what does si/do mean wen people say 40 series si/do

 

Si/Do......means single inlet dual outlet. Which is one inlet going into the muffler and two outlets coming out.

I'm getting this exact set-up on my truck tomorrow, w/ the 40 series flowmaster's. I'll let you know how I like them.

 

alright cool thanks tell me if they sound good n get sum sound clips up if u can too

 

They sound awesome.......Nice low rumble at take-off and they really get loud when you punch the throttle. If sound is important I would get the Flowmaster's

 

I've had mine on since christmas time, they are broken in pretty good now. I love them except for the drone you get at highway speeds, not that this is a problem my wife loves to talk

 

ya well i have flowmaster 50 series on and i was wondering if i should change over to 40 series do yall think that would b good or wat...

 

Haven't really heard the 50's. But from what other people say, the 40's are much louder. I hear the 50's are not much louder than stock, which I know is not the case w/ the 40's.

 

si/do setup u actually will loose power due to air movement. its not much more to run a true dual set up. but if ur gonna run a true duel get a 3" y pipe or larger put in that runs to the intlet on the muffler

 

Where does a Y-pipe go in a true dual system? What F-150 setup requires larger than 3" pipe anywhere in it?

 

ummm..... true duals don't have a y-pipe
that's the whole point of "true" duels, to take the y-pipe out and run two separate pipes to two mufflers, that's true duals.
oftentimes though, people will put a y-pipe in the exhaust and run two pipes off of that, but that's just duals, not true duals, b/c there is a single pipe in there

 

The 50 series is a nice sounding muffler. It makes some rumble under load anywhere from idle to 1800 RPM. Higher than 1800, and it tends to get quieter. I ran a 1000 mile round trip to Florida and barely could tell it was back there when the truck was pulling 2300 RPM. No drone = good road trip.

In my opinion, exhaust should be heard when you want to hear it, and not when you don't. I've had good luck with the 50 series. But I'm 26 and recently married, so my tastes are quickly becoming more refined (read: old), day by day...

Mike

 

hey i live in houston tx too wheres a good place to get exhaust on for cheap do u no of any places?

 

hey porky how do your straight pipes sound? did you do cats are did u go full out just REAL straight pipes

i want my truck to be louder, but ive got the 4.6 with the 40 series flows and a intake........just not as loud as i want it to be haha