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View Full Version : '01 Manifold install?...Not Today!!!!...



The Thaw
04-04-2015, 04:35 PM
So I drive all the way to Estabans for an '01 Manifold install to find out I've got a California spec car.? ..*$%# ughhh!!!! hate the Cali epa BS...he doesn't have an RB bung kit,... naturally...though I did get a nice strut brace.... I should have known with the front mount sensor....dohhhhhh.... apparently the retired Colonel who ordered the car new here in Florida....ended up with a CALi car... and me too....dohhhh.. again...
QUESTION???? ????? is there anything else I can change or delete?, while I'm waiting for the RB cali spec change kit to arrive?????.....I know I have to weld in the RB kit bung to the midpipe....any thing else???? what else can I delete or remove????....pre cat??? to get more power during the install???.... doing it next weekend...haven't had time to read for hours...
TIA for informed replies....

kung fu jesus
04-04-2015, 05:42 PM
I did it on mine when I moved from CA to NC.

You need the exhaust manifold, the EGR tube, an O2 bung welded in after the cat on the midpipe, and shielded wiring to extend the length of the wire for that O2. The down pipes are the same, so if you disassemble the down pipe from the 01 mani OR your current one, you need that gasket. You also need the gasket between the down pipe and the cat/exhaust. That's it. If you can get the 01 heat shield, do so and use it.

When I had the O2 bung done, at a muffler shop, I had a 2.25 midpipe and cat fabbed and installed.

Altogether, the 01 mani, dp, EGR, cat, custom midpipe and gaskets cost me just shy of $500. The power difference was night&day noticeable. Probably to best mod I did to that car. Never had a CEL either.

kung fu jesus
04-04-2015, 05:52 PM
http://mazdaroadster.net/showthread.php?5638-Blue-Lion-Resurrection/page2

kung fu jesus
04-04-2015, 06:45 PM
I just wanted to clarify, that is the OEM manifold, not an RB.

Basically, it removes the precat, moves the O2 sensors downstream a little. CA emission cars from 99-00 have a restrictive manifold. The first O2 is before the precat, in the manifold. The second is in the down pipe, after the pre cat.

With the change, you are moving the first O2 to where your second O2 currently is, and your second O2 to a new bung AFTER the second cat.

It's not too bad of a job, it just depends on how easily everything comes apart. I stayed with the OE '01 manifold for cost and to eliminate the CA precat. The precat is prone to clogging, throwing codes. It is very restrictive. The '01 mani uncorks the flow a LOT.

If you are throwing cat codes on a CA emissions car, and your mileage is low-ish, it is usually a sign your ignition is weak, so plugs, wires, testing your coil packs is a good preventative to future issues.

The precat on my NB went bad in less than 20k miles after I replaced the first one. I found the weakening coils sort of by deduction.

The Thaw
04-04-2015, 09:06 PM
Steve, many thanks for your informed responses....I just read your '13 thread on the '01 manifold install and the welding midpipe custom make on your Lion, 10AE...just what I needed....I wish I understood the custom 2.25 midpipe part better...?...please forgive my ignorance...


to review my situ....estaban is excellent ...serious Miata shop...he races at sebring and knows it all...so he has for my install....OEM '01 manifold,....OEM '01 heat shield. and OEM egr pipe with fittings.....I am ordering the wire extension RB bung kit tonight...when it comes in I will go to a local welding exhaust shop...just like you...to have the bung welded in downstream....then I'll be asking midpipe questions...just like you!!!!,

what is the diameter of the stock midpipe?...2.25 is larger?....I want to do precisely what you have done.... my 3 week old to me, 2000 se has 59,000 miles and is flawless...no codes at all..no problems at all...just want more hp and for it to breathe properly...estabans shop knows it all so I'm in good hands there..he should have any gaskets etc I need...he has at least 4 Miata engines in his shop. and many parts, ....and parts cars...

he just didn't have the RB sensor/bung kit for Cali cars for the install today...my fault....I'll be driving back next weekend for 2nd try at install.....it sounds like Cali. pre cat gets eliminated with '01 manifold? yes?...I have stock muffler for now...plan on RS3 cat back soon... I also have newer ign wires and new plugs... no autox, no race, no tracks.. for me....just my aggressive street driving enjoyment is all I'm after...again many thanks for your informed responses..... and thanks for your '13 thread which was great to read....

kung fu jesus
04-05-2015, 08:27 AM
Awesome! You are very welcome, and I am glad something I did helped you!

Let me start with the manifold differences. The 99-00 Cali manifold is a cast unit with a catalytic converter bolted to it. It is known to be a restriction and prone to clogging. Very annoying, and a very expensive fix. The '01+ is a mandrel bent, tubular manifold, flows a lot better.

Here's a rough breakdown of the differences between your current CA manifold and the '01 you are installing:

CA
Engine --> cast exhaust manifold --> pre cat (O2 sensor 1) --> down pipe (O2 sensor 2) --> second cat/midpipe --> axle-rearward exhaust

'01 retrofit
Engine --> tubular exhaust manifold --> down pipe (O2 sensor 1) --> cat/mid pipe (O2 sensor 2) --> axle-rearward exhaust --> rainbows and sunshine

The mid pipe I documented/mention is a larger diameter than stock. I do not remember the stock diameter, but 2.25" is the common upgrade that is known to benefit stock-ish, naturally aspirated motors. I did this because a) I wanted to replace to aging second cat (I was well past 120k miles) and b) any chance I get to repair AND upgrade at the same time is golden in my playbook. You do not have to do this, however. Any shop will cut a hole in your midpipe and weld in a bung relatively cheap and quickly.

I didn't need the wiring extension, I had an extra, old O2 sensor that I cut the wires from to graft into the one on the car. This lengthened the harness to reach the new bung.

Anyway, the midpipe at 2.25" diameter is the measurement most aftermarket exhausts and bolt in midpipes are. I requested a small resonator added to it, it isn't my first rodeo doing this and know the exhaust in these cars can drone while cruising at speed.

The sound is louder, the power is higher, but because your car has so few miles, you can just skip the custom mid pipe.

You should also know the CEL codes for Cali cars are different than the other Miatas of that vintage. They have a different ECU. No big deal, really.

The Thaw
04-13-2015, 01:05 PM
I got it done this past weekend!.....excellent upgrade....thanks Kung fu

kung fu jesus
04-15-2015, 07:42 PM
Apologies for the wordy replies. Very happy you got this figured out!

Blackboost
02-26-2016, 02:20 AM
Good info Kung Fu! I just posted a new thread and then finally came across this one. I like the detailed info you give. I'm going to do the same thing to the same car. Only difference is mind has a JRSC bolted to it. You cleared up my "where do I put the 2 o2 sensors?" Question :)

kung fu jesus
02-26-2016, 08:52 AM
I saw this after I replied. Glad this info is useful. I linked this thread to yours. Good luck!