Downpipe installation write-up/experience...
05-10-04, 03:48 AM
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RE-Amemiya in the blood
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Downpipe installation write-up/experience...
Well, I FINALLY got my downpipe installed over the course of a week or so. Honestly it didn't take that long but I only had an hour here or there to work on it so it took a while. First of all I'd like to say that this job is not as hard as everyone makes it out to be. I was pretty scared to give this a try because I thought I might strip a nut or break a stud but I didn't 
I thought I'd give the newbies or anyone trying this a few hints, tips and my own knowledge from doing this. BTW - I'm no expert on cars and some of my terms may be wrong but I'm trying to put this into lay-man's terms so anyone can understand it.
I got a 2nd-hand downpipe and it was unknown what brand it was when I got it or what it was made out of, etc. It was only $60 so I figured I'd give it a shot and buy it anyway - turns out to be a really nice SS downpipe but I still have no idea what brand...the welds are very nice and had absolutely no fitment problems except for one that I'll mention in a bit.
Anyhow getting into the installation:
1- I jacked my car up and put it on 4 jackstands (I'm a tall guy and needed the whole car off the ground to give my body enough room under the car).
(if you have a strut bar, you'd want to remove it at this point in time)
2- I took off all of the intake hoses (at least everything to the middle-left of the intercooler).
3- I then removed the ABS heat shield. (there are 2-3 12mm bolts holding it on and it should slide out with a bit of wiggling) This may not look necesarry but it actually will allow you to reach the top-back stud/nut.
(if you have a heatshield on the pre-cat, you should take it off now. It won't matter too much if you do any damage to it because you won't be using it for the downpipe)
(this would be a good place to tell you where to locate the 4 nuts and studs on the exhaust manifold. The top two I found the easiest to work with. You should be able to see the top one closest to the bumper, from there feel with your hand about 3-4 inches to the left and you will find the other top nut/stud. I was under the impression that you could see this nut but not once was I able to (or needed to). The bottom two nuts and studs are accessible from the bottom of the car. They're pretty self-explanatory...if you need a reference point to find them, look for the oxygen sensor sticking out of the pre-cat on the bottom of the car, they'll be the two nuts/studs right up from that.)
4- Sprayed the 4 exhaust manifold bolts/studs with an excessive amount of Krown 73 penetrant (you can use PB blaster or whatever is a strong penetrant/oil/lubricator).
5- Sprayed the two bolts/nuts connecting the pre-cat to the cat.
(Waited a day for the oil to soak in a bit)
6- Disconnected the oxygen sensor. If you trace the wire from the sensor, you'll find that it goes up just behind the Upper Intake Manifold (UIM). There's a clip that the wire is hooked in to and that clip is mounted to a bracket on the side of the UIM. To remove the clip from the bracket, turn the clip clockwise a few degrees and try sliding it diagonally. The clip just slides off of this mounting. This may not seem like a big deal but actually took me 30-45 mins to figure out since I didn't want to break anything. Once you have the clip off of the bracket you can just disconnect the oxygen sensor by releasing the clip it's connected to.
7- At this point I tried the nuts and studs. I managed to get two of the nuts undone, the other two were more stubborn. I should also mention that I'm not sure if my nuts and studs had been replaced or if it was just because I have a Canadian model car that the size of the nuts were 14mm.
8- I sprayed the remaining two nuts and studs with more penetrant and waited about ten minutes and went back at it. I managed to get them off - I put every ounce of muscle I had into them to get them loose. I think the reason people break them a lot (other than them being brittle) is that it's very easy to direct your weight on a nut unevenly or not in the correct "turning" direction...but more of a pulling direction, this added stress could cause damage to the studs. I always found that taking a few minutes for a break when I was getting frustrated helped me keep track of how I was doing on my job. Worse comes to worse leave it for the next day - don't rush things.
9- I'll mention how to get at each nut now. The top-front nut is pretty easy to reach. I used a regular wrench (one end had the "c" shape, the other end had an open socket). I just made sure I had the wrench on properly and put all of my weight into it. The top-back nut (one closest to the firewall) was probably the hardest nut to loosen since I couldn't see it. I used a deep 14mm socket with a ratchet. Once you have the socket on it's hard to move the ratchet a lot but do it slowly and take a couple breaks and it'll come around. The bottom two nuts aren't too bad. The bottom-back nut (closest to firewall) I used the deep 14mm socket and ratchet again...seemed to work well. The bottom-front nut was pretty easy since the stud wasn't protruding much I was able to use the regular 14mm socket and ratchet and it came out fine. Only one of the nuts brought the stud out with it and that was the bottom-back nut. At this point I wasn't looking forward to taking the other studs out but I decided to go ahead with the rest of the job and just get things ready in the meantime while I cursed about doing that. (it'll turn out I won't need to remove them...read on)
10- Most likely not all of the studs will come out...this is usually good since I think you can get most downpipes on with a minimum of 1-2 studs already on. It's a different story if you want to replace the studs with new studs or even bolts.
11- I then removed the two bolts and nuts that connected the pre-cat to the cat. I used a 14mm open wrench head on the nut and the imperial socket closest to 15mm (can't remember specifics) on the top of the bolt. These were actually very easy to remove.
12- At this point I was able to slide the pre-cat out from the studs. Make sure you LIFT as you pull the pre-cat out as it will put a lot of strain on the studs if you just pull. Be prepared, the pre-cat feels like it's filled with bricks.
13- Once I had the pre-cat out I unscrewed the old oxygen sensor and checked it out to make sure it was still good - seems to be in great condition so I'm keeping it for the downpipe instead of spending wasted money on a new one (it's not that hard to replace after if there's a problem).
14- I checked out the old gaskets (you'll need two gaskets, the one between the downpipe and the exhaust manifold, and one between the downpipe and the cat), the old exhaust manifold to pre-cat gasket seemed fine and I couldn't justify spending the extra money on one (although I really recommend you do if you can afford it). I took the old pre-cat to cat gasket out and it pretty much broke in my hands, there's no way I could reuse it. You can get the gasket from a few mazda online stores or even the dealership. If you need one fast, try an exhaust shop - I found one at Speedy here in town for $7 CDN and it was great quality (bring the old one in and they can probably match it up to something).
15- At this point I would recommend taking the studs out. I was curious about my downpipe since I didn't know what brand it was and wanted to see if I could make it fit. Well there wasn't much room but I could almost get it lined up. I found out that if you take off the shielding around the transmission you can get a lot more room for getting the right angle to attach a downpipe onto the studs. You can get the transmission shielding off with a 12mm socket...there are 4 bolts holding it up and it seems to be a oil/dirt pan made out of aluminum.
16- Put the new (or used) exhaust manifold gasket on the studs or if you don't have any studs in yet wait until below.
17- You should be able to slide the downpipe onto the studs that are still attached to the car at this point...or if you're replacing the studs then you should mount them (while you hold the downpipe up...this could be hard so you might need two people).
18- Without having put any nuts on the studs, just let the downpipe rest on all four studs. You can now line-up the downpipe to cat. Put the gasket you have in between the two pipes and thread one of the bolts through - you can now rotate the gasket into place without bending it or damaging it. You can now tighten the two bolts and nuts.
19- You can move back to the nuts on the exhaust manifold and tighten them up. Work between the four of them spreading the load evenly until you have them all tightened well equally. (Use the same method to tighten them as you did to loosen them) Go back to the downpipe to cat connection and make sure those bolts are tight enough again.
20- This should be it...so, not that bad right? Well we would hope so anyway. Just redo all of the connections by following the steps backwards of how you took parts off.
-------------------------------
Some problems that I ran into that I hadn't seen mentioned before:
- The nut on the exhaust manifold closest to the front of the car on the top could only fit the downpipe tightest to the end of the pipe. This was a major problem which meant that I needed to put the downpipe on the studs so about 2mm of the studs showed and screw on that one nut...then tighten the nut on that particular bolt until it wouldn't tighten anymore, wiggle the pipe a bit further onto the studs and redo the procedure. I did this until just that nut was tight on the stud and the downpipe was against the manifold...I then proceeded to do the other nuts all at once and make sure they were all evenly tightened.
- Once you've sprayed that much penetrant or oil onto a pipe you'd expect it to burn a bit. I started my car for the first time since winter storage and I swear the car looked like it was on fire. I had the hood open and blue smoke was coming all out of the engine bay. It got so bad I shot the car off a couple times and re-checked all of my fluids and gauges, it had me nervous enough to get an extinguisher. Turns out the oils I used to loosen the bolts really like to make smoke...lol The car stopped smoking after about 10-15 mins of running.
- I've seen it mentioned loosely, but a step I left out that I also did was I purchased some lock-tite for exhaust parts to prevent freezing from corrosion and the extreme heat. If you ever have to do this job again it'll make things a lot easier.
-------------------------------------
Yeah I know this is a hugely long post and I'm not trying to replace anyone else's downpipe installation guide that's out there. I wanted to write this for people like me who found that no matter how many guides they looked at they couldn't find enough information and were just worried about doing the job themselves. I also wrote this guy knowing that I would've loved another step-by-step guide to help me out since my bolt sizes and weird downpipe seemed to be one of a kind. Be prepared for oddities that don't match the "norm" if you undertake this job and don't be scared to do it...it's not as hard as you think. That being said, hope this helps some people out and enjoy your FD Feel free to PM me any questions or post a reply if you think there's anything missing or any mistakes (or if you have any questions). -Joe
PS - if I can get any pics soon I'll try to post them to relieve some confusion.
I thought I'd give the newbies or anyone trying this a few hints, tips and my own knowledge from doing this. BTW - I'm no expert on cars and some of my terms may be wrong but I'm trying to put this into lay-man's terms so anyone can understand it.
I got a 2nd-hand downpipe and it was unknown what brand it was when I got it or what it was made out of, etc. It was only $60 so I figured I'd give it a shot and buy it anyway - turns out to be a really nice SS downpipe but I still have no idea what brand...the welds are very nice and had absolutely no fitment problems except for one that I'll mention in a bit.
Anyhow getting into the installation:
1- I jacked my car up and put it on 4 jackstands (I'm a tall guy and needed the whole car off the ground to give my body enough room under the car).
(if you have a strut bar, you'd want to remove it at this point in time)
2- I took off all of the intake hoses (at least everything to the middle-left of the intercooler).
3- I then removed the ABS heat shield. (there are 2-3 12mm bolts holding it on and it should slide out with a bit of wiggling) This may not look necesarry but it actually will allow you to reach the top-back stud/nut.
(if you have a heatshield on the pre-cat, you should take it off now. It won't matter too much if you do any damage to it because you won't be using it for the downpipe)
(this would be a good place to tell you where to locate the 4 nuts and studs on the exhaust manifold. The top two I found the easiest to work with. You should be able to see the top one closest to the bumper, from there feel with your hand about 3-4 inches to the left and you will find the other top nut/stud. I was under the impression that you could see this nut but not once was I able to (or needed to). The bottom two nuts and studs are accessible from the bottom of the car. They're pretty self-explanatory...if you need a reference point to find them, look for the oxygen sensor sticking out of the pre-cat on the bottom of the car, they'll be the two nuts/studs right up from that.)
4- Sprayed the 4 exhaust manifold bolts/studs with an excessive amount of Krown 73 penetrant (you can use PB blaster or whatever is a strong penetrant/oil/lubricator).
5- Sprayed the two bolts/nuts connecting the pre-cat to the cat.
(Waited a day for the oil to soak in a bit)
6- Disconnected the oxygen sensor. If you trace the wire from the sensor, you'll find that it goes up just behind the Upper Intake Manifold (UIM). There's a clip that the wire is hooked in to and that clip is mounted to a bracket on the side of the UIM. To remove the clip from the bracket, turn the clip clockwise a few degrees and try sliding it diagonally. The clip just slides off of this mounting. This may not seem like a big deal but actually took me 30-45 mins to figure out since I didn't want to break anything. Once you have the clip off of the bracket you can just disconnect the oxygen sensor by releasing the clip it's connected to.
7- At this point I tried the nuts and studs. I managed to get two of the nuts undone, the other two were more stubborn. I should also mention that I'm not sure if my nuts and studs had been replaced or if it was just because I have a Canadian model car that the size of the nuts were 14mm.
8- I sprayed the remaining two nuts and studs with more penetrant and waited about ten minutes and went back at it. I managed to get them off - I put every ounce of muscle I had into them to get them loose. I think the reason people break them a lot (other than them being brittle) is that it's very easy to direct your weight on a nut unevenly or not in the correct "turning" direction...but more of a pulling direction, this added stress could cause damage to the studs. I always found that taking a few minutes for a break when I was getting frustrated helped me keep track of how I was doing on my job. Worse comes to worse leave it for the next day - don't rush things.
9- I'll mention how to get at each nut now. The top-front nut is pretty easy to reach. I used a regular wrench (one end had the "c" shape, the other end had an open socket). I just made sure I had the wrench on properly and put all of my weight into it. The top-back nut (one closest to the firewall) was probably the hardest nut to loosen since I couldn't see it. I used a deep 14mm socket with a ratchet. Once you have the socket on it's hard to move the ratchet a lot but do it slowly and take a couple breaks and it'll come around. The bottom two nuts aren't too bad. The bottom-back nut (closest to firewall) I used the deep 14mm socket and ratchet again...seemed to work well. The bottom-front nut was pretty easy since the stud wasn't protruding much I was able to use the regular 14mm socket and ratchet and it came out fine. Only one of the nuts brought the stud out with it and that was the bottom-back nut. At this point I wasn't looking forward to taking the other studs out but I decided to go ahead with the rest of the job and just get things ready in the meantime while I cursed about doing that. (it'll turn out I won't need to remove them...read on)
10- Most likely not all of the studs will come out...this is usually good since I think you can get most downpipes on with a minimum of 1-2 studs already on. It's a different story if you want to replace the studs with new studs or even bolts.
11- I then removed the two bolts and nuts that connected the pre-cat to the cat. I used a 14mm open wrench head on the nut and the imperial socket closest to 15mm (can't remember specifics) on the top of the bolt. These were actually very easy to remove.
12- At this point I was able to slide the pre-cat out from the studs. Make sure you LIFT as you pull the pre-cat out as it will put a lot of strain on the studs if you just pull. Be prepared, the pre-cat feels like it's filled with bricks.
13- Once I had the pre-cat out I unscrewed the old oxygen sensor and checked it out to make sure it was still good - seems to be in great condition so I'm keeping it for the downpipe instead of spending wasted money on a new one (it's not that hard to replace after if there's a problem).
14- I checked out the old gaskets (you'll need two gaskets, the one between the downpipe and the exhaust manifold, and one between the downpipe and the cat), the old exhaust manifold to pre-cat gasket seemed fine and I couldn't justify spending the extra money on one (although I really recommend you do if you can afford it). I took the old pre-cat to cat gasket out and it pretty much broke in my hands, there's no way I could reuse it. You can get the gasket from a few mazda online stores or even the dealership. If you need one fast, try an exhaust shop - I found one at Speedy here in town for $7 CDN and it was great quality (bring the old one in and they can probably match it up to something).
15- At this point I would recommend taking the studs out. I was curious about my downpipe since I didn't know what brand it was and wanted to see if I could make it fit. Well there wasn't much room but I could almost get it lined up. I found out that if you take off the shielding around the transmission you can get a lot more room for getting the right angle to attach a downpipe onto the studs. You can get the transmission shielding off with a 12mm socket...there are 4 bolts holding it up and it seems to be a oil/dirt pan made out of aluminum.
16- Put the new (or used) exhaust manifold gasket on the studs or if you don't have any studs in yet wait until below.
17- You should be able to slide the downpipe onto the studs that are still attached to the car at this point...or if you're replacing the studs then you should mount them (while you hold the downpipe up...this could be hard so you might need two people).
18- Without having put any nuts on the studs, just let the downpipe rest on all four studs. You can now line-up the downpipe to cat. Put the gasket you have in between the two pipes and thread one of the bolts through - you can now rotate the gasket into place without bending it or damaging it. You can now tighten the two bolts and nuts.
19- You can move back to the nuts on the exhaust manifold and tighten them up. Work between the four of them spreading the load evenly until you have them all tightened well equally. (Use the same method to tighten them as you did to loosen them) Go back to the downpipe to cat connection and make sure those bolts are tight enough again.
20- This should be it...so, not that bad right? Well we would hope so anyway. Just redo all of the connections by following the steps backwards of how you took parts off.
-------------------------------
Some problems that I ran into that I hadn't seen mentioned before:
- The nut on the exhaust manifold closest to the front of the car on the top could only fit the downpipe tightest to the end of the pipe. This was a major problem which meant that I needed to put the downpipe on the studs so about 2mm of the studs showed and screw on that one nut...then tighten the nut on that particular bolt until it wouldn't tighten anymore, wiggle the pipe a bit further onto the studs and redo the procedure. I did this until just that nut was tight on the stud and the downpipe was against the manifold...I then proceeded to do the other nuts all at once and make sure they were all evenly tightened.
- Once you've sprayed that much penetrant or oil onto a pipe you'd expect it to burn a bit. I started my car for the first time since winter storage and I swear the car looked like it was on fire. I had the hood open and blue smoke was coming all out of the engine bay. It got so bad I shot the car off a couple times and re-checked all of my fluids and gauges, it had me nervous enough to get an extinguisher. Turns out the oils I used to loosen the bolts really like to make smoke...lol The car stopped smoking after about 10-15 mins of running.
- I've seen it mentioned loosely, but a step I left out that I also did was I purchased some lock-tite for exhaust parts to prevent freezing from corrosion and the extreme heat. If you ever have to do this job again it'll make things a lot easier.
-------------------------------------
Yeah I know this is a hugely long post and I'm not trying to replace anyone else's downpipe installation guide that's out there. I wanted to write this for people like me who found that no matter how many guides they looked at they couldn't find enough information and were just worried about doing the job themselves. I also wrote this guy knowing that I would've loved another step-by-step guide to help me out since my bolt sizes and weird downpipe seemed to be one of a kind. Be prepared for oddities that don't match the "norm" if you undertake this job and don't be scared to do it...it's not as hard as you think. That being said, hope this helps some people out and enjoy your FD
Feel free to PM me any questions or post a reply if you think there's anything missing or any mistakes (or if you have any questions). -JoePS - if I can get any pics soon I'll try to post them to relieve some confusion.
05-11-04, 12:21 PM
#4
RE-Amemiya in the blood
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05-11-04, 12:46 PM
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Oji San
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Re: Downpipe installation write-up/experience...
Originally posted by daem0n
- I've seen it mentioned loosely, but a step I left out that I also did was I purchased some lock-tite for exhaust parts to prevent freezing from corrosion and the extreme heat. If you ever have to do this job again it'll make things a lot easier.
- I've seen it mentioned loosely, but a step I left out that I also did was I purchased some lock-tite for exhaust parts to prevent freezing from corrosion and the extreme heat. If you ever have to do this job again it'll make things a lot easier.
05-13-04, 04:05 AM
#7
RE-Amemiya in the blood
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Re: Re: Downpipe installation write-up/experience...
Originally posted by Rated R1
Do you mean anti-sieze?
Do you mean anti-sieze?
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05-13-04, 04:08 AM
#8
RE-Amemiya in the blood
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Originally posted by lopedl
good write up. Any suggestions on what selection should be made with new bolts???
good write up. Any suggestions on what selection should be made with new bolts???
08-25-08, 04:46 PM
#9
Just curious on the exhaust gasket one side is flat where as the otherside has a bit more roundness to it. Never really thought much about it but would it be better to have the rounded side or flat side facing the front of the vehicle. This is for the midpipe > catback flange.
Probably a stupid question but thanks for the replies anyways.
Probably a stupid question but thanks for the replies anyways.
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