| Author | Message | ||
| Tim Barnett (Tim_barnett)
Junior Member Username: Tim_barnett Post Number: 54 Registered: 4-2003 |
P. Thomas, I agree with you. Furthermore, for some reason the 355 cats aren't that reliable (at least in my experience). I've already replaced the cats once on the left side and twice on the right side. And all this in less than 22k miles. Although factory replacements are outrageously expensive, I believe you can get them rebuilt for less (outside of California). | ||
| P. Thomas (Ferrari_fanatic)
Member Username: Ferrari_fanatic Post Number: 435 Registered: 4-2003 |
Jon, >>>What is the benefit of putting on test pipes and is it hard to do>>>. $8,000 would be one benefit if you were past the 7/70 or 8/80 federal emission warranty and a pair of cats went bad on you. That is the last figure I heard for a set of FNA cats. Some people are "saving" there cats and puting them on only at smog inspections. FYI, 348 owners reported quicker revving engines but I never saw any dyno specs. For a 355 owner the before/after dyno time would be a waste of $$. | ||
| P. Thomas (Ferrari_fanatic)
Member Username: Ferrari_fanatic Post Number: 434 Registered: 4-2003 |
The 348's saw a greater increase in performance as those cats were more restrictive. The 355 data that I have seen is a very nominal increase in performance on the 355. It appears to be much more of a sound issue vs performance. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 687 Registered: 11-2002 |
Stephen, Can you post your dyno sheets? Did you log A/F ratio when you tested? | ||
| stephen winter (355f)
New member Username: 355f Post Number: 1 Registered: 6-2003 |
HI My own experience is as follows. Having had dyno time and rolling road on the car it would appear that the latest cats are not restrictive in the same way as perhaps used to be the case. In fact there is more backpressure built in to the exhaust than the cats!! this causes the cats to warm quicker and clean up emmissions. A tubi exhaust in my application seemed to improve BHP by 8 hp at with a slight loss of torque throughout the rev range. When the cats are taken out the management system (if you have OBD11) will place a theoretical value in order to run to some kind of tolerance. The indictations we had were the these values were simply not as good as one would want them to be. It lost torique throughout the rev range by as much as 10%. We must rememebr that maximum speed relates to BHP and gearing of course BUT! torque is what gets you there!! so if you want to have a nicer sounding car and not ruin the engines long term life keep the cats!! | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 685 Registered: 11-2002 |
How do you know? Depends on the application. You may actually lose power. You may lose 5 hp between 4000 to 7000 rpm, then gain 8 hp by redline. Testing before and after is the only way to know what the result is. The exhaust system pressure reduction may cause a lean condition at full throttle to reduce power, which can and does happen on modern cars. Some are programmed quite rich at WOT, and that's when you'll gain. The answer is 'it depends'. Some of our members here have the data on their cars, and it's been posted before. So you have two options, find someone with the same car and copy their setup exactly, or, test you car now, bolt on parts one at a time, and test yourself. The latter is what I'd do. It'd suc# to spend $500 - $2000 to make the car slower overall. Do a search for dyno results posted in the archives and also search for your own specific car and what modifications others have done, and if they have real data, or anecdotal a$$-o-meter results (sounds like I gained 25 hp!).  | ||
| Vasilis K. (Goyal99)
New member Username: Goyal99 Post Number: 23 Registered: 3-2002 |
The main benefit is increased HP by replacing the 2 cats with test pipes...There's also less back pressure with the cats removed and less heat generated. You can purchase the test pipes from several online sponsors or have them made by a muffler shop. The procedure to remove the existing cats and install test pipes is relatively easy but you probably have to do it yourself. Removing the cats is ILLEGAL in most states for use on public roads. They are approved for track or off-road use. Now as far as how much more HP you'll gain, the number is probably around 10-15 HP more or less...You should be able to notice a difference mainly in the higher RPM range. Be aware that the noise level will increase as well. For some people that's sweet music to their ears but others don't the increase exhaust rumble. It's a personal choice. No need to install a TUBI muffler when changing to test pipes. By doing so you'll probably gain some more HP by replacing the stock muffler with a TUBI and have less weight hanging out at the back of your car. Any shop can replace your muffler with an aftermarket exhaust. Again the noise level will increase with a TUBI installed but you'll gain HP. Good luck - VK | ||
| JON BAER (Bobaer)
New member Username: Bobaer Post Number: 44 Registered: 5-2003 |
What is the benefit of putting on test pipes and how hard is it to do. Is is strickly for sound or does it increase performance, and do you need a tubi to go along with the test pipes. Thanks. |