Hilux V6 with Tacoma Headers and tuned length Y pipe

Turbo, Manifolds, Exhaust, Intercooler, Internals etc

Re: Hilux V6 with Tacoma Headers and tuned length Y pipe

Postby Gulfstream8 on Sun, 18 Jul 2021 6:30 +0000

Hello 1GR-FE community

Just thought I would share a great document from Burns Stainless in the USA on Exhaust Header Theory and Proper Exhaust Tuning… These guys are highly respected in the industry, from drag racing to NASCAR to Indycar to Supercars.

The below will show you just how complex it is to design a decent exhaust system. It also shows just how critical the diameter and primary length are to a header or extractor then into the secondary’s or collectors - then if its a ‘V’ configuration engine there is the issue of the ‘Y’ pipe or in some instances the ‘X’ pipe. All components in an exhaust system are critical to sound and performance.

It is extremely difficult in a modern engine to improve on the factory exhaust - if at all.. Be aware that people will happily sell you products that you don’t need or that don’t work - Hyclone anyone? That’s why I say in our application of the 1GR-FE V6 that if you cannot afford to do what I have done, you could be wasting money.

There are so many people who don’t understand engineering principles, but will get on forums or be mates and tell you “massive exhaust mate”, “long tube extractors mate”, “shove a broomstick though the cats mate’, “you need back pressure mate”, “you got too much back pressure mate”, “you need air vortices mate” - but let me tell you, the Dyno doesn’t lie…

At lot of aftermarket extractors and exhaust systems are built by people who don’t have any engineering understanding, a lot are not tuned length and almost all are too big. They just want to sell product - if you still want to do it; well get the shop to sign a 100% money back contract including labour that if their exhaust does not produce the power they have suggested on your nominated before and after Dino results; you get your money back and your vehicle returned to its original condition… Enjoy the below

Exhaust Header Theory and Proper Exhaust Tuning

ExhaustVincent vince@burnsstainless.comSep 20, 2018

In order to explain the effect of exhaust tuning on performance, let’s take a quick look at the 4-stroke engine cycle. The first step in the 4-stroke process is the intake stroke. With the intake valve open, the piston travels down the cylinder pulling a fresh air and fuel mixture into the cylinder (intake stroke). When the piston nears bottom dead center, the intake valve closes and the cylinder travels up the cylinder compressing the air/fuel charge (compression stroke). With the piston at the top of the stroke, the spark plug fires and ignites the compressed mixture causing essentially a closed explosion. The pressure of the ignited fuel pushes the piston down the cylinder transferring power to the piston, rod and finally the crankshaft (power stroke). After bottom dead center, the exhaust valve opens and the piston is pushed up the cylinder forcing the exhaust gases out the exhaust port and manifold (exhaust stroke).


As the exhaust valve opens, the relatively high cylinder pressure (70 – 90 psi), initiates exhaust blowdown and a large pressure wave travels down the exhaust pipe. As the valve continues to open, the exhaust gases begin flowing through the valve seat. The exhaust gases flow at an average speed of over 350 ft/sec, while the pressure wave travels at the speed of sound of around 1,700 ft/sec.

As one can see, there are two main phenomenon occurring in the exhaust, gas particle flow and pressure wave propagation. The objective of the exhaust is to remove as many gas particles as possible during the exhaust stroke. The proper handling of the pressure waves in the exhaust can help us to this end, and even help us “supercharge” the engine.


As the exhaust pressure wave arrives at the end of the exhaust pipe, part of the wave is reflected back towards the cylinder as a negative pressure (or vacuum) wave. This negative wave, if timed properly to arrive at the cylinder during the overlap period can help scavenge the residual exhaust gases in the cylinder and also can initiate the flow of intake charge into the cylinder. Since the pressure waves travel at near the speed of sound, the timing of the negative wave can be controlled by the primary pipe length for a particular rpm.


The strength of the wave reflection is based on the area change compared to the area of the originating pipe. A large area change such as the end of a pipe will produce a strong reflection, whereas a smaller area change, as occurs in a collector, will produce a less-strong wave. A 2-1 collector will have a smaller area change than a 4-1 collector producing a weaker pressure wave. Also, a merge collector will have a smaller area change than a standard formed collector producing a weaker wave.


So, the trick to proper exhaust tuning is to tune an exhaust system is produce a negative wave of the proper strength timed to occur at cylinder overlap. Various exhaust designs have evolved over the years from theory, but the majority are still being built from ‘cut & try’ experimenting. Only lately have computer programs like the Burns X-design or high end engine simulation programs been able to help in this process. Practical tools like adjustable length primary pipes and our B-TEC and DynoSYS adjustable collectors allow quicker design changes on the dyno or in the car. When considering a header design, the following points need to be considered:

1) Header primary pipe diameter (also whether constant size or stepped pipes).
2) Primary pipe overall length.
3) Collector package including the number of pipes per collector and the outlet sizing.
4) Megaphone/tailpipe package.
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Re: Hilux V6 with Tacoma Headers and tuned length Y pipe

Postby Gulfstream8 on Sun, 18 Jul 2021 7:13 +0000

Sideways wrote:Yep, I've got the long tube Hurricanes and their 3" system on my TRD. Wish I'd never put it on :cry:
It DOES produce more up top but drones badly on the highway and has lost torque down low, not to mention the check engine light coming on due to the O2 sensors.......
Has anyone resolved this issue with the O2's? Upon advice from Hurricane, I fitted the 90 degree spacers but to no improvement. The light came back on after a day and of course fuel consumption has increased because of the sensor reading.


Hi Sideways - Just wanted to say a big thank you for your honest feedback and experience with ‘Long Tube’ headers and an untuned exhaust…

I had a similar experience with a similar system and its the reason why I embarked on this journey. I will never forget handing over my hard earned cash, than driving out of the shop and straight away I could feel how much slower the vehicle was; and not to mention how horrible it sounded - it sounded like a fart…

Fortunately I made a deal that if I Dyno it before and after and if the results were not satisfactory I would get my money back. The Dyno results were very telling, with a substantial drop in power and torque under 3,000rpm - right where you need it the most.

So obviously the Long Tube headers and exhaust was removed and the original Hilux system re-installed. It took a lot of research, but in the end the 2009 to 2011 Tacoma headers with tuned length exhaust and Borla mufflers made a massive difference to sound, power and torque.

Cheers

Cheers
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Re: Hilux V6 with Tacoma Headers and tuned length Y pipe

Postby SaS.555 on Fri, 21 Jan 2022 6:09 +0000

Gulfstream8 wrote:
robe0455 wrote:
Gulfstream8 wrote:Tacoma 2009-2011 Header with tuned Y pipe onto Hilux, Prado 1GR-FE 4.0 V6
The above exhaust system works because a lot of engineering calculations went into getting the pipe work size and length correct for the engine displacement and the RPM range that it operates in.


Just wondering with regard to this, whether the calculations would be different for a 2014 FJ? Obviously the newer Dual VVTI engine. Also assuming that the exhaust manifolds would be the same as your upgraded units? Have you retained the rear cats or have they been replaced with the y-pipe?

Trying to piece together the best way to go, and your post has been the most insightful I have seen with regard to the 1GR.

Cheers!


Hello

The FJ already has the better exhaust manifolds, so please keep them! For others reading this - the Dual VVTi manifolds will not fit the standard 1GR! Getting back to the FJ - as it's still a 4.0lt with similar powerbands you can copy my exhaust installation for better results! BTW standard cats are in place! Also to achieve maximum results out of the exhaust you will need the TRD CAI

Cheers

Gulfstream8


Hello.
First of all I’d really like to appreciate your effort for such extensive knowledge and research on 1GR and it’s mods. Your forum is the only one where i got to know so much about the exhaust and it’s engineering.

I’d like your guidance. I own Hilux 4000SL which is TRD supercharged from factory. I’ve been planning to upgrade the exhaust from quite sometime for performance, exhaust note and fuel economy as my current fuel economy is at its worst although its mechanically perfect and all the required maintenance is done, maybe because my running is mostly within city. Anyhow, would you please guide me the exact dimensions if i want to de-cat and free flow? Where i live, there aren’t many experts here so I’ll need the exact dimensions and the design to guide them. Everything is stock other than it’s factory supercharged and your thread is the only relevant forum where i could gain some knowledge and hoping i can get some relevant response.

Hoping to hear back from you soon!
Thanks in advance!!
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Re: Hilux V6 with Tacoma Headers and tuned length Y pipe

Postby Sideways on Sun, 03 Apr 2022 11:29 +0000

Hi all,

Resurrecting an old topic (haven't been on here forever) but my TRD is going as strong as ever, now with 240k on the clock. Now been around Oz twice, including many of the 'iconics' - Simpson, Tanami, Gibb River, Baledonia etc etc.
I can't really bear to part with it - there's still nothing on the market that goes as hard to replace it with (yet).

The 3" exhaust as mentioned years ago, was a noisy mistake but we solved the check engine light issue - it was the in-tank fuel pump of all things. This is something all owners should be aware of as it's happened to 3 other Hilux owners I know. The long range tank ingested dust past the roll-over breather that hadn't been installed properly. This resulted in the initial low speed rate on the fuel pump starving the engine - as the rpm's lifted, the pump then 'caught up'.
We cleaned the tank, fitted a new genuine Denso pump and fixed the rubber bung, zero issues with the car in 100k+ of driving.
FYI, the 3" exhaust, TRD Tacoma CAI and 4" Stainless snorkel collectively added around 15kwatw - probably more but we've gone up another tyre size which sucked a bit out of it.
Cheers, S
Good drivers have dead bugs on the side windows..........
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Re: Hilux V6 with Tacoma Headers and tuned length Y pipe

Postby Gulfstream8 on Mon, 12 Sep 2022 3:37 +0000

Sideways wrote:Hi all,

Resurrecting an old topic (haven't been on here forever) but my TRD is going as strong as ever, now with 240k on the clock. Now been around Oz twice, including many of the 'iconics' - Simpson, Tanami, Gibb River, Baledonia etc etc.
I can't really bear to part with it - there's still nothing on the market that goes as hard to replace it with (yet).

The 3" exhaust as mentioned years ago, was a noisy mistake but we solved the check engine light issue - it was the in-tank fuel pump of all things. This is something all owners should be aware of as it's happened to 3 other Hilux owners I know. The long range tank ingested dust past the roll-over breather that hadn't been installed properly. This resulted in the initial low speed rate on the fuel pump starving the engine - as the rpm's lifted, the pump then 'caught up'.
We cleaned the tank, fitted a new genuine Denso pump and fixed the rubber bung, zero issues with the car in 100k+ of driving.
FYI, the 3" exhaust, TRD Tacoma CAI and 4" Stainless snorkel collectively added around 15kwatw - probably more but we've gone up another tyre size which sucked a bit out of it.
Cheers, S


Wow, around Oz twice - that's awesome mate ... Yes I still have mine and I'm in a similar situation where IMHO I haven't really found anything that drives as well, or drives better to the point I'm willing to part with it. Very happy to hear yours is still going strong.
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