Header Installation

Installations instructions for MonsterFlow intakes, Big Brake Kits, shocks and more.
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Gordy
Posts: 28
Joined: Tue Apr 20, 2010 12:20 pm

Re: NC Header Installation

Post by Gordy »

I'd think up on a rack -- remove the mid-pipe/tail-pipe (if you're replacing them). Unbolt the (lower!) manifold mount, near the flange, where it bolts to the engine block. Remove O2 sensors, heat shielding, etc.

Then lower the car and remove the manifold from the top. Certainly would be the way I'd do it, if I had a lift. (jealous!)

If I recall, when I did my swap I thought about pulling the header out the bottom, but didn't do it due to the tight squeeze & angle (more so that you have to move the manifold towards the right wheel well as well as angling it back/fore), and there's just not enough wiggle room with that lump of Cat on it.

Then lift the car again to install the mid-pipe/tail-pipe, O2 sensor (and wire routing/stuffing).
tbdomenz
Posts: 31
Joined: Fri Jul 31, 2009 11:05 am

Re: NC Header Installation

Post by tbdomenz »

After agonizing over this header swap I decided to check out the local garages and muffler guys. Short story=$300 and 2.5 hours at Midas Muffler done! No engine lights or code issues, just a plug and play swap.
The support bracket bolts were stripped off cause they were too corroded to come off clean. I tried to soak all the fasteners and I knew the bracket was there but I could not find or see those nuts so they were excluded.
The only down side is the new deafening roar of the exhaust :shock: Before the swap, the system was OEM header + GW midpipe + straight tail pipe = prefect bark! Now I'm gonna have to git me another muffler. Car is essentially undriveable until I get a muffler. Gotta tell you, that OEM header is a welders nightmare. Muffler tomorrow and autoX testing on Sat :mrgreen:
Tom in 60193
OZMDD
Posts: 5
Joined: Tue May 04, 2010 8:53 am

Re: NC Header Installation

Post by OZMDD »

Not sure if others have found this to be true, but I went ahead and disconnected the alternator altogether, then set it where the battery box had been located. Made it easy to get to all the other header and O2 sensor stuff, and to clean the back of the alternator then apply the heat-reflective tape. You do need to unscrew the air duct on the alt to move it, but that was good anyway, since I found some leaf debris in there!

I went ahead and covered the entire back of the alt in heat tape, since an entire roll was only $15 at O'Reilleys. Plenty left over to wrap the extension wires if you want a little extra protection.
roadster_nh
Posts: 47
Joined: Mon Jun 28, 2010 5:19 pm
Location: DFW

Re: NC Header Installation

Post by roadster_nh »

I posted info about rerouting the upstream O2 sensor wires and thought it might be helfpful for others...

http://forum.miata.net/vb/showthread.php?t=462382
2003 LS FFS
JeremyJ069
Posts: 48
Joined: Mon May 14, 2012 11:42 am

Re: NC Header Installation

Post by JeremyJ069 »

ha, i find it amusing that the mazda dealer that fixed my bad cat had to unbolt the engine mount and tilt the engine over to remove the cat.
one day i might take this on. good to see some nice clear instructions on it.
JeffreyH059
Posts: 2
Joined: Wed Mar 14, 2012 11:13 am
Location: Charlotte, NC

Re: NC Header Installation

Post by JeffreyH059 »

GWR Header comes this week! Can't wait! :D

I wanted to say thanks in advance for all the DIY postings on this. I'm sure your advice/tips will save some time and plenty of headaches.
Current
'07 MX-5 Sport, GWR Header, Midpipe, RSII Duals
'06 Civic, K&N Intake, Eibach Springs/Sways, Tokico Shocks, etc

[Sold]
'99 Miata Base, K&N Intake, Mazdaspeed Catback
'96 SC300
'98 Accord, I/E, Direct Port NOS, MSD Ign, Coilovers, etc
'95 MX-6
JeffreyH059
Posts: 2
Joined: Wed Mar 14, 2012 11:13 am
Location: Charlotte, NC

Re: NC Header Installation

Post by JeffreyH059 »

GWR Header went in with no real issues. Fitment was perfect. Overall weld quality was good. One weld had me slightly concerned, but only time will tell. I don't have other headers to compare it to so I can't say if it is better or worse than others.

Install took me about 11 hours by my lonesome. If I had to do it again, I'm sure I could do it in 5 or less. I was slow and methodical and took my time working on it over the weekend. Due to the various bolts in tight spaces, I ended up using a lot of the tools in the toolbox. Having offset wrenches, a creeper, and good sockets and extensions are a must. For the manifold removal/header installation I removed two of the three bolts from the alternator and tilted it forward (thanks to your posts). Very easy to take out/put in with the alternator tilted forward, and the belt work was simple. :)

Performance gains are appreciable, and seem to be slightly increasing as the computer learns the new setup. Top end RPM's are noticably freer and throttle response is better. Prior to the header, I had installed the GWR Midpipe and RSII Exhaust. With the header, it is definitely a new animal w/ regards to noise. The exhaust when cruising/feathering the gas is still pretty quiet, near stock. When you get on the gas pedal, it is a different story. I can't wait to see what it sounds like in a month after the new header tubes gets broken in. No CEL's thus far (important here in North Carolina). :D

Would I do it again? What a silly question... of course!

So my wife drove the Miata today and called me up. "I love this car! We're never getting rid of it! This is my car, remember!" (After about a week of ownership, I was driving the Miata everyday and she was driving the Civic.) Thankfully, I wear the pants and make the money in our household.

Glad to have her onboard. Not sure if I trust her with a [future] supercharger... lol. :shock:

Maybe I'll just go Intake/Tune and be done with the engine... idk. Either way, 2013 will be my year for upgrading the suspension. Can't wait to do my next mods.
Current
'07 MX-5 Sport, GWR Header, Midpipe, RSII Duals
'06 Civic, K&N Intake, Eibach Springs/Sways, Tokico Shocks, etc

[Sold]
'99 Miata Base, K&N Intake, Mazdaspeed Catback
'96 SC300
'98 Accord, I/E, Direct Port NOS, MSD Ign, Coilovers, etc
'95 MX-6
NC'Adam
Posts: 3
Joined: Sun Jun 03, 2012 5:35 pm

Re: NC Header Installation

Post by NC'Adam »

I installed the PPE long tube header on my '07 this weekend using the instructions from this thread as a guide. Only major deviations being that the alternator had to come out completely and I had to remove the strut brace.

I cant seem to get the new header to seal to the engine block. It sounds fine at idle in the driveway and I can't detect any leaks under those conditions, but as soon as i take it for a drive i get this horrible raspy buzzing noise along with a kind of 'psshhhhht' noise that almost sound like a turbo blowoff whenever coasting/engine braking. It sounds like exhaust escaping past the gasket and making the gasket vibrate. And when I stop and open the hood it smells like exhaust in the engine bay. I started out using Brian's suggested 25 ft-lbs on the header nuts but got the noise. I consulted my shop manual which said 35-47 ft-lbs for the exhaust header nuts. So i tightened everything to 35 still got the noise. Tightened it to 47, no change.

So what gives? Should I replace the gasket?
Brian
Site Admin
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Joined: Tue Feb 15, 2005 11:44 am
Location: San Diego CA
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Re: NC Header Installation

Post by Brian »

Did you torque the bolts starting from MIDDLE and working your way outward to the sides? If not, start over and try about 20 ft/lbs on center nuts and then work your way out and then from center again go to full torque.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
NC'Adam
Posts: 3
Joined: Sun Jun 03, 2012 5:35 pm

Re: NC Header Installation

Post by NC'Adam »

Brian wrote:Did you torque the bolts starting from MIDDLE and working your way outward to the sides? If not, start over and try about 20 ft/lbs on center nuts and then work your way out and then from center again go to full torque.
Turns out it wasn't leaking at the block. It was the clamps in the mid-pipe on either side of the pre-silencer. I guess working in a small garage messes with your perception of where a sound is coming from. I took it to the local Meineke, and they put some "QuikSteel" sealant on them and it seems to be working so far.
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