I have 2 chamber flowmasters, and one of them rattles really bad at idle like there is something knocked loose in there, anyone had this problem? anyway, I was considering just cutting them off and running true dual 2.5" straights, any advantages/disad. s to this?

 

Loss of back pressure can affect HP & torque in a negative way.

 

Yabutya dont lose to much cause the cat does mosta the back presure!!

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2000f150 Lariat Supercab Flareside 4X4 Black 5.4 engine Leather Captains 3.55 Limited-slip and all the goodies, just ordered,traded my 99 f250 superduty Lariat V-10. Wife drives a 98 Navigator 4X4. Had a 97 Lariat 4x4 supercab Just ordered a lightning front and rear bumper,power tube,K&N filter,addin a maf 77", makin a 4X4 Harley ......... Toy: 91 Heritage Softail Classic/lowered and chromed LIvin in the USA!

 

Our trucks with EFI are configured to run they way they come from the factory. With regulations and such. The trucks actually run better with the single exhaust, because the computer senses your messing with him. Some new vehicles now stop firing on a cylinder if you "tune" them yourself.
I'm not trying to be a hater, but it is illegal to bypass the cats if that is what you're thinking. Here in NW Ohio, the highway patrol has started cracking down on people who are messing with their cats, and it's a $2500 fine. So if you do, please be careful.

 

I think he was referring to removing just the mufflers and running straight pipe from
the cats back. Hence, he leaves the cats
alone.

In my opinion, running straight pipes from
the cats will hurt you rather than help you.
Straight pipes work great on turbo charged
cars/trucks but ours I would not do that.
Just fix what is wrong with your muffler...

Just my $0.02 cents...



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1999 Ford F150 XLT 4x4
Off Road Package
Tow Package
5.4L Automatic
Supercab
Electric 4x4 switch
Full bench interior
Factory running boards
Mods : superchip, gibson
swept-back exhaust, k&n
FIPK. Bug deflector.
Use : Mobil1 5w30 and
k&n oil filter.

 

I have to agree that I would not go without the mufflers. I added a Flowmaster 50 series dual out catback.It ran strong, but wasn't loud enough. So, I removed it and put on the 40 series. Guess what? Lost a buttload of torque down low. Has a good sound and all, but no power. So running true duals should have killed your torque, and removing your mufflers will only make it worse. Flowmaster has a pretty good warranty, just swap out your broken muffler. And if you want some power-go with the 50 series!

 

I am not sure about the new F-150's, but I run straights after the convertor on my 93, and absolutely love it. I have had absolutely no problems with anything. Lots of people run straights out here and they havent had any probs.

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Toydestroyer1@yahoo.com

1993 F-150 302/e4od/355 Limited slip. dual exhuast w/o mufflers,2 1/4" pipes with Echo Tips, headers, accel plugs/wires(8.6mm)/rotor/cap, hypertech powermodule,5% dark tint. Alpine cd player and Pioneer speakers.

1989 F-150 XLT 4x4 302/aod true duals with turbo mufflers, 30X9.50" wild country tires, 3:55 gears w/LS Looking for Manual locking hubs

New Name:"Future-Duty"

 

I have a 95 F-150 with a 302 with installed JBA headers and a Cat-Back dual system comprising of 2.25" pipes, and this combo sounds awesome as well as running like a scalded dog. I interestingly have two converters in line with an airpump input inbetween them. I am not going to mess with this part as I want a reliable legal truck as well as a strong one....