Has anyone put an exhaust flex section (like modern cars) into their system with headers? If so, any issues with leaks or life?

The reason I ask is that I run an X-pipe, which ties both sides of the exhaust together. It seems there is much less movement possible with the pipes, and I wonder if this contributes to shorter lifespans for the header and collector gaskets (more resistance in the pipes causing more stress at the headers).

Thoughts?

don't know why you couldn't... you might need to add hangers to the spot where you have them as they would tend to sag I'd think.

I have a 14 year old TTI system with a H pipe that is solidly mounted. 14 years later it's still solid and don't leak at all.

Not worth the trouble and I bet you a flex anything is not going to last 14 years. And I drive this car a lot all over the country including in the salt at bonnville in Utah. So my system has been exposed to a lot of different conditions and has held up great. TTI is a great value.

You will just mess up a great exhaust system with a flex pipe and just give it a place to leak, don't do it even if it's not TTI.

"you might need to add hangers to the spot where you have them as they would tend to sag"

Good point. I hadn't considered that, and expect it might be a bit of a challenge to find a good attach point. The trans cross member is the only thing in the vicinity that might work.

If your going to use flex pipe, make sure its
stainless steel or it will not last and it will
leak over time.

"I have a 14 year old TTI system with a H pipe that is solidly mounted. 14 years later it's still solid and don't leak at all."

I hear what you are saying, and understand that there were even factory systems with an H that lasted a long time. I use TTI headers and X pipe. Behind that is a mix of stuff. I don't seem to be able to go a year without loosing a collector gasket on one side or another. I've tried several different gaskets types (not full metal yet though).

How choppy is your motor at low RPM and how much movement does it have?

In trying to understand why this happens, the one thing that stands out is that when both sides are coupled each side looses it's ability to move by itself.

On the longevity of the flex section, I have 13 years on a OEM solution but fully agree that the quality of these parts may be higher than aftermarket, and a factory system doesn't expose the exhaust system to as much vibration as a hopped up big block will.

I'm looking to get some work done on the tail pipe section of the system to add resonators, and now would be a good time to bite this off if I am going to do this.

Thanks for your thoughts!

An exhaust system starting with headers, even with an X or H pipe, is plenty flexible especially at operating temperatures. In my humble mechanical engineering opinion, don't worry about it. The joint attaching the headers to the engine is much stronger than those tubes, especially at 500F.

Here's a thought, one could install a flex section in an H-pipe arrangement without having to support it.

But in general it's much ado about nothing.

R.

The standard header bolts are not long enough, especially for the TTI thicker flanges.

I used longer bolts than the 7/8" long standard bolts. You can get longer header bolts than what is commonly available and that helps keep them tight. Mine have been in since 2007 when I replaced the motor and I have not touched them since.

My collector gaskets are the same ones that TTI supplied and have been in service since 1999 when I installed them and they don't leak.

I had a set of Hedman Hedders that has the Gasketless flanges on them. Never had a problem with leaks. I wonder if somebody sells just the flanges and you can weld them in?

Hedman sells just the reducer as well.. Hedman gasketless reducer.

Dogdays:
"In my humble mechanical engineering opinion, don't worry about it."

I hear what you are saying, and maybe the X-pipe has nothing to do with my problems but I really want to try something to stop blowing out collector gaskets. Having leak free header to head connections would be nice as well.

Challenger1:
"used longer bolts than the 7/8" long standard bolts."

Good tip. I will look into this. I have one side of the motor that does have a slight leak at the header/head mate.

Midnite360:

"scroll down to you find the Gasketless Header reducers."

Are you referring to their "gasketless reducer" or the "euro-style"?. It seems the gasketless bolts directly to a standard header collector flange, no? I like that idea although I wonder if it causes a flow disturbance at the joint.

1Fast340:

"ask them to make a pair of maleballs and a pair of femaleballs on the pipe diameter of choice."

OK, so it seems some sort of ball style connector is the best. My TTI's have the standard flat flange collector joint with gasket. I have already spoken to a shop about the other work I want, and will bring this topic up. On the surface though, it seems that the collector length will be increased unless there is major surgery on the current collector so that will need to be factored in. I have O2 bungs in the pipes connected to the collectors, and need to be careful about their location.

Thanks for all the feedback!

Yeah it is still the 3 Bolt. But the end of the pipe is flared out more to form a nice joint for the reducer to go into.

Our North/South mounted V8's should not flex. If anything they twist a bit. So make the connection as solid as possible and force the exhaust pipes to rock a bit with the engine.

The 3 bolt flanges that are welded are better than the loose rings.

The flex joints are for west/east mounted engines. The lean back during acceleration and an exhaust pipe can't bend like that and survive.

Well. that's the old school version.

But it's inaccurate. Put a big load on a north-south engine car and the engine tries to twist the chassis like a rubber band. It's really noticeable in my truck when pulling a big load up a steep hill. If the exhaust system is mounted firmly to the engine and pretty firmly to the chassis, it stresses any joints in the system.

My feeling is that this is not a deal-breaker, because as I pointed out to the OP, when the exhaust pipes get hot, they become more flexible. But we are trying to make things better, in general. The guy who says, "good enough" soon starts losing every race.

The downside to flat header flanges using gaskets is that they are a typical failure point, plus the flanges tend to get in the way.

There has to be a reason that header manufacturers are using ball-and-socket ends on collectors. They cost more than a flat flange. But, eliminating the flat flange and gasket cuts out one failure point. Plus they can be a little more streamlined externally so less to drag, hit, etc.

R.

Another solution to prevent blowing out the gasket... don't use a gasket! A little high temp RTV will seal and hold up well. It is so thin there is basically nothing to blow out. That's what I do and no problems.

Dogdays:

I agree with what you are saying. I understand there should be flex in the pipes, but my point has been that with an X there is less flex that a straight dual system and I wonder if this is a contributing factor to my problem. Clearly there is a reason I keep blowing out the collector gaskets, and I want to make the system better.

Ahy:

"A little high temp RTV will seal and hold up well."

Thanks for the suggestion. I can try this, but my thinking has been that if I take the car to a muffler shop, I would want to make all the necessary changes at once. My experience has been that it takes quite some time for the gasket to fail, and so it would take over a year before I would start to trust the RTV. My current plan is to add resonators this fall.

Im all for better but even the newest car or truck with a north south engine has no flex joint.

Only seen them on west east set ups. Which is necessary when an engine leans back during torque.