I’ve seen numerous companies advertising beneficial fuel economy with aftermarket exhausts. Is this true? Or even possible? I’m currently averaging 13mpg. Even adding 1mpg would make an aftermarket system worthwhile over the long run.
Marketing claims. It was much easier in the past to get improvements with low hanging fruit from intake/exhaust add-ons. Volumetric efficiency of the engine as intended by Mr. T as a system will almost always be better than anything available from aftermarket vendors. Some back pressure is a good thing, just opening up the exhaust will not magically increase power and or MPG. In fact it may hurt.
A couple of years ago someone on this forum had their LC used by a vendor to fabricate an exhaust system. I don't recall how it turned out, but that might have some useful info if you can find the thread.
You may pick up some power if it is a very well designed exhaust. But you won't pick up any noticeable MPG with an aftermarket exhaust on these trucks.
No different than cold air intakes, special air filters, etc. Given fuel economy's importance, if Toyota didn't implement such a simple solution anything these vendors come up with won't improve it either.
The Kooks headers and their one-off catback did add grunt and amazing sounds but we never could dyno it properly prior....and my post dyno runs were at 104 degrees and we still broke a pair of straps ..... but the numbers were not great. I think they never brought the headers to the US market but sell them in middle east....
as for MPG....... probably dropped 10-20 percent just due to the lovely sound it made revving thru the RPM's.....
