V2203 RX7 - Fate
 

I often browse the under $1000 vehicle ads on Craigslist, just to see what's out there and daydream about future projects. I was doing that last Thursday night without any intention of buying anything or starting another project, and I ran across an ad for a 1986 RX-7 shell for $500. That isn't any spectacular deal for an RX-7 without an engine, but it was really clean, and a rare Sport package, which basically gave it the turbo brakes/hubs, and suspension in the light stripped down base body and interior.


I bought one of these cars right out of highschool that was the same color, and also a Sport package. I had it for a few years then the engine went, as so many do, and I put it in storage for a few years before giving it to my brother because I was moving away. He never did anything with it, and ended up selling it about 10 years ago. It was the favorite car that I have ever owned, so many of the milestones in my life happened during the time period that I was driving it, and it's tired to so many memories and stories. The one car that I wish I hadn't got rid of, because I would probably NEVER be able to find another one like it...


So I'm looking at this ad, and thinking about how cool it would be to have another one just like the one that I had, and I start noticing things. It has a small ding in the hood in the same place mine did, there's a weird paint blemish on the B-pillar in the same spot that mine had one... I send the ad to my brother, and a friend that I was dating while I had the car, and they both think there can't be a coincidence. THIS IS MY CAR! I wanted to see if I had any old registrations or anything to confirm the VIN, so I look through my paperwork, and discover that I still have the title!

:jump:

There ended up being a lot of drama when the seller found out that I had the title, but the short of it is that Rangmar and some other friends came to the rescue, it's now sitting in my driveway, and everyone is happy!

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--Now for the plans --
I love driving rotary engines, but I swore a long time ago that I would never put another one in a car, they're just too much of a headache. Some people around here have been discussing putting a Kubota in something aerodynamic to make a high mpg for a while, and this seems like a good candidate. There is plenty of underhood room, people put LS1s and Toyota inline 6's in them.

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My plan is to build it for both performance and MPG. I've already bought another engine, and with some research found that someone has dropped an Isuzu diesel on one before. There isn't much information out there about that, other than two forum posts and one picture.

http://home.fuse.net/remo/diesel-rx7-2.jpg



*EDIT* Damned automerge - it's hard to break these things up into readable chunks when it won't let us post multiple times in a row!


There are a few issues. The stock gearing is 4:11, and the transmissions were about at the limit with the rotary's 138ft/lbs of torque. So to make this work, this is basically going to have to be an LS1 build, without the LS1.

Luckily, the engineering has all been figured out by others long ago. People commonly swap either a Ford Explorer 3rd member or one from a newer Cadillac with high gearing. There are a lot of transmission options, including the same transmission that is in my Jeep. Variants of that transmission were used in Toyota trucks, and the MKIII Supra, so different ratios are available, and I could just swap over the parts to mate it to a Jeep, and use the same adapter design that I already have.

Nice, can't wait to see it finished!

That is awesome! I have been daydreaming about a first gen RX7 for a while now. The 4.11 is a bit much but I think you can get a 27" tire in the back of that car and 70mph would be about 2400 RPM with a T5 (.68 OD) unless you're going to go with a T56... 6th on a .62 T56 would be about 75 mph at 2400 , the .5 OD version would be about 1900 rpm at 75. I mention the T5 because it's dirt cheap and seems a good match to the V2203's torque with a turbo. I haven't checked on a T56 or something else with a big overdrive (.62 or .5) and whether it will fit in the tunnel without mods.

I'm sure you have already looked at it but Granny's Speed Shop is full of information for the RX7 / V8 swaps. They have some interesting input on engine weight and it's impact on handling.. the V2203 is pretty light (for a diesel it's really light!), I bet it handles great! Really looking forward to your progress on this.

EDIT - when I'm saying .68 OD I'm referring to the V8 Ford T5's, they put all kinds of ratios in those things. You probably know that already, just wanting to prevent spreading bad/misleading information since there are so many different T5 gear sets. Sorry, I'm hung up on that transmission.

It will probably be getting a Ford 8.8 center section with appropriate gearing. The T5 is definitely on the list of candidates for the transmission. There is a ton of room in the tunnel, but the challenge is that the shifter on the Mazda gearbox is way off the rear. People swapping in T5s and other transmissions have had to do quite a bit of interior slicing and dicing.

I made up a quick mock up that's the same width and length as the block, and the same height as the bottom of he block to the top of the valve cover. The closest part is the steering rack. If I leave it where it is, I'll have to make the front 2" of the pan pretty flat, but it still has room to move back almost 3" before hitting the firewall, which would also help the shifter situation. Depending on what it looks like behind the dash, I'm also not against the idea of relieving the firewall enough to set it back a couple more inches. If I could do that it would have no problems with shifters or needing a different pan, and it would help centralize the 50lbs or so it will be gaining with the Kubota.

If for some reason I need to leave it where it is or move it forward at all, a Turbo II hood would be both lighter (aluminum), and have the hood scoop right where I would need to relieve the hood to raise the engine slightly.

The box off the front represents the front cover and oil pump depth.

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Interior - Not too bad for sitting in a field for 6 years!

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If you go t5, look for one from a Camaro or firebird. The shift is something like 6 inches farther back. Only thing is with the Camaro t5 is the tranny is tilted toward the drive a could degrees. Lots of info on t5 swaps on the HAMB.also you can get a s10 t5 and swap to the Camaro tailhousing/ shifter for better gearing. Also there in info there about using the cheaper ford t5 aftermarket shifters on Chevy t5

The autos had a 3.91:1 rear, which puts it at 1987.20RPM @ 60 with the .63 OD and 25" stock tire size. Not ideal, but gets it in the ballpark with a bolt in rear end. It should still get pretty good cruising economy at that RPM, and I've been considering building this engine to test some higher RPM theories anyway. A few people have spun them close to 4000RPM, which would be a bit over 120mph with that gearing if it had the power.

Someone has to try it first... :ouch:

I like that attitude.
do you think you are going to run componds?


when you did the compounds what was the small turbo? I can't seem to find it in your thread when I was looking. I was thinking compounds in my truck and am making a new manifold. Found a t15 on eBay but not sure if it is too small. I am also looking economy but want to make as much usable power as possible.

I will be doing a run of SBC adapters here soon. :w2:

The small turbo was a TD03-08 from a twin turbo Volvo. The setup didn't do much better than that turbo alone. It built more boost, but not a lot more power, so I think it had some pretty extreme drive pressure. I think the big turbo was too big, and I'm not convinced that the TD03 is a very good turbo anyway.

I don't really see a benefit to running compounds unless you're really heavy and not able to get past the lower RPM lag quickly. The setup was very heavy and overcomplicated.

Heh, I'm not sure that I can afford one :argh:

If I can get enough interest I am going to do a discounted run. Will be reasonable.

on the compounds it was considering it just to do it. My truck is light. Probably 800 lbs lighter then a s10 or ranger. Probably as light as your rx7. It is hard sizing turbos for suck a small set of compounds. Not many example out there.

Hmm, flathead V8s had round bellhousings and inset flywheels. I wonder if these are at all close to the Kubota flywheel housing diameter?

Speedway Standard Chevy Trans to Flathead Adapter Kit - Speedway Motors, America's Oldest Speed Shop

they're showing a 9" pressure plate to go with that - makes me wonder about the throwout bearing, is the Mazda a hydraulic?

Part b) that's a pretty small pressure plate, will that work with the Kubota flywheel?

The Mazda is hydraulic. The pressure plate is sized with the flywheel, if the bellhousing fit. It does say 9 to 10.5 though.

Sent from my Nexus 7 using Tapatalk

something else came to mind - the .63 number you mentioned is from a Chevy V8 T5, the S10 models had less OD, like a .8 or something... you can swap the tailshafts on them.

I wonder what the stack height would be with the Kubota housing and the Flathead adapter.

Well, this was always going to be a long term project, but it looks like it was just pushed back a bit more. It sounds like there's a tin can full of ball bearings in the bellhousing of my Wrangler. I'm going to start on pulling the engine tonight to figure out if it's just the throwout bearing or something more serious.

Hey Red, Sorry to hear that, Was it a new clutch set when you made the conversion, or old? How much time and miles did it have since the conversion?

good luck, hopefully it is just a throwout bearing

All new, I think it's a bit over 20,000 miles since the swap.

I was going to wait until I had tested the results before posting what I'm doing, but I figure what the hell. This is kind of a hijack (of my own topic), but it is related in a way, because most of these are things that I need to test out for the RX7 build.

My Jeep's problem turned out to be an exhaust bracket hooked to the bellhousing that tore out of the pipe. I had all of the ancillaries removed by the time I discovered that, so I'm taking the time to do some major updates that I have been wanting to do for a while.

So far this is what I'm doing:

• Switching from 2.25" exhaust that crosses under the oil pan to 3" that goes straight back next to the transfer case
• Changing from a Saginaw power steering pump to an electric unit from a Volvo
• Changing to a water to air intercooler
• Moving the alternator from the passenger side to the stock engine bracket on the drivers side
• Replacing the crappy junkyard dipstick with a Kubota dipstick
• Installing a fluid damper
• Replacing the turbo oil return barb in the oil pan with a threaded bung
• Replace angled Astro Van master cylinder with flat mounted one

It will be another week or so before it's back on the road, then I'll probably take it down again at some point to have the exhaust ceramic coated after I'm sure that it works the way I want.

Some custom work was required for the water neck using a Volvo charge tube (a lot of Volvo parts on this) to extend the neck around the intercooler. I'm really happy with how that and the exhaust turned out.

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Intercooler in final position, but just hanging from the couplings. I still need to build a support bracket.

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The biggest heat exchanger that I could find/fit. Some trimming was required.

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Positioning the power steering pump in it's new home.

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nice . I am very very interested to know how the Volvo electric power steering works. How much $ did it set you back. There was a Volvo in my local upull it yard. I would really like to use E-power steering as well. I had only known about the Chevy Malibu and the Toyota MR-2 units. I don't think either of those would have worked

I think it was $145 shipped from a wrecker. The MR2 units are commanding a real premium since they're so well known. There are quite a few cars with them out there now, but the trick is to find the ones that don't require the CAN bus. The Volvo unit uses the CAN to vary with speed, etc. Without it the pump just runs at a set speed and freewheels when there is no demand. It pulls around 3 amps at startup, and peaks somewhere around 70 at full lock, but that's generally momentary. I think it's regulated to 1500PSI IIRC. I've heard it works great with a steering box and hydroboost, so I've got my fingers crossed...

I'm pretty sure the Malibu is a straight electric power steering.

yeah the Malibu would not work. $145 sounds good. 70 amps sounds bad. My little NPR alt vac pump I think is 70 amps wide open.
I don't need to put the cart before the horse. I need to get 2nd gen engine mounts and Oil pan sorted
on a side note. how do you get the pictures to show up big like that, all my pics I am using the manage attachments section?

The 70 amps is just for the moment when you're fully taxing the system, which would be holding the wheel at full lock. It spends the vast majority of the time just freewheeling in bypass pulling ~3amps.

I use photobucket and just use the 'insert image' button with the direct link to the picture.

nice setup

Almost there... All of the big stuff is back together, but I have maybe a couple leisurely hours of finish work (securing wires, etc.). I must be getting old, because a couple years ago I would have pushed into the night and finished, then drove it to work exhausted the next morning dealing with whatever didn't work right...

I'm surprised at how quiet it is idling. I can't wait to hear what the 3" sounds like on the road!

Unfortunately there doesn't seem to be any clean way to route the intercooler water hoses away from the heater hoses. I'm still thinking on that, but I may make some kind of heat shield to go between them if I'm not satisfied with the cooling once it's on the road. The big 3/4" hose kinks relatively easily, so the bends have to be pretty gentle. It's just hardware store heater hose, so it could probably benefit from something a little better. The OD was too large to use the securing nuts on the AN fittings. I'm just running distilled water in it for testing to keep the mess to a minimum, and I'm also considering adding an ice/water tank somewhere. I could see that being handy for pulling mountain passes in 100 degree weather.

I'll also have to get the fan installed before this summer. I'm building a fan controller from an Arduino microcontroller. It will run off of the PCM voltage, tap into the engine temp sensor, and have intercooler coolant and ambient temp sensors to compare to decide when to trigger the fan. Eventually, it will listen on the PCM communication line, so I can trigger the fan and other accessories over bluetooth through the OBDII adapter using Torque.

I still need to clean up the engine mounts, but I think that will be saved for another time.

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For fun, here's the evolution of the turbo configuration.

The original setup with a TD04L-13 from a WRX
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Compound turbos TD03 from a Volvo S80, and the TD04L-13
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Previous evolution with the current TD04-08 from a Cummins B3.3
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how much intake air temp are you monitoring? It would be nice to know the difference between the old A-A intercooler and the A-W intercooler. Are you using the original Jeep OE intake air temp sensor from the OBDII? my new boost guage has a extra probe for trans temp that I am planning on using for Charge Air temp, somewhere, not sure if I will put it before or after the intercooler. it would be very nice to have 3 temps, IAT, pre-cooler temp and aftercooler temp.
you can get more bang than just straight ice and water, if you use Dry ice or regular ice and Acetone, or Alcohol, or the old fashioned ice-cream mix of regular salt and ice. I forget, but I think dry ice acetone is a bit warmer than minus100C, but pretty close, Salt and water ice is about minus 20C.

Alcohol And Dry Ice is the way to go. But the BIG downside is if you have a leak and it catches fire you will not see it but you will feel it and watch stuff melt and catch fire.

Besides we are not racing here so the Dry Ice will not last all that long to be reliable. So just Water with some stuff called Water Wetter would do well in a closed system with maybe a smaller radiator to pass the water through in a fresh stream of air.

If you are worried about climbing air temps for short duration hard pulls such as hills or accelerating then you could add a simple spray system made from a Windshield water set up and a few spray nozzles set to spray the mist of water against the air to air Intercooler.

Well, I got the Wrangler on the road last night and it's AWESOME!

Vibrations are virtually eliminated, and boost is nearly instant! I'm noticing a few PSI more boost in all situations, which is likely due to the water intercooler's insanely low pressure drop. Intake temps are staying about 10* over ambient temp, compared with 30+* with the air/air intercooler. During a hard pull I wasn't able to push it over 87*, where with the air/air (and 20* cooler ambient temps when I took it down a month ago) it would jump up to 130* in the same pull.

I monitor the air temp at the engine intake sensor from my Glow Shift 3 in 1 gauge. The only downside is that it's a bit slow to react, being a completely enclosed sensor, unlike the factory Jeep IAT, which is open. The IAT wiring came out of the harness with most of the other wiring, but I've been considering putting it back in and switching it out to monitor the temp at the engine intake, then putting the Glow Shift sensor at the compressor output.

It's also going to get a sensor in the outlet of the heat exchanger for the fan controller to compare with ambient temp.


The system is way overbuilt, the heat exchanger is 3x the size of the ones used by people with WRX STIs for example, so I'm not worried about it not keeping up. The only reason that I would have for adding ice or dry ice would be to cool below ambient temperature. I'm already planning a dry ice sink when I eventually build a tank though. The reason is simply that these engines are already working pretty hard (especially in my barn door Wrangler) and I want to give it all the help it can get on 100*+ summer days climbing mountain passes, so dropping it below the 100* ambient would be desirable.

Water has 3x the thermal conductivity and twice the heat capacity of alcohol. The only reason for using alcohol or salt water would be to lower the freezing point, regular antifreeze works just fine for that. I'll have to use antifreeze in the winter, or if I plan on cooling it below freezing, but distilled water is the best bet for a pure ambient closed system.


I'm not sure what you're saying about a smaller radiator. The heat exchanger is a radiator, and you want it as large as you can fit. This is a water to air system, not air to air...

Spraying water on an air to air intercooler has a good effect because you're directly affecting the charge (similar to the water in a water to air intercooler), but because the heat capacity of water is so much higher, the effect on a water to air heat exchanger is minimal.

It's showing 1PSI of boost at idle! The intake temp is a bit high, it does heat soak a little when sitting, because it's right above the water neck, and I don't have a fan installed for the heat exchanger yet. The fan and a little heat shield will solve that, but it cools right down when it starts moving anyway.

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What's your boost pressure and which turbo are you running? Is it the one like FTE is running.

Peak boost pressure is somewhere around 25PSI. It is the same kind of TD04 that FTE is running, off of a Cummins 3.3

Here's a quick video that I took with my phone tonight while driving around. Sorry for the quality, it was just a spur of the moment thing. I think the new 3" exhaust is quieter than the old 2.25"; you can get some idea of the volume by comparing with the sound from the water. The engine is very smooth, it's running somewhere between ~700-1000RPM in the video.

Yea I kinda went all over the place lol. Sorry I was too tired almost about like now But lol.

I guess I should have just asked if your running your Water to Air Intercooler with water from the Radiator or an independent system unto itself?

And is the TDO4 you are running the same as say from a stock Subaru?

I would also like to add that I like your Air Filter Set Up.

And just an FYI it looks great as usual. :)

Great looking rig, sounds great!

No worries! I was just hoping that I wasn't coming off as an ass with my explanations! lol


Yep, completely independent. There is a learning curve though. Right out of the gate it's 100% better than my little air/air cooler was, but as I've started isolating the lines and such from the heat it's just getting better and better.


It's a TD04L-10K from a Cummins 3.3, the same turbo that FTE is running. The WRX turbo is a TD04L-13G

Thanks!
The air filter is from a Ford Windstar. They used them on quite a few different vehicles. I cut it up a bit and added the cobra head on top of course...

Thanks!

Found one relatively minor failure yesterday. It's been a worry since we built it, because of the amount of stress on the small pipe. It'll be fixed and get bracing added between the plates tonight. It's just another reminder though that if something is a worry, I need to just take care if it. Murphy and all that...

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I guess I should have asked if the Subaru Turbo is the same size as the Cummins 3.3 Turbo? Or to say will the Subaru Turbo work? As I think it was FTE informed me that the Subaru Turbo was a bit bigger than the Cummins 3.3 Turbo and that the Subaru Turbo was an upgrade for the Cummins 3.3 stock Turbo? If so and someone wishes to have a Subaru Turbo I just happen to have a good one laying around now if someone wishes to trade? Mine does not have the waste gate actuator though.

There are quite a few different Subaru turbos, the one I had was off of a WRX. It was too big, and was inefficient until over 2200RPM. The WRX turbo is a lot larger than the one from the B3.3.

I got my turbo adapter fixed last night. It'll need to be re-ceramic coated, but the place is going to redo all of my parts for free, because they started showing some rust anyway. I'll run it for a few weeks to test, then haul a big box of parts down to them to be coated.

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My friend was commenting last night that my intercooler was looking a little bare, and could use a decal. I just happened to have one...
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Here's a short video I took this morning trying to capture the sound during normal driving. This is slowing down for then accelerating from several speed humps in a neighborhood. The picture is my stereo and mount. I only had a low mount with me this morning, but I just wanted to try and capture the sound.

Love the decal! Nice welds on the turbo adapter, did you do that with a TIG? Very nice clean looking Jeep, you should be proud!

Thanks! I wish I could take credit for the TIG welds, but a professional welder buddy who builds race car chassis and such did it for me. Much better than the hack job I would have done!

the Mr. Fusion sticker may exceed the bottom ends strength. I thought they were outlawed for adding 35 hp!!

Hey Red, quick question if I may? On the FC, how far is it from the crossmember to the firewall? I'm sorta looking at FB's and FC's and wondering if the carrier oil pan might be made to fit behind the crossmember or drag link. I'm not beyond trimming the firewall for it if it's close. Thanks in advance!

how is your e power steering working? I saw one from a Nissan pathfinder, I am trying to research those

did you ever look into just using a Power steering electric motor and adapting it to a OE PS pump?? you can get just the electric motor for the Saturn's for pretty cheap. Do you have any more specs on your sytems motor. I know you said it pulled 70 amps at full load. Did you get a HP or wattage rating on the motor.
I know the steering effort on the jeep would be much greater than on a Saturn. Plus I don't know if the Saturn is a electric hydraulic or just electric assist rack. The Saturn steering motor looks to be a bit smaller than a 12 volt starter.
Heck I might be able to rig up a test with a outboard engine starter I have that is a surplus
Well I look forward to any updates you have?