No tune intakes

I've seen several cold air intakes that offer both a tune required and no tune required versions of seemingly the same product. One particular I forget what it's called has an insert in the intake tube that makes the area around the MAF the same diameter as stock, while the rest of the tube is the same size (and I assume bigger than stock).

So what makes that particular setup not need a tune? Does a certain area around the MAF itself have to be the same diameter as stock and thus the OEM tune is fine? What about the rest of the intake tube diameter?

MAF reads airflow across the sensor and the sensors are programmed for the tube diameter. so if you use the same MAF sensor but enlarge the tube diameter its going to add fuel wrong becuase the amount of incoming air has changed which is why you need a tune.

So is there a set distance pre and post MAF that the tube has to be the same diameter as stock? Or does the whole tube have to be the same diameter for it to work?

basically just where the sensor is because the sensor is set for the tube diameter and reads how fast the airflow is across it and then adds fuel to match. basically with the bigger tube and the insert (no tune required) the airflow across the sensor is much faster allowing more fuel to be added

kluke15 said:

basically just where the sensor is because the sensor is set for the tube diameter and reads how fast the airflow is across it and then adds fuel to match. basically with the bigger tube and the insert (no tune required) the airflow across the sensor is much faster allowing more fuel to be added

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Actually the flow rate is the same unless it is altered by the tuner to commend higher air fuel ratio. However, according to reputable tuners best performance is achieved for a specific lambda on specific fuels, for example 0.83-0.84 on 93 octane on wot. What the tube diameter does is change the velocity of the flow and alter the pressure drop across the intake tubing. Without changing the intake manifold or force induction, the change in actual flowrate is pretty slim!

PMAS actually gives you a recalibrated MAF which is scaled to the size of their intake, so the car thinks its stock.

pmas would be the best non tune intake

Go for the Steeda CAI. Can run the stock time or down road if you want more flow...remove the restrictor & add a tune. Best of both worlds. Plus, IMHO...the best looking CAI out there.

B-52 Jetman said:

Go for the Steeda CAI. Can run the stock time or down road if you want more flow...remove the restrictor & add a tune. Best of both worlds. Plus, IMHO...the best looking CAI out there.

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Next to the Roush, which looks 300 times more OEM with the same flexibility.

PMAS FTW. http://www.lethalperformance.com/pmas-2015-2016-mustang-gt-velocity-air-intake-system-no-tune-required.html