I have a 2000 F250 SD stock V10 and went through the same issues with the Y pipe flutter. Shortly after I bought the truck used, the Ford dealer changed the 2000 Y pipe to the newer restrictive model. I've read numerous posts concerning the sound issues with Ford's Y pipes and the custom after-market Y's, and I've noticed that some have gone back to the restrictive pipe because of noise, but I am more interested in information on the performance issues in changing to a un-restricted Y. From what I recall, the restriction has to do with back pressure and low-end torque. At one time I saw a post either here or on another site, where someone explained about the relationship between pipe lenght, diameter, scavanging, exhaust pulses and so forth, so I'd also like to know about the performance issues and if there's a prefered custom design or after-market Y pipe design that works well for overall performance.

 

look for the article with stans headers in it. there is a nice picture of the difference between stock and a good aftermarket Y pipe. its not too far back. hope this helps

 

Dwinn

I did a lengthy post once a few years ago on all the peramiters your listed. Not really worth reposting even if I could find it.

Right here in the V10 forum in the last 3 months are several topics on the "y" pipe and good photos. No magic formula. All work better than stock lash up on 99-2004 V10s.

Search it or just go back 5 or 6 pages and work your way forward the topic title are obvious.

Best all around mod for pre 05 is a true dual system with "h" or "X" cross over close to the front as possible and final outlet just before the tires.

Many that just did a fabricated better "Y" pipe pre cat mod say the power add was noticable and throttle response felt snapier.

 

One of Bernoulli's laws - reduce the cross-section of the pipe, the speed of the gas increases.

In such a short span, that restriction on the stock y-pipe is not much, all it's doing is speeding up the charge significantly. If it was lengthened more than the apparent 1/2-1", yeah, that'd be a serious problem.

I do, however, intend to remove that restriction, at least as an experiment I do see it as a restriction - however, I also see the engineer's intention...

art k.

 

Oh, and I'd say that "y" pipe is really a "t" pipe

 

After reading all the posts on the aftermarket Y pipe delima I am still in no way convinced that it is worth it I am not willing to sacrafice low end torque not even a little, I use my truck to two and low end is what I need. Would I like to do it? hell yeah but not enough info to make me spend the dough to do it as of yet. I guess I am waiting for the person to come on here and say I did it and it really woke the truck up

 

I haven't tried an aftermarket Y-pipe but I do know that true duals with an X gave me more power and I dont feel that I lost any bottom end. There are a few pictures of it in my gallery.

 

Wait until you hit something and rip it out - that way, the wife's not unhappy... at least, that's my reasoning for putting it off...

 

well there are formulas for bore and stroke and target rpm to calculate the length and cones for expansion pipes to scaveng but we don't have the room necessary for 10 tuned pipes.

There are many formus for headers the most effecient are called 180 degree systems but again space is a bear to plumb them into. The after market did the next best thing with equal and unequal length headers.

In the last 5 years I have seen several different lash ups on the dyno... for a 99-2004 the best bang for the buck seems to me to be to get rid of the so called "y" pipe that is really a necked down "T" and run true duals short of the axle. Once the exhaust shops out here found the formula that is what sells and is proven to add power and sound good.

Most of the locals do not go for the bucks of the headers. Two JC whtney truck cats, summit mandrel bent tubing and an "x" pipe 2 1/2" pipe all the way dumping out of the flowmaster 40s as 3" FWIW the 5.4 and 6.8 both get same treatment

We had one stupid (friend of my son) who used 3 1/2", no cats, no mufflers and 5 inch chromed stacks up through the bed on a 5.4L and it sounded like crap (very loud too) nice lifted truck, pretty color...hit a deer and rolled it...so much for very loud pipes driving the critters away

 

What does the X or H crossover do? Wouldn't true duals be separate independent exhaust pipes? I like the idea of duals, but what do you do about the one NOS 02 sensor that's past the cat? Also, are there any PCM programming changes that need to be performed?

 

The X or H pipe helps scavenge the exhaust. A very basic explanation is that as one cylinder sends it's exhaust out it creates a low pressure area behind the pulse. With a crossover pipe the low pressure acts on the cylinder next in the firing order and helps pull the exhaust out of it.
Not all of these trucks have the O2 sensor after the converter. It depends on the GVW and calibration and where the truck is certified to be used.

 

The truck is a Calfornia model and the GVWR is 8,800 lbs. Not sure about claibration. If I change the existing restrictive "T" pipe I may just try a custom or after-market "Y" pipe. I bought the truck used and as far as I can tell, it's pretty much a stock truck. Besides looking into changing the "T" pipe, I'm thinking of buying an SCT Xcalibrator 2 Tuner. As for truck usage, we use it mainly on the coast then use it on trips to haul a 3,000 lb. camper up in the mountains.

 

My personal experience with my 2001 cc dually is as follows-First i bought the truck used with a magnaflow cat back exhaust allready onit.I had it removed becaused i hated the dronning noise.Second exhaust-I had a shop cut the downpipe of each stock manifold and tie in 3'' then ran true dual pipe with a 20''glasspack on each side and ran it out the side.The sound was unbearable and easily would have gotten a ticket that day even if i slowly creeped through town(4cylinder on a loud speaker). Third exhaust-I left the stock manifolds on;in theory to keep my trucks good pulling torque.I had 3'' ran of each manifold pipe and ran 3inch boths sides down then had a 2'' H-PIPE tied in to the duals for proper scavenging and then both 3inchers ran back on each side into two magnaflow cats(each rated for 460ci)then the driver pipe ran across to the other side and then ran side by side with the passenger side exhaust they both then ran into a dual 3'' in magnaflow muffular that has an internally built crossover and then they ran out of the duall 3'' out.They both then were ran over the passenger side axle and then welded two 20'' silvertips on.They exit on the side tuck in just under the ps-dually rear fender;tuck up/in real nice with the edges facing to the ground. This setup gave seat of the pants more horsepower,smoother shifts,increased pulling power and also the dronning is gone and the engine sounds beefy.I bought an exact magnaflow that the dodge viper car finally had to go to for there v10 sound improvement..I pull a 40 footer fifth wheel enclosed and a 24ft bayliner hardtop in the hills-no problems.I learned the hard way.Sorry so long guys!Just my experiences