What are some approxomite power/torque gains for Longtube pacesetter headers on a 05 5.4L? I thought I read somewhere that a guy from these forums dyno'd a truck with regular manifolds, then shorties, then long tube headers, and he got a power gain of like 30hp, and 35-40ft\lbs of torque? Are my numbers wrong, because I remember the shorties apparently added no hp/torque.

 

that is correct, with a tune.

 

If thats with a tune, what numbers are we looking at without a tune, because I planned on buying headers before I got a custom tune.

 

The only thing you would gain from running long tubes without a tune is a new motor after yours blows up from running lean. The motor moves a lot more air with long tubes.

 

You shouldn't have to worry about it running lean, but a tune will maximize performance!

 

to take full advantage of the longtubes your going to need to get as much air IN as the headers will let OUT. Which means you need a good cold air intake system, which means you will need a tune or you will run lean at WOT.

 

How do you run lean by installing long tubes? I would have thought that only the Mods done to your engine intake side can effect whether you are running lean or rich. All the headers do is allow the exhaust gas to get out of the engine easier and cut down weight A LOT!!!!. That's what I thought anyways. Would it run lean because you are more efficient at scavenging the exhaust from the cylinder, therefore your ignition will be far more efficient and burn hotter? Anyone care to explain?

 

8 - 10 horses & 12 pounds average un-tuned


You aren't at a great risk of running lean with LTs, but with the front O2s re-located 1.5' away from their original location a tune is necessary so fuel can be fed quicker, and the engine can perform faster. In some cases, high mileage engines mostly, new front O2s are necessary.

 

Longtubes will make ANY vehicle run leaner because they allow for MUCH faster and more complete evacuation of exhaust gasses. That means the motor is going to draw air in more efficiently as well. Not so much a matter of how much air can get sucked through the intake, but how much air actually gets used. Shouldn't make too much of a difference with the stock intake, but I don't know anyone that has put longtubes on a vehicle with a completely stock intake. But, then again, I was a chevy guy until I bought my f150 so what do I know :P

 

he got a power gain of like 30hp, and 35-40ft\lbs of torque? thats impressive gains

 

BS flag. I've got the dyno to prove it. I actually ran richer after the headers for some reason.

By the way OP here are my dyno charts before and after LT headers.

I do have a Xcal3 tuner but it's the canned tune on it. It's not written for LT's.

 

someone else pointed out to me that i actually gained about 35 or so lbs of torque and 20 or so HP in the lower RMP ranges. The peaks just didn't change that much.

here's my install write up which contains a lot of info you may want to look at

 

For only 6 HP, I would consider shorties. Cheaper, easier to install, no exhaust work needed.

I bet you would get a lot more power with a tune.

 

I guess you missed my last post. It was better than 6hp

 

Yea, I've seen them Dyno tuned in 30/35 gains. Running canned is the difference above. Glad you posted that ef, now I have a good idea what they are without dialing them in.