CAI, catbacks, and other bolt on mods

Why would a manufacturer skip something like a cold air intake and miss out on the (AEM claims) of 8 or 9 HP and a good serving of torque? For $200.00, this simple mod can't be beat.

Performance chips are another mystery. This is software to control timing, right? It flat out says the after market crowd is better at tuning a car than the manufacturer. Aftermarket claims zero drawbacks to the chip (cels or wear and tear). So why didn't the manufacturer do it right themselves?

I'm a total novice at this. Beyond changing a blown gasket and oil changes, I haven't worked on cars much. The CAI would be my first mod. Real gains in performance or just wishful thinking?

It'd be for a Mazda3 by the way. (No software yet for the timing that I know of, but I'm still curious about the chips)

Reply to
Caden
Loading thread data ...

Invest in some before/after dyno runs. If you live in CA, make sure you get one that's CARB-certified; I know someone that put a cheap CAI in his car and pulled over for his loud (Uncle Ben) muffler and then cited for the non-CARB CAI. Cost $200 and a trip to the test-only station for the ticket.

What's the mystery? A manufacturer tunes a car to provide the best combination of reliability, economy, driveability, performance and emissions compliance. An aftermarket tuner can maximize top-end power at the expense of torque, so on. The same tuning that a performance enthusiast likes might not be acceptable by an mainstream driver.

I suspect much closer to the latter.

Dana

Reply to
Dana Myers

Also gasoline of variable quality, a wide range of elevation and temperature, and normal engine production tolerances. If manufacturers programmed their ECUs too close to the edge (i.e., for ideal conditions), warranty claims would eat them alive. As for aftermarket foam or gauze filters, every one of them passes more dirt than a stock paper cartridge; on a stock Miata, airflow restriction is not an issue, so they offer no benefit at all.

Bear in mind that most aftermarket power claims are valid only in their dreams. Dunno about the 3, but there's essentially nothing to be gained from chipping a stock Miata engine, and the best CAI for NA models dynos at a 5 hp increase. A CAI's job is to prevent *loss* of power in hot weather, not to change the torque curve.

If you adopt the attitude that everything advertised in a riceboy magazine or listed on eBay is a piece of crap and a waste of money, you won't go too far wrong.

Reply to
Lanny Chambers

Whew! I was afraid you were going to say that stuff advertised on late-night infomercials was crap.

formatting link

Reply to
Grant Edwards

A manufacturer aims the car at the "lowest common denominator" buyer, which means keeping it simple. Also, they want to keep warranty work at a minimum, and, over thousands of cars, boosting performance will have an effect on parts life that they don't want to deal with.

I've done cat-backs, CAI and other bolt on mods and found them not worth the money (unless all you want is a different look or sound). Increased HP claims are measured at the peak, not the RPM range where most of us drive. An 8 HP gain at 5500 RPM might only be 3-4 HP at 4000 RPM - hardly noticable.

My $.02 is that a supercharger or turbo is the only way to make a noticable improvement in HP. Fooling with CAIs, exahust, cam timing and chips can be fun, but ends up costing a lot with a minimal gain.

Reply to
Randy Maheux

No need, Grant. Anyone who owns a Miata is smart enough that he already knows that. :-)

Reply to
Lanny Chambers

Yes, this device is certainly not junk. If you look at the stock Chevy 454 data, at 2,000 rpm, torque increases from 402 to 414, but horsepower stays exactly the same. Physics says it cannot be done, but this device does it!!

If you are one of those nasty cynical persons, and wonder whether physics really can proved to be wrong by a putting a plastic obstruction in the intake of a car, you are out of luck. This was measured by an *INDEPENDENT* testing lab!!

For a mere $53.95, you can show three centuries of basic physics dead wrong! It is a bargain!!

Leon

Reply to
Leon van Dommelen

And with mileage increases up to 28%!

But it's not plastic, it's a nice shiney _metal_ obstruction. I'm sure that's the secret: it probably has something to do with ions. Scam artists _love_ ions.

It certainly is -- what's the Nobel prize these days? About a million USD isn't it?

Reply to
Grant Edwards

Send this AEM guy right over with the detailed evidence for his claims. :)

Actually, manufacturers *deliberately* preheat the intake air to be able to optimize the engine for a single intake air temperature. The preheating is done by adding selected amounts of warm air from the exhaust area to the other intake air.

The following quote is from the 5th edition of Bosch "Automotive Handbook" as published by SAE:

"In addition to filtering the air, passenger-car air filters preheat the intake air and regulate its temperature, as well as dampening the air intake noise. Intake-air temperature regulation is important for the operation of the vehicle and for the composition of the exhaust gases. [...] The constant regulated air intake temperature improves engine performance and fuel consumption, and decreases the percentage of pollutants in the exhaust gases as a result of better fuel management and distribution of the air-fuel mixture."

Of course, this does not need to mean that a specific *single* measure such as maximum hp might not improve a bit by piping in cold air where the engine expects warmer, in specific conditions, (eg, when the car is sitting with the hood up in a dyno testing stand, thwarting the intake's temperature management by letting the hotter exhaust air escape.)

I just want to see the AEM guy to establish how the measurements were done, and how repeatable they were (if they *were* repeated.)

I will beat the mod for $200. Just send $200 and the mod right over and I will have my hammer ready. ;)

Maybe, just maybe, they think they *are* doing it right?? Modern cars are very highly optimized, so any aftermarket stuff is likely to make things worse, even if they try to optimize other items (eg power at the expense of pollution.) This is especially likely if the chip is not specific to the particular car model and model year it is used on. For example, chip mods on Miatas are well accepted to be worthless.

I have an aftermarket ECU on my Miata, but only since I also have an aftermarket supercharger on it. So OEM optimization is nonexistent.

Leon

Reply to
Leon van Dommelen

Gee, I wish I'd written that.

This one goes into the Archives, just to refute anyone who says our resident rocket scientist doesn't have an overt sense of humor.

Reply to
Lanny Chambers

Because most buyers don't find intake howl appealing.

I don't know about this specific unit, but many "cold" air intakes take their air in near the exhaust manifold's heat, while eliminating the plumbing the factory put in to take in the air from somewhere farther away where the air is cooler.

Because manufacturers have to meet emissions standards, don't want to require premium gas and have to warranty the car.

Reply to
Natman

Absolutely. You could buy this thing, get the Nobel price, and come out ahead $999,946.05 and, as you say, a nice shiny piece of metal that can be used as an ornament on the hood of your Miata if you engrave it "New ton is Old not".

Leon

Reply to
Leon van Dommelen

I dunno. This Wednesday I went to Infineon Raceway for the Wednesday night drags in my (currently) bone-stock 2002 SE. My pal Jeff took his '96 Civic EX with coffee-can cat-back and CAI. Neither one of us is very experienced at drag racing and our times consistently improved, but my times were generally 1.5 seconds faster than his.

Dana

Reply to
Dana Myers

Just wait 'till he puts on "Type R" and "V-Tec" stickers and completely shuts you down!

Reply to
Grant Edwards

LOL!! I'm surprised he still hangs out with me after the hassle I've given him along those lines...

Reply to
Dana Myers

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.