are there any downsides to Tubi Headers for the F355?

I have the HyperFlow cats with a Tubi exhaust. The Tubi will be louder than stock. The cats will also make the car louder. I had test pipes before and they are not as loud as test pipes but louder than stock cats. I am thinking of changing to the stock muffler to quite it down abit. It is all personal preference. I am also considering the Capristo but have yet to hear one. The Tubi and cat change will give the car a deeper exhaust sound but nothing like an American V-8

 

On my 95 355 I now have the Hyper-Flow cats with Tubi manifolds and the stock muffler. For me, the sound is perfect. It has enough of a rumble at low RPM so as not to be mistaken for anything but a V-8, but it doesn't set off car alarms at idle. When I get on the gas, above about 4000 RPM, the sound is awesome as the rumble changes to a scream up into 8000 rpm. I like having the stock muffler on as it seems to keep it quiet enough around my 'hood.

I suggest you start with cats and manifolds and then if its not enough sound, add on the Tubi or Capristo muffler.

I am going to try to create a sound file but right now I don't have a digital video so I've got to get a new camera or borrow one.

 

It's unlikely to really sound like an American V8 because of the flat plane crank

 

My experience with Tubi was on my 348.Nice throathy low rpm sound and fearsome high rpm,almost like a F1.Alot nicer than the stock muffler.Little better throttle response and better high rpm performance,and 1 mpg better gas milage.I now have a F355 spider and drove a friend's F355 spider with Tubi and stock cats.Sounds fantastic but alittle too loud forme in a spider.I might go with hyper-flow cats and either an Ansa Sport exhaust or Challenge muffler,which is made by Ansa.About 95db at full throttle on the sound meter at Laguna Seca.With a Tubi,it hits at 107db,too loud and will be black flagged.

 

What about "poping" on down shifts and de-acceleration? Reduction in back pressure usually amplifys to pops. Also...some Tubi's have a resonic "boom" at constant hwy speed which can be annoying..

I was talking with 2 360's owners. 1 had tubi and had poping, switched to Cap and it went away. The other owner just had tubi installed and no poping.. Funny sometime they do and sometimes they don't. Both guys started their cars and reved...so I heard it first hand.

On a 355 opening the bypass works well...might go with hyperflow cats and that's about it...

 

The heat shields on the Tubi's are as good, if not better than the stock header heat shields.
Usually the pop can be traced back to a poorly seated exhaust flange on the output of the cats or bypass valve, allowing oxygen into the muffler on decel (same is possible with bad manifolds). The oxygen going in lights off any unburnt fumes in the muffler.
Dave

 

Happy with the Tubis on mine

 

The popping usually on deceleration comes from the emission control air injectors pumping fresh air into the exhaust manifolds to burn off the over rich fuel mixture.Some cars pop more depending on speed of deceleration ,exhaust temp,fuel mixture,and what rear the car is in at the time of deceleration.Lower restriction performance mufflers usually run cooler,so the rich mixture dosen't burn off as complete compared to stock mufflers which has higher restriction and operate at a higher temps.

 

My 355 has standard manifolds, cats and a tubi muffler. It sounds great at mid and high revs. The sound at idle and up to 3k is a bit resonant, but I like the sound and it certainly isn't annoying when driving. They get quieter in this respect as you put miles on the exhaust. There is no loud popping between gear changes, but there is a gentle crackle on the overr-run and between gear changes. The sound is a perfect compromise between a more exciting sound and long-distance usability.

The cats and manifolds will probably blow at some point. The only certainty is that I will not be buying another set of OEM (OEM manifolds made by ANSA I understand), but more likely some Tubi (expensive) or some reconditioned ones from QV.

In summary, what I'm doing is enjoying the new muffler and saving my money to replace the cats and manifolds when they break...

Robert.