Headers are ordered!
98 F150 5.4L E40D/4R100
Joined: Nov 2006
Posts: 28,519
Likes: 7,630
From: MI
The 3" is more less for off road racing. Those guys are WFO just about everywhere and tuned for such. Hence the name "Off Road Pipe". Yes, you can be tuned to run it, but IMO, you'll get better "usable" HP/Tq with a DD, specially if you pull a trailer keeping it 2.5"
Keep in mind Tuning and pipes work like this from my understanding, - you can run open headers and not loose or move power or torque anywhere in the powerband. The only reason you would is because of the tune.
Keep in mind Tuning and pipes work like this from my understanding, - you can run open headers and not loose or move power or torque anywhere in the powerband. The only reason you would is because of the tune.
98 F150 5.4L E40D/4R100
Joined: Nov 2006
Posts: 28,519
Likes: 7,630
From: MI
Back then, my goal was to get the most out of the factory tune. Didn't have the choices that you do now. I had to use 94306 high flows, customized. I cut out the 2.5 flange and welded in a 3.0 ID flange that slip fit over the collectors, - then welded these right to the collectors. As you most likley know, you only have so much room with the 4x4's...it's tight! Tighter w/Pacesetters. My system is 100% welded. Figuring I'll just trash it if I need to replace. From the back of converter, the system is 2.5". Reduced thru the convertors. That being said and with the Y's 2.5" mandrel bend, I could barley get it to fit. The fit has to be perfect on the 4x4's to line up between trans and transfer. Very noticeable difference with low end torque. I didn't dyno, - just have the before and after 0-80 runs.
Joey (user built54) dyno'ed back when he was NA. With his 98, he had the PI swap. To my knowledge, he's the only guy that did this working with a tuner and the dyno. Stock manifolds to shorties, the dyno proved no gains..none. The he went with Dynatech LTH's. Dyno proved 30/35 gains, -30hp 35torq.
Joey (user built54) dyno'ed back when he was NA. With his 98, he had the PI swap. To my knowledge, he's the only guy that did this working with a tuner and the dyno. Stock manifolds to shorties, the dyno proved no gains..none. The he went with Dynatech LTH's. Dyno proved 30/35 gains, -30hp 35torq.
Last edited by Jbrew; Feb 13, 2015 at 03:36 AM.
haha i think they all have positives and negatives. I have the cheap set of pacesetters on right now and they missed about 100 different welds. Looks like a 9th grader tried to weld the primaries to the flange. Paint did fall off after about 2 hours, all bolts were mild steel and have rusted, fitment was off a tad bit.
Nothing to say about OBX never owned them
Thread Starter
Senior Member
Joined: Jan 2012
Posts: 2,333
Likes: 273
From: Northern CA
This thread took a slight right turn lol.
To answer your first question, my 98' (had a 4.6 factory) with an 03' PI 5.4.
To answer your second question, I was going to use the 3" Y and pipe it to the factory exhaust initially and maybe change it to 3" all the way later, but haven't decided yet.
This isn't my first header install, my first was on my 12' 5.0 4wd and it can't be as bad as those. I did a write up in the 11+ engine section.
To answer your first question, my 98' (had a 4.6 factory) with an 03' PI 5.4.
To answer your second question, I was going to use the 3" Y and pipe it to the factory exhaust initially and maybe change it to 3" all the way later, but haven't decided yet.
This isn't my first header install, my first was on my 12' 5.0 4wd and it can't be as bad as those. I did a write up in the 11+ engine section.
Senior Member
Joined: Sep 2011
Posts: 7,381
Likes: 435
Dont use a 3" on a stock PI engine. It will take a huge hit in the lower RPM because of the massive loss of velocity in the exhaust. Trust me I've already been down this road. As I have teh PS and 3" full exhaust. Even with my setup its too much.
