Euro Downpipe Installation

Anybody who have installed Euro downpipes, is this right? I’ve emailed them, but I’d also like to hear from forum members.

I’ve installed the right side one. I am 100% sure the old seals were removed. I put new seals on, and evenly bolted up the four nuts, and torqued them down.

There is only about 2mm clearance with the rear subframe mount, and there is a 6mm gap between the flange that bolts up and the exhaust manifold.

I assume all of this is by design, but I just want to compare with others who have done this.

Thanks!

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Flange looks OK to me. Subframe mount, not so much, I don’t recall it ever being that close, and if the engine shakes around a bit that might hit, am I right? I’d be tempted to see if I could pry that little heat shield away from the pipe a bit.

I got an email from designers, they said it looks a bit tight too. I’ll try loosening nuts and remounting. But both flanges look nice and flat, so?

Before I installed mine I sent them to be ceramic coated & I wrapped with exhaust/header wrap. I believe it makes a real difference in under hood temp’s.

I like having my dual garage heaters when I pull into the garage on a cold Seattle day! :wink:

I ‘think’ i found the problem…ME. This is the first time I’ve installed downpipes. I had got two nuts on hand tight, before getting the other two on. Now I see, the secret is to get all four nuts just barely on, and then you can see all the possible angles and ‘feel’ the one where it’s seated properly.

Live and Learn. I’ll try tightening tonight and see what happens.

Thanks for the responses!

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Continuing the discussion from Euro Downpipe Installation:

I’m following in your footsteps. I’ve ordered the Simply Performance downpipes and intermediate pipes. This is what I found after removing the stock downpipes. The third photo shows the pre cat fallen down into the pipe. It was laying sideways when I found it. It’s amazing that it ran as well as it did.
I have the intakes off and the steering rack out, so it wasn’t too bad getting the down pipes out.

IMG_20200623_142330_01|375x500

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There were supposed to be three photos attached. Anyway, here’s the other downpipe.

Putting it back together is a lot more work!!!

I loosened right euro downpipe and realized I didn’t have the flanges seated perfectly. Messed up two bronze nuts. I’ve switched to stainless steel nuts/lockwashers now. Although a bit harder to get started, I find them easier to work with once on studs. I got the flanges on correctly this time, and when I got to 15ftlbs, bam, suddenly the donuts popped into place as I felt the whole thing move up a tad and loosen a bit. Downpipe is still close to subframe mount, maybe 5mm, but a bit higher now. Should be fine. Not a lot of room! I ended up at 17ftlbs (manual says 25, but I used anti seize)

The driver’s side, oh man. I ended up taking off the two bolts that hold steering rack so I could nudge it a bit to pull steering wheel shaft off at slip joint. Need the space!

Getting that first nut started from below is a test in patience (a helper would have been nice)(I actually used bronze temporarily to hold it in place because it’s easier to start), which held it all in place so I could secure two outer nuts from up top. Then I got fourth nut started from below.
Now with flanges in place I removed bronze nut, fit the p/s shield hole to that stud, and put on stainless steel nut/lockwasher. I then removed front/outer nut from top so I could put other side of p/s shield on, and reattached that nut.
So right now left downpipe is in place with flanges in place and nuts/lockwashers loosely started. I’ll tighten her up tomorrow.

I removed two nuts on the left and one on the right from the top. One other nut was completely missing on the left. Without the intake in place, I had room to do it. I won’t put the intake back on until I install the downpipes.

Live and learn…if you don’t make mistakes, you aren’t learning! :slight_smile:

I put in the right downpipe by hand and made a mark where the O2 sensor should go. I made symmetrical mark on left downpipe. I then took the downpipes down to a shop and had them weld in O2 bung holes.

Now that downpipes are actually fitted properly, the right side has very little clearance with frame because once bolted up, the downpipes are about 1/2" higher than I had estimated. And the left side won’t fit because interference with frame, off about 1/2". DOH! The left location is NOT symmetrical with right.

I will plug up the current O2 holes, bring the car down to the shop, and have them weld in new holes a bit further down the pipe.

Perhaps I’m just the stupid one here, but anyone else just in case - do NOT weld in O2 holes until you get downpipes on car!

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When you get them back, please take some pictures of the new locations and provide any measurements of the location you can. I will be doing the same when my downpipes arrive

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Will do. But every car could be a little different, so I would just use my photos as an example of where yours ‘probably’ will go in.

I will be taking the entire car in to have them fitted. I should have realized, I can drive without the O2 sensors hooked up. It just won’t run perfectly. For some reason, I had it in my head that O2 sensors must be in at all times.

Also, the heat shields for the removed Cats may be slightly in the way, so I may cut them a bit.

Also, FYI, I went ahead and cut off the big flaps on the heat shields, the ones that attach to frame. There are big flaps up front to shield the catalytic converters from I guess the wheel wells/brake lines.

Now I don’t need them, and they may prove a bother when trying to weld in the area for O2 sensors.

Feedback on my euro pipes, and exhaust ventures on this car (88 V12 HE). I finally got them fitted - downpipe with o2s, intermediate, and box deletes. I still have OEM over axles and rear mufflers (will replace next year). I had to rent a lift for an hour to get the left side perfect. The intermediate pipe vibrated on heat shield just where fuel returm pipe runs, on hard acceleration. It is a TIGHT fit. I managed to manuever downpipe and other pipes to gain 1/2" clearance, which seems to be enough. So much easier on lift!!!

Performance:
Last year, I hollowed out front cats (they were broken) and removed rear cats. No power change, except not 100% quiet now.

Then I replaced mid mufflers with box delete pipes. A lot more HP, and a bit of sound now. Car was much faster! First time I could spin tires from a stop.

Now by replacing downpipes and getting rid of that little catalytic silencer at top of downpipes - I don’t have more power, but the rpm response is so much faster. I sometimes have to look down to see what’s the matter because I’m not used to rpms jumping from 1500 to 3500 almost instantly. I can also hear a low pitched bit of exhaust from engine on start up (like starting up old Chevy v8)

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Something important to add…

Since I’ve installed my new downpipes, I’ve noticed the car just doesn’t idle as smooth as before, and the exhaust is more smelly.

Checked ECU fuel mixture today, lo and behold it was way rich. 2.8/2.6 (supposed to be around 1.9). Ive had it at 2.0/1.9 for the last several months before downpipe installation.

It took three clicks leaner to get it back around 1.9/2.1.

Car runs much smoother again, and not smelly.

Were removing those cat silencers in the downpipes enough pressure relief to make the car not need as much fuel as before?!

Curious… I would expect the opposite, less back pressure, more air can enter the cylinder, the mixture gets leaner…?
I think it’s because the vacuum the ECU sees now is higher with less back pressure, and the ECU changed the fuelling.
I know that when I fixed, quite a few, vacuum leaks when I first got the car, it threw the fuelling way out rich.

Interesting. I measured, and sure enough, my vacuum at idle (in Park at 850RPM) has gone up from 17 inHG to 18 inHG since installing my new exhaust.

So, did you need to readjust the idle?

I think all this would do it. Freer flow, idle speeds up, so you readjust to bring it back down, less air but the ECU is still providing the same fuel.

I think I did turn down the idle, but only one flat on AAV bolt, bringing it from 900rpm back down to 850rpm. But I did that before I measured ECU.

And it was three clicks leaner, not four in ECU. But still significant.

Not sure what to make of it, but I would guess the car is running well on less fuel? The air intake doesn’t change, it’s the force needed to get the exhaust out? Less back pressure, less power needed? I’ll have to measure mpg over the next few weeks.

Also, remember, my O2 sensors are about 1" lower than they were before, and I have them at the beginning of where it goes to one pipe.