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Old 02-11-2013, 10:22 PM   #40 (permalink)
Tesla
Master EcoModder
 
Join Date: Feb 2012
Location: Australia
Posts: 355

The Truck - '02 Nissan GU Patrol ST
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Had a look at it,
No doubt that it is more of an info-mertial, but that doesn't mean there is no valid information there.

Ever since the world was privatised nearly every scientific paper you read has an agenda and is trying to sell something.

Their testing methods were poor, but there is enough info out there that suggests that in the right hands and on the right vehicle performance modifications can result in improved fuel economy.

That's not to say every performance mod will, but the right ones can.

My main criticism was that there was no refuting the actual claim of improved economy, just the method in which the claim was made.

With my vehicle being a turbo diesel, any improvements in flow directly translate to improved FE, this is a simple factor of the turbo itself being the biggest restriction, although I think even NA diesels benefit as well by reducing restrictions.

Even with gas engines I believe fuel economy can be improved by improving flow, pumping losses can be reduced even at part throttle by a properly designed intake and exhaust system.
It's not all about the size of a pipe and just because you are not running at WOT, doesn't mean your intake and exhaust is performing ideally. I think that's the part that get's me most often is when people declare that as an ecomodder you aren't running full bore, therefore your exhaust and intake can't really be improved and then there is the simple assumption if a bigger exhaust is for performance at WOT then a smaller more restrictive exhaust must automatically give better economy.

Does this tell someone how to go about exhaust improvements, if I was a newbie and wasn't aware of how complex exhaust matching is I'd be inclined to go home and put a 1/2" pipe on my exhaust manifold with the expectation of getting 100mpg.

It takes a bit longer, but better to tell them that with current offerings you will probably get best economy from the OEM design, but there is a possibility of improving on this though it will require you to do a lot of research and become a semi expert on the topic, anyway enough of that.
Appologies to anyone who took my comments personally.
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