't hurt anything except people who don't have an appreciation for the sound at more volume, including police officers who uphold vehicle excessive noise laws.
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Houckster
Champion Author Atlanta

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Message Posted: Apr 12, 2013 1:58:37 PM

L98 writes: less back pressure helps the engine breathe,economy may improve as well as performance
______
Theoretically true, practically speaking there's a big IF. Modern car engines have to be very efficient to meet environmental and fuel efficiency standards so that there are very few gains from aftermarket bolt-ons available and those gains are usually only available at the top end where people who are concerned with mileage will never go. Cars today already have very good intake and exhaust systems. To realize any serious gains, every change to the engine usually will require changes to the ECU and dyno-testing.

[Edited by: Houckster at 4/12/2013 1:59:58 PM EST]
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Houckster
Champion Author Atlanta

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Message Posted: Apr 12, 2013 1:46:41 PM

If a car comes with a catalytic converter and it is removed, it is illegal. This is true for all cars that are OBD-I or OBD-II compliant. I am unaware of any loopholes in the law that will allow the car to be compliant with the law without a cat.

That said, what is the cost of a catalytic converter in terms of horsepower and torque? The answer is very little. The link I supplied is to an enthusiast's magazine that would likely take a dim view of cats if one were to be had. To summarize the article, a car with 147 hp and a stock cat produced 147 hp. Replacing the OEM cat with a high performance OBD-II cat gained 3 hp and running straight pipes produced 1 hp more. The article points out that you can gain the equivalent of 1 hp by shedding 10 pounds.

So, you can break the law, risk fines, and gain 2-3 hp by dropping the cat or you can shed a few pounds and get the same benefit. Running straight pipes is an error or judgment.

As for gas mileage, there are so many variables that only a DAMON77 will be able to tell if he has enough fuel consumption information prior to the change to be able to compare results.

Import Tuner - Catalytic converters - horsepower cost

[Edited by: Houckster at 4/12/2013 1:50:21 PM EST]
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L98
Sophomore Author Ontario

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Message Posted: Apr 12, 2013 12:26:33 PM

less back pressure helps the engine breathe,economy may improve as well as performance
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geno700
Veteran Author British Columbia

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Message Posted: Apr 12, 2013 10:21:20 AM

survey says it will not raise gas mileage enough to notice the difference. A cold air intake and a programmer will lower your gas guzzling.
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dontuknowOH
Champion Author Ohio

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Message Posted: Apr 12, 2013 9:40:28 AM

You may not have any problems, but the exhaust 02 sensors might go out of their range of operation then causing a lite CEL. over a time span. If spark plugs change to a lighter color driving highway, exh. valve temps can increase. Don't black tape CEL view if lite.
Engines simply breath better when restricted pipes are cleared, watch your go pedal habits, My neighbor had to replace his motorcycle pipes back to stock, the Blues... got active two Summers ago ETC.(Chase Chargers with Led lights....
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OilerFan
Champion Author Tulsa

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Message Posted: Apr 12, 2013 8:12:43 AM

I don't believe it'll reduce your mileage any.
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oilpan4
Champion Author Virginia

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Message Posted: Apr 11, 2013 5:47:02 PM

I don't have a catalytic converter and I am perfectly legal.
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Houckster
Champion Author Atlanta

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Message Posted: Apr 11, 2013 5:24:57 PM

If you don't have the catalytic converter, your vehicle is illegal.
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oilpan4
Champion Author Virginia

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Message Posted: Apr 11, 2013 4:17:34 PM

The catalytic converter kind of acts like a muffler.
If you still have it then its not a true straight pipe.
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73amx
Champion Author Allentown

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Message Posted: Apr 11, 2013 4:05:32 PM

should help mileage some I would think. the better the intake and exhaust the better the engine runs.
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OceanArcher
Champion Author Mississippi

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Message Posted: Apr 11, 2013 3:58:24 PM

Ya still ain't got a "straight pipe" system, ya forgot about the catalytic converter
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