Ask Doug Thorley – Short vs. Long Tube Headers
Benjamin | Jul 28, 2010 | Comments 12
We have been having an email conversation with Jamie Joyce, who manages Automotive R & D for Doug Thorley headers. In our previous post we got some interesting background information on the differences between Doug Thorley headers and a stock Toyota Tundra exhaust manifold. This time, we’ll get a chance to hear some of Jamie’s answers regarding the thorny issue of short tube headers versus long tube headers in the pickup truck world.
We started out by mentioning to Jamie that both the short and long tube header options offered by Doug Thorley appeared to offer a similar increase in low-end torque, with only a slight advantage going to the long tube units. This seemed to go against the conventional wisdom in the truck performance world that short tube headers can actually rob an engine of low rpm torque, especially in comparison to stock manifold designs.
Jamie told us that historically, most shorty header designs were only capable of offering horsepower and torque improvements from mid-range rpm’s onward. However, the Doug Thorley short tube headers were designed in a tri-y configuration that works to maintain a constant power increase throughout the entire power band. This was a special concern when the headers were being designed given that the Tundra is heavier than most of the vehicles that the company typically builds headers for.
Jamie also said that the decision to build a tri-y design stemmed from the reality that most Tundra drivers are going to be using their extra power in a practical application, rather than heading out to the race track where top end speed is at a premium.
Despite Jamie’s assurances that there were minimal performance differences between short tube and long tube headers, we did ask him whether drivers who were most concerned about maximum towing and hauling capacity – areas where low-end torque is especially important – should stick with a long tube design. He told us that he would recommend long tubes specifically in these cases because the units produced by Doug Thorley have shown a larger power increase right around the 3,000 rpm mark, which is where most tow rigs could use an extra boost.
Do Headers Help Gas Mileage?
Our last question for Jamie was regarding fuel economy improvements associated with a header install. We didn’t expect him to give us an exact mpg number – driving style plays such a large role in this type of performance calculation – but he was able to tell us that typically Thorley customers report improvements in the one to three mile per gallon range. He also said that given this efficiency increase, if you can keep your foot out of it then a set of headers from his company will pay for themselves in about a year through fuel savings alone.
It’s always great to be able to pick the brain of an exhaust expert like Jamie, and we really appreciate the time he took out of his busy schedule to answer our header questions. You will notice that we made sure to inquire about the benefits of short versus long tube headers in a Tundra application. This is a somewhat touchy topic amongst many in the Tundra community. Jamie himself appears to favor a long-tube approach for the Tundra, especially looking at how he answered our questions about towing and daily use.
That being said, he is quick to point out that the dyno data indicates that both the short and long-tube options provided by Doug Thorley outflow the stock factory units. The short versus long-tube debate it would seem is far from over – perhaps we can present a more in-depth investigation of the pros and cons of each design for the Tundra in the future.
Filed Under: Toyota Tundra Accessories
I’m not sold on the 1-3 MPG increase and fuel cost savings in a year’s time. If it doesn’t meet my driving standards, why bother with the “upgrade?” I want to drive the way I always do…..if I want to save gas I can change my driving style for free.
TXTee – I think the mileage benefit is part of the pitch – if the part adds better fuel economy, it can justify a portion of the cost. Still, I’m with you. A lot of people would get better gas mileage if they just slowed down.
..and kept their tires properly inflated. I had to throw that in there. =) I’ve just heard so many great things about the stock headers and too many bad things about aftermarket ones possible cracking. EEP! I think headers LOOK awesome…..so I might be sold just for the aesthetics.
TXTee – So true! Tire pressure is huge. Cracking is something we asked about, and the answer is that they test and shoot for the best durability possible. Cracking is supposed to be a result of install…but who knows. I hear the same things you do. You can’t beat the factory’s iron manifolds when it comes to long life, but cracking is probably pretty rare.
Jason – Did Jamie provide any Dyno sheets for you to view? If so, can you post them.
I’ve heard good things about the Long Tube’s from Thorley, HOWEVER most people agree that installing the LT’s will likely VOID your engine warranty because they require the front-cats to be deleted. Did Jamie have any comments on this issue?
popo2239 – Great question. I’ll ask. Dyno sheets are on the way.
popo2230 – Very quickly, there’s absolutely no way that a set of headers can void an engine warranty. They might void the emissions warranty (finding that out now), but the engine warranty can’t be voided unless the headers are the cause of an engine failure…and that seems incredibly unlikely.
Learn more about what can and can’t void a warranty here: https://www.tundraheadquarters.com/blog/after-market-accessories-new-warranty/
I appreciate the response; the fellas at TRDSparks voiced their opinion the opposite way, and said they WOULD probably void the warranty, but also said it would also depend on the dealership you went to.
The guys I’ve talked to really love their LongTubes, and have claimed great results with the ol’ “butt-dyno” — I haven’t heard much feedback about the Thorley ShortTubes, or the Gibsons… Conversely, I’ve heard complaints about the JBA headers, saying the fit wasn’t that great, and they lost noticeable low-end torque.
popo2239 – Interesting…TRDSparks are pretty knowledgeable about these things. I’ll dig a little deeper, but ultimately the warranty laws are clear on one point: manufacturers can’t void warranties because of accessories *unless* those accessories are the direct cause of a failure.
I heard back from Doug Thorley regarding deleting the front cats and warranty issues and they said it varies from dealer to dealer. I forgot to ask for Dynos – doing that now.
That picture is slightly misleading…
We’re talking about a long tube vs another ‘long tube’
On the left, the 4-2-1 pictured still has tubes long enough to give a resonant peak at a lower rpm (say 3000) as well as the shorter primaries for a resonant peak at say 6000 rpms.
On the right you have an all-in-one long tube designed for a single resonant peak.
So sure between these two designs there isn’t going to be that much difference in torque … however if we are talking about a strict shorty design (4-1 shorty) then YES the difference will be more apparent.
Horsepower – I didn’t try to choose that picture 100% accurately…I was just looking for some images that showed some sort of comparative difference.
Still, none the less, GREAT observation. Thanks for commenting.
[…] In an interview of Jamie Joyce, manager of R&D at Doug Thorley Headers, Joyce mentions that short-tube headers can reduce low-end torque (depending on design). If a header design isn’t tested carefully it can change your […]