Who's In The Cold Air Intake Club and What Do Ya Got?

[barkinfool]

TRK -

It is true that you won't get the time back, but when you die, you will achieve total consciousness.

So you have that going for you, which is nice...

Thanks, your post was very helpful!

[The Radium King]

well, i too personally feel the high rpm gains associated with modifying the intake for higher flow outweigh the low rpm losses that result from any de-tuning that occurs, which is why i am currently running a 997 plenum, cayman throttle body and 85mm BMC DIA airbox.

i have located my maf closer to the throttle body (like in a 996) as well. unfortunately, this has resulted in the need for a bend in the ducting immediately before the maf. i think i will have to rework my intake geometry in general (remove the engine compartment insulation so that i have room to mount my airbox a little lower and get things straight); fact is, the oem intake geometry is pretty good as-is.

turbulance and maf reading? unsure. oem porsche airboxes do put a screen before the maf, but it is not a full honeycomb as is available aftermarket. i am currently re-using the maf housing from my old airbox so had to cut-off the screen, but am thinking i need to add something as i'm getting a bumpity idle.

otherwise, i am currently using flex duct for my intake tubing. aftermarket vendors get all up in arms about flex duct and try to sell you $300 work of pre-formed plastic pipe under the auspices that flow is less turbulent, but i'm always brought back to the stories of the russian mig fighters and the fall of communism. here was a plane that was relatively on par with anything the west could produce, but when we finally got a chance to look at one we found that it was ill-made and replete with exposed rivets, bumps, lumps etc. all this served to create a layer of turbulent airflow which was much more frictionless than anything you could design. similarly, flex tubing should create a small layer of turbulence that will enhance laminar flow within.

[jaykay]

Originally Posted by The Radium King

well, i too personally feel the high rpm gains associated with modifying the intake for higher flow outweigh the low rpm losses that result from any de-tuning that occurs, which is why i am currently running a 997 plenum, cayman throttle body and 85mm BMC DIA airbox.

i have located my maf closer to the throttle body (like in a 996) as well. unfortunately, this has resulted in the need for a bend in the ducting immediately before the maf. i think i will have to rework my intake geometry in general (remove the engine compartment insulation so that i have room to mount my airbox a little lower and get things straight); fact is, the oem intake geometry is pretty good as-is.

turbulance and maf reading? unsure. oem porsche airboxes do put a screen before the maf, but it is not a full honeycomb as is available aftermarket. i am currently re-using the maf housing from my old airbox so had to cut-off the screen, but am thinking i need to add something as i'm getting a bumpity idle.

otherwise, i am currently using flex duct for my intake tubing. aftermarket vendors get all up in arms about flex duct and try to sell you $300 work of pre-formed plastic pipe under the auspices that flow is less turbulent, but i'm always brought back to the stories of the russian mig fighters and the fall of communism. here was a plane that was relatively on par with anything the west could produce, but when we finally got a chance to look at one we found that it was ill-made and replete with exposed rivets, bumps, lumps etc. all this served to create a layer of turbulent airflow which was much more frictionless than anything you could design. similarly, flex tubing should create a small layer of turbulence that will enhance laminar flow within.

I would think flex tubing would constitute a "rough pipe" which will translate to flow losses. An open surface with dimples is a much different animal and has been found to enhance laminar flow (non compressible regime).... like aircraft skins; golf balls..

You would have to run the numbers and test to know whether the flex duct is giving significant losses but generally you can expect pipe friction losses

I can concur with the feeling that bottom end is slipping away for a more explosive top end above 4k as more intake opening changes are made. It's worth it for making passes on the track but not so much for pulling out of an underground parking garage with a cold engine

[ccstud17]

Originally Posted by barkinfool

TRK -

It is true that you won't get the time back, but when you die, you will achieve total consciousness.

So you have that going for you, which is nice...

Thanks, your post was very helpful!

YES CADDY SHACK!!!


Living in Portland, I have not had any issues with bad rain getting in the engine, First rain after de snorking, i drove on the high way pulled over and felt my intake, the grill was dry! maybe luck or the aerodynamics had the heavier water droplets moving faster than the lighter air, so at higher speeds the water does not alter its path. Just like driving with the top down while it is raining, if you go 95+ MPH top down you will stay dry! (Mythbusters did this in a boxster)

[Homeboy981]

O.K. here is what I have done to give you an update.

I have a large filter connected to a 4" silicone tube, does a 45 degree turn and it is reduced to 3.25", hits the screen from the old airbox (gotta remove that) and the Honeycomb filter, then flows into the MAF. From there it makes less than a 45 degree and it is in the Throttle Body.

I am flowing a lot more air! The system took a while to adjust to it but seems to be picking it up now after 20 on/off cycles.

The MAF is just above the AOS, maybe a little too close. Seems to be a tad warm there too. Ideally, I will try to get the MAF CLOSER to the Throttle Body, where the flow the MAF is reporting will be EXACTLY what the engine gets!

Still working on the "sealed Airbox design" to FLOW ONLY COLD AIR. But for now, it seems to be working with warm air, although not ideal….it is getting FASTER!

The acceleration seems to be better at lower RPMs. It is real nice rolling just off the clutch. The engine seems like it will REV FREE and EASIER now! Crisper response and putting plenty of power down.

So, in conclusion, some of you should check into moving the MAF closer to the TB. It seems to help the system AND a larger tube combined with the Honeycomb is getting some sweet results! Hard to ignore now!

Will update when the sealed airbox is done. I am on the fourth model of it now. Starting to come together! FWIW it has been one of the best improvements YET! All for less than a couple hundred….getting harder to ignore now?

[stephen wilson]

Unless you have a air leak, the MAF will read the same whether it's inches away from the TB or Feet. If you get it too close, it may actually disturb the air flow, leading to inaccurate readings. That's exactly what they did to the inlet side on the HPTuner site, which made the honeycomb "air straightener" necessary.

[Homeboy981]

Originally Posted by stephen wilson

Unless you have a air leak, the MAF will read the same whether it's inches away from the TB or Feet. If you get it too close, it may actually disturb the air flow, leading to inaccurate readings. That's exactly what they did to the inlet side on the HPTuner site, which made the honeycomb "air straightener" necessary.

That must be why it is working! Thanks for confirming what my butt dyno is telling me!

It GOES with the FLOW now!