Sumotoy's Multiple Exhaust Installs - Long
Some 10 combinations of hardware later... It's almost done? Hope my hyper-diligence in 80 exhaust project management can help some folks looking to travel down this slippery slope.
BACKGROUND - 94 FZJ80
Back in 2006 I installed a TRD Supercharger, and within 8 months had blown off the rear resonator (repaired by deletion), then blew out the rear over-axle pipe that squeezes down to 1.5in on a stock 80. At that point it was time to replace the system completely. My background is in turbo exhausts on Audis, usually in the 3in flavor, so I was hoping the 80 project would be simpler than it ended up being. I will do my best to recall what I had before, as the pics will be of my latest (likely not final) iteration. The best way to do this I suppose, is to go by section...
COLLECTOR
The 94 uses two downpipes into two sandwiched cats to a collector, then over the axle.... If you intend to keep the cats (and they are good high flow cats), the best bet is to build 'after' the collector, it's a nice piece (my generation 1 modified exhaust). Since that time my cats were of the rattle variety, I went with the cat delete option using a standard summit 3inch in>dual 2.5inch out collector --- reversed
The fitment was bolt-on, with no rebending of the stock downpipes necessary (albeit the ends of the dowpipes stretched to 2.5ID). I used the stock 02 sensor locations (note the shields are quite toast).
THE "SIX FLAGGS UP AND OVER RIDE" (tm FZJ80)
IME with exhausts systems, there is a diminishing rate of performance return for mandrel bends the further you get from the collector. That said, I wanted mandrel to the first muffler. A slight compromise to make it fit near Muffler 1, but the important part over the frame was mandrel (2x3in pre-bent Mandrel bent "U"s from Summit: Cut, clocked, and rewelded)
FRONT MUFFLER
Here comes 6 iterations... I have 'benched' 4 different 3in in/out mufflers here
Magnaflow 6in round x 2 - 1 shorty, 1 RV long dog = too loud
Flowmaster Offset in center out = louder than the Magnaflow
Thrush Turbo = quieter, but no quiet enough
Walker dyomax 12x9x4 = ok, but picked up a noticeable drone
Walker 16x11x6 offest in/center out = current
Notice that the muffler is slightly clocked inside-up to clear the frame and clear all driveshaft articulation (it looks tight, but never hits, bttt). Best rule, get the biggest and longest muffler that your installer can fit, it's the primary sound dampener. He will like you better if you get a universal fit (non directional) center in-offset out for more install options. We had the walkers up one direction, then the other, as we looked at pipe fitments
REAR AXLE CLEARANCE CLARENCE!
I tried to get a mandrel bend 3in over that axle, it was not meant to be. I let the boys just do a standard crimp bend, and it worked, but it's really tight, I now know why the stocker is 1.5in there. I may address this with the mandrel bent 'ovalled' pipe I use on other fitments, but I don't think it will make enough of a difference to revisit. At least until I do a Kaymar rear tire mount.
COMING DOWN THE HOME STRETCHES
I envy those that have already moved the rear spare tire, it makes this portion of the run with limitless options. I followed the stock configuration for now, and it created some interesting challenges - and I learned a lot about the 80 acoustics back here
Very first rule: That stock rear resonator bracket (near the forward trailer hitch bolt)... Do not remove it! On my 4th install, I removed it and went with a downturn 45 behind the mudflap. That bracket does more than hang the exhaust, it keeps the noise from bouncing around above it. I put it back (before adding the rear resonator back in) and it cut the sound significantly.
DUMPING THE FINAL ROUNDS OUT THE BACK
The rear resonator. What a PITA to find a replacement as good as the stocker. The maximum room outside the frame rail is 5in, and with that bracket in place, it pretty much dictates a 4in resonator. To make the bend at the rear tire, and dump prior to the rear bumper endcap, 12in muffler body is pretty much the max that will fit without issue. With a lot of measured room going up in this spot (with bracket removed), we spent a lot of time trying to get the Thrush 3in rectangular 17660 - 13x4x10 - to fit upright in this spot. Just too darn tight, so that muffler I also own for another project. Back to going 'round' (and round?)...
1 Glasspack - you *will* drive alone - and your family in another car
1 Walker 4in "resonator" - Is this the tech department? "If it sounds like a glasspack, it's not a resonator!"
1 delete and turn 45 degrees down and out - looked the best, but I think the glasspack was quieter - 2 days and that was replaced
1 Magnaflow 4in round - more great marketing of a resonator that sounds just like a glasspack
1 Moroso "Sprial flow" muffler?!?! Yes, that did the trick.
After multiple calls to various suppliers tech departments (Walker and Magnaflow) about the unacceptable exhaust drone at 70, I got the answer from a race buddy that tows with a highly modified Propane Injected Turbo Diesel Excursion. He convinced me to at least try the 'spiral flow' exhaust concept, and it works great (Summit Racing Moroso 94052 3.5in/3.5 out). Apparently the turbo diesel guys get a lot of exhaust drone too. I also spoke directly with a Dodge TurboDiesel guy that had even better noise reduction by going .5in outlet size larger than the exhaust pipe size (so for my 3in system, I used a 3.5in piped muffler, and got a 3.5>3.0 reducer (also Summit) to adapt the pipe to the muffler inlet - resulting in a 3in in>3.5out fitment. 3.5 mandrel 90 degree downturn (Summit), custom salami cut and sculpted by me, cuz I'm picky about such things...
SUMMARY
First and foremost, the stock exhaust from toyota is hard to beat. If I was doing this from scratch, I'd likely keep the Toyota center exhaust and redo the rear overaxle and add the Spiral rear. A good, quiet 3in system is not for the faint of heart or wallet. I don't want to even think how much all this cost me, luckily my exhaust guys do a lot of work for me already, so my multiple changes were well tolerated.
I'm now very familiar with what won't work on the 80, and what does. When I eventually move the spare tire, I suspect I will do a dual 2.5 from the center muffler (3in in dual 2.5 out) then go dual spirals inside the frame rails. But for now, I have tamed the Supercharged I6 drummers better than any of my previous attempts at achieving the elusive 80 'stock' tailpipe sound.
Almost as quiet as stock. Finally!
Cheers and HTH
Scott J
94 FZJ80 Supercharged 3in dowpipe back
Some 10 combinations of hardware later... It's almost done? Hope my hyper-diligence in 80 exhaust project management can help some folks looking to travel down this slippery slope.
BACKGROUND - 94 FZJ80
Back in 2006 I installed a TRD Supercharger, and within 8 months had blown off the rear resonator (repaired by deletion), then blew out the rear over-axle pipe that squeezes down to 1.5in on a stock 80. At that point it was time to replace the system completely. My background is in turbo exhausts on Audis, usually in the 3in flavor, so I was hoping the 80 project would be simpler than it ended up being. I will do my best to recall what I had before, as the pics will be of my latest (likely not final) iteration. The best way to do this I suppose, is to go by section...
COLLECTOR
The 94 uses two downpipes into two sandwiched cats to a collector, then over the axle.... If you intend to keep the cats (and they are good high flow cats), the best bet is to build 'after' the collector, it's a nice piece (my generation 1 modified exhaust). Since that time my cats were of the rattle variety, I went with the cat delete option using a standard summit 3inch in>dual 2.5inch out collector --- reversed
The fitment was bolt-on, with no rebending of the stock downpipes necessary (albeit the ends of the dowpipes stretched to 2.5ID). I used the stock 02 sensor locations (note the shields are quite toast).
THE "SIX FLAGGS UP AND OVER RIDE" (tm FZJ80)
IME with exhausts systems, there is a diminishing rate of performance return for mandrel bends the further you get from the collector. That said, I wanted mandrel to the first muffler. A slight compromise to make it fit near Muffler 1, but the important part over the frame was mandrel (2x3in pre-bent Mandrel bent "U"s from Summit: Cut, clocked, and rewelded)
FRONT MUFFLER
Here comes 6 iterations... I have 'benched' 4 different 3in in/out mufflers here
Magnaflow 6in round x 2 - 1 shorty, 1 RV long dog = too loud
Flowmaster Offset in center out = louder than the Magnaflow
Thrush Turbo = quieter, but no quiet enough
Walker dyomax 12x9x4 = ok, but picked up a noticeable drone
Walker 16x11x6 offest in/center out = current
Notice that the muffler is slightly clocked inside-up to clear the frame and clear all driveshaft articulation (it looks tight, but never hits, bttt). Best rule, get the biggest and longest muffler that your installer can fit, it's the primary sound dampener. He will like you better if you get a universal fit (non directional) center in-offset out for more install options. We had the walkers up one direction, then the other, as we looked at pipe fitments
REAR AXLE CLEARANCE CLARENCE!
I tried to get a mandrel bend 3in over that axle, it was not meant to be. I let the boys just do a standard crimp bend, and it worked, but it's really tight, I now know why the stocker is 1.5in there. I may address this with the mandrel bent 'ovalled' pipe I use on other fitments, but I don't think it will make enough of a difference to revisit. At least until I do a Kaymar rear tire mount.
COMING DOWN THE HOME STRETCHES
I envy those that have already moved the rear spare tire, it makes this portion of the run with limitless options. I followed the stock configuration for now, and it created some interesting challenges - and I learned a lot about the 80 acoustics back here
Very first rule: That stock rear resonator bracket (near the forward trailer hitch bolt)... Do not remove it! On my 4th install, I removed it and went with a downturn 45 behind the mudflap. That bracket does more than hang the exhaust, it keeps the noise from bouncing around above it. I put it back (before adding the rear resonator back in) and it cut the sound significantly.
DUMPING THE FINAL ROUNDS OUT THE BACK
The rear resonator. What a PITA to find a replacement as good as the stocker. The maximum room outside the frame rail is 5in, and with that bracket in place, it pretty much dictates a 4in resonator. To make the bend at the rear tire, and dump prior to the rear bumper endcap, 12in muffler body is pretty much the max that will fit without issue. With a lot of measured room going up in this spot (with bracket removed), we spent a lot of time trying to get the Thrush 3in rectangular 17660 - 13x4x10 - to fit upright in this spot. Just too darn tight, so that muffler I also own for another project. Back to going 'round' (and round?)...
1 Glasspack - you *will* drive alone - and your family in another car
1 Walker 4in "resonator" - Is this the tech department? "If it sounds like a glasspack, it's not a resonator!"
1 delete and turn 45 degrees down and out - looked the best, but I think the glasspack was quieter - 2 days and that was replaced
1 Magnaflow 4in round - more great marketing of a resonator that sounds just like a glasspack
1 Moroso "Sprial flow" muffler?!?! Yes, that did the trick.
After multiple calls to various suppliers tech departments (Walker and Magnaflow) about the unacceptable exhaust drone at 70, I got the answer from a race buddy that tows with a highly modified Propane Injected Turbo Diesel Excursion. He convinced me to at least try the 'spiral flow' exhaust concept, and it works great (Summit Racing Moroso 94052 3.5in/3.5 out). Apparently the turbo diesel guys get a lot of exhaust drone too. I also spoke directly with a Dodge TurboDiesel guy that had even better noise reduction by going .5in outlet size larger than the exhaust pipe size (so for my 3in system, I used a 3.5in piped muffler, and got a 3.5>3.0 reducer (also Summit) to adapt the pipe to the muffler inlet - resulting in a 3in in>3.5out fitment. 3.5 mandrel 90 degree downturn (Summit), custom salami cut and sculpted by me, cuz I'm picky about such things...
SUMMARY
First and foremost, the stock exhaust from toyota is hard to beat. If I was doing this from scratch, I'd likely keep the Toyota center exhaust and redo the rear overaxle and add the Spiral rear. A good, quiet 3in system is not for the faint of heart or wallet. I don't want to even think how much all this cost me, luckily my exhaust guys do a lot of work for me already, so my multiple changes were well tolerated.
I'm now very familiar with what won't work on the 80, and what does. When I eventually move the spare tire, I suspect I will do a dual 2.5 from the center muffler (3in in dual 2.5 out) then go dual spirals inside the frame rails. But for now, I have tamed the Supercharged I6 drummers better than any of my previous attempts at achieving the elusive 80 'stock' tailpipe sound.
Almost as quiet as stock. Finally!
Cheers and HTH
Scott J
94 FZJ80 Supercharged 3in dowpipe back
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