Quietest aftermarket intake?

[judderod]

Hi all I've searched around and had a good look through THE OFFICIAL INTAKE/ TURBO INLET PIPE THREAD (great info BTW) but can't find too much info on the noise of these things.

Hope this is the right place to ask...

Which one is the quietest for a 6? Or do I need to fab something out of a new CAI/SRI and the existing intake box?

On my last car I used a cheap SRI pipe, a K&N cone filter and some large diameter acrylic tube with 2 end caps to enclose the air filter. It had a velocity stack to the side with a large flexible pipe running inside the wing to behind the front grille with a scoop. It was quiet, gave good intake pressure at speed, and intake temperatures were low. But it was a lot of work so I'd rather just buy something this time!

[Richys10]

Originally Posted by judderod Hi all I've searched around and had a good look through THE OFFICIAL INTAKE/ TURBO INLET PIPE THREAD (great info BTW) but can't find too much info on the noise of these things. Hope this is the right place to ask... Which one is the quietest for a 6? Or do I need to fab something out of a new CAI/SRI and the existing intake box? On my last car I used a cheap SRI pipe, a K&N cone filter and some large diameter acrylic tube with 2 end caps to enclose the air filter. It had a velocity stack to the side with a large flexible pipe running inside the wing to behind the front grille with a scoop. It was quiet, gave good intake pressure at speed, and intake temperatures were low. But it was a lot of work so I'd rather just buy something this time!

I'm not sure about brands but a SRI would probably be quietest. And I've seen that the ones that come with the box are pretty quick. Like cobb's etc I have a CAI and you can definitely hear it. Why do you want a quiet intake?

[MSMS3]

I don't have a 6. My car is a gen 1 MS3. I wanted performance without a lot of noise and chose the original Mazdaspeed CAI. It is actually made by AEM. The AEM model is identical. It is a long tube CAI with the cone filter down inside the left front just behind the fog light and ahead of the driver side wheel well.

I don't know if there is a model for the MS6. I've been very happy with it. I have swapped the AEM sourced dry flow filter for a K&N of the same size, but otherwise it has remained as is. My car is an '08 model. I bought the car new in the spring of '08 and added the CAI within the first 10,000 miles. I have 126,000 miles on the car now. You would need to stay away from driving through high water, but that is sensible to do anyway. I live in a rainy area (Mississippi Gulf Coast) and have had not problems with the element getting wet, and certainly no hydrolock issues. It is very quiet, although if you listen, you can hear the operation of the BOV and a little more noise from airflow at wide open throttle, but not much. At its location, it does run cooler than an SRI when sitting in stalled traffic or slow city driving.

A quick check of AEM's website shows a different model number for the Speed 6 (21-641) and Gen 1 Speed 3 (21-642).

[WetzMS3]

Originally Posted by MSMS3 I don't have a 6. My car is a gen 1 MS3. I wanted performance without a lot of noise and chose the original Mazdaspeed CAI. It is actually made by AEM. The AEM model is identical. It is a long tube CAI with the cone filter down inside the left front just ahead of the driver side wheel well. I don't know if there is a model for the MS6. I've been very happy with it. I have swapped the AEM sourced dry flow filter for a K&N of the same size, but otherwise it has remained as is. My car is an '08 model. I bought the car new in the spring of '08 and added the CAI within the first 10,000 miles. I have 126,000 miles on the car now.

Funny note to this, AEM and K&N are the same company, well partners at least. I ordered a new filter from one, and it shipped from the other (can't remember which order at the moment). I believe one company, probably K&N makes all the filters and just brands them differently.

The only no forum article that pops on googles first page:
Transnational Capital Corp. | Recent News & Events

[Thor Hammer]

Originally Posted by MSMS3 I don't have a 6. My car is a gen 1 MS3. I wanted performance without a lot of noise and chose the original Mazdaspeed CAI. It is actually made by AEM. The AEM model is identical. It is a long tube CAI with the cone filter down inside the left front just behind the fog light and ahead of the driver side wheel well. I don't know if there is a model for the MS6. I've been very happy with it. I have swapped the AEM sourced dry flow filter for a K&N of the same size, but otherwise it has remained as is. My car is an '08 model. I bought the car new in the spring of '08 and added the CAI within the first 10,000 miles. I have 126,000 miles on the car now. You would need to stay away from driving through high water, but that is sensible to do anyway. I live in a rainy area (Mississippi Gulf Coast) and have had not problems with the element getting wet, and certainly no hydrolock issues. It is very quiet, although if you listen, you can hear the operation of the BOV and a little more noise from airflow at wide open throttle, but not much. At its location, it does run cooler than an SRI when sitting in stalled traffic or slow city driving. A quick check of AEM's website shows a different model number for the Speed 6 (21-641) and Gen 1 Speed 3 (21-642).

You sir just listed the loudest intake on the market. Maybe yours is quieter than mine. Pretty sure he asked for the least audible.

I have the AEM CAI and it is very loud. The filter sits in the front inside of the fender well. You hear it drawing the air in quite audibly and the BPV when it opens just as loud.

OP, if you want performance you have to be willing to tolerate some noise. Any of the SRI intakes will sound the same and be the quietest.

[MSMS3]

Originally Posted by Thor Hammer You sir just listed the loudest intake on the market. Maybe yours is quieter than mine. Pretty sure he asked for the least audible. I have the AEM CAI and it is very loud. The filter sits in the front inside of the fender well. You hear it drawing the air in quite audibly and the BPV when it opens just as loud. OP, if you want performance you have to be willing to tolerate some noise. Any of the SRI intakes will sound the same and be the quietest.

I guess I am deaf. I have a Short Ram Intake on my Nissan truck with 5.6 V8 engine (K&N) that is loud. I even added insulation around the K&N air box that came with it, and to the underside of the hood just above it (yes it is in an airbox, but has an open top). That offered very little improvement. This is a whimper in comparison.

[Thor Hammer]

Originally Posted by MSMS3 I guess I am deaf. I have a Short Ram Intake on my Nissan truck with 5.6 V8 engine (K&N) that is loud. I even added insulation around the K&N air box that came with it, and to the underside of the hood just above it (yes it is in an airbox, but has an open top). That offered very little improvement. This is a whimper in comparison.

One day I got my ears cleaned at the doctor and wow, could I hear my intake afterwards

I personally love the whooshing sound of the intake, whistle of the synapse synchronic BPV at part throttle, and the release of air when it opens. Makes me feel all race car.

Except for windows down next to a concrete barrier on the driver side going uphill. Barely getting into boost the noise is amplified greatly.....and a bit much. Windows up and its all good.

[sharksinspace]

Originally Posted by Thor Hammer I have the AEM CAI and it is very loud. The filter sits in the front inside of the fender well. You hear it drawing the air in quite audibly and the BPV when it opens just as loud.

I replaced the AEM/MS CAI on my genwon with a SRI because reasons, and I can tell ya...the CAI was definitely the quieter setup.

[Thor Hammer]

Originally Posted by sharksinspace I replaced the AEM/MS CAI on my genwon with a SRI because reasons, and I can tell ya...the CAI was definitely the quieter setup.

how is that possible? I am not saying you are wrong, just wondering how this occurs. perhaps the intake noise is transmitted through the firewall??? odd.

[sharksinspace]

Originally Posted by Thor Hammer how is that possible? I am not saying you are wrong, just wondering how this occurs. perhaps the intake noise is transmitted through the firewall??? odd.

My uneducated assumption is that it has something to do with the setup being on top of the engine bay instead of buried down in the wheel well, meaning less of the noise is blocked. Not that the CAI was quiet, either, it's just that the SRI is even louder; turbo and BPV are definitely more audible after the switch.

[Don]

I have Gen2 with a corksport Sri. I can hear the turbo loud and clear along with the stock BPV.. It's all very loud hahhaa

[Spectrix]

Originally Posted by judderod Which one is the quietest for a 6? Or do I need to fab something out of a new CAI/SRI and the existing intake box?

Some of the Aussie guys with big turbos use the original airbox connected to a 3" or 3.25" intake. There is no measurable power difference compared to a SRI/pod setup, but it's much quieter and looks almost standard.
The airbox inlet is replaced with a short, wide bellmouth peice and the outlet is cut out and moulded to suit.
The standard paper air filter is retained as it's not restrictive.

[judderod]

Originally Posted by Richys10 I'm not sure about brands but a SRI would probably be quietest. And I've seen that the ones that come with the box are pretty quick. Like cobb's etc I have a CAI and you can definitely hear it. Why do you want a quiet intake?

My car's used to ferry kids around a lot - my other half is a childminder... We don't want to scare off any parents! I keep telling her we need to buy a people carrier but she won't have it! Currently I have a stock intake with a K&N panel filter I can just about hear spool up which is loud enough for us, perhaps a bit louder would be OK.

Originally Posted by Spectrix Some of the Aussie guys with big turbos use the original airbox connected to a 3" or 3.25" intake. There is no measurable power difference compared to a SRI/pod setup, but it's much quieter and looks almost standard. The airbox inlet is replaced with a short, wide bellmouth peice and the outlet is cut out and moulded to suit. The standard paper air filter is retained as it's not restrictive.

PERFECT that's great info thanks. Do you know where I could get some more details or some pix? Most likely I'll copy the design.

Interesting to hear AEM use K&N. AEM are one of the best for tuning products and K&N are probably the oldest and best air filter manufacturers in the world IMHO. Others may flow a tiny bit better and give a couple of bhp, but they're doing it at the expense of particulate filtration which is not good in the long run.

[Richys10]

Originally Posted by judderod My car's used to ferry kids around a lot - my other half is a childminder... We don't want to scare off any parents! I keep telling her we need to buy a people carrier but she won't have it! Currently I have a stock intake with a K&N panel filter I can just about hear spool up which is loud enough for us, perhaps a bit louder would be OK. PERFECT that's great info thanks. Do you know where I could get some more details or some pix? Most likely I'll copy the design. Interesting to hear AEM use K&N. AEM are one of the best for tuning products and K&N are probably the oldest and best air filter manufacturers in the world IMHO. Others may flow a tiny bit better and give a couple of bhp, but they're doing it at the expense of particulate filtration which is not good in the long run.

That's probably your best option there. An SRI/CAI intakes honestly doesn't have that much more power gains over a stock box with upgraded filter and TIP/hoses

[MSMS3]

Originally Posted by Richys10 That's probably your best option there. An SRI/CAI intakes honestly doesn't have that much more power gains over a stock box with upgraded filter and TIP/hoses

Uh, very wrong. When Car & Driver dynoed an '08 Speed 3 with stock intake and then with the AEM sourced Mazdaspeed CAI they showed a 15 whp gain. They published the dyno results. The difference is huge when you switch to a properly designed CAI or SRI. Unless you modify the stock airbox radically to increase air flow into it, it is incredibly restrictive. Aftermarket TIP and or hoses adds nothing for the stock K04 on pump gas. TIP might help an already lightning fast spool a little, but that is debatable. Stock TIP looks horrible, but outflows the stock turbo for the inlet diameter.

There are many, many dyno charts here confirming this.

[MSMS3]

No Synapse for me. Just the good old trusty stock BPV. I guess that maybe my catless dp/rp (even with an added reso) might make the intake harder to hear, lol.

[Thor Hammer]

Originally Posted by MSMS3 No Synapse for me. Just the good old trusty stock BPV. I guess that maybe my catless dp/rp (even with an added reso) might make the intake harder to hear, lol.

I hear you (no pun intended) on the exhaust drowning out the intake and BPV noises. My CPE DP and dual Austenite system is far from quiet! No reso. I couldn't even hear the stock BPV with the new exhaust.

[MSP6]

Stupid question is stupid...but I'll answer

Silicon intake of any variety, full length, SRI etc will be much quieter than an aluminum intake of any sort.

Driving normally you're not going to offend the pickiest of passengers, nor is it loud or obnoxious like exhaust work is anyway.

[judderod]

^This is why I asked the question! Lots of conflicting info around. The pre-filter side of the airbox does look pretty restrictive, I guess to quieten down turbo noise. But how it actually affects power output is what matters. No point modifying it if it doesn't make any difference...

[Spectrix]

As mentioned above, the inlet & outlet of the stock airbox are modified to increase flow while still keeping a standard appearance & sound.

[judderod]

Originally Posted by Spectrix As mentioned above, the inlet & outlet of the stock airbox are modified to increase flow while still keeping a standard appearance & sound.

I think that's what I'll do. Could you help me with where to find more info/pics of the modified airbox?

[Spectrix]

Originally Posted by MSMS3 Appearance, yes. Sound, no. To open up the box you will defeat the baffle that makes it quiet. Do any of the new mrmbers even bother to search the threads on this stuff?

The airbox itself is a baffle. Its purpose is to house the air filter and reduce intake noise.
Yes, modifying the inlet/outlet as shown may allow more intake noise, but not like a large SRI with an open pod filter. It's about the best one can do when chasing a large amount of power.

Originally Posted by judderod I think that's what I'll do. Could you help me with where to find more info/pics of the modified airbox?

Sure thing. This airbox has a 3.25" MAF housing grafted in and is supporting 370HP at the wheels.
Credit to Luke Wilksy, I'm not sure if he's on these boards.

[Richys10]

Originally Posted by Spectrix The airbox itself is a baffle. Its purpose is to house the air filter and reduce intake noise. Yes, modifying the inlet/outlet as shown may allow more intake noise, but not like a large SRI with an open pod filter. It's about the best one can do when chasing a large amount of power. Sure thing. This airbox has a 3.25" MAF housing grafted in and is supporting 370HP at the wheels. Credit to Luke Wilksy, I'm not sure if he's on these boards.

That's pretty neat!! That's probably one of the best options you have!

[Vansquish]

Originally Posted by Spectrix The airbox itself is a baffle. Its purpose is to house the air filter and reduce intake noise. Yes, modifying the inlet/outlet as shown may allow more intake noise, but not like a large SRI with an open pod filter. It's about the best one can do when chasing a large amount of power. Sure thing. This airbox has a 3.25" MAF housing grafted in and is supporting 370HP at the wheels. Credit to Luke Wilksy, I'm not sure if he's on these boards.

I just got myself a 3.25" MAF housing with a honeycomb air straightener. As I still have my OE airbox lying around, I'm seriously considering giving this a shot. I must be getting old. Having a stealth-look setup is very appealing.

[MSMS3]

Originally Posted by Spectrix As mentioned above, the inlet & outlet of the stock airbox are modified to increase flow while still keeping a standard appearance & sound.

Appearance, yes. Sound, no. To open up the box you will defeat the baffle that makes it quiet. That's ok, as you can get good flow. But, if you are expecting it to have "standard" sound, you'll likely be disappointed.

Do any of the new mrmbers even bother to search the threads on this stuff?

[judderod]

I'd have thought a SRI would be louder than a CAI. A longer tube should muffle more sound than a short one (ever tried running an open header)?

But most say a SRI is quieter than a CAI!

[judderod]

^ Very much appreciated. I now know my intake upgrade path.

*Goes to check I've got some fibreglass mesh and resin in the garage

I know a little about fluid dynamics but I'm no expert... I don't think I'd put the MAF so close to the opening due to turbulence. And the opening inside the airbox would be better curved outwards (velocity stack). That kind of thing made a difference on NA cars I've tuned, maybe not so much on turbo?

[Spectrix]

Yep, I'd certainly recommend using a fin or honeycomb air straightener in the AFM housing, and flare each leading edge of pipe.
Some people use PVC stormwater pipe which is easy to heat and mould into shape with a heatgun.



This website has some info on moulding PVC.

[judderod]

There's some decent engineering there! Last time I made an airbox I just bought an aluminium velocity stack from ebay for cheap.

Interesting to read in Versatune's help guide they mention SRI intakes making more power not just because of increased airflow, but because the location of the MAF sensor on some SRI's are deliberately placed to misread airflow and cause the ECU to lean out the fuel a little = more power on our engines because they run too rich as stock. To me that shows we need a very different approach on intakes if the ECU can be tuned. Tricks like that will make tuning more difficult.

With tuning and the ability to calibrate MAF readings, I need de-restricted/increased airflow and accurate MAF readings. I like the look of the pipe going right inside the airbox so there is a good few inches between the start of the pipe and the MAF - turbulence should be minimal at the sensor.

Noob question - so 3.25" is larger than the standard MAF housing right... Is that connected to a standard sized (silicone aftermarket) TIP with a reducer?

[Spectrix]

Originally Posted by judderod Noob question - so 3.25" is larger than the standard MAF housing right... Is that connected to a standard sized (silicone aftermarket) TIP with a reducer?

That was a custom intake using larger 3.25" piping, it was a big turbo car.
The standard K04 turbo inlet size is only 2", and the standard MAF size is 2.6".

It's debatable whether or not a physically larger can increase power on a standard turbo - some have found more power, some not. Often it's a case of VD dyno inconsistencies making it unclear.

When I changed from a stock sized intake to a larger HTP (3.0") I saw the same peak airflow and load at set rpm points once I'd properly scaled the MAF.

[judderod]

Originally Posted by Spectrix That was a custom intake using larger 3.25" piping, it was a big turbo car. The standard K04 turbo inlet size is only 2", and the standard MAF size is 2.6". It's debatable whether or not a physically larger can increase power on a standard turbo - some have found more power, some not. Often it's a case of VD dyno inconsistencies making it unclear. When I changed from a stock sized intake to a larger HTP (3.0") I saw the same peak airflow and load at set rpm points once I'd properly scaled the MAF.

Interesting... That would suggest that with a standard turbo and aftermarket TIP: The only restriction on the standard airbox/intake is from below the panel filter ie. the lower part of the airbox, the baffle and pre-filter tubing.

[Spectrix]

Yes it appears that way. Give it a try and post before and after logs

[judderod]

Originally Posted by Spectrix Yes it appears that way. Give it a try and post before and after logs

Will do!

mituc - agreed. That airbox looks expensive! I'm trying to find a cheapo intake pipe but haven't found one for a 6 yet. They're all branded and £$$. I've wasted so much cash in the past on hyped up junk that just made my car worse. Now all I care about is what actually works. That leaves me more to spend on the stuff I can't DIY.



Here's my effort on my last car made from a knock off ebay intake pipe, acrylic tube air box and plumbing parts. Hidden underneath the cone filter is a velocity stack (curved flange) connected to a 2.5 inch flexible hose that collected air from up in the wing. It worked really well at keeping IAT's low and MAP didn't suffer compared to running an open filter.

[mituc]

Any intake + air box.

Also, the air box will help lower the IATs quite a bit. And that reflects into BATs because the BATs are the result of the temperature raising after compressing the air and then cooling it a bit in an intercooler. So the higher the IAT the higher the BAT.

The aftermarket short ram intakes without an air box will draw air from the engine bay. Even at high speed the turbulences behind the grille/radiator will not feed the cone filter with fresh air. Having an air box will.
Also, not having an air box in slow traffic (not that performance matters that much in slow traffic, but for me it does) will push the IATs very high in hot summer days. I've seen +125C IAT (that;s about 255F) after sitting in traffic in 35C/95F weather for about 20 minutes after an idiot did not give way and that accident blocked 3 lanes out of 4.

In my case IAT=AAT every time I drive hard or just cruising at 50+mph/80+Kmph for a significant amount of time after exiting slow bumper to bumper traffic (say, after 10 minutes).

So get an air box, besides the sound damping effect it will have a significant effect on how your car runs.

Here it is:
New Product RE-RELEASE! JBR TRU - 3.0 and 3.5” Wide Path Intake Systems!!

[WetzMS3]

[Spectrix]

[judderod]

Poor old Honda. Still I got the 0-60 down to 5.68. Not bad for a NA 2.2 Prelude.



That's about as quick as a stock MS3

Anyway I sold it and bought an MS6 so that says it all

[mituc]

It will be more efficient as well. The factory air box is a true cold air intake. Anything else is just a short ram or if it's one of those CAIs that goes down into the fender may or may not be suitable depending on how much rain you get in your area.

Vandalizing the factory air box by removing all those striations and fins it has inside and converting it into an air box for the filter of an aftermarket short ram intake may work like a charm as long as the filter fits inside.