I asked my mechanic today about putting a flowmaster dual exhaust on, and he said i would experience back pressure problems. I've heard of this before. Anyone face anything similar to this.

 

same question here, anybody have an answer?

 

mine runs great...

 

dont worry about that until you make it a huge pipe all the way down and no restriction. open headers=no back pressure
some restriction of flow is good, it just depends on where it comes from

 

Unless you are running true duals with deleted cats and no mufflers you should not have to worry about backpressure problems. If you keep the cats intact and put a flowmaster muffler in there you should have no problems with back pressure. Flowmaster is an established exhaust company they would not gain any credibility if they sold products that just cause major problems and losses in hp. If you do it right you should have a great sounding exhaust system and equal if not better performance.

 

I have definately felt a loss in performance since I too off my 3" tip last weekend to work on my exhaust. driving with it for 2 days now, I can feel a pretty big difference right off the line. I can see a 4.2L making less pressure in the exhaust than a 5.4L.

 

mine's doin just fine too, make sure whatever pressure u release in the exhaust is compensated with the amount of intake (i.e. get a CAI or do the Gotts and Silencer mods)

 

make sure u reset ur computer by disconnecting ur battery, it might help

 

i have no cats and flowmaster 40 series dual exhaust and havent had any problems, I might have lost some low end power but can definitely feel power after 3000rpms. You should be fine, get an intake if your really worried about it.

 

I'd like to hear why your mechanic says 'backpressure' will be an issue. Too small of an exhaust will restrict flow, naturally.

Too large will cause a loss of scavenging, where each exhaust pulse pulls the gasses behind it away from the head, effectively keeping exhaust gasses from remaining in the combustion chamber and allowing a more pure air/fuel mixture to be brought in. Going from single exhaust to dual, or larger diameter dual may be his concern. Your engine doesn't need 'backpressure', it needs the scavenging effect of a correctly sized and tuned exhaust system.

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