HKS Exhaust Install Issues

sandersd

I love the sound of the exhaust. It's perfect; very quiet under part or constant throttle but very sporty when accelerating. Absolutely NO drone whatsoever. It's loud enough to say "sports car" but not so loud as to be obnoxious. Not any louder than the stock exhaust at cruise. I probably will not roll my windows up till next June, it just sounds that good.

My recommendations for installation:

1. Use a high temp RTV designed for exhaust systems when assembling
2. Torque bolts to 25 ft lbs and check for leaks with the car still on the lift/stands
3. Start install at the cats, then secure and fully tighten the crossover connection before moving to the rear.
4. Jack stands work great for supporting the pipes when assembling
5. Be sure to remove the hanger extension near the differential and add a spacer when reinstalling the bolt.
6. Don't bother trying to wrestle the rubber hangers off the stock components. Just unbolt the brackets and remove the rubber when the pieces are on the ground and accessible. Use a silicone lubricant on the rubber to aid removal.
7. Have two box end wrenches for the crossover bolts, preferably offset box end wrenches to avoid rounding the bolt heads and busting your knuckles

Using the silicone will require a 24 hour wait before returning the vehicle to service but I'm not sure if the connections will be tight enough to seal at the recommended torque value for the bolts provided without the sealant. Perhaps the next person to install an HKS can chime in. I'm certain you don't want to break the bolts on the cats by over torquing because they are tack welded to the flange and that would be a major pain to drill out and grind the flange flat for another bolt, so tread lightly. Mine did not at 45 ft lbs but I don't know how the constant stress from heating and cooling will affect them over time. On a positive note if they do break I guess it'll be a good excuse to replace the cats with HFCs.

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2014 370Z NISMO -- HKS Hi-Power Exhaust -- Swift Springs -- BC ER Coilovers -- SPL Suspension Components -- Nismo R-Tune Intake -- Seibon BD CF Hood

Dreadnaught

The hangar bolt that you added washers to is factory? I'm confused on that exhaust hangar issue lol.

Oh, and the exhaust sounds soooooooo goooood! Start up = 8============D LOL.

I had this exhaust on my 06 G coupe and loved everything about it.

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Ford Diesel and Heavy Line Technician at your service.

sandersd

Yes it is factory but has an extension plate that the bolt extends through. The extension plate must be removed because it places the hanger too low. It is held on by a short bolt. Once it is removed the long bolt seen in the pic screws into the hole vacated by the short bolt after passing through the rubber hanger. Without the spacers the bolt is so long it will hit the damper as shown in the pics.

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2014 370Z NISMO -- HKS Hi-Power Exhaust -- Swift Springs -- BC ER Coilovers -- SPL Suspension Components -- Nismo R-Tune Intake -- Seibon BD CF Hood

sandersd

BTW what does this mean?

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2014 370Z NISMO -- HKS Hi-Power Exhaust -- Swift Springs -- BC ER Coilovers -- SPL Suspension Components -- Nismo R-Tune Intake -- Seibon BD CF Hood

wheee!

Hmmm, that'll be "hard" to figure out....

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JARblue

Boner

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sandersd

Oh. Sorry, I've been out of middle school for a long time...

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2014 370Z NISMO -- HKS Hi-Power Exhaust -- Swift Springs -- BC ER Coilovers -- SPL Suspension Components -- Nismo R-Tune Intake -- Seibon BD CF Hood

JARblue

lol some of us never grow up

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sandersd

BTW after more research I've determined the proper torque values per Nissan as 39 ft lbs at the CAT connection and 43 ft lbs for the resonator and muffler connection. I wanted to correct my previous recommendations based on bolt sizes for the record. See attached pdf.

Of course the torque values Nissan provides are for Nissan's components, not HKS components. Since HKS designs and manufactures the components and sources the bolts/nuts it's their responsibility to provide the proper torque values for their product, not tell customers to go find Nissan's values for Nissan components and use the same.

untitled - EX.pdf.pdf

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2014 370Z NISMO -- HKS Hi-Power Exhaust -- Swift Springs -- BC ER Coilovers -- SPL Suspension Components -- Nismo R-Tune Intake -- Seibon BD CF Hood

Dreadnaught

So how did the muffler sections line up? Are the tips centered on the two bumper cut outs?

Thank you for answering all of my previous questions.

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Ford Diesel and Heavy Line Technician at your service.

sandersd

Initially they were centered perfectly but after I had to unbolt the mid point connection to apply the RTV the right side drooped after I tightened it. I'm installing a set of Swift springs in a couple of weeks and when I have it up on stands I'll disassemble and replace the gaskets, bolts, and reapply new sealer while straightening the tips.

I know what went wrong: when I reassembled I didn't support the pipes on jack stands, I just let the bolts draw the flanges together and the tip didn't return to its previous position. This time I'll fully support everything in place while I seal and tighten working from front to rear like I did initially.

You really need a helping hand to position the tip while the bolts are tightened. It's also important when aligning to push up on the tip farther than necessary since it'll tend to snap back a bit. By overcompensating it tends to snap back to where you really want it.

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2014 370Z NISMO -- HKS Hi-Power Exhaust -- Swift Springs -- BC ER Coilovers -- SPL Suspension Components -- Nismo R-Tune Intake -- Seibon BD CF Hood

Highwind

its either you should ask for an adapter piece or get a full refund.