Project Kujira: My Over-The-Top AZ-1 Build
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I'm getting an early start on this thread. A REALLY early start. It has already been three months since I purchased Kujira, my AZ-1, but I've still got eight months of waiting to go. Kujira was built on the 6th of November 1992, so I have until November of 2017 before I can officially take ownership of the car here in the United States. Here's what I saw that made me purchase a car that I had never experienced in person or digitally.
I have big goals for this car. From what I've read on Cappuccino forums, my goals exceed the practical limits of the stock engine. For that reason and to address concerns about drivetrain age and parts availability, I am hoping to import an HA2xS K6A and FWD transmission from an Alto Works that I can be building while I await the car's arrival. Those powertrains are significantly more plentiful, modern, supported via aftermarket, and are much cheaper. My hope is that the K6A FWD engine and transmission will fit in the narrow engine bay of the Autozam. I have lots of experience in one-off engine modifications and standalone engine controllers, so the daunting tasks around achieving very high specific output aren't new to me. I will be custom fabricating the intake and exhaust, among other things, so fabricating or adapting the engine mounts is going to be a pretty small job in comparison. I will already be replacing all of the engine-related electronics with a standalone MegaSquirt MS3X anyway, so adapting that to a different engine won't add any complexity at all.
As far as which K6A to pick, I will probably need some help here. Here's what I have observed based on what is listed for sale on Japan's Yahoo Auctions site.
Suzuki Alto VIN:
x = drivetrain; A is FWD and B is AWD
y = engine; 1 is F6A, 2 is K6A, and 3 is R06A
z = generation beginning with 4th gen; 1 is oldest and 6 is current
Assuming products are correctly classified in their auction listing, HA21S uses a standard cable throttle which points toward the transmission side of the powertrain and has a distributor and single coil. HA22S and newer use throttle by wire which points across the top of the engine toward the exhaust side and have coil-on-plug ignition. The only other differences between all of the generations that I have identified are intake Helmholtz tuning and sizing of the accessory pulleys, as well as minor plumbing changes. Suzuki discontinued the Alto Works in 2000 with the introduction of the HA23S, so only HA21 and HA22 engines are in the running.
The MS3X doesn't have the ability to control electronic throttles and I'm not interested in dropping $2000 for a Haltech that will, so it seems like the HA21S throttle body is what I'm after. The height requirements are pretty different between the AZ-1 and the Alto, and it looks like the HA22S and newer intake manifolds would sit too high to fit under the hood, so again, it looks like HA21S is the way to go on the intake. I will be converting to coil-on-plug ignition, though, and having the factory wiring for the factory coils would be really nice. One point to the HA22S. HA22S also appears to have variable intake cam phasing, which could be nice for a minor driveability improvement with such a large turbo, especially if I find a way to get "bigger" cams, so another point to the HA22S.
I haven't yet found any information on the gearing for the manual K6A Alto Works transmissions. I'm hoping for ratios that are numerically lower than the ones found in the F6A AZ-1 and Alto Works because being gearing limited to 110mph makes for some very uncomfortable highway drives. The K6A engine allegedly has more torque and should have been able to handle a numerically lower rear end better than the F6A, but I'll have to confirm gear ratios before I can give a point to the K6A transmission. Regardless, I'd plan to use the K6A transmission. The F6A transmission has a speedo cable instead of a speed sensor and I think all versions of the K6A used an electronic speed sensor. Yes, this would require modification of the gauge cluster to accept an electronic speed signal, but it would allow me to use the stock 140kph speedo and do conversions through the ECU to turn it into a 140mph speedo, which will be more than enough range. It also allows me to easily adjust the speedo to account for different tire sizes. No word on whether or not the AZ-1 halfshafts will fit into the K6A transmission, but there are many companies around me that specialize in custom half shafts and driveshafts, so I will cross that bridge when I get to it.
I spent multiple months picking the correct turbo for the job. The most common two turbos to use are an unnamed GT12 (GT1241?) or the RHB31FW. Both are popular because they are bolt-in upgrades. The latter is a stock turbo with upgraded wheels and the former is an upgraded turbo that uses the stock flanges. Both couldn't get you past 130 crank horsepower even in the best of conditions, so they weren't in the running. Another commonly referenced upgrade is to an unnamed GT15 turbo. It loses the bolt-in status because it has different flanges and it also loses a water cooled CHRA, making it a lot less appealing for a daily driver. As the largest of the GT15 range, the GT1548 seemed like a good fit with respect to supporting up to 200hp, but it isn't very happy with high pressure ratios, and those will be required for an engine this small. And it has been discontinued without a replacement by Garrett and cannot be found, even used, unless you grab one from a diesel application. And that's not what you want. So I kept looking. It turns out that the "up to 20 lb/min" slot is vacant in pretty much everyone's aftermarket turbo portfolio, water cooled or not, so I turned to a turbo that I'm a little bit familiar with: the GT1446. It's the stock turbo on the Fiat 500 Abarth Essesse and Punto Abarth Evo where it makes 160hp and has been pushed up to 230hp in that application. The compressor absolutely loves high pressure ratios and should be right in the middle of its efficiency island when making 150-200hp on the Suzuki engine. The turbine section is unknown because it was hard enough to find a compressor map. I don't think that a turbine map exists for this turbo. And since a turbine is what determines the shape of your torque curve, I won't know what kind of response to expect until I get the turbo on the engine. After seeing a dyno chart of a Cappuccino running a GT25, I don't think that I should be concerned about driveability with the GT1446.
The GT1446 comes with a stupid electronically operated compressor mounted diverter valve. I don't have one of those and have no desire to acquire one and then control it, so that's a hurdle. Another hurdle is that Garrett doesn't sell OEM turbos to the general public. Fortunately I managed to find a company that is interested enough in the project that not only would the sell me an OEM turbo but they also said that they'd have a solution for the compressor-mounted diverter valve flange! I'm already going to have to design a new intake system to deal with the new turbo outlet and a water-to-air intercooler, so I'll just put a BOV flange on there somewhere.
Yes, water-to-air intercooler. The stock intercooler is a bit small and would be wholly ineffective above the factory power levels. There isn't room for a bigger intercooler in the stock location and the extra intake volume from running intake pipe to the front of the car would be really bad for throttle response, so the only options are to run an intercooler on each side of the car or run water to air. I'm not excited about adding weight to the car since the goal will be to remove as much as possible, bit this weight is necessary. A heat exchanger up front, water lines to and from the intercooler in the engine bay, a pump, and a reservoir. Cooler charge air means less knock, which means more boost, more spark advance, or both. Either way, it means more power, more reliably.
The GT1446 uses a v-band turbine outlet. The 1.4L Fiat engine is also laid out so that the engine is on the right side of the engine bay and the exhaust outlet is forward, just like the K6A. This means that I might be able to use 500 Abarth downpipes on my AZ-1, and I have found a very nice aftermarket unit with a high flow cat. The whole thing is ceramic coated for heat retention, which will be critical in this cramped engine bay. My other option will be to make my own downpipe with a catalytic converter and wrap it in heat wrap. I have no experience with heat wrap or with ceramic coatings, so I haven't made a decision on that topic yet. For the rest of the exhaust, I probably won't make a decision until I have the car to examine. I will absolutely do quad exhaust a la the picture below, but the presence of mufflers and resonators is still up for debate. The Abarth has just a turbo and catalytic converter for muffling and it is fine. My old Talon had just a turbo and a catalytic converter for muffling and it was tolerable. But those also had 10+ feet of exhaust before the tip, so I'm not sure what to do here.
Brakes.....will need help. I already know that. How so, though, I am not sure. I am hoping that I will be able to bolt on some OEM Miata brakes because they are a dime a dozen here in the States and would be a hefty upgrade from what comes on the AZ-1, but like with the halfshafts, I will cross that bridge when I get to it.
The suspension...I have no idea. There are coilovers available all over the Japanese auctions with little to no description or detail accompanying them. I haven't yet tracked down a tuning company that produces them that could provide me with product info. I am hoping that someone might be able to provide suggestions or at least point me in the right direction here, because I have heard that the base AZ-1's suspension is pretty soft and I was not fortunate enough to track down a Mazdaspeed version. I went as far as to propose an MX-5 front subframe swap, which would bring with it aluminum double wishbone suspension, a host of aftermarket suspension choices, and certainty that the MX-5 brakes would bolt on, but I have no way of knowing how much work that will be. Even if it bolts on, I'd still have to adjust steering geometry to mitigate bump steer. And since the front end of the AZ-1 is so much lighter, even the OEM MX-5 springs and struts might be too much for the application.
So I have my work cut out for me, I guess. The car arrives in November. The plan is to be well into the engine build by then, and continue the engine build while driving and assessing the stock AZ-1 until I have a chance next year to start the engine swap. So aside from choosing and sourcing a K6A engine and transmission, I also need to buy a TIG welder and start practicing, as my previous attempts at welding have been less than satisfactory. Both of those tasks have not been going terribly well for completely different reasons.
Suggestions for welders or engine importers or comments about anything else is absolutely welcome. I know that this is ambitious, especially since I am planning all of this without having ever seen one of these cars before, but I'm confident enough in my engine building skills to get this project off the ground. Assuming that I'm held up by something stupid like the engine not physically fitting in the engine bay.
I should also mention that I intend to document all of my work on YouTube under the name Randy's Rides. I have reserved the name but I haven't done anything else to the channel. I'll get that off the ground once I have something physical to show.
- Posts: 30
- Thank you received: 2
I have a few small updates at this point. With respect to the gearing question, the K6A and F6A transmissions have identical ratios for final drive, reverse, and 1st through 4th gears, but fortunately 5th gear is numerically lower on the K6A unit. Here's what I have found:
5th: 0.837 (AZ-1) or 0.783 (Alto Works K6A)
Final drive: 4.705
So that means that the K6A will keep the incredibly short ratios and acceleration of the original F6A unit while offering slightly reduced RPM for more comfortable highway cruising (4100 RPM vs 4400 RPM at 70 mph). Fuel economy might be a little better, but for all intents and purposes I am going to label this as insignificant. My original quest for better ratios was based on bad data stating that the AZ-1 would be cruising at over 5500 RPM at 70 mph in 5th, but I created a spreadsheet to compare gear ratios and different tire sizes and found that that number was way off. If anyone is interested, the spreadsheet can be found here .
I haven't looked around for suspension components at all yet, but with the tire size that I'd like to run (because it's the smallest available sport tire here in the US) I have to be absolutely certain that I will not lower the car at all. There is a possibility of the tires fitting in the rear on a sport suspension but no hope at all on the front. Hopefully the tires that come on my AZ-1 have plenty of tread and aren't old because it looks like I might need to do some work to make this work. I guess I didn't mention it in my first post, but 185/60R14 is the smallest Extreme Performance Summer tire that I can source here in the states. It also happens to be the stock size for an NA Miata, and I have a spare set of 14x6.5 Miata wheels that I was intending to mount to the AZ-1. The wheels that are coming on my AZ-1 are RAYS TE37s that, going by availability on the RaysWheels website, are 14x5 wheels. If that's true, I could mount the tires on those wheels and hope that the narrower rim width will help the fit, but at this point I won't be doing anything with wheels or tires until I have the car to measure.
I've been talking with two engine importers to try to acquire an HA22S engine and transmission. Both have said that they will call me back when they get through to their suppliers in Japan and both are coming up on two weeks without any contact. I think it's time to follow-up on those. There's still one company in Texas that has a K6A and FWD transmission from an EA22R. The price is decent but the transmission would be useless to me. I'd still want to source a K6A transmission or other small FWD transmission and adapter plate, and I'd have to start completely from scratch with the engine mounts. I'll call them up again now that I have a better idea about what I want.
@ThunderAlto Thanks for the offer! I don't know how much international shipping would be on something as heavy as a turbocharger, but I'd expect it to be unpleasant. My current sponsor is providing the turbo at half cost and it will carry the standard Garrett OEM warranty, which will be nice. As much as I like having spares of everything just in case, I can't really come up with a good reason to invest in a spare turbocharger at this point. I'll definitely keep that in mind, though.
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What perfect timing! I'm currently shopping for tires! That's great news! Those tires are quite a bit shorter than the ones that I have, but it's good to know that wider tires are possible. Did you have to do anything special with regard to the fenders to make that fit? Were you running the stock suspension or lowered or anything?
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So what you're saying is that I should remove the tie rod links in the rear and have all-wheel steering? That sounds like a fun and really terrible idea! But seriously, that's good to know because I only see AZ-1 specific suspensions from Silk Road and Aragosta but there are Alto Works suspensions from several other vendors like Monster-Sport. I'm new to suspension tuning, but I was reminded yesterday that Gran Turismo has a very accurate suspension model and I can play around with spring rates and damping settings in there to figure out what I want. Given the snap oversteer characteristics of the car, it seems like it would be ideal to have either identical springrates all around or to have slightly softer springs in the rear. I guess I could also check to see what people are putting on AW11s and scale that down a little. Either way, I've got more research to do.
fxdlidon (or anyone else that has an AZ-1), I have a request. When you get the chance, could you either take a picture of the factory radio connector or tell me what other cars used the same connector? I'm trying to get a new aftermarket radio for mine so that I can have audio for the three day drive back from picking the car up. I looked through some auction sites for radios that came out of AZ-1s to see if they had a picture of the adapter harness, but all of the ones that I found had the harness cut in half and the connector in question was not included.
Some people use radio adapters for Japanese imports, adds 20Mhz to the frequency. Could be a cheap alternative instead of replacing the entire radio.
I'd like to know the harness info myself as I plan to replace the radio eventually with something more modern.
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The needle isn't attached yet because I have some other work to do still, like adjust the odometer to match the mileage of my AZ-1 and fabricate the trip reset rod holder, so that's why it's at a weird angle. And I need to source some new gauge face screws for the speedo since the old ones are now too long, but this project is looking pretty good!
Here's the rear:
The top left wire is signal in (hence the green) and the bottom left wire is +12v (hence the red). The bottom right screw is GND and conveniently pops out next to the cluster's ground trace. The top right screw is not connected. So I still need to find a source of +12v and, barring that, add a connector to carry the +12v and signal lines from the chassis.
Separately, I spent some time playing around with the chassis harness that I bought.
I identified the side indicator connectors and was looking around there for something that looked like a speaker connector. I found a few different ones, but for every single connector, only one of the two pins was connected to a connector in the middle of the dash. Since that didn't work, I went to the fuse box and found the fuse labeled "Radio" (15A, third from the right in the top row). I followed that wire to this connector:
And at this point I'm beginning to feel like I'm loosing my mind. At least it's confirmation that the group of connectors that I had assumed are in the middle of the dash are, indeed, near the radio. Here they are for documentation purposes:
It seems like most or all of those are involved in the radio somehow. So that's fun.
On top of all of that, I followed up with my three K6A import leads yesterday. One took my name and number as though they had no record of me calling a week ago. The second said that they hadn't heard anything yet from the supplier. The third recognized me by name, said that he hadn't heard back from the supplier, and that he would follow up with them and call me today. I got a little caught up with the gauge cluster project and forgot to call the second half of my importer list before everything closed. So maybe I'll have another update today.