Hi,

I recently bought a 1985 300D. The Trap Ox has been replaced by a Cat Ox, but I want to remove it and replace it with a replacement pipe. I've searched all many forums but didn't come up with current info.

If anybody has one for sale please let me know.

I would also be open to visiting a wrecking shop but don't know these cars well enough. If someone could lead me in the right direction as for which years and models have the correct fitting for my 85 it would help a great deal.

The easiest way to ditch the trap is to find a pre 85 car, or an 85 thats not the CA emissions standard, and swap over both intake and exhaust manifolds. everything will bolt up and you will no longer have the trap, or the more expensive 1985 CA only air filter.

one of the members here, Jeremy5848, had a pipe built... I know because I helped him source the flanges from pick and pull. FYI p'n'p is convinced that the trap ox is a catalytic converter and CA law prevents the sale of a cat from a junk yard... at least that what the p'n'p guy told me. luckily the guy said i could buy the flanges, and my roommate went back the next day with a hack saw and cut them off the trap for me. all in all building a pipe is a pain in the rear end... but it can be done, its just a matter of how much effort you want to put into your car. Jeremy's 85 was so clean you could eat off it, and he wanted it to stay looking clean and stock... but if it were any other car, I'd say swap it over to the pre 85 manifolds.

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Here is the thread about a trap by-pass pipe.

Trap Cat Bypass almost ready to roll


Click on his website for sales information.




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1983 123.133 California
- GreaseCar Veg System

The straight pipe cost me $400 to have built as a one-off (California prices - 4 hours of shop time at $100/hour). The machinist/welder who did the job used my trap cat to build a jig and then made the straight pipe out of the flanges that Nik got me (thanks, Nik!) and a couple of pieces of exhaust pipe. He did a near-perfect job such that the test pipe fit with no adjustments, hammering, levering, etc.

The guy who said he planned to build them for sale was looking at a price around $200. I don't remember his forum name, sorry.

Swapping the manifolds is a fairly easy job as long as you have a complete non-CA car to take parts from. You need more parts than just the manifold:

1. That includes the air cleaner with its mount and oil drain pipe (the 85-CA car doesn't have an oil drain pipe so you will have to figure out where it is to go -- I don't remember whether the 85-CA engine has the proper hole with a plug in it or what). Reviewing my photographs, I don't see a place for an oil filter drain pipe -- maybe the CA-85 engine has a different upper oil pan?
2. You will need the intake/exhaust manifold; DIY removal instructions (elsewhere on this forum) say that it's easiest to remove the manifold and turbo as a unit, whereas the CA-85 engine's turbo is removed first and then the manifold comes off.
3. Remember to take the down pipe from the exhaust manifold to the exhaust pipe under the car (85-CA has a different down pipe).
4. You will need to 'clock' your existing turbo but otherwise it can be re-used.
5. The turbo oil lines (supply and drain) are probably different because the turbo is in a different place so make sure you get those too.
6. The rubber hose that connects the air cleaner to the turbo intake is also different.

I have probably missed a few things but you get the idea. Personally I prefer the replacement of the trap cat with a straight pipe as it keeps the engine bay closer to stock. If necessary, you can go back to original by replacing the trap cat.

To install the straight pipe I removed the air filter, the turbo, and then the trap cat. The manifolds did not have to be removed. Some of the trap cat bolts were really difficult to access.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

That "Test Pipe" might be ok, but seem like a lot of time and fabrication. there are parts already available with some scrounging around at the PNP`s.

Find a 78 or 79 W116 300SD, these are pre EGR. just remove the manifolds, and they will bolt right on the 85 617.952 engine. look real clean and not block off plates to make to plug off the EGR holes.

will have to replace the down pipe for a FED pipe, the Cali pipe sits up higher. might be able to cut out a section, shorten and weld.

Iam not sure on the Cali Turbo, might work if it is clocked around some.

the Cali upper oil pan doesn`t have the oil drain from the air cleaner. that would have to be worked through. the Cali set up is kind of messy the way it works.

May be able to use the Cali air filter set up with some modifying getting the air to the turbo. at least you won`t have broken air filter mounts and bracket to contend with. the filter does cost a little more, maybe this is why I have seen a few at PNP w/o a filter in the can .

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

I did this for my exhaust manifold.... What EGR????????????

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