I love my mods, but that whistle under very light throttle that comes with a Cold Air Induction system is annoying. I believe that it's related in some way to the bypass valve since it went away when I was running VGS (vacuum gain system.)

Does anyone know another way to get rid of the whistle short of the VGS mod or going back to a stock intake? Does the Detroit Tuned valve make a difference in the whistle?

TIA,

Richard

 

[SIZE=2]That sounds strange that the whistle went away after doing the VGS mod, I believe the general consensus from CAI manufacturers is that it is caused by the throttle body.
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it is indeed a throttle body issue - and there is nothing that can be done about it. bugs me sometimes too!

 

I too was told that it's a throttle body issue, but there is no doubt that the VGS mod eliminated it almost entirely.

 

The whistle is indeed caused by the throttle body as the air enters at a certain velocity, angle, etc. It is most prominent on a new or freshly-cleaned CAI, since that is when the most amount of air flow is entering the throttle body. It's not heard on a stock intake, due to the restrictions and sound-deadening properties of the filter housing.

Is your CAI relatively new? It has been 6,000 miles since I last cleaned my Alta intake, and I hear nary a whistle.

HTH, and best of luck in finding a solution!

 

I just replaced my Alta with an HDI.... Whistle Gone! The HDI is noticably quieter than the Alta and all I hear now is a little supercharger whine.. It's about as perfect as I can get, IMO...

One thing you may want to try, which also reduces the sound... go to a craft store and pick up some 2" foam. I cut a piece and placed it in the cowl induction area, right between the firewall and the filter and it helped. Easy $2 mod.

 

dare i ask... what is the vgs mod?

 

Vacuum Gain System:

https://www.northamericanmotoring.co...&highlight=VGS

$5 Mod that moves the vacuum source for the bypass valve. Reported to make the bypass valve shut a bit quicker, allowing for more boost earlier.

 

I don't know why the VGS made the whistle go away, but it did. I recently reversed the mod and went back to stock only to find that the whistle had returned.

I'll look into the HDI if that gets rid of the whistle... it's that annoying.

 

and is this really worth it? is there a noticeable difference? i only ask because i am about to swap out my jcw intake for a helix intake which sounds (and performs) much better.

thanks.

 

Consider switching to the JCW CAI. No noise under 4500 RPM.

 

I can't really speak for the JCW or the Helix.. but the Alta was cool for about the first 3 stop lights after I had it installed.. then it got just kind of annoying. I learned to live with it but it drew my attention whenever I had my driver side window down.

I would have to think that the JCW intake is on the quieter side. It's supposed to be stock sounding until about ~4500 rpm when the "flap" opens and you get more fun-noise... like promking said.

I wouldn't think that there would be any noticable difference in power between aftermarket intakes.. maybe a couple HP on a dyno.. but no one's butt is that sensitive.

I'd probably look into an HDI over the JCW if you don't mind a little more supercharger whine. It's much cheaper than a JCW and Dave at DDRworks is great..

 

having had the jcw intake i can say that it indeed does do what it promises to do: quiet under 4500 rpm, and them screaming after 4500 rpm, when the flap opens up. that being said, i recently rode in a car with the helix intake and the sound was amazing at all speeds - much more supercharger sound (which i happen to love). i also felt that the helix intake (which is probably similar to the alta?) gave the car a little more life over the jcw.

 

Hey NYC...

I wonder (and I'm sure there's been dozens of discussions on this) if the flap allws for better flow which rpobably give's that little torque bump you can feel.. When it's closed, the engine is more starved for air.. Oh well.. just me thinking out loud..

 

I actually just completed an installation of an Alta CAI. I removed my previous JCW intake. I'm very pleased with the responsivness that I have gained from the Alta. As far as the whistle goes, yes it's there, yes it's noticeable, but it's not all the time. I get it when I'm probably around 2.5-3k rpm, but like it was said above, it's at a specific rpm where the angle and speed of the air entering the throttle body, that you get the whistle.

I for one am a fan fora little whistle as long as it means the next time I step on the Go pedal, I hear her scream!

 

Oh, that banshee wail makes my heart pound with pride!

 

Thad, just wait until you have had that whistle for a while and it will annoy the *%#@ out of you. I had my installation guys put the plastic backing (that goes in between the firewall and the CAI) back in as it cut the noise alittle. But I also agree it is more than annoying.

 

by the way, my CAI is a helix

 

I can appreciate the pride factor.. but my screaming intake phase ended about 5 years ago, just about the same time as my drive for the elusive 3 ponies I was chasing by running a straight pipe, AEM intake and a straight through exhaust.. I'm now in the quest for the Holy Grail... quiet power. It's easy to make power including noise.. Whine is okay.. but personally, I could do without the whistle... I like my banshee to bite more than bark..

 

DOH, just realized it was in my signature, sorry for the extra post, which including this one, now makes 2 extra posts. Yes, I am bored this morning.

 

steve - regarding the helix intake - were you coming from a stock airbox? did you notice much more power? is the supercharger noise really great on the helix?

hmmm....

thanks.

 

I went from a stock intake to the Helix, but I did the 15% pully at the same time. The increase in intake noise is remarkable! I've grown to like the howl, but not the whistle that comes under light throttle at cruising rpm's. I'm wondering if closing the top of the Helix intake box and insulating would do the trick?

 

not sure hopper - but isnt the vgs mod supposed to cure the whistle???

 

The VGS mod does indeed cure the whistle. The question is why/how?? I reversed the VGS mod as I think that the car is smoother without it, but now I have the whistle back. :-(

 

hmmm... when you say smoother, what exactly do you mean? what is the vgs mod supposed to do anyway?