Building The Optimal Catch Can Setup For the 400HP Miata! (No Welding Required)

There are many different ways to do a "catch can" setup on a Miata, which leads to a lot of confusion on the topic. Hopefully this clears some things up and helps you figure out which route to take with your build.
Edit - Since I've received multiple inquiries about my flannel, here it is LOL amzn.to/3lcbCRy
Seriously the best looking and most comfortable flannel I own.
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Parts Used/Mentioned:
3/8" NPT Tap Set amzn.to/3mpch16
1/2" NPT Tap Set amzn.to/2ZVDZuX
Evil Energy Catch Can amzn.to/3isZJEO
Mishimoto Air/Oil Separator amzn.to/3oucRgN
3/8" NPT - 10AN Fitting amzn.to/3vwQiJM
1/2" NPT - 10AN Fitting amzn.to/3iuW1KW
10AN Hose (5 feet) amzn.to/3F9cWwp
10AN 90 Degree Fitting amzn.to/3FkXnBN
10AN Straight Fitting amzn.to/3BgZ0Oy
Testors Red Model Paint amzn.to/2WB4pkg
VHT Wrinkle Black Paint amzn.to/3mm3Cwr
CitriStrip Paint Stripper amzn.to/3a2oYcr
SPS Motorsport Vented Valve Cover
sps-motorsportshop.com/shop/e...
Mazda 323 GTX PCV Valve
treasurecoastmiata.com/i-2379...
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Forum Links & Videos Mentioned:
How to Wrinkle Black/Letter Fill
• How To Make Your Valve...
MiataTurbo Catch Can Thread
www.miataturbo.net/engine-per...
fourwhls AN Fitting Upgrade Thread
www.miataturbo.net/engine-per...
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0:00 Intro
1:02 PCV Valves, Breathers, & Blowby Oh My
2:27 Why Upgrade?
3:45 Seeing The Parts On The Engine
6:05 Valve Cover Disassembly
6:50 Modification Variations & Explanation
9:18 Breather Passage Drilling & AN Fittings Install
13:13 Paint Stripping
14:51 Kraken Manifold & Can Location
15:35 Catch Can Comparison
16:35 Custom Built AN Lines
17:04 Painting Valve Cover & Lettering
18:28 Final AN Line Routing/Install

[@gedas3419]

3 Things I thought would be made in a 'optimal' setup. 1 Air oil seperator. 2. Oil drain back to oil pan. 3. Air back to intake turbo suck side.

[@TheCarPassionChannel]

1. Air/Oil Separator not needed unless you're running lines back into your engine 2. Drain back might be needed, but might not. If it's a small amount of oil collected it's really more complexity than it's worth to add an additional fitting into the pan. 3. This can help evacuate pressure, true. But my concern is sucking oil into the compressor at full boost. To avoid this I could still use an oil/air separator in the breather line but need a 2nd can on the PCV side which I wanted to avoid. This video is meant to provide enough information to make those decisions for your own car 😃

[@gedas3419]

@@TheCarPassionChannel yea, good answer. TurboBandit runs 900hp on Mercedes with breather preturbo.

[@TheCarPassionChannel]

@@gedas3419 Yeah I have nothing to back up that it could be bad for the turbo, and I know it's good to pull a vacuum on the crankcase. I may switch over to that. I actually have hooked a MAP sensor up to my turbo inlet and it pulls decent vacuum, drops from the normal sea level 100kpa down below 90kpa while in boost

[@gedas3419]

@@TheCarPassionChannel ♥️

[@miatafied]

@@gedas3419 Not all cars have the same PCV requirements. When I went over 350hp on my miata I had to eliminate pre-turbo plumbing because I was getting a ton of oil in my turbo and IC pipes. This setup is the result of decades of R&D amongst turbo miata enthusiasts. Any research you do will lead back to this exact setup if youre seeking above 300whp. This was the ONLY PCV setup that worked well for me after trying multiple different configurations

[@evancotten8466]

Stop it Greg Peters. Stop it. Your passion for the Miata is contagious.

[@michaelbull6906]

Sold my Miata a long time ago but never stopped watching you, your content is great and a lot of it can transfer over to any car not just the Miata. Keep up the good work chief.

[@cdsprech]

I've never owned a miata, and likely won't, but I still get excited with every new video!

[@Hipsters_N_Hippies]

@@cdsprech same here.

[@alberthernandez4362]

Dang. I sold my Miata yesterday.

[@Hipsters_N_Hippies]

Don’t feel bad gentlemen, I am pretty sure I can say with most certainty that a REALLY large chunk of his current 121,000 subscribers are not Roadster/MX-5/Miata owners.

[@estewar03]

@@alberthernandez4362 Hate to say it but I also have sold both my Miata's. Today's prices I couldn't afford not to for the offers I got. But still a loyal sub for Greg & still wanting more Canyon driving uploads.

[@RyedaleAirsoft]

I remember commenting on one of your broke and boosted videos back when I was a very smart 20-year-old expert about everything, saying imperial bad, metric good. I have since grown as a person, turboed an eunos roaster of my own (with a kraken kit no less!), and have come to realise metric and imperial are not so different after all. In fact there's one thing both systems have in common. They're incompatible with imperial 😂 Honestly though your videos were a major help for myself and countless others on their quest for POWAAR and they only seem to be getting better. Little things like outlining the breather lines at 4:12, oooh, yes. Just knowing that I get to watch your videos for free, I almost feel guilty! World's best (Miata)Dad

[@NappMotorsports]

Looks great as always! Awesome alternative to welding them like we typically do, saves you the pain of a respray if it’s already a finished cover. If you do want to put scrubbers in the baffle passages (def not required), the trick is to only put it in half of the baffle passage, on the side farthest from the AN fitting. It scrubs the oil out, but won’t let the oil weep towards the fitting and into your catch can.

[@sk88rdude999]

You can bore out -10AN to 3/8 NPT fittings to match the -10AN ID. Pretty easy with a drill press and opens it up significantly. There's enough material on the 3/8 side to get away with it safely on a low pressure line.

[@zu_1455]

Clicked to learn automotive stuff….now I’m meditating. 😎

[@rogerd943]

Quick tip on wrinkle paint - the quality/tightness of the wrinkle is dependant on curing temp. If you are painting multiple parts that are in the same visual area, do your painting/curing all at once. Letting paint cure outdoors on different days with different temps will cause different wrinkle finish on the parts.

[@kevinsaeed9817]

Great video and explanation, very helpful. Thank for the hard work and posting this for us to watch!

[@outdoorswithjess]

I haven't had a mx5 in over 5 years and I'm still watching your videos. You're awesome Greg, thanks for content

[@mannys18s]

I was just talking about this with one of my coworkers. Great video, appreciate the link!

[@KayneWalshNZ]

Once again Greg top quality content love your work keep it up man 🙏

[@deeproller]

What a good & original way to start this upload….. thanks from Australia

[@cartermaneki]

great video as always Greg! Definitely going to be putting some of your tips to use on my supercharged 2.4l LE5 NA. The baffles in the valve cover on that motor are strikingly similar to the Miata ones.

[@garrydeimert7397]

I am absolutely loving your vids, you have a great way of explaining things. I had an issue with my vw golf (rabbit) gti, slipping clutch, when I opened it up it was drenched in oil, worked out that the crank case was not venting well enough and was blowing past the crank seal into the bell housing at high revs . Better vent, better clutch........subbed.

[@taylorbynam1929]

Just what I needed! 😀

[@jmpcrx]

Crazy that you bring out a vid on catch cans when that's the thing I'm just about to buy for my nearly done mk2 turbo 👍👍👍🏎️🏎️🏎️🚔

[@PANTYEATR1]

good job bro, looks good💪

[@hildamcsulla2741]

Really good to know about the Testor's trick! I have a bunch of model paint lying around... perhaps I'll give it a try!

[@leobezryadin3896]

That exhaust manifold looks crazy!!!

[@jp2246]

Looks great, the lettering came out super!

[@miatafied]

This is the only catch can setup that worked for me when i went over 350hp. I tried multiple setups and nothing worked except this

[@MrKsmith65]

Another great video Sir! I used loctite on my baffle screws during reassembly as you can imagine the outcome when pushing the redline…😇

[@Eviking101]

420th like! I think I'll put a catch can or two on my stock NA8 in preparation for a turbo some day, I'm really excited for the low mount Kraken video!

[@kevinmcinnis7180]

I needed to see this!!!

[@michaelbenno]

thanks for the video. It was helpful in my non miata 928 GTS motor which has a lot of blow by.

[@slyonme]

always showing good vids...greeting from australia

[@J4rn0]

Thanks again!

[@mrfixit892]

I like it! Love the Channel. I’ve got a 1996 MX5 that I bought a few years ago, it was put together by Flyin Miata. forged internals, ARP studs everywhere, Garrett turbo charger I don’t remember the size or at the moment, Full stainless dual exit exhaust, lowered with a Full adjustable suspension set up, under body bracing, interior upgrades. paid 6000 for it with only 53,000 original miles on the odometer and all of the original paperwork from the build. I also did several other modifications to it it. New ECU coolant reroute LS coil conversion added some dedicated power and ground cables. was tuned to 300hp unfortunately due to a few bad parameters while setting up launch control Number three connecting rod left the Chat and the engine bay.

[@madspikes205]

Great stuff, this hopefully solves my track day oil oil leak!

[@hashematassi6953]

On my motor I removed the pcv valve so I have two open ports on the valve cover hooked up to a three port mishimoto oil catch can and I have that third port connected to a fitting I drilled into my air filter on the turbo to pull vacuum on the entire system under all conditions, no issues so far!

[@handleymachine4421]

Jesus man! I gotta start taking notes here! PCB valve tip. Nice!

[@SkylerB17]

That Testors paint has been around for millions of years. (Joking) But forreal theyve been around for a minute and its enamel so it should hold up super well. thanks for the head up. Might use it on my entire valve cover.

[@mikefletcher5168]

Sorry, I'm just here looking for stuff for my escort gt. It's the same 1.8 bp05 as the Miata. Already learned a good amount from you.

[@benthleydorcin6160]

Really the best INTRO. breathing is so important

[@Trinidrift3]

I feel like I am quite sure you need to rtv the baffles back in. My old turbo setup was filling the catch can after 20 mins of normal driving. Couldn't figure out why. Pulled the valve cover to find the rtv was worn. Resealed it, and the issue went away. Multiple track days and still no issue

[@EncomICA]

Same thing happened to me, definitely seal those baffles.

[@HellFireno88]

Nice!

[@dunnebug]

Sweet!

[@shirtz69r]

thanks greg, exactly how i plan to do it. hows your re-route going? piping looking good in the bay

[@MK-ig4ku]

Great video Greg! Does it matter which side hose goes higher or lower on your catch can? Any advantage or disadvantage one way or other?

[@menehune-mx5186]

Nice, creativity rules :-)

[@caveone-365]

If you're a cheap ass like me, into fab work, an old A/C receiver dryer can be repurposed as a DIY catch can. You don't even need a welder if you're planning on drilling/ tapping the dryer can as well. You can find certain ones that work better than others size/ bracketry wise. Depending on how much time you take/ materials you use, its possible to make yours look store-bought and even better than some that are dedicated catch cans. You can add a drain, sight glass, barbs for filter/ inlet/ outlet, etc👍👍

[@johnmurraycompton569]

Dude, I'm breathing better already! Namaste

[@Victor-wp2be]

The “demo engine” will never be forgotten I remember seeing the video when u first got it. 😂

[@Friendsofdonr]

namaste Greg! hitting like just for the intro hahahah

[@fentuz]

I had to fit a 2L catch can (FIA regulation) on my breather side only which was enlarged because on NA high compression, the oil fumes lower the overall fuel RON index which is not good on a race engine...

[@madmiata1887]

That is the PCV setup I settled on, but the catch can would fill up with 10-12oz of oil during a track day session. The oil would spit out of the catch can filter, travel through the hood vents and onto the windshield. At first I thought the puking oil was from worn rings, so I rebuilt the engine with your videos as a guide :) I take it back out on track and same exact issue. Same amount of oil too. My guess is the extended G's from cornering and high rpm boost is over powering the stock oil/air separation. So I fabricated an aluminum 6in x 6in x 4in vent to atmosphere catch can with loads of baffling and stainless steel wool. Then I added a drain hose from catch can to oil pan just like mazda speed miata does from the factory. No more overflowing catch can issues. I would be curious if you run into similar issues on track with your setup. The Catfish camaro guy on donut media had a video on power to weight ratio and was looking for someone to do a trackday with at button willow(mentioned it at the end). That would be a neat collab video. GL man

[@whippingstar]

Might be in the catch can thread linked in the description, I think I remember it being mentioned to plug the coldside port during heavy track use due to this exact issue.

[@ReubenHorner]

Do you have oil pressure logging? It sounds to me like the oil is hitting your crank and getting whipped up. It will change oil pressure when smashing those corners but also throw oil out the breather

[@madmiata1887]

@@whippingstar I have tried that, it just pukes out the hot side. Thanks for the input tho

[@madmiata1887]

@@ReubenHorner I never thought to log oil pressure, yet that's crucial info. I have an aftermarket oil pressure gauge on top of the dash that I keep eyes on in the straights, but it would be interesting to know oil pressure in corners and braking. During the build I installed an oil pan baffle with trap doors. Thanks for the input, I will hookup the oil pressure to MS3.

[@wills_garage335]

I had a dual breather setup with no PCV just like this, just without enlarging the passages. I would notice while letting the car idle for a while, I'd see vapors come out the catch can and out the tailpipe upon initial throttle. Sadly I didn't get to put enough miles on the setup due to thrust bearing failure, but I am curious to hear how this works out on the street for you.

[@paulmason7871]

your giving away my stock block secrets now !! only clean air to me is how an engine should run ;

[@TheCarPassionChannel]

Stock block king in the house! 👑

[@hjsckd]

Could connect the oil catch can to the intake of the turbo help to the ventilation system? Since it’s a vaccum point should help to suck the vapours on the top of the head.

[@AGRFABRICATIONS]

coool video Greg just small note regards of math - increasing diameter from original 6.39mm up to 9.15mm will increase area (which is what matters) by over 100% not 43% so you should be good :D

[@TwinTurbo46]

That cold open! I'm W E A K!!! 🤣😂😅

[@HD-eu3zs]

You mentioned at idle and low throttle there is a vacuum at the intake manifold through the pcv valve. What happens to your car since you essentially deleted the pcv valve?

[@cory45x]

that paint crawl is called capillary action. has to deal with surface tension force

[@mr10ae45]

Hey Greg! Awesome video! I will definitely be doing this to mine. Just a heads up, the link for the "3/8 npt - 10an" links to a "1/4 npt - 4an"

[@TheCarPassionChannel]

Thank you, the link should be correct now

[@averageasianalchemist69]

i wonder if the exhaust is gonna sound different with the offset turbo

[@bigercat]

Hey Greg do you have any links to information on pcv and breather systems for itb applications??

[@codeninja100]

Nice

[@andrewshaffer4250]

I’ve thought about running a VTA can from the old oil drain from the 323 (plug behind the alternator on the 1.6) but unsure if it’ll be beneficial or not?

[@nue_kids_drift7588]

Is a vacuum from the intake not needed? Watching your video for future knowledge of doing this myself and am curious if you found this efficient over time?

[@christophercasale7961]

Please get a bench vise! It will make everything so much easier to drill and tap.

[@dylankaduce7751]

I’ve seen other videos of older small block engines that instead using the intake to pull pressure they use the exhaust which would reduce carbon build up id think? Anyone think this would work on a Miata?

[@frenchmanremy]

Could very worn valve seals cause crankcase pressurization?

[@AngusOutram]

I was literally just researching this the other day for my NB and then gave up after reading 3 different answers. My Turbo BRZ has a dual catch can set up with a breather pre-turbo because emissions laws where I live. I’m thinking it’s overkill for the MX-5.

[@gumpgroce1]

The only thing missing in your list is the AN ends for the hose I was just looking for the easy way out and order form the link Love your channel Thanks for the info

[@TheCarPassionChannel]

Ohhh shoot you're right, I'll get those on there in the next half hour

[@DJimeku]

do you feel like the loss of pcv really affects the additional sealing of piston rings as they say? I'm worried about venting both sides. What do you think

[@crustynolzz4218]

you sold me on the citrus paint stripper with "it smells great"

[@Striball]

I regret not getting my Kraken manifold and DP powdercoated. Would recommend doing it before it gets tarnished Grag!

[@robertmellor7059]

Hey Greg, I've forged my motor and may be going close to 18psi, I am mainly concerned about crank case pressure and my seals. I see Level7 do a oil cap 'QuickVent' product that looks a great way of venting pressure without messing with the cam cover. I plan to utilise this with a suitable AN10 catch can, but I was wondering once I install it, and I've got 2x AN10 venting the cam cover from the oil cap, should I still keep the PCV/mani hose in place (it has a GTX valve) or cap this off completely?

[@bauerlimitedproduction7398]

Run a breather hose from the valve cover to the catch can. Run a second high-temp hose to North of the catalytic converter (wink wink) to a welded bung that is angled pointing downstream of the exhaust. Yes, the hose should be flex steel for a foot or two as it connects with the exhaust. Place a high temperature one-way valve inline, in case of backfire. The suction from the exhaust will pull out the oil mist from the crankcase, and it will "generally" burn up as it exits the tailpipe. Prolly better for race cars than something that needs to pass emissions...

[@MendicantBias1]

Pro Tip: use a PCV valve from a turbo 1995 Supra (and a grommet too). Fits the Miata without mods and is all metal and definitely holds boost!

[@TheCarPassionChannel]

Mazda 323 GTX PCV falls into the same category 👍

[@gonzalocastillo749]

Could you make a Mac valve (ebc) install video !? With changes in megasquirt ?

[@TheCarPassionChannel]

Check out my MSM tuning video, I'm pretty sure I cover it there.

[@miatafan]

damn, i tapped my exhaust side 1/4 npt because I didnt think there would be enough metal for 3/8

[@mr.magicman8001]

When I first turboed my miata I ran the non valve port straight to atmosphere and after a few weeks both of my cam seals walked out.

[@DerekWongJC]

Hey Greg what's your thoughts on DIYing an oil filler cap that breathes directly with the catch can, while keeping the stock exhaust PCV that is connected to the same catch can? It runs 12psi with

[@ReubenHorner]

Sounds dodgy. Follow these exact instructions is my options

[@phillhill7579]

Hi Greg, did this end up solving your leaking oil seals on your red car? I have a freshly built motor with oem seals and have leaked through two front main seals. Breather system is AN6 and I'm thinking it might be time to go bigger

[@370zTEK]

Went ahead and ordered the same as you to make a catch can. Unfortunately the engine builder of my forged 1.6 put the thrust washers in backward and destroyed my motor. Lasted 100 miles. Should have new motor up and running within 3 weeks. Would love to race you when its ready. My Garrett 2867r Gen 2 would make an interesting run.

[@TheAdatto]

Damn that sucks

[@alundrasrt]

Hi, so did you remove the pcv?

[@speedsquadracing6090]

that testers paint survived 6 months on my big brothers C6 Z06 calipers before he sold it

[@ryangregory1364]

I blast wrinkle black with a heat gun straight away after 3 or so coats, aint right but it works

[@ioriOki]

It all makes sense, but I'm still trying to figure out what an inch is. lol

[@HyperspeedMedia]

put RTV .. don't skip that step. It only take a few minutes, never had any problems on my build

[@one234569and10]

PSH, that red paint, ain't gonna last! ;)

[@rauldeu719]

Hey Greg where did you get that Mazda flag from?

[@travdripdrip382]

R there any downsides to putting a tiny air filter on the valve cover, on the other breather on opposite side of the PCV breather? NA set up

[@TheCarPassionChannel]

No and that's a common setup. Reading through that catch can thread will help cover all the different setups

[@TotoGeenen]

I see one problem with this. Sludge. The factory PCV system is there for a reason. It's to prevent sludge buildup. Tho maybe with a car that doesn't get to see a lot of miles, it's not such a big issue. For a daily driver tho, you'll definetly wanna keep some sort of vacuum on the valve cover

[@777MAV]

Not a big fan of open systems... Also, placing it on exhaust side has its own potential problems. Have you considered adding a vacuum pump or something like that?

[@narutolovesbleach]

That model paint won't die LMAO

[@str8slayn1]

Same exact taps I bought lol

[@CarKevO]

You definitely need to RTV the baffle plates. I didn’t and was squirting say too much oil. Once I RTV’d the plates, no more oil squirting!

[@minialmond3769]

what is that hole on the top of the valve cover

[@TheCarPassionChannel]

For the VVT Actuator

[@SkylerB17]

Yo. my guy. Please please PLEASE tell me what brand shirt that black plaid one with the brown collar and cuffs is. that thing is fire and i need one.

[@TheCarPassionChannel]

I got you covered my dude - amzn.to/3lcbCRy It's 100% the most comfortable and best looking flannel I own.

[@SkylerB17]

@@TheCarPassionChannel You sir are a legend. The black one was out of stock but I got myself a nice one 👍 Thank you.

[@SkylerB17]

@@TheCarPassionChannel got my flannel in the mail today. It's amazing. Incredibly soft and comfy. Thank you so much 🙏

[@CallMeDugan]

Is there a risk for those Phillips screws to back out and fall into the cams? Would it be worth using blue loctite? I don’t have a Miata so I have no idea.

[@TheCarPassionChannel]

Yeah, definitely a good idea.

[@thatstaticgti7531]

I have a turbo 1.6 and I noticed a ton of blow by should I upgrade the pcv valve and port out the breather side I’m going to be drifting with the car what do you recommend? I’d ask the fb groups but rather get intelligent responses instead of 100 smart ass comments

[@TheCarPassionChannel]

Any catch can/air oil separator system is only going to manage the blowby, nothing is going to reduce it. But, it is important that the blowby is able to escape, otherwise it can cause leaking seals. You also want to avoid constantly feeding oil into the intake.

[@thomasmedhatt]

Made the valve cover mod myself (welded because im a pro of course). Cleaned the rtv from baffle plates and DID NOT put any new rtv... Tried it without any hoses and no hood on the car, *fuckyyes* and after a couple of minutes when oil got up to temp it started squirting all over my windshield (yes while driving). Let me tell you there's no windshield washer fluid for that scenario... To sum up, a lot of oil got into my baffles just by creeping thru the non rtv'd surfaces and then when crank case pressure came it looked like I were running a fryer at McDonald's. Rtv your baffle plates (if you dont have the old rtv intact) Don't run without a hood Don't make the AN10 fittings point straight up. My 2 cents

[@TheCarPassionChannel]

You're the second person to report the issue with not RTV'ing the baffle plates so it definitely sounds like a good idea. I've done this to 2 other valve covers and had no problem, so mixed results are possible. Another thing someone else mentioned is using loctite on the screws, typically I don't worry about this myself because the soft aluminum does a great job at holding screws in, but it won't hurt anything.

[@thomasmedhatt]

@@TheCarPassionChannel Just to add, welded the fittings straight up and also got the cheapest AN fittings. Guess who had lots of problem closing ny hood? Had to mash my fittings from 90 degrees to somewhat like 130 degrees. At last I ordered some higher quality fittings with much shorter neck and larger diameter. Still hits the hood but its something 🤷

[@TeddyD802]

I’m considering the Kraken kit myself. Why would I go with a low mount over a high mount? I was going to get the high mount because I didn’t know

[@TheCarPassionChannel]

I love how straight the downpipe comes out, and that it keeps that hot unit of a turbo down low and somewhat "farther" from the engine bay. It gives you more engine bay space as well, but the downside is that it's quite a bit harder to work on, which you'll see in the manifold install video, hahaha. I could not imagine installing this thing with PS and AC.

[@TeddyD802]

@@TheCarPassionChannel I really want to keep PS and AC, even though my AC doesn’t work now I want to get it repaired… my power goals are low 200’s at the wheels so I think I’m good with the high mount but I’ll continue researching

[@Belialzero]

Goodbye whatever video I was on, hello (checks notes), Catch cans!

[@rappit4]

lots of confusion on forums about what catch can setup to go for high hp. This is the way!

[@GibbyRipps]

Hey Greg, quick question. I have the same old mishimoto can that you had and if I go rip around all day I can easily fill the can up almost halfway every time. Is there a reason for this or is it just poor ventilation? My car is a 1.6 turbo that makes roughly 225 whp.

[@TheCarPassionChannel]

Is the catch can in the breather system, or in the PCV system? Usually just more blowby means more oil vapor is going to enter the can.

[@sammorgan31]

The metrics can't complain about tap drill sizes. Their tap drills won't be whole millimeters either plenty of times.