WackyRotary

Please read before asking any questions, PLEASE.

Wacky’s Turbo 12a project: begin date: December 13th End date: April 17th
I could of gave updates all along, but I don’t want to bore everyone with strung out threads were as one MASTER thread would be more informative and more remembered when someone else wants to have a good resource on how to turbo a rotary old school.

(Started and worked on April 17th only 5months after starting with a few issues in the first couple weeks of blow-though to start with). Also it should be noted that it could have been done from scratch in under 2weeks with the proper resources and having dedication.

Modifications=>
Fresh mildport 12a, weber sidedraft, free S4 turbo(no flapper, ported twin scroll, ported wastegate, larger wastegate cover for the larger ported wastegate), modified S4 manifold to fit on a 12a(1inch thicker with 12a mounting holes and transitions to the stock manifolds exhaust holes to clear the intake manifold and not by much – ¼” clearance from the turbo housing), friend wielded my aluminum carb bonnet free similar to the ones floating around out there with a few differences. Stock FC silicon bends and 2” IC piping all around. Aeromotive pump and RRF regulator. Locked distributor@ max advance. Free 2-1/2 downpipe, unknown manufacturer donated it to me free, Stock S5 intercooler-later to be upgraded, nice blow off valve. Tall oil filter tower from a pre FB-13b endplate so my high pressure feed line would easily fit to the turbo from the fitting I made to the banjo fitting on the endplate. Oil filler chopped and wielded lower so the bonnet would fit easily and for space reasons. TII / FD cold type spark plugs-L&T, not platinum’s though since they were over double the price, I’m on a budget folks!! But its still faster then many newer cars, but doesn’t sound like it would. J

A special thanks goes out to MoreMazda!!!! You were my main inspiration for this project 1st and for-most and with a decent write up to get ideas from, and not any of the people out there offering half-assed turbo kits(with no prices listed on any of their sites which is the clincher), I ONLY did one thing similar(yet different dimensions) to one of the bonnet “box” designs floating around as a guide for cutting mine out, only but mine has a few important differences that are to my own needs, costed me only $15 in aluminum stock.

A friend wielded it together for free after I cut it out and instructed how to wield it together. I have wielded aluminum tubing as velocity stacks with radius shaped ends to smooth the transition; I guess you could call it a dynamic chamber of sorts. They are the same length and size of the velocity stacks the weber came with, but narrow enough to fit the custom made 4 long threaded studs I made from mild steel rod that extend all the way through the box and bolted on by the original nuts that came with the carb and can be made normally aspirated pretty easy from the turbo box. I made a throttle holder onto this box as well as the float pressure reference and RRFR reference vacuum hose fitting. It seals well and no issues with fuel leakage yet so far. I am very happy so far, I may make another bonnet sometime that will make more use of tune-length velocity stacks and see if it broadens or increases horsepower any.

As the IC piping is routed to this bonnet, I used a 2” electrical conduit 90degree turn fitting and dye grinded smooth the threads inside for smooth airflow. The rest of my turns are all TII silicon bends. It just clears the hood, and I mean BARELY! The main differences between mine and Moremazda’s write-up is the IC and IC piping and I have a mildport engine I ported and assembled fresh, J-spec S4 turbo I know is in great working condition, with less then 3000miles on engine (1000miles n/a running first), excellent pick-up even without boost! I mounted the FC intercooler right in front of the radiator with both inlet and outlet going to the passenger side to maintain the stock battery position. I wanted to be able to transfer to another car or replicate this system easily if other FB’ers out there wanted to do it.

I had been using a 12a Bridgeport/lightweight flywheel I first setup December 2001, but was getting bored of the way it guzzled fuel and only made power at high rpm(great for track use, not so good for regular drives or long trips->loud and a gas guzzler). It was quick, and wanted to rev mad above 8000rpm, which is fun drawing attention, but very hard on gas no matter how light it was driven. Not true of a TII turbo fitted to 12a N/A engine on the highway cruising. So I took it out 12a Bridgeport and am keeping it as my “back-up” engine, who knows, maybe I will get crazy and throw the turbo on it later and see what it can do!!! …EVEN with the carbon apex seals it has!!!! LOL, but for now, I want a smooth wide torque band that feeds impressive acceleration with low to moderate boost levels (remember FB’s are quite light with almost everything in them), and bump it up for timed runs.

I had thought about a EFI S4 or S5 engine conversion, but I already had SO MANY 12a parts wrote off and I wanted to have a 12A TURBO for the rare shock value I could use on some 13b owners when I was done with moderately safe boost levels also. And indeed it is reliable once I got most of the bugs out, still a few minor issues-boost spikes a little and weak leading coil resulted in hesitation one day (which I swapped with the Trailing that fixed that), so eventually a better coil for sustained higher boost levels probably.

Well I could start by saying this project was not as easy as I thought it would be, sorry to all the 12a turbo inspired people by MoreMazda and other home-made rigged turbo setups with S4’s, S5’s, or other various turbo’s. The number one reason above all else is money! I am VERY poor, there was no time during this ENTIRE project were I had more then $500 in savings/checking while paying for other bills on the side which dragged on and on from the first thing-> exhaust manifold completed in December, to the IC piping I cut out homemade on April 14th. The hard stuff: custom fitting up oil lines, altering the front cover for oil return (which hooks up to the stock oil return line), the fuel system (larger main line (3/8”) and return line (1/2”) into the tank and plumbing new piping up to the engine bay), most importantly wielding carb bonnet and exhaust parts when you don’t own any wielding equipment seems to slow things down and friends willing to wield live to far way to hassle back and forth from. All stuff I have done while engine is apart, except the bonnet was wielded together while I did the 1000mile break-in period with n/a setup. I cut out the carb bonnet pieces, cut, bent and flared the high pressure oil feed-line and fitted oil lines, ported the intake exhaust ports with a old worn carbide bit, ported S4 turbo scroll that was small to start to match the other larger one, no more dynamic flapper. I’m probably forgetting a bunch of less important stuff. On a positive note, I have wrote off the fuel system, turbo manifold, bonnet and could easily be used on later turbo projects if I want to turbo 12a engines again with S4 turbo’s or someday sell the setup. Again, a lot of this stuff may seem easy enough, but when you do it yourself, you tend to find out the opposite is true once you get to the actual process, no I won’t be helping anyone outside of this thread/write-up as its your own project should you choose to do it! I’ll be happy to answer questions though on this.

On the bright side, I wrote off most of the engine parts before proceeding since I had a set of good low mile stock apex seals from another engine I rebuilt and took apart when I built the Bridgeport before this project. Other necessary seals, and fairly good rotor housings and mint side/endplates were all free-sort-of/trades and exchange of services/etc. I will probably use new housings/apex seals if I do this again to get more overall compression and greater overall power since I predict I will break something by summers end related to rotors/apex seals/housings. LOL!!! Actually I predict if the boost is kept below 10psi, it will last 30-50,000WackyRotary miles! And that does not concern me all since I’m not afraid of the little rotors.

But now that its done, and working good, I can clearly say it was worth the effort. Not only was this a project to get more power, but also get more efficient usage of the components I already had to make considerably more horsepower. I didn’t want to sell the performance parts for half of what I paid for them and buy a Haltech at this time and also buy a 13b turbo engine/parts of sorts, anyway I already had a weber and a side draft intake. And parts I acquired from people that handed them to me for free so I could produce this “old school” turbo engine for as cheap as possible. A big thanks go out to them too. However I’m somewhat disappointed with the lack of constructive help that I had to twist arms to get that was promised in a timely fashion.

OK the results, finally!! When first getting it running and not leaking too much, took it out with the stock controlled boost that is lower since I have a ported wastegate. I had ~4-1/2psi boost, and a great increase in power over the same mildport with headers and the same sidedraft system. I had a fuel leak from the carb spraying onto the hood (initially thought I had the base fuel pressure too high), but a little thread sealant later on all the brass fittings and it was dry, important blow through mod, to avoid a fire! One of the big differences is its MUCH quieter then a mildport with n/a setup, the intake roar is replaced by turbo spooling sounds and actually is a quieter car when boosting then off boost driving! Lag is not bad above 3000rpm, builds it almost instantly above 3500rpm for 4-1/2psi boost level. I’m am not at all disappointed with the lag because it is much easier then a Bridgeport below 4000rpm. It doesn’t have hardly any bogging issues at low rpm common with webers unless you slam the gas at idle instead of easing onto it, a lightweight flywheel really helps bring it up to the spooling point quickly since it quickly gets above 3000rpm. But, its common to a side draft system for minor bog. 0-60 was ~6seconds due to bald tires. With good tires, I’d expect 5’s easily and 13’s with some boost around/above 8psi. I managed 140mph with 7-8psi boost with it still accerating, but slowly, so I know its fast enough for me, too dangerous to go that fast without effective down force and higher rated tires…. for now. Lower 13s(with slicks I hope) with the boost set higher to 14-15psi max since its near the limit of the fuel pump and realistic limit you want to push n/a rotors for a short period along with the dowel pins. I need a higher clamping power clutch too obviously for that level. Not too bad I suspect for the overall budget, which I will lay out later.

Now, with a fairly controllable boost controller, I upped to 10psi, cross my fingers it won’t break on the first try and not give signs it will be its last time that high, no detonation occurred. WOW! Now it was a super FB! On the interstate, got along someone at 70mph, downshift to 4th and floor it, and ~5car lengths ahead I’m at 110mph. The boost was really fun at those levels, but I will keep it lower for longer component life normally, no reason to blow the engine up pre-maturely.

IT is scary that a mildport 12a with stock components and turbo fitted can match/beat many other late model high end cars for the amount spent on this project in modifications on a 1st gen 12a’d RX-7 with stock HP of 101hp at 6000rpm. The moral of the story is that you should never doubt that a n/a 12a block powered FB can be MUCH quicker if you want it enough and willing to go the extra mile(s) in my case to get everything done as fast as possible/but correctly (money wise and most labor on my own except wields). Also stock driveline and clutch-which I anticipate a need to replace with a stronger one soon. LOL! Actually I’ll just back off the boost to 7-8psi so I can save money on gas/clutch/tranny for a while. 8psi is more then enough boost to keep a FB owner satisfied when I’m not being timed at a 1/4mile track. I have no ego issues, I know at that level, it will beat any stupid looking rice mobiles encountered with ease, and or just impress myself!

My advice for the GSL-SE owners is to not follow this route though, go to a 13b TII engine as your base or better, and Haltech it or some other controllable ECU. I did it the way I did it because I wanted a 12a turbo badly enough in a 12a chassis’d car and already had the parts to make it pretty good with the knowledge, tools and connections I had to make the special parts I couldn’t make without buying my own expensive equipment. 13b chassis cars should be EFI controlled if you ask me. Carburetor and 12a just plain mix.

I don’t really know how long the engine can handle my abuse, but I don’t take it easy on something I know I can fix! Oh yeah, my mpg was of course worse when boosting a lot, but on interstate restraining from going over into boost yields 17~19mpg. Lots of boosting results in 12mpg on the street. I’m going to get leaner idle jets and smaller main fuel jets, because I haven’t encountered any detonation with it working correctly, and high end air correctors I have seems to be only mildly rich so I will concentrate on main fuel jets and idle jets that will help with MPG some. Also later I will redo the jetting to make it run with E-85 fuel sold here in MN for ~$1.22/gallon last time I checked and make about 20% more horsepower, and its ~105octane so very little chance of detonation and can up the boost safely, 85%ethanol, 15%gasoline. About 65% of the fuel economy of gasoline, so its going to be lower mpg, but also smell better and run a lot cleaner (less carbon build up and less contamination of the oil) and not make me sick at stop and go traffic.

WackyRotary

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R.P.M.

iTrader: (3)

Wow that looks nice!

Sudox_E

Its good to see people taking the initiative and doing something different to their fb's. Hopefully I will have a setup similar to yours in the future. Now you get to be an inspiration to others.

Mschafe

I've been cruising around with Wacky, and I can say for sure his car *really* impressed me. Makes my poor stock 12A feel like a tank.

Matt

Sammymatik

I have the exact same mannifold

I am still considering undertaking this project, I have many of the parts I need.

Did you have to modify the carb at all? I have read that the floats must be replaced with solid units to avoid crushing them with the boost presure. I'm thinking Holley carb cause that's what I've got.

Do you have a picture of the high pressure oil line going to the turbo? you had just tapped into the oil filter pedastal?

WackyRotary

I didn't touch the oil filter pedastal, the high pressure feed for the turbo is tapped directly into the banjo bolt down below were the main oil line feeds into the block. Look at "bencha.jpg" and you will see how I did it. Its actually "unfiltered oil" at that point, but I figured, a percentage of the oil flow will go through the filter everytime and eventually filter all of the oil, and it works fine this way.

I used a 5/16brake line and I flared it and drilled and tapped the banjo bolt to with a compression fitting for the connection at the turbo. Very cheap oil delievery, and works with no leaks!

The only modification I HAD to make to the carb, was thread sealant on the brass plugs for the idle jets/etc brass fittings since they leaked fuel during boost.

I have a carb that doesn't have a choke, so its pretty much straight bolt up. I am unaware of any float issues? I think as long as its got equal pressure above the float and the fuel pressure is referenced 1:1 with boost, it works just fine. The weber carb has the float vent right next to the velocity stacks which is exposed to boost pressure to keep from flooding over. VERY important since its a "blow through" setup.

moremazda

iTrader: (4)

This brings a tear to my eye!!

Good job

What did you set your timing to??

WackyRotary

Ah, there's MoreMazda! Thanks. I'm still playing with timing by imgaination. All I can say is its not more advanced then I had with out the turbo and its not detonating. I actually had it too retarded when I began for safety. When I upped the boost the first time, the engine would backfire like crazy. I thought at first it was detonation and leanness, I did everything from using my richest jets and retarding it even more to bumping up the base pressure.

Then I wized up! ..and put everything back the way it was, and bumped the timing and that changed EVERYTHING dramatically. Power increased at base boost pressure and no detonation occured at any boost I forced into the engine.

I plan on making a trip to someones house to set the timing and timing split for best power pretty soon(I don't have a timing light). It would probably be better if I could use a dyno for this also, but can't afford to for a while.

Again, thanks to MoreMazda, your thread showed how possible this type of setup is and how good the results are.

Also, I plan on showing a MPEG here when Matt makes it! HURRY MATT! LOL!

mperformance

really impressive....thanks for a great report wacky.

zaridar

iTrader: (3)

Hey just curious, How many horsies you think youve got it pushing? Also How much was it with just the mild port before the turbo? Or is the mild port equivilant to a street port?

WackyRotary

Whatever hp it is, its able to exceed 140 at moderate boost=>8psi(found out a few days ago, then remembered I had H-rated tires), also achieved 6's to 60mph.

I do plan on a 1/4mile run, and when money allows, a dyno pull. But don't want to simply go on a dyno to find out what it has, unless I can make changes with 3 runs(when I can afford).

It makes my '88 n/a feel VERY VERY slow.

Street port usually confuses me. Can represent either stock or mild, depending how people use their terms. Heres how I represent them: stock port, mild porting, Bridge porting, J porting, Monster porting, and finally Perpheral porting.

gamble302

great writeup man. my fpr and carb bonnet need to get here so i can enjoy some boost too

moremazda

iTrader: (4)

This is what I am dealing with right now. I'm going to go bump the timing right now....

Ryan

WackyRotary

Yeah, actually when I first ran it with boost, I had the timing retarded from stock as I mentioned above at worked good at that timing position. But anything above stock boost wouldn't work at all. So clearly the engine requirement for "exact" timing becomes more and more critical the more air/fuel you shove in it. Right now, and I MEAN now, I have it set slightly more advance then stock(also this is a stock distrubuter I wielded with the mechanical weights fully out), so its only slightly more then stock overall advance. ...and the engine LOVES IT! I kept bumping it up and no detonation occured at any boost level I forced at it.

That is why I ended up leaving it were it is now, and it works GREAT there.

So MoreMazda, you were having the same backfiring issue? Let me know if that fixes the issue? I'd be really happy if I helped the person who gave me the inpiration to do this,

Wacky

WackyRotary

Also I should mention boost above 11psi or so causes the clutch to slip if you shift too fast and apply too much throttle so the clutch can clamp before appling high boost levels. I KNOW I am in need of higher clamping pressure.

Anyone who decides to run more then 10psi, you will need a street strip disc/and higher clamping clutch cover of sorts.

I think when I can afford, I'll go to a S/S heavy duty disc and race pressure plate from Mazdatrix. I'm sure that will eliminate this issue.

moremazda

iTrader: (4)

I now have it set to 20 deg leading and 12 deg trailing. I let you know tomarrow how it turns out. Just to much stuff around the house to take the car out tonight.

Hyper4mance2k

iTrader: (40)

what a good thread

WackyRotary

Thanks to all for the positive comments so far. Work in really does = worked out sensationally. I have got most bugs tackled.

However earlier today, I noticed a serious leak in a tire, and found it to be a nail in it! However my spare looks really sexy on the car! LOL I tried a tire plug which worked, but then I found ANOTHER leak too close to the sidewall to be repaired with a plug safely on the same tire! So I guess I'll need a new tire or have a tire place put a couple patches inside of it maybe will work.

moremazda

iTrader: (4)

It worked!!!! Sort of. It won't back fire until around 5500-6000. I'm going to go up in two deg increments until either a0 the back fire goes a way or b0 the engine goes away. I'll let every one know on Sunday. (I'm going to be gone this weekend)

Ryan

WackyRotary

Thats good to hear. I'm tell ya, it REALLY liked stock or slightly advanced from stock timing in my case. I probably am holding it back somewhat with the wrong trailing split, but soon I will find out for sure when I experiment and confirm were exactly i have the timing set at.

One of my major issues is I'm burning too much fuel from boosting too often. I hate it, on top of that, it HAS to be premium fuel it uses a lot of. I need to go to a water feed system too I think so I can go use 87octane again...

Does anyone know what the prefered split is for a n/a 12a block with boost? I'm sure 13b-engine to engine has a different prefered split also depending on porting and other modifications and at different boost levels, but will have to probably get my answers on my own as usual.