Simple question about mufflers

I'll be happy to trade you my stock muffler!

Feel free to search, there is a lot of debate about running the bypass valve open and the downstream impacts it had to engine health. Now the inverse, imagine cannot be good as it would overheat your stock cats and cause a potential fire hazard.

 

The factory exhaust is quite a bit quieter than any of the aftermarket noise makers (err....that is mufflers)--I like mine quiet most of the time (which is why I still have the stock exhaust on the car.

You can simply pull the rubber hose off the bypass valve and disable it--until you want the sound back.

 

I would think stock setup should be perfect if you want quiet. I have not driven one with a stock exhaust but they seem pretty tame from video's I've seen.

Not sure I would disable the bypass however. If you really must, I would test exhaust pressure and make sure it isn't excessive at higher rpm/throttle openings.

 

John just before i sold my spider i removed the tubi and put my stock muffler on.It has tubi cats and with the stock muffler its not loud at all.Don't disconnect your bypass valve because with the stock muffler you cant tell much when it opens.yes my valve did work because you sure could tell with the tubi when it opened.The car still sounded ok and i could not tell of any performance loss.

 

I had a Tubi and sold it for the same reason as you stated. I now have an OEM muffler that I bought with supposedly low mileage. So my experience relates to this muffler which may or may not be typical. It certainly looked like it was in good shape though from the outside.

My main objection to the Tubi was its drone. It was often difficult to carry on a conversation without having to talk very loud to be heard over the drone, especially with the top up (I have a Spider). The stock muffler completely fixed that. No drone at all. It is definitely quieter than the Tubi when the valve is closed but you still know its a Ferrari. Its definitely not dead quiet like a typical passenger car. However, when the valve is open, I don't believe there is much difference between the OEM and the Tubi. The famous Ferrari scream is definitely still there. Perhaps a bit less than the Tubi but just a bit.

I'm very satisfied and like it much better with the OEM. You sort of have the best of both worlds. With the valve closed, sporty but not obnoxious. With the valve open, screams nearly the same. Just exactly what I wanted.

 

Leaving the bypass valve always closed or always open WILL throw a Check Engine light for a malfunctioning bypass valve (on the 5.2 Motronic cars). There is a thermoprobe just past the bypass valve that monitors the exhaust temperature. That verifies the valve is opening and closing as expected. If you force it always open or closed, the Motronic will detect that, and throw the code.

Antonio Capristo states on their website that if you drive flat out with the valve always closed, engine damage will result, and has been documented in Germany. That was one reason he developed his bypass valve that if disconnected, it will default to open, rather than closed. I would advise to source a stock exhaust if you want the car quieter...they are super cheap on the used market. Hell I have one that is near perfect, low miles I would sell for a reasonable cost...

I just bring these thoughts up, as a counter to the idea of keeping the valve closed as an option. It is "probably" okay if driven gently...that is, in such a way the valve would never open anyway.

 

Fwiw, Capristo is quieter than tubi when valve closed.

 

Really? I had a Capristo stage 1, and it was still pretty damn loud at idle, seemed comparable to my friends with Tubis. Definitely louder than stock, and freakin' all hell broke loose on bypass!

 

f355spider is right about Toni Capristo and his research done in Germany. It is well documented by Toni in a German forum.

As the Capristo valve is a really good improvement, for me Tubi and Capristo exhausts are too loud. I have a Fuchs Export exhaust which is a good compromise. Not as quiet as factory, but still acceptable for the neighbors. Fuchs is having in my opinion the best sound for the 355 and other F-cars of that time.

 

I have the low decibel 355 challenge exhaust with stock cats. Relatively quiet at idle, louder with the bypass open. Had Hyperflow cats before, too loud at idle and around town. Probably sell the Hyperflows soon. Stock cats with the tubi may give you the sound you want.

 

I am not a big fan of louder is better, I do love to talk to my passenger and enjoy that more then the car.

I had the Tubi on my spider hiflo cats

Pretty loud I could see it startling wildlife on some of the roads up in NE, don't want something jumping across the road or scare some new borns

I went to stock 300 cell cats and a little quieter.

The stock exhaust is sill a bit loud when your running 5-8000 rpm. As long as your not winding it up stock is pretty manageable even when the bypass starts to open

I just would not chance keeping the bypass open as too much flow will eventually cause an issue.

In a nutshell, yes the tubi is way louder then stock

I have a 99 muffler but shipping is huge, your best bet is get one locally and sell your tubi if you want to sell it

 

I had a tubi with straight pipes before my capristo. Tubi is definitely louder just driving normally around town. I can drive my car with Capristo/test pipes around town and make it as quiet as a BMW if I wanted to.

 

I am curious - is there any way to add a siliencer to the exhaust/muffler to make it quieter at low RPM/idle?

 

http://www.ferrarichat.com/forum/ferrari-parts-collectibles/471810-oem-ferrari-f355-muffler-%2Aexcellent-condition%2A.html

 

I might grab that one... It's good to have stock parts just incase

 

pm sent

 

Yup, they are very heavy...they can also fail. I had one that got an annoying buzz/rattle over 3500rpm. Started around 40k miles...took forever to diagnose....loose baffle inside the muffler. Got a very low miles (excellent cond) used one...but removed it a few months later for a Capristo. Gotta put that used one on Ebay one of these days....Yours looks like it has been used some...based on external condition...you might be able to clean it up some with some metal polish...worth a try.

 

Johnk, did you fit that stock muffler? how did it sound compared with the tubi?