348: power increase with Tubi only ?

I don't think you will get ANY power gains at all, as the exhuast is getting choked "upstream" in the form of a catalytic converter. If you remove the cat and install a test pipe, the Tubi would probably give you 10HP or so. Just my opinion though.......The cat might give you 5 and the Tubi around 10??? Maybe.....

Bill

 

Here's what you need to go with your Tubi.

http://cgi.ebay.com/ebaymotors/Stebro-euro-resonators-for-Ferrari-348-strait-pipes_W0QQcmdZViewItemQQcategoryZ42610QQitemZ8060485670QQrdZ1QQsspagenameZWDVW

 

I would tend to agree with Bill - perhaps 15 total when combined with straight/test pipes in place of the cats. Tubi muffler alone might give you 5hp. Every car needs a little backpressure as without any the intake runner pulsing is usually adversely affected, lowering hp.

Of course, some hard data from some dyno runs would be real helpful here....unfortunately, I don't have such data.

 

It will certainly sound faster, and weighs a lot less than the standard 2 box system - probably the biggest factor IMO.

 

While the tubi itself may not produce a large increase in horsepower, it would increase your driving satisfaction and overall performance in two areas. First, the sound is better, agreed by all. Second, the car would corner significantly better since there would be considerably less weight hung on the back end.
Additionally, it would enhance any other exhaust modifications you did upstream, as the whole "stream" needs to be channeled to see maximum performance. Just adding horsepower is not the only answer to better performance. Think "power to weight ratio". It is generally agreed that it takes 15 more horsepower OR 100 less pounds to improve 0-60 mph times by .1 sec. So, by removing weight (Especially in an area outside the axles) and increasing horsepower, you get a much better performing car.
Don't listen to the naysayers, do it and you'll be glad you did!