sup ya~ I heard if U install intake it decrease torque and increase horsepower.. is it true?? and which intake ya think best??

 

what i've heard is that there is a loss of lowend torque but i don't think that to be the case.

i installed my AEM Cold Air Intake last week and, if anything, i think i've gained noticeable torque. at wide open throttle from a standing start, i get much more torque steer...the power really comes on.

i really like my AEM though i dont have the Bypass valve (loss of efficiency) because i dont really need it in southern cali. when i step on it, theres this beefy piston churning sound, kinda like a V8 exhaust funny enough. its louder than my exhaust. but under normal driving its not loud though there is this wheezing sucking air sound.

 

First off, torque twists wheels, and twisting wheels make us go!

When it comes to engine breathing in regard to torque and power, you have two opposing situations.

Free breathing is generally a good thing for any internal combustion engine because the cylinder must act as a vacuum pump to pull in the fresh charge. The less forcefully it has to suck air and fuel in, the more "go" power is available to the wheels.

However, you must be aware of what is required to produce power. You need a turbulent flow of the fuel/air mixture to maximize burn in the cylinder. If the flow is laminar (which happens when flow is slow and unhampered), you get a slow burn, and therefore less forceful burn (and less torque). The turbulent flow is caused by restrictions.

This is why two valve (one intake) per cylinder pushrod engines make such stump-pulling torque - at low RPM, the are producing a very turbulent mixture, providing the best possible burn (8.0 L of displacement doesn't hurt either!). This same situation however strangles the engine at high RPM.

This is where 4 valves/cylinder come in. 4 valves (two intake) provides easier breathing at high RPM, and therefore a turblent stage is found higher in the rev range, as the engine begins to reach the limit of air consumption. At low RPM, we have a laminar flow, and low available torque.

Finally, from fizix 101, we know torque is twisting force, horsepower, as the name suggests, is power. Power = Force * Distance. Therefore, power is tourque times RPM (angular distance) with a few conversion factors thrown in.

With this in mind, consider the Honda S2000. If you were to do a zero-60 run in this car, shifting at a sane 3500 rpm, it takes almost 13 SECONDS to hit 60 - all of the 200 horsepower is produced in the higher rpm range, where the engine is also making all of its [limited] torque.

Here is the formula:

P = T * w * 1.904 e-4

P = horsepower (hp) at a given RPM, w
T = Torque (lb*ft) at given RPM, w
w = RPM at which we are evaluating.

The TL-s, producing 232 lb*ft of torque at 3500 RPM is producing 154 hp. At 6100 RPM, and 260 hp, you have 224 lb*ft of torque. This is a pretty good (flat) torque curve.