JB911

I've been searching for more info on this-this seems like the only solution if you want the valves open or closed all the time, regardless of rpm, and whether or not you have a bypass pipe- because just unplugging the solenoid can send a code/flag to the DME, according to a post I read-
Anyone get codes from unplugging the solenoid?

http://www.carnewal-europe.com/cpx_p97084.htm

Best,
JB

M3EvoBR

No check engine light unplugging the solenoid. Maybe a code in the ECU, but no harm. A code in the ECU can be erased with a U$ 50.00 OBD2 reader.

Be careful with running the car at high RPM full throttle with the valves closed. Greater back pressure higher exhaust temps therefore higher exhaust valve temp which can lead to detonation... this can effect in the long run.

ScorpionT

Agreed. The GT3 has enough heat issues, and running the car even at 6/10ths with the valves closed will exacerbate things. Other than that, the Carnewal solution works just fine.

Serge944

The carnewal remote is a great mod - best of both worlds.

Nothing wrong with leaving the connector unplugged all the time...that's the way I run mine and really have no desire to change the exhaust.

And people blow the fault thing out of proportion. Putting in an aftermarket stereo causes a fault...so what? Doesn't affect anything.

TAI2

I would be concerned with toasting your engine (mufflers, headers, exhaust valves, etc....) versus throwing a code.

Serge944

There is hardly any backpressure in these exhausts. The valves primarily manipulate the exhaust length to take advantage of scavenging throughout the rpm range. If Porsche could infinitely adjust exhaust length (like a variocam adjuster), believe me, they would do it! You are not going to toast an engine by manipulating the exhaust valves.

Besides, unplugging the connector leaves the valves permanently open.

M3EvoBR

Serge,

So you're stating that the stock exhaust in a GT3 has hardly any back pressure and by closing the flaps, you also wouldn't increase the heat, EGTs and back pressure in the system ???

Serge944

I don't think there will be a substantial difference - certainly not enough to worry about damaging your engine!

"Backpressure" is a huge misconception. Your exhaust system affects the pressure inside of it in the following two ways:

1. You lose exhaust gas velocity through friction in the exhaust plumbing - for example when you change the direction of the flow, e.g., bends.

2. You gain exhaust gas velocity through vacuum that is generated through pulses traveling upstream (scavenging). This changes with the "tuned exhaust length" which is characterized by the pipe diameter, length, expansions boxes (mufflers, cats), etc.

Now the important thing is that scavenging has a MUCH greater effect than the minor plumbing loses. A properly designed exhaust has a higher exhaust gas velocity. The faster the exhaust gas velocity, the more power you make. Like a restaurant, the faster you get people out, the more can come in, and the more money you make.

In a different scenario, say your catalytic converter is melted and acts like a road block, then yes, that will be a huge flow loss, that would increase your exhaust gas temperatures substantially. THIS can damage your engine.

All of this is less applicable for turbocharged applications, where scavenging has a smaller relative effect.

M3EvoBR

I understand the concept on how the diameter, length and form of a exhaust / headers work or doesn't.
Did you ever used a EGT probe to verify how the temps rise without the appropriate flow ?
Even better, use like I did many time on turbo cars, a boost gage in order to test back pressure from a system.
The side muffler itself is already restrictive enough on a 3.8 car, and by blocking the bigger diameter exit will def. implicate in higher exhaust gases. Would be interesting to test it at a track so we can see how high the temps go, and if they go to the point where the DME will retard ignition on a closed flap exhaust under full temp over and over again.
In turbocharger cars you still need the scavenging effect, but with a different effect (headers) spool up the turbine faster, but of course you're than limited by the hot side housing and wheel, tune and boost and after that the exhaust itself.

aircavscout

Ok, perhaps I am a bit slow, so unplugging them closes them correct? Close is loud or open is loud? What do they default to when you unplug?

M3EvoBR

Unplug is louder as it opens the 2 exits from the side mufflers to the center muffler.

JB911

I'd think those manufacturing the bypass pipes have data and know what happens when you run the solenoid unplugged(?) Do they recommend unplugging it?
Also there's not a lot of info on the Carnewal product...I'd be worried about long term use, I guess
But what about complete racing systems, headers etc. Cracking, etc... and I wonder what codes do cars get with other complete systems (headers, no mufflers, etc)
JB

M3EvoBR

What do you mean, by running the solenoid unplugged ? There is absolutely nothing bad that can happen by doing that.
The data in fact here discussed was about restriction and also high EGTs caused by restrictions.
When a system crack, can trow off the O2 readings, which you have 4, but only 2 of the 4 are actually important for the health of your engine (primaries) while the other 2 are there for emission purposes.
Depending where you have a crack you will have false O2 readings which can throw of your short term fuel trims, and eventually throw a check engine light by having the 2 banks with big discrepancy.
This of course in case of defect.
Exhaust systems that are designed with maximum power in mind will eventually compromise, maybe sound, drone, 1000 RPM, 2000 RPM, or not at all ... question is to find what you're looking for and what is important to your needs.

JB911

>>What do you mean, by running the solenoid unplugged ? There is absolutely nothing bad that can happen by doing that.

Well, the post I had read on another forum mentioned a code registered because the cable was unplugged, and I believe the dealer said could cause denial of warranty claims-
Anyway, do most people running a bypass unplug the cable? Seems a lot of people running the stock exhaust unplug it-

Best,

JB

M3EvoBR

Really hard to believe an unplugged solenoid would cause warranty denials.
Usually if you keep your headers stock they don't give you any hard time, that means aftermarket exhaust OK.
The ON / OFF sound on the stock system is really annoying.