come on guys is there any gain in WHP going from duels to Headers??
on an FI truck?? Can't find any one that went FI first with dyno numbers then added headers.

 

Headers are usually done before or at the time of install. interesting to see if someone has done the comparison.

 

Not so much as a gain of power but, you lose boost ie increase flow effienecy while keeping the same power.Its better all around safer on the engine and allows you to increase the boost at or above the original level.Which is where you gain power.

 

If my boost number drops will my HP drop? Or are you saying the free flowing will drop boost number and power will stay the same?

 

You will pick up, or free up is probably a more accurate term, horsepower from adding long tubes, probably 30-40rwhp for FI trucks seems to be average after a retune. Boost per a boost gauge is just a measure of resistance, so increasing the exhaust flow will reduce the measured resistance, but you will be making more power. To get back to the same boost level, you can pulley down and make even more power.

I have a set of long tubes I have been wanting to install for a couple of weeks, shouldn't be long now, but I will post up when I get them on and run an "after" pull.

 

Well i guess it would depend on the setup.There is alot of variables involed its like saying will i pick up power with a said cam and not knowing what your heads flow.
Now if i were to share my opinion i would go with it will lose little down low but, come on more up top given no change in the compressor.Is it worth it well depends on your goals.If you tow with the vehicle which im pretty sure you do then i would have to say yeah.

 

I can tell you that you will have NO gains with a 5.4 Ford motor until you get to the 500rwhp zone. Our stock manifolds are pretty good.

 

Here's a N/A dyno results thread I came across, I imagine FI would benefit a bit more from the increase in exhaust flow: https://www.performancetrucks.net/fo...d.php?t=361385

 

I want to say BlownChevy has done this before and after pull on his old 5.3L Radix Ext. Cab truck I believe it was. Since he was in California and LT headers are illegal....he kept the manifolds for a while and then tried the headers if my memory is correct. His setup was one of the first ones (I saw) that was running 500rwhp in a 5.3L Radix/Cam GT2-3, 90mm Throttlebody only with no nitrous, head swap, etc.

 

When I put on my long tube headers I flowed so much better I had to get a walbro 255. Edit: Im a liar, only gained 40 whp