Installed the REVISED DTH/4smartcar.com center tipped exhaust

[VinceLA]

Figure that I should start a new thread on this. I was one of the first few who installed the DTH/4smartcar.com exhaust. That review can be found here. Just about a month ago, Tiger Wong posted his discovery of a broken hanger weld in this thread. And it turns out that few other owners have experienced it shortly after. Recently, mine gave up too.

A call to Nick @ DTH last week and he assured me that they know about the issue and that the revised design will solve the problem. I even spoke to one of the engineers there and he explained the list of improvements he did. After a bit of a wait, I picked up the revised exhaust from Elie @ 4smartcar.com.

So here it is:



Please don't panic just yet. The head pipe is not broken. Here are the explanations to the arrows that indicate revisions from the last model.

Green arrows: The hangers are redesigned. And of course the head pipe, header to muffler piece, is now a separate entity.

Red arrows: t-bolt clamps for fine adjustment of the exhaust tip and the muffler outlet pipe.

Orange arrows: Hooks. Yes you heard me. Hooks for latching on extension springs so that the head pipe will mate with the muffler.

The idea here is actually quite simple, yet ingenious.

So with the previous design as one rigid body, vibrational forces travel from the flange to the hangers. Since the hanger dampening rubber are rather stiff, from a rigid body point of view, the weakest link has to suffer. And that, as some of us have discovered, was the hanger weld to the head pipe.

Now, the question is how and where to dissipate the vibrational forces?

And the answer is through a spring loaded mechanism. DTH's idea is to dissipate the forces through the springs instead. I would imagine at some point the springs may lose its tension and have to be replaced. But it's really cheap and a piece of cake to replace.







Also the installation for this revised design is so much easier since the head pipe is a separate entity. No more struggle to thread the M8 bolts. Below is a picture of just the head pip installed.



The t-bolt clamps are interesting additions though I haven't really found the need to adjust anything. If you happen to cut the valence a little to low or too high, they might come in handy. Again, another thoughtful design from DTH.

See when Nick said "We will get to the bottom of this!", he really means it!

So if you have the older model, get it replaced soon.

[Turbo42]

nicely done very informative

[cubefx]

Looks like a lot of changes. My concern with this two piece design is that it might leak exhaust gases thru coupling and possible more noise, because it is looks like coupling is not completely sealed (I do not see any gaskets or seals).
Maybe one day someone will design smart exhaust with flexible coupling similar to this one:

.

CUBE

[Turbo42]

I had this type of design with the springs on all of my r/c cars aftermarket pipes. No leaks works very well

[Smartfor2guy]

Anyone with the DTH Exhaust have the Curt trailer hitch?. I have the hitch and I would like the center DTH exhaust but i think there will be a interference problem

[soareyes]

Originally Posted by VinceLA

So if you have the older model, get it replaced soon.

Do we have to wait till ours breaks, or can we exchange it now?

Thanks for the writeup!

Stan

[Dunerunner]

OMG! CUBE!! What does that go to? Bet it doesn't get 40mpg!!!

Vince - Very well documented!! It goes in the "What the members area should be" thread!!

[cubefx]

Originally Posted by Dunerunner

OMG! CUBE!! What does that go to? Bet it doesn't get 40mpg!!!

Vince - Very well documented!! It goes in the "What the members area should be" thread!!

LOL I was talking just about coupling!!!!! That is part of exhaust of '83 Porsche 944 with Corvette 5.7L LT1 engine.


CUBE

[MB DNA]

"Installed the REVISED DTH/4smartcar.com center tipped exhaust"

Vince,

GREAT job in sharing the latest info on the DTH changes. From your crystal clear pix to color coded arrows and narrative you are the man!

While I think a true factory style flex tube could have utilized a proven approach, the spring loaded "flex" slip joint looks like a potential solution. My concern would be possible heat differentials between the two parts and the impact of road grit, grime and salt compromising the slip feature. A reasonably snug fit should eliminate any exhaust leak concerns as by the very free flow nature of the cat-back there is little back pressure on the joint.

It would appear that the two part system makes the actual install much easier.

Again, thanks for sharing!

Tom

[Doug Thorley Headers]

The slip/ spring connections have been used for a long time. We actually got the idea because another big part of our company is motorcycle exhaust and accessories. We do alot of OEM syuff as well such as Kawasaki,Suzuki and Honda. You will not have any problems with leaks due to the fact that the muffler body has a slight taper to it. Similiar designs are used exhaust systems on other vehicles. The flex and slip is just exough to allow slight movement and expansion. As far as using a metal flex coupler like stock that would be a great idea. A few downsides are we have tried extreme amounts of these and cannot find an aftermarket supplier that has one that will last. They also would add huge expense to the system as the junk aftermarkets would run approx 60-70 or so our cost. Vince thanks for the thorough write up.

Nick