Just did the Orange Cap Mod

I didn't expect much for a free 5 min mod but I really does make it sound much better. My only question is whether or not the cap will stay put. I am concerned that the cap is going to get sucked in to the engine somehow. Which way is the air pulling on the cap? If it's towards the intake, which is my guess, I'm not sure that its secure enough to stay in place forever.

what is this mod?

glue it

where did you get this mod from?

What is it supposed to do? More throaty sound? Increase HP yeah right!

Sorry I thought this was a more well know mod. Here is one of the links talking about it. https://rennlist.com/forums/showthre...hlight=niagara

I doubt that there is enough pressure in the intake track to suck it in, especially since it would have to go arround a bend to get in the engine. What the mod does is to block off air going into the air box muffler. This mod give you a more throatty intake sound and the air that is blocked off is resonance air thus not under much pressure. I have done some more soficticated mods by taking out the muffler and putting in place a PVC pipe and cap to block off the tube. Removing the the muffler is suppose to give more volume in the airbox. The best improvement is to remove the plastic screen in front of the MAF.

i've had my cap in for 6-mos. i pulled it out a few days ago, it still looks sturdy. it's a lot cheaper than the fabspeed bypass, which in my mind, does nothing more than what this *free* mod does.

just ordered my niagara by-pass vortech hyperspeed ***-induction supercharger. cancelled my order for the evo kit, not as cost effective.

Why would you want a 10 cent piece of plastic on your intake? Not worth the risk and way too little benefit IMO.

gomo I had that mod on my car for over a year with no issues...just enjoy the new sounds.

Makes me feel better that people have had it for a while with no ill effects. I can tell you I definitely don't want to give up the sound, it's awesome. Jetskied - do you have any pics of what you did? I have been thinking about how I could improve on the mod a little and it seems like you have already done it.

I've had mine in for over 1.5 years and looked at it last week. It looked like new and was still as "soft" as the day I put it in. I was concerned that over time the plastic would dry out and it hasn't.

What I did was to take out the top of the air box out of the car. Look inside towards the MAF and you will see a plastic screen. It is snaped in and you can pry it out carefully. This is the same thing that a Fabspeed mod does. Then there is a small trapazoid box( muffler) item screwed to the inside of the lid with 3 screws. You can remove it. Buy some 1 1/2 inch PVC pipe and a cap for it at a hardware store. Glue the cap to one end and cut the pipe so it will fit out of the hole left by removing the muffler. On the muffler there is a o ring you can reuse on the pipe, this will help keep the airbox better sealed. The pipe is sort of small and you can wrap electric tape to thicken it up so it will fit the hole a little more snug. You need to wrap the tape about 7 or 8 times. Put the lid back on and the hose clamp will hold in the pipe.

Any butt dyno gains from this mod, or is it all sound related?

FWIW, I tried this last year and removed it after a week. I have PSE, so the sound difference wasn't that noticeable on acceleration, and the thing I didn't like was it caused the wonderful PSE gurgle on deceleration to go away.

removing the screen in front of the MAF will screw up the MAF readings. The screen smooths the airflow that's turbulent before it hits the MAF sensor. This is pretty funny, because these types of mods have been around for ages. Starting with removing the 'snorkel' in my VW Jetta airbox. End result was absolutely nothing except potentially screwing up computer calibrations regarding the MAF. In the S4, it was about drilling holes in the airbox. I find this thread amusing that you're willing to pretty much void warrantees for a non-existent gain of that 1 hp holy grail on a 80K+ machine.

"... I find this thread amusing that you're willing to pretty much void warrantees for a non-existent gain of that 1 hp holy grail on a 80K+ machine" void the warranty if it gets sucked in? i don't think it's possible. there's no power 'gain' as it were...it improves induction sound, for which the bypass was desiged to mitigate. blipping the throttle on heel-toe downshifts is far easier to discern now, especially w/ the radio blarring. i had mine w/ and w/o ghl exhaust, with both, the cap mod only enhanced the pleasure

The mod I did is suppose to be similar to what Fabspeed kit is, but I really notice more sound than real performance. The butt dyno does not feel anything. Fabspeed claims that their mods improves mid range power by saying that the sweep from 3k to 6k rpm was a few tenths quicker. What ever that means, I believe that no air box can really improve on the OE. I remember that Excellence did a test on an air box that actually lost HP. I'll try and find the article.

Where do you get the cap...I've read all the posts twice and don't see any reference to the source of the plastic cap?!?

could you not make your own cap? i.e. cut a carboard circle, cover the entire surface area with duck tape and call it a day? wouldn't that work just the same? or am i missing something here...

It would be great to see that Excellence article on intakes...

I did the orange cap last week. It made no difference in sound, but I have fairly loud GHLs on. However, after 150 miles of the orange cap mod, my CEL came on this morning and the car hunts for idle. Coincidence? Assuming the MAF needs replacing. 99 996 with 13.5k miles. Steve 99 996 76 930 64 356C 62 356B 00 M5

I thought that "sound related" and "butt dyno gains" were the same thing.

Someone in UK wanted the orange caps but Niagara wouldn't send them out of the US. Well, I've got them, but I can't fine the email to send them to. Help!

I've got the GHL Loud Exhaust, and I just did the orange cap mod two days ago. My impression....It's awesome! I felt like the GHL Loud sounds a little ricy sometimes... Around 6000+ RPM it would be loud, but almost sounds like a tearing or ripping sound. Now, the car feels like it sounds a little deeper, and definitely a lot "cleaner". The revving sound is a lot smoother without any roughness around the edges. My parents were really critical of my exhaust, but they claim it sounds a lot better now. I am definitely keeping it on!