I have a 2005 Nissan Titan King Cab off road package. Needless to say I make my contribution to the oil companies. Trade in values are terrible so I have been thinking about how I can increase fuel effeciency. Someone told me that true dual exhaust systems and something like a cold fusion chip increase gas mileage. Can anyone comment on the reality of this helping out. Are the dual headers difficult to install for a DIYer. I’ve done brake pads and rotors before and other minor repairs but not on this vehicle.
Don’t expect a big increase in fuel efficiency with dual exhausts, unless your stock system is so totally clogged that anything would be better. Ditto with high flow air cleaners. When you are cruising down the highway at legal speeds, the biggest restriction to air flow is not your stock exhaust or air cleaner, it is the throttle that is just barely cracked open. How do you fix that? Well if you simply open the throttle more, you go too fast and that makes the engine burn even more fuel. Higher gearing is one option, at lower rpms, the engine needs to make more torque to make the same power and that means the cylinders have to fill up more which means less throttle restriction.
Another driving tactic used by many people who set gas mileage records is to run the engine for a short pulse at nearly full throttle and then coast for a while and then repeat. An engine that is making 120 horsepower for 10 seconds and then rests making zero horsepower for 90 seconds is making an average of 12 horsepower with nearly the same efficiency that it can make 120 horsepower continuously although there is some idle fuel consumption if the engine is not switched off during the coast. This should be left to the pros however.
Something as new as that probably won’t benefit from an aftermarket exhaust. Once the manufacturers realized that flow efficiency was key to power AND mpg, they built it in to all the OE systems. Both intake and exhaust are already maximized these days.
Have you done a cost-benefit analysis of adding dual exhaust. It’s been my experience that modding late model imported iron like this gets pricey.
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If this vehicle is going off roading, I’d be leery about changing the gearing. Make sure you’ll have adequate torque to get unstuck!
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Please don’t encourage anyone to do that stupid “gun it and coast” business. There’s a bozo near here that does that in the middle of the night, and at full throttle the truck is extremely loud. And don’t forget that if the engine has a carburetor, the accelerator pump enriching the mix could well eat up any savings. Even with EFI, I doubt there will be much improvement. Be careful about confusing steady-state operating conditions with unsteady-state (transient) conditions.
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All in all, it’s doubtful that there is anything the OP could bolt on to improve mileage all that much. Just take it easy, keep the tires inflated (oops, the republicans are going to ridicule me now), keep everything tuned up, and don’t carry unneeded cargo.
I don’t know a thing about a chip called cold fusion, but it sure sounds like a SCAM. As for the exhaust, it could well have made a noticeable change in a 1965 car, but it is not going to make any real change in a 2005
Lean to drive for mileage and that is likely going to save you far more and cost nothing. Just go easy on the peddle on the right and try to avoid THE NEED for using the brakes by slowing down early for stop signs etc.
Thanks everyone. I figured the chip was another scam but the dual exhaust marketing made sense with letting the engine breathe. I expect that the comment that late models are already close to max on effeciency it right on the money.
I’ll keep to my current attempts to keep under 2k rpm.