355 bypass valve removal

I doubt they are widebands. I have only encountered one stock car so far that had a wideband O2 sensor. It was a Honda Civic HX and the reason it has a wideband is because they run it lean to save fuel. It was rated at 44 MPG when it came out. The other models of Civic had regular o2's.

Widebands are about 4-5 times more expensive than a standard O2 sensor. I think I paid about $285 for that o2 sensor off the net and the other civics were about $65.

My headers and bypass valve are currently fine and working, but I have ordered a header already to do what you are contemplating. I need to do a major service soon and was thinking I would just do a custom exhaust while I had the engine out. I ordered an Agency Power 360 header that they are putting straight collectors on (no Ferrari flange). This way I can use whatever flange style I want (something common). The rest of the exhaust will be custom using off the shelf cats, mufflers, and tips. It's kind of a tough decision because my exhaust is fine and I have a Tubi muffler, although I am getting a check engine light that I have not spent time diagnosing (could be cats or 02's).

 

I just have wonder why Ferrari would have used a narrow band oxygen sensor on a $130k car. Ah, well, I should have expected as much... along with the cheap electrical connectors and paper thin headers.

Part of the fun will be fixing the shortcomings.

I see a gold connector kit, headers, a major service kit, and a fair amount of work in my future.

 

No need for a wideband in most cases. Once a car is tuned a wideband is not needed any more in most cases. Production cars are loaded with a generic tune that works for all minor motor variances usually and simple 02 sensors do the job fine. The car does not solely rely on the oxygen sensor for air/fuel ratio when it's operating off the fuel map. It will monitor it for a problem to flag it though. Research closed loop versus open loop....Widebands would be a waste in most cases on production cars.

Just imaging the Ferrari tax on wideband O2's and you will be happy they did not use them $2000 oxygen sensors? LOL

 

And then you can breathe easy!

 

Lol, ya $2000 sensors. I am very excited to get started, a little bummed that I will need to drop $10k on a car that runs ok already, but it will be worth it.

Still its only money, I will make more.


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Bringing this back to live, I've noticed that when going very high on rpms obviously the valve is open and you get the high pitch sound, but the moment you let the throttle go, even when you're still at 7 or 8K rpms, the exhaust goes silent, so I suspect the valve is closing. This is really annoying to me because it makes it impossible to get feedback from the engine when downshifting in sport driving.
I haven't noticed this weird behavior in other cars, nor in modern Ferraris.

Anyone else experiencing this same thing?


Now on this video (which is a bit weird because I have no idea why the driver is doing that blip/clutch combo in the 35) I can clearly hear the engine when he lets the throttle go at the end of the clip. My car is not doing that though, it just goes very silent:
https://www.youtube.com/watch?v=hDXXdGfbPnA&list=FLaGPZ1bDQ7ATyf357gTSEiw&index=215

 

The bypass valve will close the moment you are off the throttle or in cruise mode.....regardless of rpm. This is normal.

 

And that is why i have my bypass wired open

 

So...
Wasn't the general opinion leaning towards it's bad for the engine to get rid of it?
What about a switch that could leave it open? that way on the track it could stay open all the time since we're going higher than 4000 rpms anyway all the time.

 

when I bought my 355 a 5.2 car.. I noticed it was pretty quiet.. all stock exhaust..
there was no change in exhaust note even at higher rpms..

when I brought the car to my mechanic.. he confirmed the bypass was not opening..
he tested it, and it was functional.. but was not opening under operation.

mine is not wired open, instead he re-routed the vacum hose to the valve.. so that it remains open at all times..

i read the other comments that this could cause damage.. but I much rather have it open at all times, to releive restriction, then it being closed at all times.

this will be further addressed in the spring when I get the car back to him..
but for the 3-4 weeks I drove the car.. before storing.. i did not get any CEL or issues at all.

I addressed the issue of leaving it open with the mechanic, as i read this thread in the past. he is very knowledgeble of the 355, and he suggests there is no issue to leave it open, and has many other client 355's, with it open all the time, with no side affect issues.

overall, I do prefer that it function properly, and this will be something to tackle in the spring... but for now, I have no problem with it being open.

another note, is that I have a Euro 5.2 car.. which does not have the 3rd Tc at the bypass. so potentially this goes to my favor.. as there is no cat ecu up there to read the temps..

but again, im the only Euro car in the area.. as mentioned my mechanic has many other client cars with it open, and said they dont have issues etc..

 

This is a great read!!!
So it's ok to have the bypass in open mode all the time?

 

Why don't you guys just get an exhaust valve controller?

That way you can open it for short stints when you want to hear it scream or if you're on the track?

 

b-b-b-but fuel trims and reverse vacuum and melting cats!!!11