Any gains to be had going from a 3" air filter and tubing to 3.5" or 4"?

[turbovanman²]

My cone filter is done, its a 3"x6" cone filter, so looking to replace it, is it worth anything to upgrade the pipe and filter diameter? Its currently a short 3" pipe going to a 4" inlet at the turbo.

[bakes]

I would go 4" to the turbo if you could . I have seen 2 turbo motors(non mopars) on a dyno now make up 10whp more from a 3 to 4" swap.
I also think shadow made this upgrade as well and saw improvements

[turbovanman²]

Hmmmmmmmmmmm.

[16valvecharger]

i would make the pipe 4" if the turbo inlet is that size. if the turbo inlet is smaller you will see no gains. Also try to get the air from outside the engine compartment .

[turbovanman²]

Wonder how you can measure if its a restriction?

Also try to get the air from outside the engine compartment .

Already taken care of.

[John B]

Has the stock inlet hose been found to be a significant restriction? I used a step up adaptor from my stock T2 inlet hose to the hybrid and used the stock T2 airbox.

[Mopar318]

The smaller cone filters will flow less than a flat filter in the airbox.

If you calculate the surface area you will see a gain with the larger surface area.

A 3"X6" cone filter would have a surface area of about 56 in.^2

4X6" cone filter would have a surface area of about 75 in.^2. That is almost 50% more airflow!

[csxtra]

Has the stock inlet hose been found to be a significant restriction? I used a step up adaptor from my stock T2 inlet hose to the hybrid and used the stock T2 airbox.

I do know that the stock airbox is definitely a restriction once you get over 300WHP (maybe sooner). I was stuck at 110mph in the 1/4 running the stock airbox with a K&N drop in panel filter, and when I switched to a big K&N cone filter (sucking in hot underhood air) I picked up 4 MPH with no other changes on back-to-back runs.

[Dave]

The smaller cone filters will flow less than a flat filter in the airbox.

If you calculate the surface area you will see a gain with the larger surface area.

A 3"X6" cone filter would have a surface area of about 56 in.^2

4X6" cone filter would have a surface area of about 75 in.^2. That is almost 50% more airflow!

Just curious as I suck with math, how did you calculate that?

I do know that the stock airbox is definitely a restriction once you get over 300WHP (maybe sooner). I was stuck at 110mph in the 1/4 running the stock airbox with a K&N drop in panel filter, and when I switched to a big K&N cone filter (sucking in hot underhood air) I picked up 4 MPH with no other changes on back-to-back runs.

Wow that's incredible.

Simon, I know Garrett's turbo calculator takes into account on average a 1psi drop in inlet Pressure P2c so it is truley important to have a free flowing system. I try to always go as big and free flowing as possible.

A quote from Garrett's website, "In determining pressure ratio, the absolute pressure at the compressor inlet (P2c) is often LESS than the ambient pressure, especially at high load. Why is this? Any restriction (caused by the air filter or restrictive ducting) will result in a “depression,” or pressure loss, upstream of the compressor that needs to be accounted for when determining pressure ratio. This depression can be 1 psig or more on some intake systems."

-Bryan

[turbovanman²]

Alright, I'll order the 4"x10" cone S@B filter with a open other end and make up a 4" pipe.

[trannybuster]

Good topic and Ive been wondering same thing myself , solved!

[turbovanman²]

Where to get some 4" aluminum piping, it doesn't need to be thick walled, I need 2-3 feet of straight and a 90 deg section. Ebay doesn't have anything really, our pipe vendor nothing.

Good topic and Ive been wondering same thing myself , solved!

Its tinkering and getting ready for racing season mode, so thinking out loud,

[Mopar318]

Just curious as I suck with math, how did you calculate that?

Circumference of a circle = pi*D
Multiple that by the length of the cone to get Surface area.

[Shadow]

Charger has had full 4" with 4x10 cone filter the whole time I've been running it. Even on the 57 trim I had a 4 to 3" adapter at the turbo.

Originally did this over 8 years ago on the mid 11 sec 46 trim, just because and never looked back.....

[glhs727]

Where to get some 4" aluminum piping, it doesn't need to be thick walled, I need 2-3 feet of straight and a 90 deg section. Ebay doesn't have anything really, our pipe vendor nothing.

Try Vibrant. They have 4" aluminum intake tubing and they are in Canada

[turbovanman²]

Charger has had full 4" with 4x10 cone filter the whole time I've been running it. Even on the 57 trim I had a 4 to 3" adapter at the turbo.

Originally did this over 8 years ago on the mid 11 sec 46 trim, just because and never looked back.....

Ok, so did you ever run a 3" setup and if so, any difference?

Try Vibrant. They have 4" aluminum intake tubing and they are in Canada

Thanks, I'll try that.

[shadow88]

As far as reading a rectriction, I would suggest a water manometer. You might even have one around with all your multi carbed bike carburetor experience.

Is the inlet to your turbo 4" diameter? I decided to go with 2.5" on mine because that's the inlet size of my compressor housing.

[Shadow]

Ok, so did you ever run a 3" setup and if so, any difference?

Nope, never tried 3". After coming to a firm understanding of how a turbo works most efficiently I have gone to lengths to help it do exactly that. Maybe after the Charger goes into the 9's I will try "demoding" certain things to see what effect they have.

[turbovanman²]

As far as reading a rectriction, I would suggest a water manometer. You might even have one around with all your multi carbed bike carburetor experience.

Is the inlet to your turbo 4" diameter? I decided to go with 2.5" on mine because that's the inlet size of my compressor housing.

Yeah, I do, I'd have to video it or something, lol. Would be nice to actually datalog but at this point, I don't think its worth the energy.

Yep, the inlet is 4", run an adapter to knock it down to 3" as all my old turbo's had a 3" inlet.

Nope, never tried 3". After coming to a firm understanding of how a turbo works most efficiently I have gone to lengths to help it do exactly that. Maybe after the Charger goes into the 9's I will try "demoding" certain things to see what effect they have.

That would be interesting to see,

[Dave]

Where to get some 4" aluminum piping, it doesn't need to be thick walled, I need 2-3 feet of straight and a 90 deg section. Ebay doesn't have anything really, our pipe vendor nothing.




Its tinkering and getting ready for racing season mode, so thinking out loud,

http://www.siliconeintakes.com/produ...b86803e55fabad

http://www.siliconeintakes.com/produ...b86803e55fabad

---------- Post added at 04:54 PM ---------- Previous post was at 04:52 PM ----------

Circumference of a circle = pi*D
Multiple that by the length of the cone to get Surface area.

Right but how would you account for it's taper? Maybe I'm overthinking this. lol sorry just bashed my head around calculating volumetric flow rate vs face velocity and filter area for my filter because of this thread, for my Audi's new CAI.