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69 Posts
Discussion Starter #1
Hi everyone,

I am more a searcher/lurker than poster (until I know something about a platform), so let me start by saying thanks to you all for providing the wonderful resources on this forum. I just picked up my 08 Solstice GXP about a month ago and love it - first drive and I was hooked.

Because I can't leave well enough alone, I ordered up an Autowerks hfc/downpipe during their last sale. Great service and communication. However, when I tried to install it tonight, I found it did not fit. I cannot get the dp/turbo flange over the last stud (bottom of turbo/engine side) as the cat hits a hard line that runs along the engine there - looks to be a coolant hard line to the turbo. Pics (from the top of the engine; the offending area circled in red):

Even if I were to force it on, I suspect the threads of that last stud would be ruined, and the cat would still be in direct contact with that line. It cannot be started on that stud and have the other 3 line up at all. If anyone else has run into this problem, or has advice on a solution, please post up. I am also emailing Autowerks, but I wanted a wider pool of advice (plus, it's night time and I'm impatient :))


144 Posts
I bought a new cat during the sale too. They had a mix up with the order, so I haven't got mine yet. Anyway, this is the research I gathered to help guide me through the install when the time comes. Hope this helps.

Installation Guide: GXP/Redline Catalytic Converter
Always exercise caution when working on, under or around any vehicles. Serious injury or death could occur if safety measures are not followed.
Warnings and Safety Measures
• Allow the vehicle’s exhaust system to cool before removal. Exhaust system temperatures may cause severe burns.
• If working without a lift, always consult vehicle manual for correct lifting specifications.
• Always wear safety glasses and ensure safe work area.
• Catalytic converter are to be used for off road use only.
• Professional installation is recommended.
Some Catalytic Converter Installation Tips
✓ It is very important to have your car cool down completely before taking apart the 4 top nuts that bolt the cat to the car. The studs are stainless steel and you’ll want to be careful in order to avoid breaking them by accident. The studs usually break flush or inset and it’s very time consuming to repair once this happens.
Here are a few tips that may help:
• Let the car cool down completely.
• Spray small amounts of penetrating fluid on the nuts/studs.
• Don’t force the nuts off. If they bind, work it back and forth.
✓ Just because you have them off, the battle is still not won. You could break the stud when you tighten down the new cat.
Again, here are some tips that might help:
• Make sure the nut is not cross threaded.
• If it binds while going in and if it’s not cross threaded, apply a small dab of grease or penetrating fluid to the stud in order to help the nut go in.
• Tighten evenly and do not over tighten.
✓ GM’s bolt pattern is irregular and therefore the upper gasket will only fit properly one way.
✓ There is an O2 extender included with your cat. This O2 extender is to be placed in the front pipe at the O2 port. The oxygen sensor is threaded into this extender. This takes the O2 sensor out of the direct stream of the exhaust system.
✓ Professional installation is recommended. If you’re installing this alone and if you start having trouble, please call 905-703-1557 or 905-897-6833.
Don’t wait until you’re in a lot of trouble. Call early and possibly save yourself some big frustrations.
Top Gasket 4 Holes to the Turbo
✓ The edges are extremely sharp. Please be careful.
✓ There is an inner ring to this gasket for a better seal.
✓ Tighten to 40-43 foot pounds of torque.
✓ Because of the inner ring, there appears to be a small gap between the Turbo and the cat flange. This is proper and normal.
Installing Your New Catalytic Converter
1. Take off cat heat shield – 10ml bolts x 3.
2. Take out O2 sensor that goes into body of cat. 7/8 or 22ml wrench.
3. Undo the 4 bolts that hold the cat to the back of the turbo. 15ml x 4.
4. Take off two bolts from pipe flange to cat – 15ml x 2.
5. Make sure the exhaust system is supported.
6. Take off two bolts from bottom cat flange to hanger bracket – 13ml x 2.
7. To get more removal room for the cat, take off bottom hanger bracket – 13ml x 2.
8. Cat is now loose but it can’t come out yet.
9. Remove 15ml bolt from the passenger side, bottom motor mount.
10. Lift the engine (tilt the engine) up 1 to 1 ½ inches. This gives you enough room to rotate and manipulate the cat out from the bottom.
11. Reverse process to install your new catalytic converter.
12. Make sure the turbo flange is clean from any debris.
13. Re-install the hanger bracket. Install the bolts from the cat to the hanger bracket. Leave all these bolts loose.
14. Evenly tighten the top bolts from the cat to the Turbo.
15. Install the O2 sensor into the cat.
16. Tighten the hanger bracket.
17. Relocate the O2 sensor bung if you have a 3″ front pipe. (See Relocation Instructions)
18. Tighten the cat to front pipe connection making sure your exhaust tips are properly aligned.
Solo performance cat install videos

69 Posts
Discussion Starter #3
Thanks for the reply - I used the Solo removal videos; they were VERY handy. I got the stock cat out on ramps in the garage, without jacking the engine (seriously - follow the "turn clockwise as you lower" and it comes right out).

Lol @ this step
3. Undo the 4 bolts that hold the cat to the back of the turbo. 15ml x 4.
Not the easiest buggers in the world. Total time getting my stocker out was a bit over an hour. Haven't heard from Autowerks just yet, but I'll keep this updated. Anyone else?

69 Posts
Discussion Starter #5
Werks was in contact with me on Friday - via both email and phone. Great service from Matt.

I wound up just using a pry bar to bend the line slightly out of the way. It took very little pressure, and now sits a few mm off the cat. I don't have a pic of that, but can take one if there is interest. Buttoned it all back up and it drives great. Next up - Trifecta tune on Monday so I can take advantage of this thing!
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