triangle123

I have always heard tales that if you a drive a car without an exhaust the cold air after shut down will warp the valves over time. That just doesn't seem to make any since to me since there are still the resonators and headers which will be hot and when your engine is running it sucks in cold air. Seems like complete BS. Other than being annoyingly loud, is the really and damage to be done to the car driving with the exhaust off? It is something that has been weighing on my mind recently. Would like to know others input, thanks.

itsslow98

iTrader: (18)

Are you syaing open headers or literally no exhuast at all?

bmylez

iTrader: (3)

What resonators are you talking about.

UnsafeAtAnySpd

Sounds like you're talking about driving the car with the stock manifolds and stock cats? That's fine. Do it.

bmylez

iTrader: (3)

Yeah, if there is any sort of pipe hanging off of the header, no problems, especially if they are cats.

4doortypels

iTrader: (39)

ive ran open header when i put my diff bushings in to make sure every thing was good. the stabiltrak went crazy and nearly lost control... felt like the brakes grabbed when i was at WOT. rear end got loose and swayed... not sure if it was bad luck or what as i would love to run some cut outs and no one seems to have that problem

isis

iTrader: (1)

That sounds like the rear broke loose and the car caught it. Not sure what that would have to do with the exhaust??

UnsafeAtAnySpd

No, it's because of the exhaust. I believe the yaw sensor is under the center console area which is about where open headers dump. The vibration sets of the stability control. I run mine full off with cutouts open or it will try to kill you.

isis

iTrader: (1)

That's crazy. Makes sense tho. Few layers of dynamat under there might help?

BigBlock.Condor

Though I'm not sure if it is because of the yaw sensor, this is 100% true. I had that same exact problem every single time I banged 4th going in a straight line. The rear right brake would lock up momentarily and kick stabil-track on. It happened from the moment I ran open cats all the way up until I put the catback back on (almost 2 years). It's annoying as **** but the car sounded MEAN! Oh and for what it's worth, I lost massive amounts of torque and the motor revved out about 1.5x faster.

In conclusion: it sounds fantastic but performs like **** (and dangerous if you aren't expecting that 4th gear fishtail). I don't suggest running it that way for an extended period of time unless you have to for some reason.

black_ax

Its not going to be the YAW sensor. Its most likely all the new exhaust flow causing the rear of the car to get light and you are more likely to get strange handling when this happens.

ravenls6v

Exhaust flow changing handling on a nearly 4000lb sedan...do you smoke rocks?

metalmilitia606

iTrader: (8)

black_ax

So you think that in a car going above 100 mph (4th gear) in a something that creates no downforce (the CTS-V makes lift like most cars ) That a new charged air flow (high pressure) under the car will have no affect on the handling??

The car was built to handle a certain way for a 4000 pound car, when you start changing things , other things might start to act different.

Now I'm not an expert just a aerodynamics and CTS-V fan.

ravenls6v

Not the effect these guys are talking about...and no you most certainly are not an aerodynamics expert. Are you running a space shuttle or a cadillac? Maybe if I run straight headers my V will fly too I guess. Time to be quiet Chet.

black_ax

Isn't the affect these people are experience is stability control activating, and locking the rear wheel?? I'm not sure of anyway that exhaust could lock up a wheel by it shelf.

You might also be surprised how little it takes to upset a car at speed. Judging from how condescending you are instead of sharing ideas and having an adult conversation about a issue that affects our cars in a very limited case I'm forced to assume that you haven't setup up a car for more then "street" use

ravenls6v

So you're telling me that the exhaust flow has enough pressure to make the rear end of the car light, light enough to affect traction activating the stabilitrack and momentarily locking up a brake? Is that it? Enlighten me expert. Because on this car, I say bullshit.

black_ax

Well something called an exhaust blown diffuser can make up to 1 sec a lap difference to an F1 car. The principal would be reversed because the energized air is not flowing over a diffuser but under the car/diffuser.



So on the F1 car the energized air flowing over the diffuser raised the pressure difference and makes more downforce adding more rear end traction.

Since our care is built more like a wing to make lift to help with gas mileage and such we don't make downforce.


so adding even more energized air to the bottom of the car can make the rear end light. couple this with all the air flow that is already under the car at 100 mph and I can see how this could unsettle the car and cause the stability control to step in.

Again i'm not an expert when it comes to air flow I just know that at speed our car is not stable and adding even more lift would not be a good thing.

ravenls6v

Ya you just explained lift...Look under an f1 car and then look under a v1, apples and orangutans...

black_ax

Correct, one makes downforce. One makes lift.