5 different F355 exhaust configurations

Well this past Sept marked 2 years of ownership of my 1997 F355. Subtracting 2 winter storages in that time frame and downtime while car was at the shop for other misc things.. maybe accounts for 12 months total drive time.. maybe even a little less..

Surprisingly, in this short time.. ive already experimented with 5 different exhaust configurations..

So here are my thoughts/experiences..

First: all stock setup:

When I bought the car.. the exhaust was all stock. Being my first time driving a 355 or any Ferrari for that matter, it was still exciting and sounded nice. But very quickly realized the stock exhaust note was not too eventful/dramatic. So not much explanation here. But would be the basis of comparison as I progressed with other setups.

Second: all stock + Nouvalari Super Sport Exhaust:

Very quickly after initial purchase of car, max 3 weeks, I found the Nouvalari here. I snatched it up right away and got it installed, while the car was at the shop, working out some initial issues with the SDL system, Cat ECU’s etc. the Nouvalari, provided the much needed character to the exhaust tone. Very nice sounding on its own. Not too crazy loud, but far better then the stock exhaust. In terms of performance, nothing really noticeable. I was just happy to get the stock piece of junk exhaust off.

Third: all stock Cats + Fabspeed Headers + Nouvalari:

After one full summer ( 2015) running the car, it was due for a major. Which I had done over the 2015/2016 winter. Nervous about the whole stock header risks, and despite inspection by my mechanic that the stock headers were still ok, I still went ahead and picked up a set of Fabspeed headers. And had them installed while the engine was out. During initial drives in spring 2016 after engine out was finished, the car did seem to pull nicer/harder. So the headers seem to have added some gains. Or could just be the result of the fresh major? Sound wise it was more or less the same, but lost just a touch of the very high pitched tone at the very top of RPM range, which has been attributed to the 4-1 design of Fabspeed headers.

Fourth: all stock cats, Fabspeed headers + Fabspeed (tube only) challenge exhaust:

By June range 2016, after hearing my friends 355 with test pipes, I was hungry to unlock more sound out of my car. But since I have a 5.2 car, did not want to deal with CEL etc, so after much debate, went for the Fabspeed challenge exhaust. This way I could retain my stock cats etc. by far this setup was the most dramatic, loud, crazy sounding. Even with stock cats still on. And up to this point, easily showed the most noticeable change in performance, with very noticeable pickup in throttle response. So it appears a traditional exhaust, even if aftermarket, is still restrictive on the exhaust flow. it was night and day difference with the challenge in place of the Nouvalari. As soon as I got on the throttle during first drive after challenge installed, it was noticeable immediately.

Fifth: stock y-pipe, Fabspeed headers, gutted hyperflows + Nouvalari SS:

Last but not least, around Sept this year, I picked up a set of used Hyperflows here. One core was broken. So I had both gutted and installed as a test pipe setup. I was still too curious to run this setup. But I swapped back in the Nouvalari. I think it would have been just too crazy to keep the challenge on. Luckily and main reason I bought the hyperflows is cause they came with straight/hollow O2 spacers. So I figured this was my best chance to test this setup on my 5.2 car. I had steel wool stuffed in the spacers in hopes this would prevent any CEL. Got the car back this past Friday. Surprisingly it is not as loud as the challenge alone. But still sounds great and a lot nicer then setups 1-3. Initial feel in regards to performance, the very quick throttle response offered by the challenge is lost a bit. So this definitely has to be related to the Nouvalari back on. But from a standstill, bottom end/mid, pickup/torque feel seems to have been improved. So this is most likely due to the empty cats. Very top end more or less the same. So it seems with no cats helps open up gains, but still offering back pressure with the Nouvalari.

Conclusions:

During my research.. is seems every 5.2 car reacts differently with a no cat setup. Ive driven ~100 quite hard miles already enjoying the car with this new setup, and has not trigger any CEL. So for now the steel wool in the spacers seems to actually work! we’ll see if it continues. The only thing ive gotten is if the car is left at idle for more than a few minutes, the SDL will start to flash. Technically this makes no sense at all, cause theres no cats to overheat now, but something is spooking the computer to trip the flashing SDL. But it will always go out as I get rolling/driving again. Get going through the gears and voila it shuts out and stays off, until the next extended idle period. So I have no problem with that. So for the moment my no cat setup has been successful..!

Anyways.. just thought Id share my experience with 5 different setups in relatively short amount of time. Offering a pretty good gauge how the feel of car changed with each configuration.

 

thanks for the feedback.. I must have spent hours reading/research.. all kinds of posts etc.. regarding no cat setups etc.. so thought Id share my personal results..

indeed that makes sense.. regarding the exhaust flow.. with empty hyperflows.. but thanks to a member here, I got them for very cheap.. so I went for it.. the hyperflows are a lot narrower then stock cats.. but obviously not straight like test pipes. and perhaps given the shape of the hyperflows + spacers/steel wool has offered my "luck" thus far with no CEL..

believe me ive been looking for a set of used test pipes for a long time and could not find a set..! and did not want to pay for a new set..

if I can find a set or if someone comes forward with a set for cheap I would do it..!

but this current setup would remain for the last 3-4 weeks of this season until storage. if I find a set would do it next year

 

hi there..

the spacers screw down into the post O2 bungs already drilled out of the cat.
at the bottom of the spacer threads that screws into the bung.. there is a very little hole.
this is the hole that allows the exhaust gases to pass through the spacer so that the O2 sensor can sniff the gases for reading..

by my research.. leaving the spacer empty can/would still result in a CEL.. cause the gases are not scrubbed anymore by a cat core. with an empty spacer the results have been random. but with the use of steel wool.. the results seem to be good.. and working in my case for now..

inside the spacer is a chamber.. once stuffed with the wool.. it cannot blow out.. and does not interrupt the flow of gases from the header through to the exhaust inlet..

the net effect.. is that the wool is offering some amount of scrubbing of the exhaust gases.. so that the O2 sensor is happy enough not to trigger a CEL for cat efficiency etc..

 

I think it has to do with their manufacturing process, with the 4-1 collector..

where it looks like they are using that collector for many other products.. so in terms of "economy of scale", they just adapt this collector for many exhaust parts.. including the 355 headers..

honestly the tone difference is minimal.. but I guess enough to notice there is a difference.
for the price point.. more then enough for the sacrifice.. and no more worries of melting headers..

Tubi headers hands down.. is the best product available..
although it seems pricing has come down somewhat from the claimed $6000USD.. I still just could not accept paying anywhere within that vicinity..

 

so I've driven close to 200miles with the new gutted hyperflow's setup.

no issues and no CEL. car runs great. bottom/mid range torque feels livelier.

sounds great.

but as Mike mentioned above, he got me thinking that the hollowed cats may be holding back the test pipe scream we are used too?

given the cat is still oval shaped they may almost be acting like a resonator?

would it be the consensus that a straight test pipe would offer more high pitched sound?

here's a picture of the gutted hyperflows with spacers that are on the car now.
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UPDATE: exhaust configurations continue! a little late as ive been running this setup a while now, since beginning of 2017 season.

SIXTH: Fabspeed headers, Fabspeed TestPipes, Fabspeed Mini cat spacers, Nouvalari SS and Stock Y-pipe.

given I had success with no CEL with the emptied Hypeflows + spacers/steel wool. I was on a mission to run test pipes. but during my searches previously it seemed to be hard to find a used set. and that's why I went with the hyperflows when they popped up. so finally found a set of used Fabspeed testpipes and bought right away. sold the hyperflows along with the spacers they came with. so now was a chance to test the Fabspeed mini cat spacers and picked up a set. with the test pipes now, is by far the best overall sounding, returning the glorious high pitch sound, that was lacking from empty hyperflows. performance wise no noticeable change from setup #5. but that sound with the straight pipes, nothing beats it. the fabspeed mini cat spacers are working flawlessly. not a single CEL in 1500kms. so 5.2 car owners out there, you can run this without worry. the mini cats are beyond over engineered. there are full cat cores inside the spacer/cylinder. all other setups had their positives, but like this configuration the best. however performance wise, the Fabspeed tube only challenge exhaust.. offered the most notable change, especially with throttle response. it would have been interesting to see/feel the result with testpipes+ tube only challenge exhaust, but it wouldn't have been a setup I could keep long term, as the tube only alone was crazy loud. as well I sold pieces as I was moving along.. next configuration will be an aftermarket y-pipe.