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Quote:

Originally Posted by trentcdrums (Post 1152666)

Wonder with the angled adapter of you used them for the post 02 sensors if the light would even come on!!?

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Certainly worth a shot - it's cheap and easy and others have had success with this method. I would guess the longer the adapter the better, and I've also seen some with restrictors (smaller hole into the exhaust pipe).

No, the factory manifolds do not use all 24 stud holes.

Quote:

Originally Posted by trentcdrums (Post 1152760)

Not understanding what you're referring to when you say the ones none had a stud in? Should they all have studs in them when you're removing them?

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The stock manifolds only have 16 studs/nuts attaching them while headers have holes for all 24 (4 per cylinder). There shouldn't be any 'junk' in the unused holes as they would have been covered up by the original manifold/gasket. Maybe blow a little shop air in them just in case?

Quote:

Originally Posted by e39_touring (Post 1152763)

So that would make sense on why I have to buy new studs

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This should illustrate m52/m54 eBay header install.

https://youtu.be/Cc3DxEE-0pc

Quote:

Originally Posted by e39_touring (Post 1134190)

I finished up the install, and everything mated up just fine - no leaks! There was no way I could get a torque wrench on most of the header-to-head flange bolts, but I did add the missing studs and snugged all of them up the best I could.

I decided to delete the rear o2 sensors and use the supplied bung plugs. And, even though I was super-careful not to swap the front o2 sensor wires, somehow I did. The car would run rough and hunt for idle after warm-up. It's easy to tell in INPA if you swapped the wires, just run the lambda sensor test, and you'll see the values move on the wrong bank.

Overall, even though it's a tough install job, I couldn't be more pleased with the quality and fitment of the russian ebay headers - they bolted right up without trouble.

The CEL came on after about 5 miles of driving. I just got a spare ECM to mess with tuning. More on that later...

Sound - not much at idle. It sounds maybe slightly quieter than my old Z3 3.0 but with two tailpipes. At cruise, you can barely hear the exhaust from inside the car. It is a bit louder at higher RPM's during WOT.

Performance - I feel no difference in torque or at lower RPM's. From 3.5k on up, it feels peppier, and I'd say the +15hp or so dyno tests others have reported on e46fanatics seem to be spot-on.

Next up - ESS twin-screw supercharger?

Everything eventually bolt up? I am a few weeks away from doing this. I am going to stick with stock cats as I don't want to deal with the mods around headers again and the smell.

When you are bolting the studs back in with the 2 nut combo and backing it back off, do you actually have the room to work with the wrench doing this? Curious if you had more tips around this since you probably completed it.

Everything bolted up perfectly, and I'm enjoying about 10% better mpg and what feels about the same increase in power.

It is tight in there, but I found room to use the 2 wrench/nut combo when screwing the studs back in. I used a combination wrench and a 1/4 ratchet with shallow and deep sockets depending on where I was working. Also, some were easier to get at from the top while others were easier to reach from underneath.

One other key is to buy two regular (non-locking) M7 nuts to screw the studs in. That way, when the stud is in, you can back one nut off slightly and unscrew both with your fingers.

I got mine bolted to the head, but I'm still vband flanging my new cats to the end of my headers. If I can't figure out a good way to get from the cats to the stock x pipe, I might have to cut that out as well and put in a borla.

I figured out something interesting...no E53 exhaust manifold gasket has 12 holes per gasket in it. That means if you want to put OEM gaskets on headers for the sleeper look, you would have to drill press the gaskets carefully. Also, the gaskets that come with ebay headers look suspect, so you can use E36 328i gaskets, which are MLS gaskets with all 24 holes. No heat shields though. If you wanted to (I thought about this but did not have the patience) you could chop down the OEM E53 gaskets and mount them outside the headers.

Getting the nuts on with the heat shields on is terrible, though, if anyone is wondering.

Quote:

Originally Posted by e39_touring (Post 1155875)

Everything bolted up perfectly, and I'm enjoying about 10% better mpg and what feels about the same increase in power.

Do you have data to back that up? Nothing about intake and exhaust mods should ever change MPG in gasoline engines. Power yes, mpg no. That's not absolutely always the case, but it's so rare that I'm always skeptical unless there are fuel logs showing it to be the case. (Not dash readings)

Less restriction will give you less power loss means more power to the ground vs heat loss. This will mean better mpg but 10% not likely at all. If that was possible all the X5 would have high mpg headers.