360: Disconnecting exhaust by-pass

Just for kicks, I disconnected the stock exhaust by-pass valves in my 360 spider, yielding a more robust idle tone, and more gusto during low rpm acceleration. Has anybody else tried this? Does anyone know if it hurts performance?

Btw, it was easy; I disconnected the electrical connectors from the vaccuum switches.

 

Update: I've put a hundred miles or so on the 360 with the exhaust by-pass valves held open. Verdict: sounds great! More bass at idle, more exciting low speed sound, and no resonance. It's not all that loud either. Let me know if you want instructions.

 

Please PM me the instructions.

 

Please send me a PM with the instructions. I would like to give it a try too.

 

Did it last night, oboy, imagine my smile as I heard what was close to my ex 348 tubi sounds coming from my 360, fantastic. Disconnected the leads (all of 30 seconds work) started her up and hey hey, thats sounds better. Shut car off, reconnected and started her up again - oh dear, just another muted engine. No guesses what mode I will be driving around with this weekend. I hear that Porsches have an option for an inboard switch do do this on the fly - hmmm methinks this might be an idea.

 

Forgot to thanks Ray for this - Thanks BUD!!!

 

Hey guys,

please pm me with the instructions too!!!


thanks in advance,

 

Please EM the instructions to me also

 

Interesting, it must work in reverse to the 355 which is closed until the vacuum control is opened by the solenoid wheras the suggestion is that by removing the wires it stops the solenoid thus leaving the valve open. I can't believe it would do any damage, it's just there to meet driveby noise regulations (at least for Europe), i had to wire my 355 open last year when the valve failed and it sounded much better and I still believe pulls better as well

My P4 replica project has a pair of 360 valves diverting the exhaust to straight through pipes with a dash mounted switch to open/close them

 

Let's see the instructions - sounds like fun!

Thanks
Dave

 

Does not hurt performance, but just watch your cat temp...

Price to pay for extra noise.....thousands(when you can't pass emissions)

You should just wire the by-pass open if anything.

 

Vaughan,

For some reason I can only find the connector on the right side, not the one on the left. What year is your car ? Did you find one or two connectors ? Assuming it is a single valve in the muffler flap, why would there be 2 anyway ?

Thanks

 

The way a 360 was meant to sound is to remove the cats and that 900 lb stock muffler, replace with bypass pipes and a Tubi. Your engine will appreciate it!

 

Will post some pics tomorrow, there are two, one for each side as each side has a valve. Can only do the car good as it breathes easier!!

 

Thanks. It would be great to see the picture of the one on the left side.

 

Hey Mark,
I'd quite like to try this on my '97 355, to see how it sounds. Do you have any instructions on how to do this on a 355? Is it easy?

I've already got a Tubi, but my cats are still on (they might be coming off in a couple of weeks after MOT).

Thanks
Adrian

 

Ok here are the pics, the blu arrow is the connector that is now unplugged and the Amber arrow is the valve solenoid or whatever that controls the exhaust valve in the muffler. The first pic is the left connector as your facing the engine.

 

Question to those in the know, should I cover up the loose connectors to prevent water from getting on the connections??

 

I'd cover them....

I'm not clear on those pics - do I need to pull off the muffler to get to the solenoids? Or go in from the bottom?

Thanks
Dave

 

How does this increase cat temps?

 

Vaughan,

Found the connector. Thank you for the pictures.

I cant wait to give it a try !!!

 

Here are the instructions again:

1. Open the engine lid. On the spider, remove the two access panels on the sides at the rear. You'll need a metric #4 allen wrench (or a 5/32" allen wrench).

2. On the coupe, look directly to the left and right of the muffler. On the spider, look under each panel you removed. There is an electrical connector attached to a gray or white plastic block; the block is a vacuum switch. If you look closely, there is a black hose that goes from the vacuum switch to a vacuum can which operates the exhaust flap.

3. Disconnect the electrical connector by pressing on the underside of it while pulling it out. You might want to twist-tie it to something to keep it from flopping around. Btw, you can disconnect and reconnect this with the motor running to hear the sound difference.

The one on the right side (passenger side) is easier to reach because the left side has an electric air pump mounted in there. (At least on my spider there is.) I didn't disconnect the vacuum line itself because the left side was too difficult to get to. All you need to do is disconnect the electrical connector at the vacuum switch.

4. On the spider, replace the access panels. Be careful not to drop the screws or washers down below because they will get trapped in there. You might want to use a towel over the muffler area.

That's it! Enjoy,

-Ray

 

I don't see how it affects the cats, since the by-pass is downstream from the cats. It should be the same volume of gas passing through them.

 

Thanks for posting this information. Here is me experience:

I tried the exhaust flap bypass mod today and must agree that the exhaust note at idle sounds really fantastic. BUT, I do think that there is a loss of low RPM torque with this arrangement. It is most noticible when accelerating from 60 mph in 6th gear without downshifting. I would like to dyno or do timed acceleration runs to be sure, but I really do think it must be a significant loss of torque for me to notice it. Maybe the ECU will re-learn and things will improve ? I dont know. Above about 3500 rpm everything is fine. Also, once the car is moving, the induction sound is still louder than the exhaust so the sound is improvement is only noticed at very low rpm.

Do Tubi or Capristo have these issues ?? I dont think they have a flap/valve.

 

Thanks for the description Ray - easy enough. Sounds great in the garage, I'll need to get out and drive it!

Dave