So I was on another forum (don't know if I can link the forum) but the poster linked videos that show long tubes actually give you more torque down low then short tube Headers, which I found interesting.

 

Not from the dyno tests I have seen.... Long tubes are better in the upper RPM range, but, mid range, shorties got 'em beat.

 

That's what I thought but he posted a video that showed proof that's it's the opposite. I just found it strange lol. So you think running true duals would have any benefit on a build with a better cam?

 

What proof?? Did he have some variety of comparison??

 

Yes he did a dyno

 

These guys disagree. As do these guys......

I suppose a fair bit of the results you get depend a LOT on what types of headers you are comparing....... (design, tube length, etc.)

I would love to see a dyno test of pacesetter shorties, vs. pacesetter longtubes. Those results would likely be more meaningful.

 

Yeah I skimmed through the talking to get to the dyno results 🤣

 

Honestly, I have a hard time telling the differences between shorties and long tubes. If the primary tubes are the same then the power numbers should be similar. I used shorties on my 85 vette, just welded up 3in exhaust to header outlet flanges. Works pretty decently, the engine revs strong to 6000 rpm, but its a near stock LQ9 6.0L engine.

 

The problem with these threads is most people don't know how exhaust works and is the reason for the myth of "short for low end, long for high end"

The longer the tube, the greater the torque production and the lower in the rpm range it is produced.
The larger the diameter of the primary tube, the higher in the rpm range torque is produced.
The inverse of both statements is also true: shorter the tube the less torque and the higher in the rpm as well as smaller diameter the lower in the rpm range the torque is produced.

Shorties are traditionally made to fit up with factory Y-pipes and because of their short length and the need for fitment in confined spaces, they usually have smaller diameter primary tubes.
Longtubes don't typically have this problem because they do away with all that garbage. They're typically made with larger diameter tubes to broaden the effective rpm range.

Headers are a balancing act, you want length for low-mid range torque production BUT you need to have enough diameter to support your desired rpm. These trucks for example, every single shorty uses 1.5" primary tubes while the longtubes use 1-3/4. If you want to spin a 360 with a decent cam to 5-6000, those shorties wont support it. Theyre simply too small. Now the Pacesetter longtubes on the other hand, they're large enough they'll support that all day yet do it without cutting out all the torque you do produce.

If you want maximum stump pulling low end torque, you'll need a longtube with a smaller 1-1/2" to 1-5/8" primary. They don't really make that though. Doug Thorley's would actually be the most appropriate in my opinion for that application with an off the shelf product. Tri-Y tend to work primarily in the mid range hump but they have little 1-5/8" primarys.

OP, for most N/A builds that are non-stroked, a single 3" or dual 2.5" exhaust both will more than support you. With the duals, I'm not sure what you mean by true dual. SOME people get all worked up over the definition of "true dual" saying an exhaust with a crossover doesn't count. With or without will support it though. For broadest powerband, Pacesetter longtubes are an excellent product. Shorties on these trucks do a little bit for low end but ultimately they don't do a whole lot. If you really want a set of shorties to produce gains that are actually worthwhile you need to cut the teeny ball collectors off and run 2.5" flanges off them with matching downpipes. And at that point, you're at or higher than the cost of longtubes that are easier to install and produce better results.

 

If anybody wants to read up more the subject, google "scavenging" and look for articles about how the physics of it actually works. If the word "backpressure" is used in any other way than claiming its BS, the article is BS.