How necessary is a new intake?

[OCS12]

Seems to me, the only 'true' CAI is a drop in filter and adding the Velossa Tech big mouth, which is about half the price of every other intake available for our car.

I think that, and maybe replacing the induction hose from the air box back, pretty much maxes you out. The rest is eye candy.

 

[Original J-Pat]

Seems no one can get the Velossa big mouth to fit, maybe I'll wait until they fix it.

 

[Turbo65]

Seems no one can get the Velossa big mouth to fit, maybe I'll wait until they fix it.

Mine fits fine, just follow the instructions

 

[Siestarider]

The traditional method of evaluating intakes is to measure pressure drop at each major component. It is easy with a manometer and small diameter probe, you place probe perpendicular to air flow, measuring from first inlet to last throttle body, add up all the pressure drops to total restriction, change out the most restrictive parts, etc. Seal the probe holes back up.

Modern cars (since 2000) are pretty efficient and do not offer the same intake improvement options that older cars did. Turbos add another level of complexity.

The 2J intake has proven some hp gains. Pressure advantage is part of it, short, bigger, round intake pipe with two 90's is another.

We can easily log lbs/min air flow through turbine with AP. My logged highest stock turbo #'s approach 25 lbs/min. At sea level assuming 100 F air temp, air volume is about 14 cf/lb. So 25lbs/min x 14cf/lb =350 cfm at 6500 rpm. With air flow we can calculate pressure losses.

If I knew more about HVAC I would calculate the pressure loss in our intake system, we can measure cross-sections at different points in the intake system and there are tables for pressure loss/area by velocity.

My suspicion is that our stock intake does not loose much. Putting an air scoop in front of the stock intake seems like it should help. But so does opening up the grille to "let more air" into the radiator. Regarding the latter, I did a bunch of calcs reported in aero mods and cooling. I had to conclude our stock grille opening is fine. Pressure drop across the cooling system is what matters, not how big the opening is (as long as the opening is no smaller than about 1/3 of diffusion area behind radiator system).

 

[BiigMe]

We can easily log lbs/min air flow through turbine with AP. My logged highest stock turbo #'s approach 25 lbs/min. At sea level assuming 100 F air temp, air volume is about 14 cf/lb. So 25lbs/min x 14cf/lb =350 cfm at 6500 rpm. With air flow we can calculate pressure losses.

If I knew more about HVAC I would calculate the pressure loss in our intake system, we can measure cross-sections at different points in the intake system and there are tables for pressure loss/area by velocity.

My suspicion is that our stock intake does not loose much. Putting an air scoop in front of the stock intake seems like it should help. But so does opening up the grille to "let more air" into the radiator. Regarding the latter, I did a bunch of calcs reported in aero mods and cooling. I had to conclude our stock grille opening is fine. Pressure drop across the cooling system is what matters, not how big the opening is (as long as the opening is no smaller than about 1/3 of diffusion area behind radiator system).

As far as head loss in our intake system I really don't think its much. The only real place where we would get significant head loss would be the stock intake tube, just because its not completely smooth but you could still replace that with a silicone hose. And as far as friction in the tube goes, those accordion looking sections would only really trap air and create a boundary layer I think, which would reduce friction- but also reduce the cross section. So as far as I can make out the only real hindrance on air flow other than the stock filter is the hose- and by a fairly negligible amount.

I agree that the stock intake is fine, but the reasoning behind the Big Mouth is to change the location of the air pulled into the intake. Stock intake pulls hot air from above the radiator and in the engine compartment. The Big mouth is basically more piping that puts the intake location in front of the radiator, and outside of the engine bay so it gets colder and more dense air. And as it has the same cross section as our stock ram intake the head loss is negligible as well.

From my perspective its not so much designed to improve air flow, but to reduce intake air temperature. My only problems with pulling the trigger on one, is how much more efficient is it than just using the stock intake and say a 2in elbow in the same location. If I can open up the shroud and make a hole with small amounts of piping, then wouldn't it nearly be the same? Comparing that; the Big Mouth forces the stock box to only pull air from outside the car, in front of the radiator. With my idea, the box is pulling air from the same location, that location also happens to have a direct inlet from the outside air, which is also in front of the radiator. I just want to know if the efficiency of the Big Mouth is worth the extra cost over doing something myself.

 

[Siestarider]

My understanding of the stock intake is that it mounts to shroud above and exterior to radiator, so intake should see the same air the radiator does when car is moving. Of course my main interest is 80 mph and up, for tracking.

When stationary, my fan runs, so I am assuming even stationary, stock intake location is not much affected by radiator heat.

 

[Bluedrank]

Mine fits fine, just follow the instructions

Uhh, mine fit fine. You cut the shroud like the instructions say, and a simple heatgun to the top shroud can help mold it down a bit if you want it flush like stock.

 

[BiigMe]

My understanding of the stock intake is that it mounts to shroud above and exterior to radiator, so intake should see the same air the radiator does when car is moving. Of course my main interest is 80 mph and up, for tracking.

When stationary, my fan runs, so I am assuming even stationary, stock intake location is not much affected by radiator heat.

That's what I'm thinking. I'd just love to be able to test the intake temperatures of the Big Mouth against a DIY snorkel through the shroud. A snorkel would be a 1/10th of the price, and the only change would be opening up the shroud then you get colder outside air but other than that there is no real change.