Hey, got a question for you guys. I'm getting ready to buy the Flowmaster y-pipe replacement (referred to as a Y-collector) from Jegs online catolog. However, I have three choices, all differing in the size of the piping. I have a 1999 F150 ext. cab with the 4.6 and auto tranny. my choices are 2-1/4'' Inlet to 3'' Outlet, 2-1/2" Inlet to 3" Outlet, and 2-1/2" Inlet to 3-1/2"Outlet. I'm pretty sure I don't want the latter of those three, too big. However I'm not sure how big the stock piping is. Here is a link to look at the pic, I had to see it to understand it when somebody first told me about it.

http://www.jegs.com/cgi-bin/ncommerc...6&lastcat=2306

Anyways, thanks for your help.

 

My pipes were 2.5" forward of the Y and my cat-back was 3" behind the Y, so I used the Y250300A. It's a very beneficial mod, the interior of the driver's side factory intersection was really lame. I took (and would recommend taking) a 2.5" mandrel bent 90 degree pipe in with me for the installation. Exhaust shops don't have mandrel presses and the driver's side pipe is curved sharply to install it (almost exactly 90 degrees). I bought mine from J.C.Whitney for $10; one of the best $10 that I've spent .

 

Try RacerPartsWholesale in Indy. You'll get a much better price.

 

Your '99 is 2-1/2" in and 3" out... Max_mitchell quotes the right part number. I bought mine for $34 and it cost me $50 to have it welded in. While the exhaust guy was at it he cleaned up the install of the cat back I had to get rid of the clamps and adapters the idiots put in when I had that originally installed. The Y made an instantly noticeable difference. I got about 1 mpg better mileage on the highway too. Great mod...

 

I keep hearing how you guys are getting your Y-pipes installed for $50, $60, or $90. Everyplace I have gone to around me wants like $180 or more. Two places won't even do it because they think it is pointless. I bought mine 3 months ago and it is still sitting in the box.

 

I know what you mean. I was ready to have mine installed by a shop and muffler guy I really trust and he said it'll be a waste of time, money and I'll have nothing but problems..........

He said, "I'd love to take your money, that's what I'm in business for, but I also don't want you coming back and saying your truck drives like $h!t now." Went on and said, "it'll probably work as long as you keep the RPM's up around 4 grand all day. It's a high rpm mod but these heavy trucks need low end power to get moving."

He listed out several examples of different rigs he's worked on and regretted doing them.

I know what eveyone is saying on this board about this mod and that it has helped their setup in both the low and high ends. I don't doubt that, but I also don't have all the other mods some of these guys have either, so maybe that's where the difference is.

At any rate, I've decided that I'm satisfied with the way I've got my rig running now and it has pleanty of power for me. If I wanted to race everything that moved, I'd have kept my '86 5.0 GT! (actually, wish I did keep it anyway)

I did however, kill a little "ricer" one night. I saw him in my rear view switching lanes all over the place, and we ended up at a stop light together. He's revving his little 4 banger with the fart can, so when the light changes, I just nail it and I could tell he did the same (could hear that damn thing from behind shifting at what sounded like 7 grand!). He never came close to me. He turned right before the next light....... Sorry about the story, but it did feel good!

Hummmm...... Maybe I should reconsider that Y pipe mod!!

 

It's a great mod; instant sound and performance change. Trust me, the installers that you've talked to are idiots. Inside the joint where the driver's side pipe attaches to the Y-area there is a jagged hole that is less than 2". It's like your exhaust is flowing smoothly, then it has to fart through a washer right in it's way. The engineer that signed off on that "turbulence maker" knows/cares little about flow. Why should one side of your engine breath 2.5" and the other have this??? My truck started laying second gear scratches at very low throttle, shifted manually, immediately after the install. I took in a mandrel 90, had it installed, had the passenger's side "snake" pipe replaced with perfectly straight 2.5" pipe, and the cat-back's "snake" pipe replaced with perfectly straight 3" pipe for $80. It's the best mod that I've done for the money next to taking up the slack in my throttle cable.

 

I have noticed that everyone that replied to this thread has had 5.4l V8's, does this restriction apply to all F-150's or just the 5.4? I have the V6, and I am interested in this mod. Any help would be appriciated!

Chris

 

i have the 4.6 and did the same change. i was under the impression that it was only the 4.6 motors that had the crappy factory y with small inlet diameter. from hearing from the '5.4' guys, i guess that was not the case.

also, believe it or not, meineke was the only local shop that would weld it in & used stainless steel pipe.

i was very happy after doing this, and it complimented the gibson cat-back nicely.