My girlfriend been *****ing bout my loud exhaust so I put on the silencer on today and the car didnt really feel different. There must be something wrong with me but I cant really feel the difference when I put it on. Its like that feeling you get when the car is so loud you expect it to be faster with all that noise but when its quiet and doesnt sound fast... but the feeling you get actually seems faster. lol

My gf also told me the car felt faster, not sure if she just saying it so ill keep the silencer on BTW I have a Greddy Ti TBE.

 

the silencer may rob 10 hp or so, i think.
Doubt if you can really tell the difference.

 

I would say the same about the ac being turned on.

 

I thought the same, so when I got my car dynoflashed at Pruven, I asked them to run back to back with and without the silencer.

On on a 3" Helix CB, the silencer cost approx 50 (yes FIFTY) hp.

My baseline was ~250 WHP with the silencer, and 300 WHP without. After tuning, I hit 331 WHP and 338 TQ actual on Pruven's dynojet.

There was an article in a back issue of D-sport where they compared the unsilenced exhaust, to silenced exhaust (similar design as Helix), to an aftermarket silencer of a different design. This was a big HP car, and the silencer cost almost 100 HP or so, but I can't remember the details.

In my car, the a/f probe was in the pipe, which may have restricted exhaust flow even more, so perhaps it's not quite that bad, but it is probably worse than you think. There is a thread on it in the Dynoflash forum called Helix silencer sucks or something to that effect, hehe.

With that in mind, I ended up putting the silencer back in, since it's just too loud for me and I got a few indirect complaints from neighbors here on my dead end street, heh. I'm looking for a way to quiet it down, without the drastic power reduction, perhaps a different muffler. It would probably be better to re-install the stock cat-back, since it's ~2.25" or whatever, but at least it doesn't neck down to 1" or whatever the silencer does.

Other experiences or thoughts?

FB

 

If youre going to put on a silencer, just sell your exhaust system, its not doing anything anymore

 

It defeats the prupose to get aftermarket exhaust and then cover the exit hole so its the same diameter as stock (or even smaller).

 

can someone explain why some exaust are more quiet than others, it must be because they also have a built in silencer but just not as big?

 

Im going to guess the material, the piping, and basically the design.

 

If the catback has a resonator it will also be a lot quieter like mine. HKS.

 

The AVO exhaust is quiet because of the size of the muffler and the thick piping.

 

I've been looking into the Apex'i Active Tail Silencer. I may order one, but they're pretty pricey (~$130). They have a valve with a spring that opens under WOT exhaust pressure but closes during idle and cruise. There is a little blurb about it on the Apex'i website, and they claim it only costs 5-10 hp if I recall correctly, whereas there normal silencer cost about 50 hp. If any Apex'i dealers want to give me a deal on one I'd be happy to write up a short review and video with sound. I could also log some 3rd gear pulls without a silencer, with a normal silencer, and the ATS.

-Paul

 

Ahhhh,

That's the silencer I was referring to. I remembered Apexi, but not the details. In the D-Sport article I referred to, the Apexi silencer made significantly more power than the traditional silencer, but it still lost 20 or so HP on a 500 WHP car IIRC.

I may try one too, it's gonna cost me one way or another to quiet my exhaust down.

Per other threads, adding a resonator would change the tone, but not really the volume of the exhaust. I could get another larger muffler, which would probably help.

What I want ideally is quieter at idle and partial throttle at low rpm (below 3000). So I can sneak past cops and not attract attention idling at a stoplight. If I go WOT, I don't care how loud it gets, heh.

Do any vendors carry the Apexi silencer and would it fit in a Helix exhaust?

Thanks,

FB

 

It would probably more cost effective if you kept the system and simply had a new quiter muffler welded in place of the helix muffler and add a resonator to tone it down a bit. Magnaflow mufflers are as quiet as you can get for a performance muffler.

 

Thanks for the feedback, that's probably the route I'm going to go... Gonna hit up a local muffler shop and see if they can hook it up.

FB

 

as somone mentioned before - the resonator will quiet it down. I beleive some even ahve two resonators. Also, titanium piping will make the exhaust louder as well.