Exhaust power gain question.

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MuzzleFlash40

MuzzleFlash40

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My 2006 grand marquis has the performance package with factory dual exhaust. The factory exhaust I believe is 1-7/8 in diameter. How much of an increase would be had by installing 2-1/4 inch pipes? I was just going to maybe add some flowmaster 44 mufflers, but if its worth it I would do some bigger pipes as well since I can get it done from a friend for free all I have to do is buy the hardware from his shop.

Would the slight increase in size increase power that much?
 
I dont think it would do that much unless you have some power adders.
If you want more power, get a 2004-up interceptor airbox and intake tube and get a tune. Also get a set of the Stainless Works long tube headers, but those will cost you some coin.
 
Typically if you take away too much of the backpressure you will lose low end power. True performance increases are had with Cat-back systems that are performance tested and tuned to give you real increases in power throughout.
 
So, it's probably worth it to just weld in some flowmasters on the stock pipes, lol I have a 93 octane canned tune on it already.
 
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You're biggest gain will probably be from the nice sound and looks of the bigger pipes from behind. Power wise I would estimate you might pick up 10-15hp tops depending on how restrictive the stock muffs are. Now if you were going from single exhaust to duals, you would see a bigger difference. But already having duals, you are already ahead of the game.
 
You may actually lose power.
A few years back a German motorcycle magazine tested 20 aftermarket exhaust systems. all claimed increased HP and Torque.
The 1100 CC bike lost HP and torque with every system compared to stock, only one came close to the power of stock. They were all louder for sure but other modifications were needed to take advantage of the free flowing systems.
I'm sure the same applies to all engines.
 
It all depends on the car.

I still remember how well my performance exhaust system worked on my Saturn ION, and I did no engine tuning.
 
You're already winning by having the dual exhaust compared to the singles that used to strangle that motor in the 90s. "They" say bigger exhuasts help top end but hurt bottom, if you seriously drive around at 4k RPM all the time you might get something.
 
Not trying to put you on the spot but what were the improvement numbers HP and torque?
Louder exhaust note works marvels for the ol butt dyno.
 
Singles strangled that motor up until almost the end. My car has single and without a performance option thats what you would get.
That is the gain on these cars, is going to dual exhaust from single. 15HP according to factory ratings. Adding the interceptor airbox is good for another 10-15 as well.
 
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Thanks guys. I think i'm just gonna go with switching out the mufflers. I've owned a few of these boats, and I think the larger gear is probably the biggest gain. The 3.27 is a hugh improvement over the 2.73. The tuner was nice as well to liven up the engine and transmission. I just want some better sound without being to loud. I love the way a stock marauder sounds.
 
I don't know why but when they tested the police cars the 3.55 vic was slower than the vic with the 3.27 gear. It was wierd but it was across the board too.
 
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Don't put the Flowmasters on it. Go with Magnaflow or something like that. I have 44 Flows welded into the stock exhaust on my mustang and once I put the offroad midpipe on the car I can tell the Flows are too restricting in exhaust flow.

For the most FEEL in power increase. First would be gears. Then you'll need a handheld tuner to calibrate the the speedo. You can also get a few HP on the performance tune from the tuner.

If you really want to change the exhaust Get a full catback setup and a midpipe with high flow cats.

Then go for the intake side of things. More air in, more air out.
 
Originally Posted By: MuzzleFlash40
I don't know why but when they tested the police cars the 3.55 vic was slower than the vic with the 3.27 gear. It was wierd but it was across the board too.

Wierd, where'd you see this? I just looked up the 2006 MSP tests and the 3.55 was quicker.
Code:


3.27 3.55

0-60 8.93 8.63

0-80 14.43 14.21

0-100 24.12 23.38

Dist to 110 .67mi .65mi

Dist to 120 1.09mi 1.34mi

Top speed 130 120

It does have a lower top speed and is slower to 120. The crossover where the 3.27 gets faster is probably around 115mph if I had to guess.

Oh yeah, try to tell me you dont want a set of THESE babies.
 
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Originally Posted By: MuzzleFlash40
The factory exhaust I believe is 1-7/8 in diameter.
stock is 2". I had one. crownvic.net is your friend
 
Originally Posted By: Colt45ws
Originally Posted By: MuzzleFlash40
I don't know why but when they tested the police cars the 3.55 vic was slower than the vic with the 3.27 gear. It was wierd but it was across the board too.

Wierd, where'd you see this? I just looked up the 2006 MSP tests and the 3.55 was quicker.
Code:


3.27 3.55

0-60 8.93 8.63

0-80 14.43 14.21

0-100 24.12 23.38

Dist to 110 .67mi .65mi

Dist to 120 1.09mi 1.34mi

Top speed 130 120

It does have a lower top speed and is slower to 120. The crossover where the 3.27 gets faster is probably around 115mph if I had to guess.

Oh yeah, try to tell me you dont want a set of THESE babies.


Yeah, Those would be wicked. I can't imagine that they would be too hard. Lots of room unfer the hood.

Here is the link from the LA county sheriff test. Scroll down to the acceleration test. The 3.27 has the advantage in their test. It's wierd that the results can differ between departments.

http://www.lasdhq.org/sites/car-test/2011.pdf
 
That is wierd. If you look at their 3.27 numbers and compare to the MSP numbers I posted, they are pretty close. Almost right on for 0-60 and 0-80. Then their 3.55 numbers are way high. Makes me think something was wrong with their 3.55 test car.
 
Larger pipes should help max power.
This applies up to a point - in your case, a 4" diameter pipe will lose power everywhere.
Your bottom end will most likely be soggier. But NOT because of less back pressure. No engine likes back pressure. It retains exhaust gas in the cylinder, and there is more mass of gas in the pipe to push out. This is why low end suffers with big pipes.

Normal driving is not at full throttle and high RPMs a lot. 98% is just normal driving at part throttle. But if you want the power, the bigger pipes make it available.
How much? Good bends make a world of difference, as do the mufflers. But 10-15HP should be in the ball park.
 
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