Exhaust System Upgrades

I was checking out TRD parts and accessories, and I came across the TRD headers and Borla exhaust. I've seen a lot of you guys with upgraded exhaust systems. If I'm going for the HP gain and mileage gain, then wouldn't it make sense to upgrade the headers? Is there any sense in upgrading the muffler if I don't upgrade the headers?

My thought is that the factory exhaust manifold is more restrictive than any muffler would be, even the factory muffler. Any thoughts on this?

 

Do you have a link to the TRD headers and Borla exhaust? I have yet to hear of TRD headers, would be interested to find out more about them. Thanks in advance

 

Sorry, they aren't TRD headers. They're Doug Thorley headers.

 

Here's a Dyno Sheet of the HP gains just by adding the headers. Any thoughts?

 

Looks to me like the stock manifolds flow pretty well if you're only picking up 7hp/5tq. That's why I haven't even considered them.

 

What's the HP gain with the TRD Borla (or any other for that matter) exhaust set up?

 

Let me restate that last question. What is the HP gain with just a new muffler? With out any other mods to the exhaust system.

 

That depends on the muffler, but i bet you could gain up to 15 horsepower. Headers will only benefit if you do intake mods, if you want to run a basically stock engine with an air filter mod, then dollar for dollar a free flowing muffler is the best bet. I would say that the flowmaster would produce a very good power gain.

 

TRD told me that they have ported and polished headers on the Taco.

 

honestly.....i doubt you will see considerable gains with just a muffler.

 

That was the whole reason I started this post. I hear a lot of guys saying that they see gains with just a muffler replacement... I would figure there wouldn't be much, unless you changed out the headers and the intake as well.

 

yep.....and i didnt get my flowmaster thinking i was gonna gain alotta hp......it was all for the sound. i figure with a truly free flowing muffler....the max is gonna be minimal......maybe 2 or so hp, not enough to tell.........unless its butt-dyno that you are after.

 

Side note. When I was just out of high school, just before I went to college, I worked for a Ford dealership doing oil changes, tire installs and rotations, and PDI inspections. Anyway, the 2000 Cobras were way underpowered, I can't remember if there was a falsely advertised HP or if they just wanted to give it more. There was a recall in which they changed out the intake manifold for one that was polished, therefore, more air passed through, more smoothly. It was suppose to add a couple dozen HP. I wonder what it would take to do the same with the Taco.

 

yeah.....not alot on these trucks you can do for airflow.....better filter(or a good intake), headers.......maybe hi-flow cats and exhaust....to get the air in and out quicker. something that would help with everything....mileage and power, would probably be the urd maf calibrator.

 

What they said was in relation to installing the SC. The heads are ported and polished. It is a bolt on for headers.

 

I can`t find the remark on the intake manifold. You can ask them yourself. Or take my word for it.

Thank you for your interest in TRD COL.. For more low end torque, we recommend the TRD supercharger for the Toyota 4.0L engine, Toyota/TRD part numbers PTR29-35070, main assembly, and PTR29-35072, Tacoma fit kit. Horsepower gain is 304 SAE hp @ 5400 rpm and Torque gain is 334 SAE ft/lbs @ 3600 rpm. In addition to the supercharger, we recommend the TRD cat-back exhaust system, Toyota/TRD part number PT910-89061. Horsepower gain from the exhaust is 8 to 10 hp. For your reference, the TRD cold air intake or any other intake system isn't compatible with the TRD supercharger.
I need the power at 500 to 1,000 RPM
for my push bars. And dragging trees.
The exhaust valve outlets are ported and polished, thus larger, as I understood them.