My 1978 GLC Project...
06-23-11, 08:51 PM
#127
Thanks Jeff. That thread was a little creepy at first. I felt like I was looking at my car...lol. I have a question about your exhaust. Were you able to bolt up a rx3 header? Or did you go custom? You also mention running racing beat springs. I have a set and was thinking of trying them out, but it will lower the front even more lol. as for the rear...are they a fit? All the issues you ran into were the same for me too right down to the brakes being a little scary.
06-24-11, 01:24 AM
#128
The header you see in the thread rubbed the steering in two places. 
It gave an interesting exhaust note, though, due to the unequal lengths. The rear primary was cracked right at the engine flange. The collector flange was cheap and leaking at one of the bolts.
The rest of the exhaust was grossly undersized for a ported 13B. RB thickwall 2" OD which is actually 1.75" ID. This is fine for header primaries but too small collected. The first muffling device is a resonator from an RX-4, because it actually fit and didn't scrape when the front end was very low just like yours. The resonator let a lot of noise out into the outside world which I guess counts as muffling lol. Only one of the glasspacks did any real muffling. The other lost its packing.
The whole thing was wrapped in fiberglass, making handling it unpleasant. Also for only being 2", the system was just too loud. Kinda raspy as there was no expansion until after the tailpipe. Also super loud inside the car as there is like no sound deadening in these. It had a nice distinctive note, probably caused by the uneven header primaries, but I'm willing to give it up in exchange for an exhaust that allows a conversation while driving with a little tone out the back, without the anoying rasp and headache inducing volume this little 2" system has.
I decided to junk the current system and go with a 2.5" system with lots more muffling.
The name of the game here was oversized mufflers and oversized pipes, spending as much time engineering things to fit in the limited space as necessary. There is no danger of the system ending up too quiet as there is simply not enough room, so some exhaust note out the back is ok. It just needs to be quieter on the inside.
I redid the header based on one from an FC, had to get up over the steering so I had to add some short pieces from a thickwall u-bend from RB. Collected to 2.5" using the collector from the FC header turned vertical due to limited space (I ended up with two header pipes about 5 inches long left over heh). Added an O2 bung on the side and blocked off the one it came with as it's aimed right at the floor. Then on to a set of RB flanges trimmed for space reasons and because they come really large for huge gaskets, but the gaskets they sent were really small. Lightens them up too.
Then one magnaflow 5x8 oval 14" long in the cat location (this fits with less than 1/4" front to back in the "cubby hole" under the passenger seat). The muffler is closer to the ground now/not as nicely tucked as the old resonator, but again I'm going for oversized here. Plus the front end isn't lowered anymore (teehee). Then 90° over to the other side as the GLC had its exhaust on the driver's side as you know. Then 90° rearward, following the stock path. Then into a magnaflow 4x9 oval 14" long with a center/offset right in front of the rearend. I could go up over like last time or go under the rearend. I decided to go up over for clearance reasons. Had to trim this next set of flanges as well due to limited space. The over axel u-bend fits nicely up there. Then 90° down and rearward with the old hanger from the 2" system. This is as far as I am at the moment. I'm about to get out there to see if one more set of flanges is necessary. Lastly I'll reuse the Borla I added last year as a last ditch attempt to quiet this 2" beast down after the rear glasspack lost its packing. It's got a 2 1/16" ID. It was kinda oversized on the old 2" system, but will be kinda undersized on the new 2.5" system. It's ok to contract down a little toward the end of the system as the gasses cool a bit. This keeps velocity up. It also helps with noise control without hurting performance. I test fitted it last night with the Borla, and it looked like it will still fit and align just like on the old 2" system. I won't even need to change the angle of the nice SS tip. Wow, could things have worked out any more perfect? Well I gotta get things welded up first before I start thinking like that.
It gave an interesting exhaust note, though, due to the unequal lengths. The rear primary was cracked right at the engine flange. The collector flange was cheap and leaking at one of the bolts.The rest of the exhaust was grossly undersized for a ported 13B. RB thickwall 2" OD which is actually 1.75" ID. This is fine for header primaries but too small collected. The first muffling device is a resonator from an RX-4, because it actually fit and didn't scrape when the front end was very low just like yours. The resonator let a lot of noise out into the outside world which I guess counts as muffling lol. Only one of the glasspacks did any real muffling. The other lost its packing.
The whole thing was wrapped in fiberglass, making handling it unpleasant. Also for only being 2", the system was just too loud. Kinda raspy as there was no expansion until after the tailpipe. Also super loud inside the car as there is like no sound deadening in these. It had a nice distinctive note, probably caused by the uneven header primaries, but I'm willing to give it up in exchange for an exhaust that allows a conversation while driving with a little tone out the back, without the anoying rasp and headache inducing volume this little 2" system has.
I decided to junk the current system and go with a 2.5" system with lots more muffling.
The name of the game here was oversized mufflers and oversized pipes, spending as much time engineering things to fit in the limited space as necessary. There is no danger of the system ending up too quiet as there is simply not enough room, so some exhaust note out the back is ok. It just needs to be quieter on the inside.
I redid the header based on one from an FC, had to get up over the steering so I had to add some short pieces from a thickwall u-bend from RB. Collected to 2.5" using the collector from the FC header turned vertical due to limited space (I ended up with two header pipes about 5 inches long left over heh). Added an O2 bung on the side and blocked off the one it came with as it's aimed right at the floor. Then on to a set of RB flanges trimmed for space reasons and because they come really large for huge gaskets, but the gaskets they sent were really small. Lightens them up too.
Then one magnaflow 5x8 oval 14" long in the cat location (this fits with less than 1/4" front to back in the "cubby hole" under the passenger seat). The muffler is closer to the ground now/not as nicely tucked as the old resonator, but again I'm going for oversized here. Plus the front end isn't lowered anymore (teehee). Then 90° over to the other side as the GLC had its exhaust on the driver's side as you know. Then 90° rearward, following the stock path. Then into a magnaflow 4x9 oval 14" long with a center/offset right in front of the rearend. I could go up over like last time or go under the rearend. I decided to go up over for clearance reasons. Had to trim this next set of flanges as well due to limited space. The over axel u-bend fits nicely up there. Then 90° down and rearward with the old hanger from the 2" system. This is as far as I am at the moment. I'm about to get out there to see if one more set of flanges is necessary. Lastly I'll reuse the Borla I added last year as a last ditch attempt to quiet this 2" beast down after the rear glasspack lost its packing. It's got a 2 1/16" ID. It was kinda oversized on the old 2" system, but will be kinda undersized on the new 2.5" system. It's ok to contract down a little toward the end of the system as the gasses cool a bit. This keeps velocity up. It also helps with noise control without hurting performance. I test fitted it last night with the Borla, and it looked like it will still fit and align just like on the old 2" system. I won't even need to change the angle of the nice SS tip. Wow, could things have worked out any more perfect? Well I gotta get things welded up first before I start thinking like that.
06-26-11, 11:25 AM
#130
I started out with a manifold for the same reasons; it fit perfectly. It was an R5 13B manifold but physically is the same as the common 81-83 12A type, only with stud holes drilled for a 13B. Interestingly the exhaust port holes are in the same location. It was easier for Mazda to mass produce them this way.
The manifold helps with noise control. Going to a header really upped the noise levels.
The manifold helps with noise control. Going to a header really upped the noise levels.
06-26-11, 08:47 PM
#131
Little update. The center section is done. Now working on the rear section. I had to make a set of flanges. The cheap ones are stamped from 1/4" steel plate. The good ones are flame/lazer or water jet cut from much thicker material.
I looked up prices for some RB flanges and a gasket. Like 50 bucks before shipping. Hmm, I have some 1/4" plate here and a little time... All it needs to hold up is the final muffler, which is a Borla, and they're really light being made out of wimpy gauge 304 (probably 18 or 22 gauge). Plus it's the last muffler in the system so if the flanges warp during welding, it's less likely to leak as there's like very little backpressure potential back there.
So I went for it. And they did warp a little. But as you tighten the bolts, the warpage straightens out, being only 1/4" thick.
You don't have that luxury with thicker flanges. If they warp, you've got to grind/machine them flat again.
I grabbed an old thermal reactor engine flange gasket from a 13B because it had a hole pretty much the right size to use with 2.5" stuff. It cuts well with tin snips. Lucky find in my pile. I also found a set of stainless bolts, nuts and lock washers. I didn't know I had those.
Ok the Borla is held up by a scizzor jack as I move it around until it looks best. Then I get to tack it in place...
I looked up prices for some RB flanges and a gasket. Like 50 bucks before shipping. Hmm, I have some 1/4" plate here and a little time... All it needs to hold up is the final muffler, which is a Borla, and they're really light being made out of wimpy gauge 304 (probably 18 or 22 gauge). Plus it's the last muffler in the system so if the flanges warp during welding, it's less likely to leak as there's like very little backpressure potential back there.
So I went for it. And they did warp a little. But as you tighten the bolts, the warpage straightens out, being only 1/4" thick.
You don't have that luxury with thicker flanges. If they warp, you've got to grind/machine them flat again.
I grabbed an old thermal reactor engine flange gasket from a 13B because it had a hole pretty much the right size to use with 2.5" stuff. It cuts well with tin snips. Lucky find in my pile. I also found a set of stainless bolts, nuts and lock washers. I didn't know I had those.
Ok the Borla is held up by a scizzor jack as I move it around until it looks best. Then I get to tack it in place...
07-13-11, 07:16 AM
#134
Thanks so much Bro ,the feeling is mutual on this end! You are one helluva cool guy and it's strange that we traveled in the same circles and didn't know each other back then. Well you know what they say..better late than never........lol. Your project is awesome and I'll definitely keep you up to date with the Cortina.
02-08-12, 11:29 PM
#135
Damn...its february already...?
I had a bunch "little" upgrades planned on this car for the winter, but working on the fb has taken up quite a bit of time and now its time to start "looking at" houses with the mrs so spending will be at a minimum.
The real issues that need to be addressed are the flooding after shut down, ride height adjustment (higher in the front, lower in the rear), u joints for the driveshaft, and "scary brakes"...lol!
Last season was great with this car. Took it to a bunch of gatherings/meets and want to do the same this upcoming season so it may be time to start getinng to the gettin'. Stay tuned...as soon as I can move the 7 out of the way, this one will be coming out to play.
The real issues that need to be addressed are the flooding after shut down, ride height adjustment (higher in the front, lower in the rear), u joints for the driveshaft, and "scary brakes"...lol!
Last season was great with this car. Took it to a bunch of gatherings/meets and want to do the same this upcoming season so it may be time to start getinng to the gettin'. Stay tuned...as soon as I can move the 7 out of the way, this one will be coming out to play.
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Sniper_X
2nd Generation Specific (1986-1992)
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08-06-02 11:01 PM
12, 12a, 1978, 7733015887, 78, car, craiglist, craigslist, craigslistorg, glc, image, mazda, ny, orange, sale
