January 2014 Question IT

Fixing what you broke

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Got a burning question or simply need some advice with problems you've encountered while wrenching on your current/future projects? Ask our automotive guru Eric Hsu anything-literally, he's going to answer every single question, as long as it's automotive related.

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350Z ECU and Air Intake

I own a '06 350Z and want to install a cold air intake. With the two sensors that control the throttle body, based on readings from the intake, I have a feeling that just installing a cold air intake would be rather moot without ECU tuning. Is there some sort of plug-in chip that will do a "learn as you drive" tuning to the air/fuel mixture? I heard of something called a g-force chip. Is this total bunk or is there actually something out there like that, or I'm going to just have to suck it up and pay for some dyno runs and a professional?

-Frank, via

Some of the intake systems developed by larger companies with true research and development programs, such as AEM Induction or K&N, develop their intakes around the stock mass airflow sensor and ECU. While their intakes do genuinely make power on the dyno just by simply bolting them on, oftentimes a custom tune can extract additional power. Whether or not the costs are worth it is entirely up to the size of your wallet. If you were to add headers and an exhaust system along with an intake system, I would definitely recommend a custom tuning session. Not only will a good tuner be able to make more power and torque, but oftentimes he can make the car drive smoother and get slightly better gas mileage at the same time. Plus since your VQ35DE engine has variable inlet cams, the tuner can tune the cam angles for a broader powerband by taking full advantage of the improved exhaust flow.

When these intakes are developed, the engineers and techs can often increase power by designing the intake system with different sized tubes, filter sizes, tube lengths, velocity stacks, and/or ducting. It can take some time and testing of many different combinations to come up with a combination that makes a healthy power increase while keeping the factory ECU happy. K&N claims a 10.65hp gain with their 57 series intake, which is a pretty healthy increase. And, of course, if you live in a state with emissions testing, it also helps that the K&N intake systems are CARB legal.

Function Over Form?

I've been in heated debate with friends on whether stretching tires is more of a fad or functionality on cars. Obviously the "stance" crowd does this for the sole purpose of fender clearance, but I've seen race cars, like the Zero Sports Subaru STI, slightly stretch their tires for a RevSpeed Evo vs. STI Time Attack that took place a few years back. What are your thoughts on this?

-Anonymous, via

In general, by stretching a sidewall, the tire becomes stiffer and transfers more energy directly to the spring and damper. Depending on the tire's design, this can either be a good or bad thing. On a street car, stretching a tire generally translates into a stiffer and harsher ride. On a race car with race tires, outside of having to retune the suspension, it could be a disastrous thing if the tire was not designed to be stretched. A slight stretch isn't going to hurt much, but stretching a tire into a rubber band probably isn't the wisest thing. A tire's sidewall construction typically only has two plies of polyester cord, whereas the tread section has multiple steel belts, nylon and/or polyester cap plies, sometimes even Kevlar plies, and, of course, at least 1/4 inch of rubber tread. The tread section has much more protection against nails, screws, and other crap sitting on the streets waiting to puncture your tire. Stretching the crap out of a tire will then expose the sidewalls to all of the junk on the road too. Then again, nobody said style was easy. Of course, whether you like the style or not is up to your personal preference.

Mitsubishi Eclipse Love?

Why has the fourth-generation Mitsubishi Eclipse gotten so little aftermarket support? It's very underrated, and earlier models had tons of products for them. I bought mine a year ago and was shocked to find how lacking options are. In many ways, it's superior to the previous models. With the exception of no all-wheel-drive option and being rather heavy, the car delivers 260 hp, offers great gas mileage, has amazing looks, good price, and handles well, which makes for a car that deserves more attention. There's a growing underground community of owners dedicated to these cars, so what gives?

-Jeremy Richards, via

What gives is that the V-6 is hard to work on, expensive to modify, and heavy with too much weight over the front wheels. The 2.4L version was completely lethargic while attempting to accelerate a 3,500-pound car. Besides, when the V-6 4G Eclipses were new, you could have bought a Subaru Impreza WRX, Mitsubishi Lancer Ralliart, or Mazdaspeed 3 that dusted a 4G Eclipse for the same money. As if these cars didn't already dust a 4G Eclipse of any trim, the simple addition of a COBB Accessport for under $800 would guarantee that the 4G Eclipse could never catch up in any race. Unfortunately for you, that's still true today.

Mitsubishi offered the Ralliarts and Evos as their performance models, while the Eclipse was marketed to normal people who wanted a cushy and comfortable coupe to drive around every day. They succeeded, which is why you now own the big, heavy, coupe that you have today. Naturally, aftermarket companies built performance parts for the sporty models that had larger customer bases. While there are a few intakes, exhausts, and suspension components available from the aftermarket for 4G Eclipses, there isn't going to be much beyond that. If you want to go fast, I'd recommend you start with a platform that was intended to go fast. In the end, you'll spend less and find it more rewarding for the money spent.

Need for Speed

I am looking for a nice import car. It has to be under $20K, fast as sh*t or potential to be fast as sh*t, two-door (or sedan, or hatch, I don't really care), its 0-60 has to be under 5.5 seconds, manual transmission, and, of course, no FWD platform. Perhaps something that's comparable to a WRX STI, Evo, 240SX, or Civic. Any recommendations would help.

-Jason Roy, via

How about a used WRX STI, Evo, built 240SX, or built Civic? You've answered your own question. You could also buy a stock 240SX or Civic for less than $5K and spend $15K building it. Not only would you be able to personalize it, but you could also make it "fast as sh*t".

Transmission Upgrade

I own a '05 Subaru STI that I've been drag racing for over a year. Since then, the car has been through three transmissions and numerous ring-and-pinion sets. If I cryo-treat or shot-peen them, would it improve the reliability and strength or do you suggest going with a set of aftermarket gears? I'd hate to daily drive on a dog box or straight-cut gear setup.

-Mike, via

You must be either making a lot of power or beating the crap out of the transmission, because the STI six-speed is a pretty strong box. You didn't mention how the transmissions and ring-and-pinions are failing, but, in general, cryo and shot-peening are processes that would extend the service life of steel parts. A generic shot-peen is '60s technology so there are much better processes available today.

If you were going well beyond the gear material's capabilities, then you would probably be better off with multiple processes to improve the metal's structure at the molecular level so that the gears stand a chance of living. I would recommend cryo, REM, and then finally WPC. Cryo stabilizes the molecules throughout the entire part, decreases brittleness, and adds a couple points of hardness (HRC scale). REM is an isotropic super-finish that is completed with a series of chemicals and special vibratory media. It removes microscopic peaks and valleys, and finishes the part in what appears to be a dull, polished appearance. WPC is a patented, high-pressure, micro shot-peening process that introduces microscopic dimples to retain lubrication on the face of the parts. Additionally, WPC also increases the surface hardness of the parts. With these three processes, your gears will be as strong as they ever can be using today's commercially available technologies. If your budget is somewhat limited, then I would recommend cryo and WPC. And if you can only afford one, then I would recommend WPC.

Pfizner Performance Gearbox (PPG) makes a 1-4 gear straight-cut, dog engagement gearset that allows you to cruise on the street with the factory helical, synchromesh Fifth and Sixth gears. While you'd still get some whining from the straight-cut gears and the crunching from the dogs, you'd still be able to cruise in peace in Fifth and Sixth gear. PPG starts off with a much stronger alloy to manufacture their gears and parts, but all of the previous processes also still apply to the PPG parts. After you get the transmission to withstand the power, it's likely the next weakest link in the drivetrain will start to fail, which I believe are the tiny R160 rear ring-and-pinion and rear axles.

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