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1K should cover the bottom end if you are doing your own assembly. I think my last one was 700 out the door iirc but that was a few years ago. Those Probes should handle 500 with no issue at all but the comp will definitely help with the street fun at that power level. Do you have E85 available in your area?
 

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Discussion Starter #22
1K should cover the bottom end if you are doing your own assembly. I think my last one was 700 out the door iirc but that was a few years ago. Those Probes should handle 500 with no issue at all but the comp will definitely help with the street fun at that power level. Do you have E85 available in your area?
Yeah, I think the Probes would be fine, but I didn't choose them (they came with the car along with a ton of other parts) so if I can bump compression a smidgen to help with usable torque that seems like an easy swap to justify.

E85: I think so, yes. I haven't kept an eye out in quite some time though. There's a gas station right by my work that used to have it.
 

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9:1 is not all that high but the 7M is more detonation prone than the 2JZ. If going high compression especially with a smaller turbo which I am sure you are after based on your goals, I would plan on E85 or running water/meth injection to make 500 on pump. With E85 you could even go up to 10:1 maybe 10.5:1 and really get great spool & mid range like the 2J's are doing.
 

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Food for thought, Miatas run 10:1 and boost, have for years, reliably, at that. Their limiting factor is the factory rods, and eventually the transmission... never really understood why 10:1 and higher was such a big deal in the Supra world, like you HAVE to have ethanol to make it work. I mean, safety factor is always a good idea and all, but consider cylinder pressures that high boost levels put into the engine anyway, are we really pushing the limits of the fuel when the Miata guys have been doing this for years?

All that said, by all means have a machine shop do the machining, but if you have the capability (I don't doubt that you do), then do the assembly yourself. I would have saved an embarrassing amount had I known to do this with mine... Considering the 500whp goal, bottom end like you're planning, appropriate turbo, standalone, and ethanol. Any work in the top end would most likely be just to fatten up the area under the curve. Mine's making around that, and has a usable torque curve of about 4000 rpm, it's a hoot. Lot of effort though, for maybe 500 or so rpm of extra powerband.
 

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Iirc miata 1.6 and 1.8's have a combustion chamber design similar to the 2jz. The more substantial quench area in the 7m makes it more prone to detonation. That is why it was rare to see anyone choose 9:1 with 8:1 being more common in builds. The 2j guys have been building with 9:1 or 9.5:1 for ever and recently up to 10.5:1 with e85 becoming available.

Most of the miata guys I have seen are running relatively low boost on a small turbo (8-10psi) or running strictly race gas on 10-15psi. I will admit i am not that plugged in to the miata scene though. I think a 7M would be fine with 10:1 on 10psi with a good tune or 15-20 on race gas.
 

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I think 9:1 is a pretty mild and safe increase to compression and also nearly no cost adder. If that will buy me a small improvement in the powerband that'd be great. That's a big part of what I'm targeting: power under the curve. I'll have to research more into what tuning tricks can be used to keep higher compression, boost and power increases all safe. I think lots of other high performance engines run high compression and high boost nowadays. I know a lot of that has to do with direct injection, head design, piston design, etc... but I think a lot is tuning as well and could probably be duplicated with an AEM or ECU Masters. I think a redesigned EGR system could also be used to help control detonation. I know the Supra world likes to shit on the EGR system, but I think it's actually very valuable in tuning and the 7M just has a shit routing system that localizes it too much in the #6 area of the engine.

This isn't my daily either, so I won't be just piling on the miles. It's unlikely it'll see more than a few thousand a year.

And yeah, assembly actually sounds super fun to me. I've done one other motor years back that I assembled in my garage. Other than that I've done all top end work. Anyways, assembling is half the fun for me!

Shimless buckets: Worth the hassle of switching over? I've got a good catalog of 7M shims already stocked in my garage, but have never gone the shimless route. That's expensive to buy new from scratch, and I don't plan on pushing much past the factory redline, if at all.
 

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For a 500hp goal you wont need super high lift cams and if you keep the stock redline there really is no benefit to shimless buckets. I've been revving to 7500 on the stock shim over buckets for a few years now and have never spit a shim.
 

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Iirc miata 1.6 and 1.8's have a combustion chamber design similar to the 2jz. The more substantial quench area in the 7m makes it more prone to detonation. That is why it was rare to see anyone choose 9:1 with 8:1 being more common in builds. The 2j guys have been building with 9:1 or 9.5:1 for ever and recently up to 10.5:1 with e85 becoming available.

Most of the miata guys I have seen are running relatively low boost on a small turbo (8-10psi) or running strictly race gas on 10-15psi. I will admit i am not that plugged in to the miata scene though. I think a 7M would be fine with 10:1 on 10psi with a good tune or 15-20 on race gas.
With a reasonably priced standalone a Miata B6 or BP engine can handle 12psi, on a GT2560 turbo, no problem at all, on pump gas. That is the standard FM2 setup, and they have been running similar setups since the very early 90's. Pressure isn't what kills the engine, bad tuning will though.

I'm not particularly versed on high end 7m builds, I'll admit. I know I'm running a bit over 20 psi on pump gas and a fairly conservative tune on my 1j, although that was as far as my tuner felt comfortable taking it on 91, for a long lived engine. Ethanol in particular on a 7m, I don't think detonation would be a big concern. Certainly not at 500whp levels...

I think 9:1 is a pretty mild and safe increase to compression and also nearly no cost adder. If that will buy me a small improvement in the powerband that'd be great. That's a big part of what I'm targeting: power under the curve. I'll have to research more into what tuning tricks can be used to keep higher compression, boost and power increases all safe. I think lots of other high performance engines run high compression and high boost nowadays. I know a lot of that has to do with direct injection, head design, piston design, etc... but I think a lot is tuning as well and could probably be duplicated with an AEM or ECU Masters.

And yeah, assembly actually sounds super fun to me. I've done one other motor years back that I assembled in my garage. Other than that I've done all top end work. Anyways, assembling is half the fun for me!

Shimless buckets: Worth the hassle of switching over? I've got a good catalog of 7M shims already stocked in my garage, but have never gone the shimless route. That's expensive to buy new from scratch, and I don't plan on pushing much past the factory redline, if at all.
I wanted high compression simply so my torqueless wonder had some oomph off boost. Ordered 10:1 2j pistons, and as I found out through some reading, you end up with lower compression in doing that with a 1j. Oops. I never did do any compression tests on the engine, but it feels a lot like it did on the stock pistons, so I don't think it was raised by any significant amount. The 4.10 gearing, on the other hand... Anyway, high compression makes for a fun off boost engine, and if detonation could be kept controlled, I think a 7m would be well suited to it, given the natural torque characteristics of the engine.

Direct injection, as you mentioned, is a large part of why modern engines make so much power and are still emissions friendly. When you burn more of the fuel, you make more of the power out of its potential energy. Simple enough, and I still have it in the back of my mind to get a JZ-FSE engine to experiment with. ;)

As far as assembling your engine goes, my only suggestion would be to do it in as clean an environment as you possibly can. I know it might sound a bit crazy, but if you can make yourself a clean room to build it in, all the better. Some 1x1 lumber and thick plastic sheeting would be enough to keep dust and other debris to reasonable lows, and could double as a paint booth of sorts too.

Shimless buckets, not necessary, and an easy way to make a snowball out of your head haha. However... I went with them on mine for two reasons. One, weight savings. I selected the parts for my engine with response being the priority, and for a medium sized turbo, it's not bad at all. Has more lag than I like at our altitude, but down south? She's a whole lot of fun, all the rpm range, for the most part. Second reason for shimless on mine? I also wanted to rev mine to 10k, merely to hear it sing. I could care less how much power it made up there, it was likely going to be way more than the grip available, so, a net waste anyway, but... worth it, if you ask my ears and loins haha.
 

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Part 8! Exterior Overview. I'm going to try to get the exterior completed first. Here's my rationale:

1. Exterior in perfect or near perfect shape adds more sell-able value to the car in case I don't finish this project. Sad thought, but pragmatic. Engine build is fun, but expensive and hard to recoup later on, unless it's in an excellent chassis.
2. I need to do some work on my wife's car, body-wise, so I'll be practicing painting skills and techniques this winter/spring regardless. Might as well go all in with the paint work this season.
3. A pristine exterior is extremely satisfying for me. In my 10+ years of various mk3 ownership I've never had an 8/10 or 9/10 exterior. The car spends a lot of time on top of the lift in my garage, hovering over my daily Land Cruiser and having some good eye candy in the garage is worth something.

I installed the exhaust, but I've got lights coming for the lift that will better show it off so that video is on hold.

For exterior mods, I'm planning a Kaminari carbon wing, a 2 hole front lip ducted to provide brake cooling and possibly spec B side skirts and rear addons. I also plan on the turbo A vent in the new bumper. More air flow, why not? The carbon wing would remain unpainted.

The front lip is something I really want from an aesthetic and performance standpoint, but goddamn if I don't already scrape the factory lip every single time I pull out of my driveway - even at a 45 degree angle. I'm not sure what to do there. I discovered "air cup" lift systems recently and am debating that as a solution. I hate the idea of adding a tank and compressor, but maybe that's what's needed to have a mildly lowered mk3 with my driveway.

I'll be trying my hand at some PDR soon. I have a few dents on the fenders and elsewhere that would be great to fix without a repaint.

I need to setup a paint booth in my garage and that's likely one of the next steps. I'll be using the 4 post lift uprights as the starting frame for the booth, and adding some wings to pull the walls a bit beyond the footprint of the lift. That should provide the needed space to walk around the car. I tested out a quick spray of clear on a project for my wife. I used a TINY amount of clear and without the doors open in my garage it was a cloud of noxious fumes in no time. It was a great example of the importance of a good booth. Of course, I was protected with sealed goggles and a respirator, but I still worry about fumes getting into the house and creating an explosive atmosphere since I've got the compressor and a gas heater in the garage.
 

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Super clean cars are two things: beautiful and nerve racking to own. I've had a few really clean cars over the years, but I'll be damned if you don't worry about where you park, driving on the highway for fear of chips, plotting out all the places you can't drive because it's too low, etc... It's a double edged sword, unfortunately.

Speaking of lowered, is there anything you can do to the curbing in your driveway entrance? I've seen some folks use cuts of pipe bolted into the gutter to smooth out the transition from street to driveway that works quite well, if you can get away with it.

Paint at home can be fun, but as you point out, dangerous. Make sure you shut the gas heater and pilot off before painting, and make sure you aren't forgetting other potential sources of ignition. Plus... keep a fire extinguisher or two handy, just in case. ;)
 

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Super clean cars are two things: beautiful and nerve racking to own. I've had a few really clean cars over the years, but I'll be damned if you don't worry about where you park, driving on the highway for fear of chips, plotting out all the places you can't drive because it's too low, etc... It's a double edged sword, unfortunately.

Speaking of lowered, is there anything you can do to the curbing in your driveway entrance? I've seen some folks use cuts of pipe bolted into the gutter to smooth out the transition from street to driveway that works quite well, if you can get away with it.

Paint at home can be fun, but as you point out, dangerous. Make sure you shut the gas heater and pilot off before painting, and make sure you aren't forgetting other potential sources of ignition. Plus... keep a fire extinguisher or two handy, just in case. ;)
Brad, yeah I'm pretty much already that way with the car though, haha. At least if it is nice, I won't be quite as crazy to try and protect it. It rarely gets driven and that'll probably be how it is for a while. I'll drive it to work, occasionally and otherwise just to shows and on weekend fun drives. At least that's the plan as of now.

Curbing: I've thought of that. I've even thought of paying to have the sidewalk in front of the driveway torn out and replaced with the low approach shape. Problem is, I still have to deal with other local drives and steep angles. The nose of the Supra is just so far out there. I think the air cups are really the way to go. They'd probably cost less than having the concrete changed at my house, and it would be usable everywhere I go. I think with some fab work you could shoehorn some tanks into the hatch area where the speaker boxes reside and have enough volume to make it work. The compressor could be mounted somewhere hidden in the rear of the car opposite the exhaust, I think.

Paint. Yeah. I think I'm going to invest in a ~$250 Extech VOC meter and an explosive gas meter for the garage. I may also be able to borrow a professional gas meter from work. The ones at work are exactly what I'd need, but I could never justify the $5k pricetag for personal use. Borrowing the one from work during a test run and then using a permanent install of the explosive gas meter and the handheld Extech will probably keep me covered. Even if I turn off the gas to the heater, there's still a huge list of problematic stuff in the garage. Air compressor (which is in the room and must be left on to paint), lift (I plan to raise and lower the car for good access throughout the job), static build up anywhere along the huge amount of plastic sheeting I'll use, exhaust fan (they won't be explosion proof, because explosion proof fans are like... $500+ each, the breaker box for most the garage is located IN the garage, etc... I think I just need to make sure I never let a dangerous concentration of gas build up in the garage. Removing all the sources of ignition seems near impossible without a massive investment.
 

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Do you still have the stock floor intact? If so, one could easily fit a pancake compressor in where the stock spare tire goes... the normal floor that came in the USDM cars had the raised trunk floor that allows quite a bit of storage underneath it. I like your thinking on tanks in the hidden pockets in the rear. There is a fairly substantial space above and behind each rear wheel tub...

Failing that, the passenger side of the car in the back, like you're thinking, you only have the fuel filler and fuel tank in the way. :p Might be some space near the fuel filter though? Hard for me to say, since the rear of my car is slightly not stock anymore...

As far as the garage setup goes, sounds like proper ventilation would be paramount. When we did the plastidip on my car, we unplugged the lift as a precaution, had a fan and some openings for airflow. Might get a window fan or three to promote even better flow if we ever do it again. Would hate for a sneeze and an accidental spark to blow the place up haha.
 

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Do you still have the stock floor intact? If so, one could easily fit a pancake compressor in where the stock spare tire goes... the normal floor that came in the USDM cars had the raised trunk floor that allows quite a bit of storage underneath it. I like your thinking on tanks in the hidden pockets in the rear. There is a fairly substantial space above and behind each rear wheel tub...

Failing that, the passenger side of the car in the back, like you're thinking, you only have the fuel filler and fuel tank in the way. :p Might be some space near the fuel filter though? Hard for me to say, since the rear of my car is slightly not stock anymore...

As far as the garage setup goes, sounds like proper ventilation would be paramount. When we did the plastidip on my car, we unplugged the lift as a precaution, had a fan and some openings for airflow. Might get a window fan or three to promote even better flow if we ever do it again. Would hate for a sneeze and an accidental spark to blow the place up haha.
The compressor for the air cup system would be real small. Those little 12V compressors are like the size of a tissue box. It's the tank that I'm more concerned about. The typical hot dog shape is just hard to conceal, I think. It looks like Stanceparts.com offers a ~$700 complete kit for two wheels. I should only need it for the front so that might be my ticket. I can start with their tank as is and mess with building my own later. I think two slim tanks mounted behind the stock cargo trim panels is the way to go. I never plan to run speakers back there anyways.

Yeah, I'll have at a minimum 3 fans. Perhaps two exhaust and one intake, maybe all three exhaust. Gotta keep that air moving.
 

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I have the same issue with my driveway, no sidewalk but all of the curbing is rolled all the way down the street. It's just high enough to scrape the stock lip and even my exhaust if I down creep in and out, (4in problems). I am hoping to come up with something in the spring like a ramp section I can bolt in. I really want to run a 3 hole lip next year.

The CUPS system looks great, I just cringe thinking about adding the weight because......racecar
 

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If you're keeping the stock floor panel, should have plenty of room underneath it for a couple of small diameter hot dog style tanks, no? Or did the 91 / 92 cars have the carpet that has a hump for the spare tire, but otherwise is flat against the floor? I know the JZA70 had that style, but I'm not familiar with the interior on the later cars as much.

As far as weight goes, given the focus of this build, I think an air lift is appropriate. Andrew, you're not using this one as a track car or anything, just a nice cruiser, enjoy what Toyota had in mind to begin with, with a little extra oomph and style? I mean, unless you're willing to go to some pretty extreme lengths, focusing on weight with a Mk3 is a silly pursuit. Josbeat's car comes to mind, the Bemani cars, that sort of thing, sure. They're a great chassis, but a Miata built within even a degree of the same level will obliterate a Mk3 around a track.

If performance is the goal, should probably start with the best platform you can afford, I would think... this coming from a dude who put a LOT of effort into making a Mk3 a super fun car. It works, but frankly, there are better options.
 

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If you're keeping the stock floor panel, should have plenty of room underneath it for a couple of small diameter hot dog style tanks, no? Or did the 91 / 92 cars have the carpet that has a hump for the spare tire, but otherwise is flat against the floor? I know the JZA70 had that style, but I'm not familiar with the interior on the later cars as much.

As far as weight goes, given the focus of this build, I think an air lift is appropriate. Andrew, you're not using this one as a track car or anything, just a nice cruiser, enjoy what Toyota had in mind to begin with, with a little extra oomph and style? I mean, unless you're willing to go to some pretty extreme lengths, focusing on weight with a Mk3 is a silly pursuit. Josbeat's car comes to mind, the Bemani cars, that sort of thing, sure. They're a great chassis, but a Miata built within even a degree of the same level will obliterate a Mk3 around a track.

If performance is the goal, should probably start with the best platform you can afford, I would think... this coming from a dude who put a LOT of effort into making a Mk3 a super fun car. It works, but frankly, there are better options.
There's some space under the carpet, but not much. Not enough for any tank I know of. Maybe 4 inches?

I'd like to even out the weight balance and shaving some weight is always good, but I agree it's silly to go nuts. It's a heavy car, down to it's core components. It's easier to add power than reduce weight!
 

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Update! So this video is actually from 2017. It shows the process of chasing down my leaking 7M prior to the Dyno I showed in episode 5. UV dye was very handy. I still haven't gotten into the rest of the engine, but the front is at least clean now!

Upcoming: Interior revamp including alcantara wheel, boots and console cover. Exhaust - Tanabe and BIC is already installed, just haven't uploaded videos yet. Exterior paint prep - I need to do some welding and a lot of tear down.
 

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Can't say I envy you, chasing down leaks... seems like every time I fix one, I find another. :p
 

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Interesting update!

I'm in final prep for paint and just learned PPG does not offer the OEM Metallic Blue in their better line, DBC. They also don't offer it in the Omni Plus line. Only the regular Omni. Omni is known for being semi-transparent and less vibrant than the top end DBC. Omni is also pretty rough when it comes to color matching, in large part to the transparent nature of it, I think.

They do, however, offer the Teal Metallic from the 92's in Deltron DBC. I think the Omni paint would be fine, but I'm thinking this is my opportunity to make this 91 the color I have always thought was best on the mk3 - Teal. That way I can use one of the better lines of paint from PPG and have my dream color.

The additional consideration for this is that the Blue interior will not go well with Teal... at all. But I'm planning on changing most the interior over to a Shadow Grey-esque color anyways so I think this all works out.

Watch out for a primer updates soon with Basecoat and clear coming soon after!
 
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