WELP I Think I Found The Problem With The NB Miata... [Project 2SJ Ep13]

[@coreyscarrepairs]

In my humble opinion, Cylinder #4 must have not been tested on the compression stroke. 95% just doesn't make sense.

[@TheCarPassionChannel]

Yes... and same with cylinder 2 actually. Rookie mistake by me and will be addressed with a short video when I re-test.

[@gbmgaming]

Me: Having a normal day Miata Dad: *Y O U G O N L E A R N T O D A Y*

[@TheCarPassionChannel]

Goals 🙏

[@mrcompatable]

lemme just sit you down here real quick boi

[@mtbiata]

This is why we love you Miata Dad. Instead of just building the NB's engine and sending it, you're teaching us every little thing that we want to know. Thanks Dad.

[@evannoriega-thomas371]

I think the first option of repairing the head with no mods and going back on the dyno is the best option. Add the nitrous set up after the head is fixed and then later on, swap the magical modified head on.

[@lcq4blackstar]

Agreed this is the best option, a video solely with a fresh head and on the dyno compared to your previous peak numbers would be interesting and a video to stand on its own IMO. Remember the last tests and numbers were a wash because of the tired head so basically just verify the engine is healthy back at 0* cam timing and dial it in from there.

[@slomant]

This! 👍

[@R03333]

Yeah knowing how Greg/Craig/Grape thinks, you'll be going to bed at night forever wondering if the OEM head with bolt-ons could have hit the 155hp level if it was healthy if you don't do it. So best route is OEM->NOS->Thicc ported boi.

[@ghostpunkkilla]

I vote this/

[@austindoud273]

Sauce the f out of it see if helps the rings lol

[@emppu011]

I think you should go with stock head fixed and continue testing bolt ons. And later on the series put modified head in and make project 2SJ 2.0

[@CashedOutCars]

I’d love to see the modified head on there to see what you can make!

[@Spear911]

I agree! Also liking your content on the boost build cash!

[@CashedOutCars]

@@Spear911 thanks man I appreciate it!

[@AlphaKingsMachinima]

Rebuild the head to hit 155, then come for Quinn's record!

[@KateLSx]

This! I love Quinn but the time has come.

[@quinthuyers126]

Today we have witnessed the inception of a rivalry for the ages. May the lord forgive us for the horsepower gains we are about to recieve, amen 🙏

[@EddoWagt]

Definitely keep the head stock, I think it's great to see what you most people can realistically achieve with their car and swapping heads and some big cams is not really part of that

[@biggboysouth]

Thing is he is already beyond what most miata owners do. Most people aren't running a aftermarket ecu they tune themselves on a naturally aspirated car so I don't see why not go full build, eventually. Personally for best content I think he should repair the head and keep the mods he currently has and see how that performs. From there he can keep moving more and more down the performance spectrum, that way we get to see what really makes a difference along the way. Eventually leading into that ported head and Cams. Which is honestly what I think he is planning on doing which lines up with how he's been doing the series so far. If I could have changed one thing about the series is I would have wanted to see how far these cars could be pushed on a stock ecu. Mega squirts cost big $$$$ and honestly I think with a wideband 02 and an aftermarket adjustable fuel pressure regulator you can achieve quite a bit.

[@EddoWagt]

@@biggboysouth I believe he's going to put a stock ECU back on when he's a bit further in the built, to see how big of a difference it makes

[@biggboysouth]

@@EddoWagt If he does that’d be very appreciated! But I don’t see how he’d control the fuel with a stock ecu. Would then need to install a adjustable FPR as well

[@sjorsangevare]

These 18 minutes flew by! I did not notice any boringness in the editing, perfectly done imo. Also, I think doing the stock head first and the new head later is definitely the best option!

[@theelichtje3]

I'd say, repair the stock head, and see what it does then. It'll be a great source of information for everyone. Afterwards, put the modified head on it! I'd love to see how much that can do. Finally, I'd love to see a comparison between the VVT head, the stock head, and the modified head! Some mods on the VVT head (skim, port&polish, and perhaps even cams) would be amazing aswell! It would really give a great insight into the differences between the different heads!

[@jp2246]

Yes, agree with the above post!

[@BrokePremiere]

Mannn, I just found your channel. The editing you use, is very cool! Making me inspired for my Channel. Looking forward to more.

[@TheCarPassionChannel]

Thank you man! I think this one was a little boring but I do my best haha

[@BrokePremiere]

@@TheCarPassionChannel Nah man very informative. Well done 👍🏼

[@0xGRIDRUNR]

people like you are why miata modding is so accessible to newcomers, we appreciate you miata dad!

[@bdcasey11]

I dont get why people hold you to such a high level of scrutiny, you do so much for the miata community in proving and disproving the validity of mods to 100 hp cars and I'm just glad I have this resource to reference while I modify my own miata

[@ChromaticVideos]

Loved the in depth debunk in the beginning! Also my suggestion, although boring, would be to get the head rebuilt normally just to complete that data set. Then definitely use the ported head and go thru what steps make N/A power. This aligned with my current path so of course I'm being selfish but I know everyone loves an N/A built ITB setup

[@DarkDMD]

It cant be overstated how gutted i am not to see this engine hit 155whp. I spent the last 3 days sick as a dog watching these nb1 videos and was so hyped to watch you get the car back out with the new head. I just spent an hour on the phone retelling the story to a miata buddy and when i told him he was as crushed as i. If you were going to rebuild it, i think you should. You have a lot of head content, time for some block! Lets go 155!

[@NappMotorsports]

NA Build for sure! You definitely have the knowledge and skill to get everything out of one of these engines. We'd love to see your take on making max power on an NA setup. We decided to bail on the idea at 155 WHP on a Mustang dyno, because cams/lifters for a VVT is the cost of a self made turbo setup, which is more fun on the street as you know.

[@Kyring]

Definitely stock head back on. Cure the issues, get the results. Then superflow head down the line with fat cams and then ITBs.

[@CashedOutCars]

The problem is lack of pop-ups! (Jk I want an NB myself)

[@ioriOki]

This is the definitely the issue. Would recommend pop ups asap.

[@tonymorfin8750]

NBs look way better. tf you walking about. Front looks better for sure. DA BOODIE LOOKS WAAAAAAAY BETTER THO!

[@blackthornmotorsports381]

Popupblockergaaaaang

[@kallsop2]

Just my $0.02, I would like to see the difference with the cam/intake/exhaust mods on a stock head compared to using the ported and polished head with the same mods. I learned how to port & polish heads 40 years ago on VW Beetle engines with mild camshafts and better carbs and exhaust, and have done numerous one since. I just never had access to an actual chassis dyno to see definitive results.

[@bingoberra18]

Top tip, compression test again after head rebuild, to see if there are still differences between the cylinders BEFORE the dyno.

[@mikeysan4]

I'd love to be able to see a re-run of you last dyno tests with the head fixed. That's the only way we would be able to truly see what the mods did.

[@nickwild7]

This man doing pulls knowing there's an issue 😂 You're my spirit animal, lmao trying to figure out my pressurized crank case issue I began to race 2 mustangs and a GTI...... Needed that good data 😂😂

[@davidkris]

Loving the methodology you're using on all of this taking one step at a tine learning and teaching as you go,. Thanks. This is of particular interest to me with a '95 block, 1mm bored, 10.5:1 pistons, '00 head shaved, ex-intake swap, stock header with welds ground down to open them up, 2.25" exhaust and RoadsterSport 3 muffler, with stock electronics (thanks CA smog laws) that I hope to upgrade to a megasquirt but leave the stock in place to switch between for smog (though I don't know if this is possible). Have not tuned it or touched the timing but it runs and pulls much stronger than pre-engine work. Looking forward to watching as this progresses and learn a thing or 2 for my build.

[@atotalpro]

10,000% go with option number one. I think running a stick head for a while will produce the most meaningful content for people (myself included). I'm looking to do these exact bolt ins and was super disappointed when your dyno day was a bust.

[@paolovitale7429]

Repairing the head and going back to the Dyno is the best option for what you're doing, you could get a new baseline for the healthy engine and keep showing us what works and what doesn't. Awesome work on the videos! I've been following you for about 5 year and while I still don't own a miata, I'll definitely know how to set it up properly once I have it, greeting from Venezuela

[@marcotine5847]

The most videos you can probably do (and what i think a lot of people would like to see) Rebuild the head to stock Put on the ported head Bigger cams VVT head Or, if u wanna build up the VVT head for the NA, once you're done put the current head of the NA on the NB and build that up. Port with big cams oversized valves etc... I have a BP-Z3 in my NB and would be excited to see how you'd do some VVT tuning with big cams.

[@danielegel7143]

I've been so excited for this video to come out...got a spare exhaust cam sitting in my garage just begging to be put in my '99 but I needed to see what happened with you first. Thanks Miata Dad!

[@wout3rXNL]

The best way to show all miata owners what "bolt-on" does what for the money you spend on it. So refurb the stock head and show dyno results with every change you make. So that all miata owners can choose their own prefered bolt-on to use. Love the content keep up the good work!!

[@scottmason2245]

Well, one things for sure. Whatever you end up doing is gonna be awesome! Looking forward to the lessons. You inspired me to boost my 90 na and I haven't regretted one minute of it. I'm 50 years old and have driven many cars. My boosted red na takes the cake.

[@8JustARegularGuy8]

First, Greg, your vids are the best, love the content! Second, getting a fresh stock head on there will definitely be the best going forward. Personally, do I want to see the magical modded head? Of course, that sound nuts. But using a stock head first would be WAY more relatable to the viewers. To me, and I'm sure to you, that's what your channel has always seemed to be. The channel has always been about learning, and that would be the best option as far as that. But hey, I'm one guy, everyone has their opinion, and more importantly, it's your car! Do what makes YOU happy! If you want to throw that magical head on there, go for it, because if I was in your situation, that's what I would do. Thanks for taking time to ask the viewers and read the comments, even after getting as big as you are! Keep up the great work!

[@lindkvistandreas]

This curiosity and exploring of the potential in this wonderful miata platform is really entertaining to follow, thank you for sharing !

[@markharper6138]

Go the stock head, check the rings and develop the intake. Then put the nitrous then the modded head. That gives a great progression of what can be done and the Gaines that can be expected. Awesome work G

[@tonybleach9468]

Umm maybe valve angles being different matters eg. Triumph motorcycle old twin we use to run 2 inlet cams but intAke and exsaust valve Angals are 45degs so swap works put a Westlake 4valve head on it valve angles are maybe 60degs intake 40degs exsaust...? So valves same length so if run same cam in both sides one will have less lift than the other because of the valve Angals is this what happening with the mx5 when you put exh on intake = less lift

[@lpruler1]

As much as I know it’s tempting, I feel like the more methodical approach of refurbishing the stock head would provide the most data, and I know your all about the DATA!

[@Binarymein]

Really solid diagnosis! The hot head sounds pretty good, tough to mess around fixing the OEM one when that's sitting on your table.

[@Domas64]

If it's a project to learn, definitely try to narrow down the issue here, it's very interesting. Probably valves are not seating properly? Need to grind the seats or what's the procedure callled. Next the ported head would be very interesting to see. How much difference it makes across powerband with just the port.

[@jannevot8515]

I was about to go to sleep... I guess my day is going to be 18 minutes longer.

[@bencelengyel8043]

Although I have sold my miata I still keep coming Back to watch your videos, they're Just pure information and entertaining and I love them! Please do a rotary swap one day 🙏

[@Drumheros]

I had the exact same problem with my NB2, cyl 1 was 50 psi under the rest on compression. Was throwing a nasty misfire at idle though, surprised yours didn't do that. When I took the head in for a rebuild they had to replace 3 valves (2 intake 1 exhaust) cause they were bent. Looks like you're leaning towards the madlad head and would like to see you smash that record or come close to it!

[@J4rn0]

This series was interesting to me because it was simple hardware wise. We all know, and are already being drowned in, crazy builds on youtube. We know anything is possible if you get better and more expensive parts. Using knowledge instead of money is what made this interesting to me. Therefore my vote goes to keep it as stock as possible.

[@federicoloffredi2467]

Great stuff, and this is true, we are not talking about huge cam profile differences!!! Still, I suggest to try an NA exhaust cam next time on the dyno, it has 5° less then NB (but also 0.4mm lift less). This is something to consider because we bumped from 226 duration up to 242. On m NB I did the same, with the centerline at 110 I achived a depressive 150PSI on compression test, at 95 (I was scared) I finally reached 175 PSI on the gauge, but the engine wasnt able to start. I have to try to put back the original cam and gear and check the compression. Thanks master keep on!!!!

[@shrimp562]

I think for sure go with the stock head before anything. Just to prove the gains you get. Then I think trying the ported head would be awesome.

[@devonswindell9735]

Thanks for all your help over the years!

[@jhuds88]

Thanks Greg, i wasnt watching the video really to learn something. Im loyal to your channel and i had a terrible day and you made me laugh and i learned alot. Keep it up man i love your content.

[@Hefe179]

Stock head please, I’m using your vids to guide my 99 motor build for my 94 Miata :)

[@BullPlop11]

I would love to see you just repair the stock head. It would be a great learning experience for those of us who may also have bad valves but don’t have the budget to throw a bunch of performance mods at it.

[@brownianmotion2373]

Super helpful as always Greg! My car's smoking like a clown car and I reckon it's the valve guides gone bad (I recently rebuilt the engine and didn't do these). You've shown me what a leak down test is now, so I will hopefully be doing this next!

[@analoguedrives3781]

Your problems are real world and really helpful to learn from. Would be really interested to see how you tune this car with a NOS set up for daily driving. Ie it’s on tap when you need it only. I fancy trying this set up for my mx5 kit car as an alternative to the usual turbo route 😁

[@wahaha6961]

Thank you for the goodies! 🙏 Much appreciated! 👏

[@Zesserie]

So the stock head comparison is nice, but here(in sweden) the best mod you can get away with is pretty much a new head and N/A tuning. We have really boring laws preventing us from turboing an N/A car. It's kinda technically possible with the right amount of money, but an R32 skyline would be cheaper to buy, then to have a legal turbo swapped Miata. If it would be possible, a video on the head swap would be nice! but if there is no interest for it then its fine too, the videos are fantastic anyway :)

[@jakefear]

Hoping you choose the ported head and play with some variation in cams. Super curious what kind of power you can get and how the drivability turns out.

[@CameronHall-wq9tk]

I'd be most interested in seeing you put the VVT head on, but there's always the risk that head isn't perfectly healthy either. It could give you content for the down time of having the BP4W head repaired though.

[@matthewquinn937]

this is super interesting, I love your level of detail w/ troubleshooting. When I achieve my dream of living in my own house and can buy another Miata, I will use this as reference

[@RobWhittlestone]

Awesome knowledge presented in easy to digest bite-size chunks! Love Greg's channel. All the best, Rob (2009 NC 2.0l Sport).

[@petert.naujoks1572]

Go for stock first, modified head secoond! And rememder to walk us through the modified head in detail please! Before installing. I'm right at the point of digging into my second BP4W head with plans to do a multi angle valve job and some velocity boosting, all DIY apart from a drastic skim to raise the compression. Ah, and exhintake mod of course! Keep up the great work!

[@hellfireclub86]

Thank the Good Lord, a TCPC friday video to fix my otherwise shitty week! You rock! I'd say repair stock head and see what she would have done with bolt-ons, that's what we are stock NB Bois are here for... BUT - machining and repair work ain't free unless you "know a guy" and even then...

[@hillbillysportsman5818]

Thank you for all your work from the Miata nation!

[@RogueCowTurd]

would be cool seeing the power gains and graph comparing factory head turbo set up with the ported head. but in terms of this series i think stick with the head that came in the car just so its more useful information for others

[@Buzz65]

Fantastic info....and I can't even get mine to idle properly after cleaning the throttle body.

[@mattwiser7982]

Excellent diagnosis tips for low compression!

[@nathanielh7677]

I think rebuilding the head to stock fits the most with the goal of this project, but I definitely would like to see some awesome vvt head swap stuff in the future!

[@ioriOki]

I learn more than I can retain every video I watch on this channel and I love it.. My brain is curious, but it hurts. lol

[@awesomecooly123]

I've watched every video at least twice and I still come back to reaffirm my knowledge. His website is good too!

[@le5025]

Excellent video and just in time. My headgasket recently blew. Hope you gonna show us how to install a head. Keep up the good work and take care.

[@enok82]

Option 1 for sure, rebuikd and improve step by step! Maybe even try porting it yourself when all other things are done!

[@MiataMods]

Go for option one! Just make it work and finish what you started! After that’s finished and done, go for the record 😌

[@georgimirchev7385]

Please do a vvt head swap

[@philjones5728]

I'd love to see you top Quinn's 185 by using the ported head - it'd be an amazing feat! Hey, what about ITB's too.......

[@the209bee72]

Well lucky for you, you pretty much know it’s a valve issue I had a leak between 2 & 3 and was like oh ok head gasket. Had a weekend to do the job in my small garage with problem after problem with parts not included and having to clean up everytime to close my garage to run to the store and after everything was put back together still a leak runs better tho but I’m an idiot not thinking and just needed my car to run so I can have a car didn’t check the head or block with a straight edge and more than likely my head warp and will have to do all that work once again and send the head out for repair. Yay.....

[@yp360]

This is a hard one because I want to see all three of your options! I want to see what your current setup is supposed to make, I want to know how much a vvti swap is worth and I want to see that modified head turn that motor into a screamer 😬 get to work Miata dad. I’m here for it.

[@brenthullander8057]

I think in the end you should put the vvt head on so that you makes as much power as you can on the bottle but maybe save that for the final iteration.

[@patrickfargie1146]

In your last video, you went over how tuning VVT could see awesome gains across the power range. It would make the nitrous build an absolute beast.

[@michaelswitzer9220]

I say go straight for the mod head. I appreciate the step by step gains, but let’s put down 200 horses on a naturally aspirated motor already. Cheers! Excellent content as always Dad.

[@NewGenesisHQ]

Glad you found the problem! waiting for a engine disassembly and rebuild video now.

[@caledoniacation]

Straight to Modified head and throttle bodies. Would love to see detailed installation videos of that.

[@alberthernandez4362]

VVT head swap on an nb would be very informative. Good content.

[@BigBenlolz]

Im just here to say no matter what you do with the head I just cant wait for a new vid so I dont have to rewatch your older ones 😄

[@KreepaEvoX]

it could be the reason power was builiding as consecutive pulls were made. Something to do with seals expanding as engine was hotter

[@biggboysouth]

Hey Greg not sure if you are aware but I came across a german channel called sps motorsports who claim they build 225+hp ITB MX5 engines for street/track use (fully built motors). I started digging into the specs some to see if I could tell how they're accomplishing this and saw they were using custom spec'd cams from a company called Cat Cams (also some custom wiseco pistons but no specs found yet). The site is in german but the cam spec sheet is in english. Looked into those cams and though there isn't much user info online I did find one video and a couple random forum posts so far reporting achieving over 190hp and good torque on mildly modded engines, ITBs, minor head porting and valve springs type stuff. I'm super fresh on the hunt so still learning what I can about them. I was hoping if some of the miata gurus became aware you'd look into it also and give them a real shake down. If they work as good as it seems these could be an awesome choice for the green NB project! I don't know much about cam specs so maybe they have a ridiculous amount of lift or something but the dyno sheet I saw in the video looked to have a nice curve. I'm interested in their VVT cams just don't know if a BP-Z3 is identical to a BP-6D or not. Dyno vid - 192 hp @7500rpm / 161ft/lb @5700rpm: kzbin.info/www/bejne/Z53NZ4l_qraZmas SPS motorsports vid: (english) kzbin.info/www/bejne/jqfQcqCDrK9kfdk SPS Cat Cams: ("Sauger" are the N/A cams) sps-motorsportshop.com/teileshop/performance-teileshop/mazda-mx-5-nb-1999-2000/motor/1-8-liter/ventiltrieb/

[@DrifterDavid]

I was about to say until saw the pinned comment. Gotta be tdc on compression stroke. Easy way to check is pull valve cover and watch the cams so you know for sure.

[@TheCarPassionChannel]

I just cycle the crank 360° if it shows 100%, it's been like 6 years since I did a leak down and I forgot how engines work apparently loll

[@guiguitonicmotorsport]

Nitrous it's cool with a good setup . I have a 1.6 europan miata with 2 stage of nitrous and little progressif controler. If your afr, egt, fuel pressure and advanced ignition it's correct and you IS reasonable in shot . No problem!

[@jonathanfoster8835]

Let’s see that stock head replaced first. I wanna see what those mods were worth on the dyno.

[@umoview]

Go big boy cams in the ported head man. Ive just put a set of Kelford cams in my new build. I cant wait to get it back in the car and on the dyno.

[@sonofthehill1320]

I'm surprised that you don't have a nice spare forged motor on a stand. Good to see you.

[@TheCarPassionChannel]

Don't tempt me 😂 good to see you here too, I haven't kept up with your 12 second sleeper but I hope it's doing good!

[@sonofthehill1320]

Thanks, they had us running 1/8 but next week is the first 1/4 mile day of the year. I did manage high 7's at 97 and put down an 11.85 at 120 something last year. Running great just like yours will after it gets built.

[@jouninraz]

My suggestion: Skip VVT head swap. Send original head off to get worked on. WHILE that head is being serviced, install performance head with big boii valvetrain, and get to work on the dyno. Once original head is done, swap it back in, and dyno with simple refresh AND with new 4 fogger direct port nitrous DRY system. This would allow to keep making more content, while addressing various types of builds for your various Miata kids.

[@TheMapleDaily]

I honestly hope you keep the stock engine or find another 1.8 from the same models.. the VVT really did make the rebirth series impossible to follow on anything but a VVT turbo due to the tuning aspect! But Either way Ill watch and follow along!

[@Thejsniper007]

Notifications enabled, gotta see you chase that na nb record ;)

[@olilarsen-wright5404]

Very much looking forward to seeing the VVT head swap in the future! Go chase the NA engine record!

[@ciao716]

Amazing video, I love this series. Things are getting interesting. Looking forward to see the results after problems will be fixed and wondering how many whp it will make.

[@Stranio34]

I would say go with option 1, I would love to see what the ported head does. But I'm a patient boy ^^

[@Silverboy005]

You could do the first option first then down the line go for the third.

[@TheAwkwardBanana]

Definitely rebuild the stock, see how much power, hit your limit/pop the head and then upgrade!

[@joro8604]

Learned so much. I need to watch this about 5 times. Pimp out the stock first.

[@taylorbynam1929]

I think you should do what you said. Do stock head, then do modified head! I think that would be the best route! 😀 best of luck!

[@FeralGhoulash]

I really would like to see the built head with itb’s, but I feel like the stock head would be better for community knowledge.

[@honzaskvaril2259]

Hey man, congrats on finding the issue. 👍 What do you think you gonna find wrong with valve train? As for next option, i'd love to see vvt head swap. I didn't find this info anywhere. And the nasty head with exhintake sound fun too. Could be interesting how much power you can make usig dramel tool and not spending money on cams. Looking forward to whatever option. :D

[@eliasswierczewski186]

I like the stock head idea! But you do you man, love the content, excited for more!!!

[@jannevot8515]

Please Greg, go for the stock NA power record !🙏🏼

[@curlyoakley]

As always, super interesting content. Always learning more! Keep it up man!

[@doc7amod]

Most realistic dude on the internet. Do the modified head.

[@c0c0asauce]

Couldn't a leak down test change if the cam is twisted or if someone did a heinous repair on a lobe? Neither of those things happen much but still.