DIY - Solo High Flow Catalytic Converters Installation
 

This is a pretty straight-forward installation. Make sure you bite the bullet, and get the right tools for the job before you start. You'll thank yourself later. I spent less than $60 at Autozone getting ready for the install. $25 of that was a deposit for the O2 sensor socket.

Pictured here are the parts to be installed.

• Midpipes with high flow cats
• Solo midpipe to manifold gaskets
• O2 sensor extenders (already installed in the rear bungs)
• bolts with 2 flat washers, 1 lock washer, and 1 nut each

Attachment 382968

I measured the depth to the rear manifold bolts before I went to buy my tools. Nothing sucks more than struggling to get a wrench on something. I wanted to be sure that I could clear the top of the engine with my breaker bar. The rear bolt is also at a slightly tilted angle, so a swivel joint is recommended.

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List of tools used

• 24" 1/2" drive breaker bar
• 3/8" drive ratchet
• 24" extension
• 1/2" to 3/8" drive coupler
• 3/8" swivel joint
• 15mm socket
• 15mm open face wrench
• O2 socket tool
• needlenose pliers
• PB Blaster (thread loosening spray)
• anti-seize
• beer

Ready to get started!

1. Preparation
   Jack the front of the car up and place your jack stands. The higher off the ground you can get the front end, the better. You definitely want room to work comfortably while under the car. Don't forget to pull your parking brake before you start lifting the front end.
   
   Attachment 382967
   
2. Spray rear O2 sensor threads with PB blaster
   There's no reason to spray the sensor bodies. I don't know if it will cause a problem, but try to avoid it. I didn't even try to spray the front O2 sensors. It would have taken some serious marksmanship. If you're doing these first 3 steps while the exhaust is still hot... be careful!
   
3. Break the rear O2 sensors loose
   Put the O2 sensor socket on your breaker bar and carefully slide it onto the rear O2 sensor. The wires should exit the socket through the slit in the side. Carefully apply pressure until the sensor threads break loose. Stop as soon as it breaks free. You'll finish taking them out later. Don't put more than about a half turn on them with the O2 socket. You'll twist up the wires and possibly ruin them.
   
4. Let the car finish cooling!
   Grab a beer. It needs to sit for a couple hours at least.
   
5. Disconnect all 4 O2 sensor harnesses
   Note the way the O2 wire harness is routed on the rear passenger side in the pic above. There is another pic below that shows it a little better. I used needlenose pliers to pinch the locking insert on the rear connectors. Pinch it, pull the lock out, and then pull on the connector from the tab side to disconnect it. Disconnect both rears then move to the front. Do the driver's side first because it will help you understand what you're dealing with on the front O2 connectors. They are the same on both sides, but they aren't mirrored, so the green lock is actually behind the engine on the passenger side. From the top of the car looking down: Support the connector itself and pull on the green locking tab until it comes out. Pull the tab side of the connector (firewall side) towards the floor. It should pop right out. Repeat for the passenger side now that you know what you're dealing with.
   
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6. Unbolt the stock midpipes from the manifold
   From the top of the car, using a 15mm socket, swivel joint, and long extension, carefully break both bolts loose on both sides of the car. Try not to touch any of the engine electronics while you're in there. Disconnecting the battery probably wouldn't be a terrible idea ;). Once they're loose, switch the breaker bar out for a standard ratchet and finish removing the bolts. I slid back under the car and reached up from the bottom to get the bolts off of the ends of the studs.
   
   Attachment 382950
   
7. Break the midpipe/manifold connection
   Push/pull on the midpipe from under the car until both sides come loose from the manifolds. The passenger side took a little effort for me. Just be patient and don't go crazy. Once they both come free, the cat-back section of the exhaust will rest on the cross brace.
   
   Attachment 382951
   
8. Make sure all of the O2 wire harnesses are clear of the vehicle
   You don't want any of the wire harnesses getting hung up when you pull the stock midpipes off the car. I just pulled all the wires down so they were hanging off of the pipes.
   
   Attachment 382952
   
9. Loosen the band clamps at the rear of each midpipe
   I used the breaker bar again here... probably wasn't necessary, but it made it easy. I loosened both bolts on both sides until I could "walk" the midpipes out of the front of the band clamps. There is plenty of clearance in the engine bay for the procedure.
   
   Attachment 382953
   
10. Move the O2 sensors to their new home
    The O2 extenders should be screwed into the rear bungs on both of the Solo midpipes at this point. Mine looked like they had red thread locker on them. I probably wouldn't have done that if I had been the one to install them. I likely would have just anti-seized them like I did to the rest of the connections. Move the O2 sensors from old to new one at a time. Don't get them mixed up. They should go to the exact same spot on the new midpipe. Once they break free, you should be able to remove them by hand. Put a little anti-seize on the threads and screw it into the new midpipe. Move both of the rear sensors first, because you're gonna have to get a little rough with the front ones.
    
    Put the O2 socket back on the breaker bar for the fronts and position the midpipe so that you are pushing the breaker bar towards the floor. Pulling up makes it almost impossible to keep the pipe from rotating when you pull. I just stood on the cat while pushing and broke them free pretty easily. Move the front sensors just like you already did the rears. Don't forget the anti-seize. Tighten all 4 sensors before you install the Solo midpipes.
    
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    Good bye ugly.
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11. Bolt the Solo midpipes to the manifold
    This can be a little tricky for one person. If you're doing this by yourself, try clamping vice grips on the bolt heads from the bottom of the car. Then move to the top and start cranking. If you get it clamped right it will work.
    
    I had a little trouble with the Solo gaskets on my car. I'm not sure that they fit a 2012 properly. I'll probably end up getting some different gaskets and redoing this part. Anyways... From the bottom of the car the sequence is: bolt -> flat washer -> Solo flange -> gasket -> manifold flange -> flat washer -> lock washer -> nut. The rear O2 sensor should be angled toward the center of the car. If it's not, you're on the wrong side. Do the rear bolt first. That will make the front bolt a lot easier. Once you get everything lined up, tighten the bolts down from the top side of the car. You may have to slide the rear of the midpipe into the loose band clamps to get it positioned where you want it before tightening down the front bolts. My passenger side didn't quite reach the band clamp, but driver side did. No big deal.
    
12. Put the Solo midpipes into the band clamps
    You may have to adjust the position of the band clamps on the cat-back side of the exhaust. I had to slide the clamp towards the engine a little bit on the passenger side. You just need to get an inch or so worth of midpipe into the front of the band clamp. Once you're happy with the alignment of everything, tighten the band clamps back down.
    
13. Reconnect the O2 sensors
    I routed the rear passenger side O2 harness just like it was before I pulled it out. The driver side is just a straight shot to the connector. Push the wire bundles for the front O2 connectors up from underneath the car. They'll stay where you put them. Go back to the top side of the car and reconnect them just like you took them apart. It's up to you whether you want to mess with the locking tabs for the 4 connectors. I didn't bother putting them back in. The connectors are already positive latch.. I don't understand the reasoning for the locking mechanisms.
    
14. Done! I would advise more beer here.

I would say just about anyone should be able to pull this off in a few hours by themselves. I used the 15mm open faced wrench on the bottom of one of the bolts while a helper tightened the top side enough for the lock washer to do its job.

Everyone should do this mod if you're not ready for long tubes yet. I love the new sound.

Great write up! Thank you.

Thanks and no problem. Sometimes a pictorial howto is all someone needs to take the dive. I hope this helps people get down and dirty with their cars. I was kinda surprised there wasn't already a Solo DIY since so many people have done this already.

I went to Autozone and bought a sheet of Felpro 2499 gasket material for $10. I need to make new gaskets, and this is the quickest solution for the time being.

I took the stock midpipe and pressed the studs onto the gasket sheet to leave indentations. I used a 3/8" paddle bit to drill out the bolt holes. Lay the sheet on a piece of wood, and just make sure you hit the center of the studs when you drill through.

Once you have your holes drilled, slide (more like force) the sheet of material onto the OEM midpipe studs. Use a pencil to trace the outline of the flange. While the gasket material is laying flush to the flange, apply firm pressure to the circumference of the 2.5" diameter hole in the center. This will leave a mark for you to trace with your tin snips.

Cut the flange outline with your tin snips. Use your drill bit to remove some material inside the 2.5" circle. Cut the inner circle with your tin snips using the drill hole as a starting point.

When finished, you should have an exhaust gasket that perfectly matches the layout of the exhaust manifold. The Solo midpipe has slots to aid in alignment. The holes in your gasket, that are lined up with the actual factory holes, will ensure that your new gasket lines up properly with the actual piping.

I feel a lot better about this set of gaskets. I just hope the material isn't crap. If it doesn't last, I'll just repeat this process with something less crappy! :thumbsup:
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This isn't the best pic I could have taken, but it sorta illustrates the problem with the solo gasket. If you use your mind to align that bottom hole, you can see that there is no way this lines up properly with the piping. The OEM gaskets have a ridge that sits nicely in the stock midpipe. It doesn't fit in my Solo midpipes. It just causes the gasket to sit 1/8" or so above the actual metal face. Also keep in mind that I don't think this is a problem with most installs. I don't know what the deal is. It could be a 2012 thing, or it could be that the L99 and LS3 have different flanges or something. I only say that because I noticed that juiced sells two different versions of the Solo HF cat midpipes. Pure speculation on my part. Someone please educate me!

I was under the car holding the gasket and my camera.. so forgive the crappy angles!

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Do this with two people, and it takes a fraction of the time. It's a 1 on a scale of 1 - 10. Buy a nice 7/8 open face wrench for the O2 sensors. You'll be glad you did when you have to tighten them down again 2 days later and don't like the idea of leaving a deposit every time you need a 1/4 turn.

1 hour complete removal/re-install cranking down all the O2 sensors and extenders.

Nice write up. I'm thinking their HFCs coupled with their Mach X cat-back might be a very soon mod for me.

That would sound good. All i want now is something that accentuates the mellow and throaty tone of the midpipes. I'm sure the solo cat-back handles that nicely.

I think my muffler delete and res x-pipe setup will probably hit pretty close to the mark too. Sure does sound mean.

I ended up calling Jeff from Solo, and getting some gasket advise. I've blown every homemade gasket thus far.

For $15 he sent me two new gaskets for my application. They will be here early next week. I'll be sure to update this thread. The felpro 2499 material has been a disaster.

Thanks for keeping us updated.

Great writeup... thanks. I think these will be my next mod - I just wish they weren't so expensive.

Just curious... if you're planning to install long tube headers, why did you bother with the solo cats? Won't you have to get rid of them before you install the long tubes?

Yep. I'm not willing to void my warranty though, so LT's and cam will be a long ways down the road. I decided that I would just use these for 4 years and replace them with the cam and headers when the time was right.

So here's the deal.

As an engineer, i'm not really impressed by this design. With that said, the solo gaskets seal fine when torqued properly... About 18 foot/lbs. The do NOT look right and aren't right.

Here's my analysis of the situation. Solo buys their gaskets from somewhere as standard 2-bolt gaskets. They are good gaskets. The camaro manifold flange bolt holes are not centered on the flange. They would require a custom punch with the holes off-center to line up perfectly. Instead, they count on the slop, or tolerance, in the bolt holes to make up for the poor alignment of the assembly. I got the solo gaskets to line up right this time. The entire time i was thinking that this is unacceptable design practice.

It makes economical sense though. It's not cheap to set up tooling at a machine shop. Custom punched gaskets would make them even MORE expensive. Noticeably so.

So the lesson here is, the alignment of the gaskets is kind of a bitch, but crucial to success, and entirely possible. Just pay attention when you're tightening the bolts, and make sure the piping and gaskets are truly aligned. This point is glossed over in their instruction pdf. I would re-design these gaskets if i were them to add a slot instead of an oversized hole.