Author Archives: Nathan Morris

Performance On a Sip of Fuel

How do you balance performance and fuel economy? What really affects fuel economy and what doesn't matter as much? Does weight loss really help gas mileage, what about an air intake system? When does better performance ALSO mean better gas mileage?

Is there a way to build a fast and fuel efficient car?

All these questions and more were talked about in this Tuner University exclusive class and now you can listen in anytime you like, anywhere you like. In the package you get the full unedited and uncensored recording of the class as it was delivered as well as the 103 companion manual that went along with the class.

Price: $69.95


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Pressure/Flow Loss in Pipe Bends: Better to Go Long or Bend?

The other day I ran across a useful table in a very old and rare book on Air Conditioner design of all things. You may never have thought about it, but air conditioner ducts need to be relatively well flowing as well to minimize the size of the blower needed to get adequate cooling to the final location and in most cases the runs of ducting are VERY long relative to intake or charge piping for a turbo system.

There are several things that add pressure loss (restriction) to any pipe system, for the purposes of this article we'll focus on length and bends. It turns out that bends have the same effect as adding additional length. In other words, if I have two intake ducts that are 5' long but one is straight and the other has a 90 degree bend in it, the one with a 90 degree bend will flow as poorly as a straight pipe with a longer length. (more…)

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The Dirty Secrets of Oil

If you want to know what the best oil to protect your high performance engine is, who better to ask than a guy who has spent 15 years of his life analyzing oil samples from nearly every type and make of engine in existence.

In "The Dirty Secrets of Oil" Ryan Stark of Blackstone Labs and I talke about his work and experience in oil analysis. Oil analysis is imply a series of tests that a lab can do on a sample of oil from your engine to determine how the engine is running, how it's wearing and if the oil itself is performing optimally. During the interview, Ryan shared with us: (more…)

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Modifications that Work Every Time: Engine

I write a lot about modifications that either don't work or work poorly but that's not to say that there aren't a whole slew of tricks that work every time.

In this two part article, I'll explore just a few of the "tricks" and modifications you can use to increase the output of any engine without paying "gimmick tax." Gimmick tax is what you pay when you buy parts or invest in modifications that don't really work or have such small gains that they're hardly worth doing. Let's get started..

Fitting a larger exhaust than factory, always works. The key is not to go too far, but going up one or two pipe sizes will almost without exception produce more power and better overall acceleration. The reason that going to large can hurt you is that the pressure differential between the exhaust and the atmosphere at the end of the tail pipe actually helps the exhaust exit. In other words, some "pressure" (not necessarily back pressure) is good. I recently published a TU Premium exclusive article that gives a chart you can use to find the right pipe size for your exhaust system. (more…)

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Ideal Exhaust Size for Displacement and Power

Size does matter, after all.

Over the years I've compiled data from various sources and personal tests to put together a chart of ideal exhaust pipe diameters. These diameters are of course only a starting point, but in my experience they have been pretty "bang on".

These diameters are specifically for "cat back" exhaust systems and are generally the best compromise between velocity and overall flow. John Grudynski, in an class I did with him for TU Premium members back a few months ago (Available Here: The Secrets of Header & Exhaust Design) talked about how he frequently achieves better results with relatively "small" exhaust systems and how he will occasionally use a "step system" on really radical street and race cars. The chart (a TU Premium exclusive) covers everything from 1.5L to 4.5L or so, both dual and single exhaust diameters, and various power outputs. Use this as a guide, then always test for absolute optimum results.

More information about how to use this chart, inside.

(more…)

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Engine Tuning Secrets: Ben Strader of EFI University

This month I talked to Ben Strader, founder of EFI University and the author of two great books on tuning EFI systems and now also a Tuner University Certified Expert award winner . Ben's company EFI University is one of the top organizations teaching people from every walk of life from hobbyist to OEM engineer how to tune their engine from the ground up.

In this TU Premium class, Ben told us that engine tuning isn't a black art, it's simply a problem solving exercise and anyone with the proper training can do it. At the end of the day, Ben shared, tuning is about maximizing the airflow the engine can already flow and allowing the engine to remain reliable in its intended application. (more…)

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Impreza Not Too impressive: Handling Upgrades

Reader asks how to improve handling of his car without voiding warranty/attracting cops.

Today I'm sharing a reader's question that I thought would resonate with a lot of you.

"Hello,
I have been reading some of these articles and I am very impressed by the information provided.

This is my first all-wheel drive and I have to say, the handling is NOT as good as I thought it would be, especially on wet roads.

I have noticed that if I turn hard into a corner in the wet, the front seems to have a mind of its own and it looses grip. If I back off a bit, if feels like I'm not going to make the corner. I would like to achieve better handling, but I am unsure of the best way to go about this. Looking at the wheels, it seems obvious that there is plenty of room for wider wheels, but after reading your articles, I am reluctant to change the wheels. So, the next thing to consider is better rubber? Suspension improvements? Anything I do to this car, I need to consider that I can not make any changes that disrupt the  warranty conditions and I certainly don't want to risk turning the car into a danger and/or a cop magnet. Any suggestions? -- Peter W.

(more…)

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High Flow Filter Showdown: Factory Air Box vs “High Flow” filters

As most of my readers know, I'm a big proponent of modified factory air boxes rather than expensive intake systems. Not because I'm too cheap to buy an expensive intake system (I've owned many), but because they simply don't work as well. It also helps that modifying your own airbox (or even swapping to a bigger factory one) costs a lot less. Some articles from the past that contain some of the already presented evidence.

Today I was out browsing the interwebs when I came across two Australian guys who have a youtube show where they modify cars in a fairly cheeky way, kind of like Top Gear meets Pimp My Ride or something. None the less, they have added "myth busting" to their show and so they did two great dyno shoot outs to test "cold air intakes" and "pod filters" versus factory air boxes. Needless to say, they found the factory stuff worked very well (the best) in various setups. (more…)

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