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. Continue reading

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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.

Continue reading

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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. Continue reading

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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.

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.

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Posted in Braking & Handling | 1 Comment

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. Continue reading

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Don’t Block or Remove the EGR Valve, It’s Saving You Money

Typical Older EGR Valve

The EGR Valve (Exhaust Gas Recirculation) valve is found on almost all modern engines and is considered part of the emissions package of your vehicle. In some states, removing it will cause you to fail your emissions inspection. Unfortunately, there is a huge misunderstanding about it's function circulating around the internet and sadly a lot of folks have actually removed it in the search for "free power."

The EGR valve is not simply about re-burning exhaust gasses to try to clean up the emissions. In fact, it's more about saving fuel and as a side effect, reducing emissions. Continue reading

Posted in Engine, Fuel Economy | 1 Comment

Restoring Faded Plastic Trim with Back-to-Black

The foreground shows the "after" while the background shows the "before"

Oxidized plastic and rubber really shows the age of a car. Want to help make your old car look new off the show room floor? No amount of polish and cleaning will do it if the unpainted black plastic surfaces and rubber moldings look nearly white from UV exposure.

Project Lexus' cowl area was starting to look pretty rough after 10 years of sun exposure and the rubber weather sealing strips could use some help as well. So I wanted to share with you this quick detailing tip and share my results.

Mothers back-to-black is a product that restores black rubber and plastic surfaces to their original black color with pretty amazing results. While it's not a permanent fix, it does last a long time and the results are certainly worth it. You could buy new panels, but aside from the expense, they'll eventually wind up the same way as well so it's easier to simply treat with back-to-black occasionally. Continue reading

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Tech Tips: Save Gas, Find an Oil Leak, Stuck Bolts, Brake Flushing, Sticker Removal

Tech Tip Monkey

Tech Tip Monkey

Today I'm sharing 5 little tech tips that don't necessarily warrant their own article but are really useful to know anyway.

The first tip is how to find the source of an oil leak using foot powder. Clean the area where an oil leak is suspected really well, then spray the area with a generous coating of foot powder. Then run the engine for a few minutes and you'll easily be able to see the source of the oil leak by the presence of a nice dark stain in the powder. (Thanks to Matthew Crawford). Continue reading

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