Long Tube vs Shorty

[Supercharged111]

Here's an apples for apples comparison with shorties and longies of the same primary diameter. More low end from the long tubes and more mid range and top end for the shorties.

http://www.mustangandfords.com/how-to/engine/29618-short-long-tube-headers-test/

Remember how I said the difference was negligible?

 

[df2x4]

I know literally nothing about Ford products of any kind (and I don't plan on changing that) but don't the 5.0 Mustangs have computer controlled EFI? If so, did the article authors re-tune after those swaps? Seems to me that people who publish these articles rarely take things like this into account. I'd much rather see tests like this performed on older vehicles with no pesky computers.

 

[Supercharged111]

I know literally nothing about Ford products of any kind (and I don't plan on changing that) but don't the 5.0 Mustangs have computer controlled EFI? If so, did the article authors re-tune after those swaps? Seems to me that people who publish these articles rarely take things like this into account. I'd much rather see tests like this performed on older vehicles with no pesky computers.

Yeah, just like those guys with the 383 didn't retune between header swaps either, but at least they echo what I said.

Length plays an equally important role in tuning the power curve, as does the diameter of the tubing. Long-tube designs (typically 30-plus-inches) create a strong exhaust-gas pulse signal throughout the pipe that enhances low- to mid-range torque and horsepower. On the other hand, as the tubes become shorter, the tuning effect has less time to enhance the engine's low-speed benefits. A short header tube will allow the low- to mid-range power to fall off while increasing the upper-end potential of the engine. Many companies offer headers in intermediate and short-tube lengths mainly for clearance reasons, but these same applications can be used to alter the power curve of the engine.

Let's not forget they compared a 1 1/2" primary shorty to larger diameter long tube headers, not at all apples to apples.

 

[df2x4]

Yeah, just like those guys with the 383 didn't retune between header swaps either, but at least they echo what I said.

That was a carb setup, though. As long as it wasn't running lean for any of those tests I'd be more inclined to trust those numbers than the 5.0 article.

Let's not forget they compared a 1 1/2" primary shorty to larger diameter long tube headers, not at all apples to apples.

Agreed on that point. Like they said though, they couldn't find an applicable set of long tubes with 1.5" primaries.

 

[Supercharged111]

I'd say neither was more accurate than the other because the change in airflow between either wasn't significant enough for the EFI to go crazy. Total airflow was damn close, and the only difference was a slight change in the curve. I'd be willing to be there was more of a variance in the Chevy engine's untouched tune because of the massive swing from 1 1/2" primaries to 1 7/8". Either way the Chevy article still proves my point by stating that long tubes build more low end torque and shorties more top end. IMO they should have sniffed out a 1 5/8" shorty vs long tube as I'm sure I could find some in 5 minutes on either Google or Summit.

 

[99'Subourbon]

I'd say neither was more accurate than the other because the change in airflow between either wasn't significant enough for the EFI to go crazy. Total airflow was damn close, and the only difference was a slight change in the curve. I'd be willing to be there was more of a variance in the Chevy engine's untouched tune because of the massive swing from 1 1/2" primaries to 1 7/8". Either way the Chevy article still proves my point by stating that long tubes build more low end torque and shorties more top end. IMO they should have sniffed out a 1 5/8" shorty vs long tube as I'm sure I could find some in 5 minutes on either Google or Summit.

Hey - Just wanted to say thanks, for the legitimate argument; made me question what I thought I knew about tubing diameter/length. I've read done plenty of research, and have always come to the conclusion that shorties are minimally better than stock, with gain on the low end, and long tubes are better for the upper end (reason being the diameter is to great for low rpm cfm flow to promote proper exhaust pulses and scavenging). Subconsciously I've made the connection that short tubes are smaller, and long tubes are larger [in diameter], but that is not always the case. In an application where long tubes were appropriate size (for the application) in diameter, I can see how that would be optimal for low end.

Never know enough to think I know everything, glad to be schooled and learn something new.

That was a carb setup, though. As long as it wasn't running lean for any of those tests I'd be more inclined to trust those numbers than the 5.0 article.



Agreed on that point. Like they said though, they couldn't find an applicable set of long tubes with 1.5" primaries.

And thanks df2x4 for chiming in, you're input is always appreciated.