Increase in torque

a little more than that probably, $1,200 minimum average would probably be ~1,500

Just my guess though, if you shop around/know someone you could do it cheaper.

 

Do you actually have thousands of dollars to supercharge your engine, or is this just talk?

 

Learning talk

 

Ok. So far we're already on the same page there.

Just to be clear... You're saying that long tube headers produce more top end horsepower, and that short headers produce more bottom end torque?

I'm saying the opposite. Others say it too:

(Autoanything.com)

"For a variety of reasons that involve physics, it turns out that long tube headers do a better job expelling your exhaust at low and medium speed RPM. So, this means you get more horsepower and torque when you're taking off from a standing start or fairly low cruising speed.

On the other side of the coin, shorty headers can deliver more power when your tach is running at its upper end and this is accompanied by less power at low to medium RPMs when compared to long tubes."


Could you identify the engine equipment differences for which color run on that dyno chart?

 

Good idea. See if you can find more info, because this is an interesting question.

The really big question is:

When the DT headers were installed, was the rest of the stock exhaust system also swapped out for an aftermarket exhaust? Opening up the system would sacrifice low end torque in exchange for bigger top end gains.

 

Ok. So the rest of the exhaust remained stock even with the headers.

I found out by trial and error that the long tube header/stock exhaust combination worked best for me.

And the spacer/header/stock exhaust combination was even better. Those three working together lowered the torque peak on the dyno by 900 rpm from 3,800 rpm to only 2,900 rpm.


Greg

 

Everything I have seen on here and XR-Underground over my 2 years of browsing these forums, states that the shortubes are better for low-end power/torque and long tubes are better for top end power/torque.

I've always attributed this to shorttubes being a better header than OEM so that is why you have an improvement. The Longtubes are an improvement as well but they are so free-flowing that they hurt exhaust scavenging at lower rpm which hurts your power/torque, but that extra free-flow allows the top end to get the exhaust out of the way better.

As far as N/A I have been told that replacing the OEM y-pipe is the biggest gain (this is for a 2nd gen though, not sure about 1st gen).

Also torque and HP are basically 1 in the same. A dyno will measure the torque you put at an RPM and punch it into a formula to calculate your HP. The more torque you have the more power and vice versa.

HP = Torque x RPM / 5252

So if you make 100 ftlbs at 1000 rpm, you will make 19 HP at 1000 RPM. If you improve that to say 150 ftlbs at 1000 rpm you now make 28.5 HP at 1000 RPM. They go hand in hand. This is why on all dyno charts the torque and HP curves will cross at 5252 RPM.

 

Also if the short tubes header pipes are smaller diameter than the long tubes the smaller tubes will scavenge better down low than bigger ones that are made to flow.more air.

But if the pipes are the same size I dont know why one would work better.

 

Keep in mind, that long tubes depending on quality of design, around (which will also be affected by available space) can increase the low end tq of the engine more so than short tubes. However, that depends on a long list of variables all working together to increase the scavenging ability.

In the case of the 1GR, the DTLT's were "the best available" long tube headers. The URD Spec U EQUAL LENGTH, are much improved with immediate "seat of the pants " low end gains. Although, there have not yet been comparison dynos posted. The DTLTs and JBA long tubes are not equal length but are still far superior to the older log style OEM headers, and newer swept back headers.

As for the 5vz, I don't know much about the headers available for them. But with looking at what is available, I would be able to point out quality design over not. Less restrictive flow will increase HP and TQ. Less restricitve is not to be confused with scavenging. Design of header for optimum exhaust pulses , and if Tri-y style is available, will both increase torque.

There is a great article on headers on www.MotoIQ.com

 

Just a couple of comments, so far I've seen 3 different engines discussed in this thread, each engine will respond differently to long tube vs. short tube, so no single statement is valid across these engines. And take the above note from Torspd to heart also, header construction is a big part of what gains you get, and where they occur in the rpm band. I know in the 1GR world ST vs. LT is totally backwards from what I dealt with in the Dodge V8 world, so you need to keep the discussion on track with your engine.

 

Torspd is one to trust on power gains lol. So from what I'm getting, short tube headers will produce more low end, but struggle at high end RPMs.. But, all this also depends on the header design, so if the header is designed awfully, then it wont matter, LT vs ST headers... Am I right, or did I miss something?

 

Basically the reason short tube and long tube affect power the way they do has to do with thr design of them. That's why Tor said the URD headers provide better lowends even though they are a long tube header.

 

Suck * squish * bang * blow

http://www.motoiq.com/MagazineArtic...ed-to-Know-About-How-Headers-Work-Part-1.aspx

 

Keep your weekend plans to yourself!!

 

That makes sense.

The instant I opened up the stock exhaust I lost low end torque, so I went back to the stock exhaust to provide the backpressure, and combined it with the free flowing long tube header, so now the truck pulls really good at very low rpms.