Just bought a 2004 F250 4x4 Crewcab 5.4L had some questions after doing some research on mods:

1. Why did Ford put these restrictions in the y pipe? Meeting emissions standards?
2. Will modifying the y pipe void the warranty in any way?
3. I saw a replacement pipe on eBay claiming 30 hp gains by eliminating the restrictions. Sounds optimistic to me, so what kind of gains can be had realistically?
4. Any drawbacks to this mod other than losing some low-end torque?

 

I wouldn't rely too much on those HP gains. I played around with my exhaust and find that the OEM system works because it allows some restriction or backpressure (that the V10 seemingly needs) since you are talking about the V8, that I think would be a different story. My advice would be to remove the OEM system propery meaning from the bolts instead of cutting) and save them. After playing around with different setups, you can always go and put the OEM system back if you like.

 

Funny thing my 99 never had any restictors on it. Maybe you could order the front pipe for an early 99 3-3-98 early.


Dick

 

Thanks for the replies. Any 5.4 owners do this mod?? Seems like a no brainer to me looking at the stock setup. Don't know if the earlier (nonrestricted y pipes) have the same configuration as mine, but might work if they do. I would think that the cat alone would provide enough back pressure to retain decent torque. But I don't know for sure.

 

Mine doesn't have the restrictors but it does make those bends..


Dick

 

That looks like an expensive part if I'm reading it right, but I can't find a part number for the pipe without the restrictions.

 

I know someone...My Dad did the mod. He took his '01 F250 SD CC 5.4L Auto 4x4 to a local muffler shop. Cost about $45.00 for the removal of the old restricted setup...and the weld in of the new free flow y-pipe.

The results are all seat of the pants feel, but that 5.4L did wake up some. The throttle response is so much better too. The mpg has increased by 1 on highway driving. My Dad's SD now has 104,000+ miles...and running strong. If I remember correctly...he did the mod this past summer '06 and had about 90,000 miles at the time.

Hope this helps...

biz

 

The main reason Ford went with that pipe is to reduce flutter sounds.

 

summit raceing has a y pipe mod. kit.part number fmy250300 and the price is $39.88 . we use it a lot for many different cars and trucks .

note that it is a universal part and that cutting and welding must be done to make it fit.
how it works on a 5.4 we can't anwser that.

 

Thanks for the responses. What about the warranty?

 

I have a 2004 F250 SD CC 4x4 with the 5.4 also, and I had a muffler shop cut out the restrictions in the Y pipe. I looked at the cutout pieces after they were removed, it is pitiful how Ford did this. The pipes are reduced down to an inch and a half at these points. I work at a Ford dealer, and spoke to our lead tech about this. He said that Ford put these in to reduce noise. I agree with the earlier post, it does increase your "seat of the pants" power. I dont have access to a dyno to see, but it will not be 30 hp. Maybe 5 hp, but still worth it to me. What impressed me most was the fact that the transmission seems to downshift much easier than before.

As long as you dont remove the cat you will not void your warranty.

 

i looked under mine and it doesn't look like the bottlenecked ones i've seen in pics... is it a '00+ thing? something to do w/ the newer heads?

 

According to the Parts catalog, 99 - 04 all used the same pipe on the SD 5.4

 

Prob the newer heads or the early engines had a valve in the intake to control flow at low rpm. None had it in 2000 so they were prob not concerned with exhaust since they had it covered on the other end..The valve opened up at a certain rpm to allow more air through the engine, thus a restriction at lower rpms to increase torque..


Dick

 

My 5.4L 1997 Expy was bottlenecked inside.
Magnaflow replacement was like $30 back in the day.

I run duals with an x-pipe now.