Was speaking to a Capristo representative today in conjunction with a Ferrari Tuner I was wanting to get the Capristo test pipes on my 5.2, but they told me that despite gaining some HP in the top end rev range, I would experience a loss of low down/mid range power down low. This is not desirable as this already is not a strong point for the factory 355 They told me that 200 CEL cats were the way to go in a 5.2 F355 with the OEM ECU. They said the car runs better with some back pressure in the exhaust. So is it true that for a road car you are better going 200 CEL rather than test pipes...? Besides sports cats these days are terribly expensive.. so it begs another question.. Compared to the OEM (600 cel) F355 cats, do 200cel cats actually provide any proven power gain.. or is it just hype..? I have heard that they just increase sound level, and don't offer any power advantage over the OEM cats..
Yes, it's true. A 200 cat is better than no cat. The aggravation of CEL, the exhaust smell, and the standing wave are really not worth it.
Ok Thanks But is a 200 cel cat better than OEM..? If there was a gain in HP in the 355 wouldn't Fabspeed or Nouvalari publish the results..?
Peter, do some reading on Exhaust Scavenging. 200-cell cats will net you less hp, but more torque than cat replacement pipes. 200-cell cat is better than OEM, OEM is something like 800-cell as standard
Have to chime in with a contradictory word of support for cat delete pipes. They don't make the car appreciably louder (I'd say 5-10 percent), I personally do not find they create an exhaust smell problem, I have noticed no change in performance in any direction, and they enable the deletion of the trouble-prone cat ECU/SDL system (use the Technistrada dummy load plugins). And the biggest upside is a major reduction in engine bay heat. They are great for reliability. I also have not had a CEL problem. I used o2 sensor extenders on the downstream sensors with some steel wool stuffed in. And if a CEL does pop, it takes 30 seconds to delete it.
Ok so in your experience Targatime, there is no appreciable loss of low down power /torque with cat delete pipes.. Do you have a 2.7 or 5.2 car..? Ive heard the loss of power down low is worse with the 2.7 car. Any others here that can chime in on their experience of HP gain/loss with test pipes. Quite frankly if there is no Torque loss down low I prefer to go test pipes.. Anyone?
No, this has been disproven many times. Back pressure does not improve performance anywhere. I went from test pipes to high flow cats and noticed a loss of power overall. However the reduced noise (I'm running a challenge straight exhaust) and cold idle smell were worth it for me on a street car. If you're after maximum performance, test pipes and a gutted secondary pipe will provide that. This was on a 2.7 car, the cold idle would make your eyes water until the car warmed up without cats. It also was quite a bit louder, but I'm not running a muffler (at all), so won't apply as much to a car with one.
On my 95 355, the test pipes was noticeable louder, but the exhaust smell was unbearable for someone driving behind me. Finally, every couple hundred miles the car would foul plugs and misfire like mad until I got tired of it all and put the hi-flow cats back. And then all was well.
HJS Germany states the following.. 100 cells flow 96% of a straight pipe 200 cells flow 93% of a straight pipe 300 cells flow 88% of a straight pipe So 100 cels must be better than 200 cel cats right..? Not necessarily so.. for these reasons.. The 100 cell catalytic converters do not have enough surface area to sufficiently scrub the exhaust on OBD2 late model cars and as such cause a CEL The 200 cell matrix is 3 times more durable than 100 cell ( according to HJS) as the cell structure and matrix is much stronger and will not break down and unravel Often 100 cell cores have internal braces that GREATLY reduce exhaust flow on cheap non HJS units) So given the 300% better durability and almost guaranteed no CEL Lights 200 cell HJS is the only want to go. Taken from post 18 here.. a very interesting read indeed.. Flow Bench tested the Kline 100cell Cat vs Bypass pipe. - Page 2 - Rennlist - Porsche Discussion Forums Thats why I want to steer away from Cats altogether and run straight pipes.. Straight pipes offer 7% more flow than the best 200 cel cats. Im only hesitant because of reports from Mr Capristo himself that test pipes in an untuned 355 cause a loss of low down power but a gain up top. If anyone should know it would be him right..? Well thats what the representative told me.. Does anybody know if anyone has successfully cracked the 5.2 motronic ECU and successfully tuned this out..? I mean is it even possible..?
Meantime anybody else running straight pipes on a 5.2 car.. ? Im inches away from pulling the trigger and I need some encouragement..
I can't encourage or discourage you to do anything, but my '98 is a 5.2 and I haven't had any kind of plug fouling problem. As for power, I am sure it's possible that I have less low-end torque and more high-end HP than before. But I haven't dyno'd the car and I personally cannot tell any difference. You just cannot actually notice a 5-10hp difference on a street-driven car that's already pumping out 380hp, at least I can't.
lets be honest; unless youre a professional racing driver you are not going to notice any difference in power! some sound maybe but not power. personally i just buy cheap 200 cell cats to stay legal over here.
It's not even legal over here. If you change out the factory cats, it's an automatic FAIL of the smog test. Most if not all 200 cats will throw a CEL on a 5.2 F355 and you then need to fake out the light. All 100 Cat will cause CEL. Having a bypass test pipe will cause a CEL. And any CEL is an automatic fail of the smog test.
