Do my Tubi back boxes add any hp to my 575?

Darius, your thoughts are in line. Difficult to measure differences with silencers alone, likely single digit hp changes at best. Removing the center resonator would be a slightly better result. There are actually numerous restrictions in our exhaust. Besides the manifolds and cats, the rear pipes around the transmission and the factory "straight pipes" have numerous crimps and bends to allow for clearance. Included on those straight pipes and rarely mentioned are heat shields with a mat material inside around the trans area. Those crimps and bends have to accommodate space for those as well, all inhibiting air flow.

Most of the restriction however is at the front. As you mentioned replacing pieces upstream accomplishes most with Fabio's complete system adding about 10% hp per his research.

Bill
FL
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Darius- Send a PM to Rob and see if he will change his mind. I already tried unsuccessfully.

In general, any lessening of back pressure will result in a slight increase in hp, and the Tubis will do that. To take full advantage, the center muffler/resonator/cork needs to be replaced with straight pipes (maybe too loud with Tubis), X-pipes, or one of Sergio's H pipes (straight pipes with balance tubes). That will probably loosen 10-20 hp compared to the OEM center piece. Since you already have Tubis, no big deal to fiddle with replacing the center resonator, which is really restrictive.

 

I cut my OEM rear boxes open and looked inside... they seem to be very restrictive compared to "straight-through" mufflers such as Capristo, Tubi and several others. According to the 550 press kit, the superb exhaust system has variable back pressure to enable both great torque at low rpms., and "open up" (the Valnes) for high rpm performance. The question is what backpressure that is ideal......?!?! I feel with 95% confidence that t
my 550 is considderably faster with my Capristo rear mufflers than the stock mufflers.... And I do have Hyperflow sports catalyzers too. So in the end, I would say sports rear mufflers adds horsepower. And definately more Ferrari-fun to the car.

 

I tried several combinations on my 456GT.

1) Stock exhaust system = too quiet but inoffensive.

2) Tubi with rest stock. = loud but "felt" like better performance

3) Braden "resonator delete" center pipes with Tubi. = raspy sound,
and WAY too loud for me !

4) Braden centers with stock rear mufflers = the way I kept it.

Little more V-12 sound, but nobody complained. Best sound of all

 

Is there any difference in an aftermarket straight pipe like a Bradan vs. the OEM version on the late models

 

Dan- Not a bit of difference, except cost. A good muffler shop could make you a set out of stainless pipe, too.