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CA Smog: Failed This Time. Need Help with Action Plan.

Alright, in my effort to address (most) issues that could fail me, I need to install the cat converter right behind the connection to the downpipe. Currently the cat converter is configured to 4" pipe and the length is the same as the muffler with the pipe flared at each end to go over the compressed ends of the Diamondeye kit.

Should I cut a section from the Diamondeye starting at the 4" behind the downpipe connection, compress that 4" there and at the other end and slide and clamp on my existing cat converter?

Or should I cut one side of the 4" close to the cat and weld that that to the 4" behind the downpipe connection?

Or to I cut the 4" close to both sides of the cat and simply weld both sides into place and get a back-up Diamondeye section from Leroy?
 
Personally I would leave the cat where it is and just explain that is where it went with your exhaust. You chose the cat instead of a muffler.

Jay, GM rumored alot in 98 that they were coming out with a "NEW IMPROVED 6.5" for 99, but it never made it as GM decided to instead pursue the DURAMAX starting in 98 and dropped the 6.5 redevelopment. The sales flyers were already printed, and some peopel got ahold of them posting them on the internet claiming it to be truth. To my knowledge only a few of the last 6.5 vans got the improved GM block castings, but they never made it into the trucks. And there is plenty of posts over at DP from back in the day of people with 99 BURBS losing there kitty during an exhaust install. And the 00 truck that a friend of mien had definately had a cat on it to. You will also notice the ad says the new 6.5 runs at 10 pounds of boost, but as many will tell you the factory capped it at 1.5 atmospheres(roughly 7.5 pounds of boost at sea level).
 
Alright, had my appointment with the smog referee. They spent more than an hour trying to calibrate their dyno and never got there. In addition, he said he couldn't pass me unless I returned the section of the exhaust from the downpipe to the cat back to stock sized. He gave me a diagram of the exhaust. So as suspected, I need another stock cat and I'll need the bubble compression flange that mates up to the Diamondeye downpipe. Then I have to get 3" pipe welded and bent to fit in there with the cat in front of the muffler.

The sole remaining test is the smoke test and it cannot linger (coming out the exhaust) more than 3 seconds after he snaps it up to 3000 rpm. It will pass that as it only has a puff before the turbo spools up. On that note, the GM 5 turbo hits 15 psi with this Heath tune and it whines something awful. I don't care as it's temporary just to get it passed.

Good news is that it passed the rest of the visual inspection, including the PCV lines :hihi:

Leroy, will need your help sourcing said bubble flange to connect to the DE downpipe. That or I have to get a stock downpipe. Paul is working on getting me a cat from a wrecked 3500 up near him.
 
You might want to call me so we get on same page.
You want the pipe section right after the DiamondEye DP right?
 
Correct.

Then I will need to adapt 3" to 4" after the cat. So that would be one of those funnel connections.

Your phone #?
 
Big T said:
Alright, had my appointment with the smog referee. They spent more than an hour trying to calibrate their dyno and never got there. In addition, he said he couldn't pass me unless I returned the section of the exhaust from the downpipe to the cat back to stock sized. He gave me a diagram of the exhaust. So as suspected, I need another stock cat and I'll need the bubble compression flange that mates up to the Diamondeye downpipe. Then I have to get 3" pipe welded and bent to fit in there with the cat in front of the muffler.

The sole remaining test is the smoke test and it cannot linger (coming out the exhaust) more than 3 seconds after he snaps it up to 3000 rpm. It will pass that as it only has a puff before the turbo spools up. On that note, the GM 5 turbo hits 15 psi with this Heath tune and it whines something awful. I don't care as it's temporary just to get it passed.

Good news is that it passed the rest of the visual inspection, including the PCV lines :hihi:

Leroy, will need your help sourcing said bubble flange to connect to the DE downpipe. That or I have to get a stock downpipe. Paul is working on getting me a cat from a wrecked 3500 up near him.
Click to expand...

Just get the whole exhaust off the wreck and put it on to pass this time. Then make sure you have a 4" cat on the 4" exhaust you put back on. The ATT runs fine with a 2008 Duramax kitty in place. Smells better too. They last 2-3 years before earning the soot trap name. The closer to the engine the hotter the cat will run and more carbon burned out. Closer to the engine risks a meltdown under extended full power. The DPF Dmax cats appear to take quite a bit of heat and raw fuel without melting.
 
View attachment Exhaust.pdf

This is the diagram they handed to me. He specifically stated that it needs to be stock size and the diagram shows that size to be the same as the downpipe. So WarWagon, the 4" Dmax will not work. At the minimum, I need the cat with several inch long stubs of 3" off each end to join to 3" pipe.

I need the section within the ink. If I can't get the exhaust side ball joint section at the down pipe, then I need a stock down pipe to go with that stock 4 bolt connecting flange.

From the back side of the cat I need something that starts at 3" and flares to accept 4" and don't tell me all I need is a nice steak and lobster dinner capped with a nice bottle of cabernet.:hihi::rolleyes5:
 
Big T, I've got my complete stock exhaust, still in good shape, I think (been setting outside), from when I put the DE system in. If nobody else closer to you comes up with what you need I'm offering the use of any part of my system you may need. I'm thinking the down pipe on back to just behind the cat. I did make one cut in the pipe to make it easier to remove the system, but don't remember where just now. It's pitch black outside, and raining (finally, but that's another story), but if you are interested I'll go check it out in the daylight.

It's yours to use to help you pass the inspection. All you need to do is pay shipping.

Don
 
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