Installation tips and measured sound levels for Lt Headers w/ cats

[audiomikej]

First I want to thank Maryland Speed, for great service, prices, and fast shipping. My Kooks headers shipped within an hour of the order being placed. I was emailed UPS tracking info promptly.
Install tips.
Tools needed:
3/8” air ratchet
½” impact driver with ½” to 3/8” socket adaptor
13mm, 15mm, 9/16 sockets (short and deep all sizes)
9/16”, 7/8” combination wrench
Oxygen sensor socket (Oxygen sensor socket is cheaper than a replacement oxygen sensor)
10”, 6”, 3”, 1” 3/8 drive socket extensions
18ft lbs. torque wrench
Tin snips (to trim corners of the header gaskets)
Anti seize compound (For header bolts and oxygen sensors)
Heat gun
4 good jack stands and floor jack.
Tips:
1) Remove rear oxygen sensors with 7/8 wrench or oxygen sensor socket when the car is hot.
I was unable to remove one rear sensor and had to replace. ($70 from dealer)
2) Remove cat assemblies, then use heat gun to heat up pipes before removal of front oxygen sensors
3) Use OEM manifold bolts to get things started, then switch out to Kooks supplied bolts
4) You will need two people to reinstall oil dip stick. (One up top and one from underneath)
5) If you buy Kooks you do not need to disconnect steering shaft.
6) You do not need to remove spark plugs.
7) Reuse stock manifold gaskets.
8) Re-torque header bolts after 1000 miles.
Sound levels:
Note: I already had GMPP axle back installed
Before/after
Idling open hood 74 dB/83 dB
1 meter from exhaust tip idle 85 dB/ 89 dB
Driver’s seat idle with windows down 76 dB/80 dB
3000 RPM 1 meter from ext tip. 90 dB/93 dB
3000 RPM decelerating to idle 96 dB/98 dB
WOT not measured but it does sound great.
My other car for comparison Chrysler 300C
Driver’s seat idle with windows down 65 db
1 meter from exhaust tip idle 68 dB
3000 RPM 1 meter from ext tip. 76 dB

[audiomikej]

One other tip, blow out the header pipes with compressed air before installation.

[Wileytrigger21]

Thanks for the tips. Im Installing the LG pro headers and exhaust Friday.

[audiomikej]

Two more tips, spray WD-40 on cat assy to manifold studs. Use 1/2" impact driver to remove nuts.

Place a temporary shim between mid muffler/resonator and cross support during cat installation to keep resonator from touching cross support after installation. I just used a handle from a pair of pliers.

[Silver Ice]

What did you torque the headers bolts to. Thanks

[Ivan @ Southwest Speed]

Originally Posted by mccd34

Thanks for the tips. Im Installing the LG pro headers and exhaust Friday.

MOST AWESOME!!! Keep us posted as to how it comes out.

WD40 on all the joints is a blessing on ANY catback/exhaust install. It allows for some really good lubrication and corrosion prevention.

Good luck with everyones installs!


Ivan @ Southwest Speed

[audiomikej]

Originally Posted by Silver Ice

What did you torque the headers bolts to. Thanks

18 ft lbs, then recheck after 1000 miles.

Do I dare say it? I have had my headers installed for a week and no CEL. Also MPG's use to run 16.6~17.3 now 17.9~19.5.

[Silver Ice]

Thanks

[karen33marcus]

Your tips are quite informative.
I always wanted to upgrade my Camaro, but was not getting proper tips.
So thanks for helping me.

[audiomikej]

Originally Posted by camaroguy10

Hey man I have a question for you. Did you torque the bolts besides the header bolts? If so how much?

Originally Posted by camaroguy10

Thanks

I do not have one, I would say less than 18 ft lbs.
I just tightened down the cat to header bolts about half way down the threads, then tightened down the band clamps.

Then I used a soapy water spray bottle and sprayed down the connections looking for bubbles to indicate leaks. I did not find any leaks on my install.

[KerseySS]

So I dug up this old post, I just bought a 2011ss l99. Is anyone having problems removing exaust manifold bolts? Should the heads be hot or cold when removing bolts? My silverado was a nightmare!

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