Installed Fabspeed headers and cat-delete pipes ... now too loud

At the end of all this, I may be at the same point you are ... i.e., Fabspeed headers and stock cats. I have the Ferrari "racing" exhaust and that is same as is on the CS.

Steve

 

Hope to learn what that setup sounds like with my 360 ... except with resonators in place of the cats. I am hypothesizing that your cats are, acousticaly, acting like resonators.

Steve

 

I should have the 12" resonators installed in the cat test pipes tomorrow. If this mod is disappointing to me I will be coming back to talk about the sport cats

Steve

 

I recorded a short video yesterday with my iPhone. It actually sounds better on the video than in actual fact. I believe too much raspiness in the exhaust sound. The video was merely a hand held iPhone will driving a city street in Scottsdale. Engine revs between 2500 to 7500 RPM. Obviously, taken from driver's position, windows open.

Here is the Youtube link to the video.

https://www.youtube.com/embed/ptI8pBjUuow

When I get the resonators installed I will do this again and post another to make comparison.

Configuration:
- Ferrari 360, 2004 model year
- Fabspeed headers
- Fabshpeed cat test pipe (i.e., no catalytic converters)
- Ferrari racing exhaust with bypass valves forced open using a Forza Exhaust Controller

Steve

 

I have to disagree ... a bit ... resonators change the sound, they are not supposed to muffle. It is likely that the sound will be different between cats and resonators. Resonators are typically used in partnership with mufflers to suppress excessive noise. The purpose of a resonator is to cancel certain ranges of sound frequencies ... not to necessaryly quiet the sound, although the overall effect when combined with a muffler is to do that. I am hoping to eliminate the higher pitch raspy sound and to also eliminate the "drone" that occurs when the exhaust bypass are open and steady RPM on highway.

Now that said, on the 360 cat test pipes, I only have room to add a 12" resonator. Resonators come in longer lengths to filter different frequencies. Because of the limitation I have with only a 12" length, I will not have the luxury of trying different lengths. I am hoping to achieve a better exhaust tone with a bit less volume and to filter out the higher frequency raspy sound I have now. I will let you know the outcome.

Steve

 

Exactly what I was thinking. At lower RPM sounds much too raspy. At higher RPM is really screams and sounds pretty good. I hope after resonator mod, it continues to sound good at higher RPM.

I will post another clip when I can.

Steve

 

I do. With the bypass valves open, I get snap crackle pop burble when coming off the throttle. With valves closed don't hear them.

Steve

 

In my previous posts I described that I installed Fabspeed headers, Fabspeed cat test pipes on my 360 with the Ferrari racing exhaust setup. It was too loud and the tone of the exhaust was very raspy. I was disappointed.

I decided to install a short resonator in each of the cat test pipes. I used Vibrant 12" resonators. The photo below is a PhotoShop image of what I intended. The second photo is the actual test pipes with the resonator tack welded in place so we could do a test fit.

The result was very good. The resonators eliminated the raspy exhaust sound and toned things down a bit as well. I can say that now it is far less obnoxious ... but still retains the sound that I like. Oh, by the way, I still retain the snap, crackle, pop and burbles when you back off the exhaust. I even get the occasional flames shooting out the exhaust tips. I will make a short video in the next day or so and post it on YourTube with a link.

My only problem is that I am getting Check Engine Light. I have the Fabspeed O2 extender with mini cats, but they do not seem to prevent the CEL. Would like to learn how others may have prevented CEL without any catalytic converters. I get P0421 code in Bank 1 and P0431 code in bank 2. I have read that these codes which relate to Warm Up Catalyst Efficiency below threshold are the result of cat deletes. Short of tune would love to hear if anyone has avoided these CEL issues.

My conclusions and recommendations from all of this ...
- If you are going with headers and cat delete, you should expect very loud exhaust and more than likely a raspy sound.
- Resonators really do a good job toning down the exhaust note and eliminating the raspy tenor.
- If Fabspeed is listening, they should offer the cat test pipes with an option to include resonators. It makes a huge difference.
- If you were to use high-flow cats, I expect the difference in sound level would be similar.
- I have the Forza exhaust controller which is really a great for opening the bypass valves at lower speeds to hear the sound at all engine RPM.

Steve
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Yes ... was there all day yesterday ... actually helped out. Installed resonators and sound much better. The A/C was simply that they forgot to plug it in when they installed the headers. Made the electrical connection and all is better now with the A/C.

Steve