vw diesel into a mazda rx7

lews930

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UPS brought my little turbo to me today. I quickly caressed it:) I cant wait.

Where on this sit can I find info about the motor such as what the little pump is on the botom. I'm guessing power steering. Wiring diagram, etc

lewis
 

rotarykid

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Yes the power steering pump is a little pump on the bottom of that engine . I have this engine in my 1985 A2 , the complete setup . From the injection pump with the fuel control switch on the front to the CAT & small displacement turbo . Along with all the vacume system . I've had this engine in my 85 car since fall of 1998 .

PM me any questions you might have about this engine .
 

12MPGHWY

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On the drive home from getting the TDI, It was 8PM for 73 miles on the freeway which meant the speed of traffic was about 85MPH. I got an actual 51MPG in the TDI, this is completely stock and somewhat maintinence deprived.

The RPM in my TDI at 85 is about 3K, in the Rx7 it would be about 4K.

The Rx7 for this same drive would get 25MPG, and I have tuned it to be as economical as possible, running opem loop off a wideband with a maped target value. At freway load at that speed it runs about 18-1.

I will aplaud you when you finish your project, but I still think you should go for a larger merc diesel instead.

Hell for about 5K you can get a merc CDI and trans, have a drive train thats matched and desined for RWD, you could have the power and torque with a chip to put an FD to shame and still get 45-50 MPG.

You could have it all.

lews930 said:
I drive at 60 mph to work. I like the way the rx7 feels.I cant describe it but it just feels good. It aint pretty but I like it. I dont know if going 80 in a Jetta will give good mpg numbers either. When I drive my 5.9 cummins powered dodge I get 20 mpg if I set the cruise at 58 mph. As I stated I'm in no rush when going to work. Besides I want to be the first to convert a Rx7 to diesel. Where would the fun be in buying a jetta?
BTW, my 1.9 TD arrives today:)


lewis

I'm sorry to tell you that you won't be the first to convert an Rx to diesel.. There is a 1g with a big cummins diesel.

Also radial as this sounds, a plain old 12A will start and run on diesel. I did it with my old 85 model when I ran out of gas at a rest stop. It didn't run well but it got me 40 or so miles to a gas station.
 
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lews930

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gees, what is it with you 12mpg? I can only guess by your repeated suggestion that you must have a Mercedes engine for sale. I'm going to explain this a slow as I can so that you'll understand it. I dont drive 85 mph to work. I only drive this car to work. I drive at 60-65 mph. Get it? It saves $$$ As for the 1st gen with a cummins, that's great. Quit being a nay sayer and post else where I've got some fabricating to do:)

All others are encouraged and requested to offer help

thankyou

lewis
 

12MPGHWY

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I have no MERC engine for sale.

I do however think it would be cool to get 45 MPG and also be faster than a stock FD.

I understand what your saying and do support your project.

At least look at the gear ratio's and consider a granny's or other ford 8.8 rear end with a higher final drive.

Using stockish rx7 gear ratio's (the rx7's transmission ratio's are pretty standard) you could end up with an unusably low first gear, and over drive where 4th gear should be.

In the very least put the tallest tires that will fit on the Rx7. Which would be pretty dam tall you could probably get a 235 60 16 (27 inches tall) on your stock 16" vert rims. I drag race on et streets that are 27 inches tall with no issues and my car is lowered about an inch.

Its the same situation that most V8 conversions end up with, but to a greater extent with any diesel.

A higher final drive will certainly improve your milage at any speed.
 
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lews930

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Ok, I tired a search but there are over 57 pages of realted material. Are there technical drawings available for the fly wheel end of the engine? I'm leaning toward aving a machine shop make an adapter plate to fit my Mazda trany. I think this would save time and money in the long run

thanks

lewis
 

bigblue

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I'm sure somebody will post the link but there is a great set of original factory drawings on somebody's vanogan website where somebody engineered a TDi-vanogan swap
 

12MPGHWY

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A couple of observations.

The NA Rx7 tranny doesn't have a removable bellhousing.

The turbo trans does.

It would be good to use a turbo trans as a TDI can easily deliver roughly twice the torqe of an NA Rx7 motor, I also think it has a higher 5th gear.

The turbo trans and NA trans have the same belhousing but the clutch has a different spline on the input shaft.

Turbo 2 trans's are avaiable for about 150-200 dollars at the JDM importers, they are allmost allways good.

What you would need if pursuing this course would be an aftermarket Rx7 flywheel and an adapter to adapt it to the TDI engine and space out some then an aluminum plate or correct thickness (it will end up being thick) behind the flywheel that the trans can bolt to.

The flywheel adapter would need to have a provision for the Rx7 pilot bearing which is in the e shaft.

The adapter plate for the trans would be easy, but adapting the flyweel would reuire a very strong precicly machined part.


lews930 said:
Ok, I tired a search but there are over 57 pages of realted material. Are there technical drawings available for the fly wheel end of the engine? I'm leaning toward aving a machine shop make an adapter plate to fit my Mazda trany. I think this would save time and money in the long run

thanks

lewis
 

je

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You might want to peek at this page:
http://members.aol.com/solomiata/Drivetrain.html
Im not sure there's a lower-ratio 5th gear than the NA RX7. IIRC the turbo had a higher gear for more RPM. Still, they're just about the same, and I'm not familiar with a ratio on any car lower than that.

IIRC also, the TII transmission was the same as used in Mazda small trucks, also the contemporary Ford Ranger manual, these would be much easier to find.

I remember that over time, the NA transmission would wear out (mostly 3rd gear synchro) from the torque of the NA engine, if abused in the normal fashion.
 
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12MPGHWY

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Its not the same as a ford ranger trans, or any mazda truck trans it is similar.

It is also true that they wear out often in the NA cars, particularly in the vert which is by far the heaviest.

The gear ratio's do change through the years, but your right about the turbo bieng ever so slightly higher.

The best trans to get would be a turbo from 89-91

They are easy to find, all of the JDM importers which carry rotary engine have them. Plenty of these guys in florida and they are cheap enough.

It would be a significant task to adapt the rx7 trans to this engine, perhaps a better option, albeat 1K dollars more expensive would be a T56 which would have a far higher 6th gear than the rx7's 5th gear.

gear ratios for all years of FC found here: http://www.rx7club.com/showthread.php?t=642372
 

lews930

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The n/a tranny is just fine. while not as strong as the turbo tranny it will do the job as long as it is not abused. And since I cant find anyone to fix my stuff for free I dont make a habit of abusing it. In all the 2nd gen cars I ve had several were over the 125k mile mark. My convertible has 154k and no issus at all. I'm going to contemplate my swap hurdles
 

Pat Dolan

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Lewis:

Check your PMs. I found a .dxf file for an adapter plate.

Surpisingly, what I DON'T have, is the same stuff for the VW or Audi engines. I would dearly love to add that to my collection.

BTW: did you try Kennedy?

I also agree with you to just get it together and running with the older gearbox and diff, and make your choices for upgrades later. It is nice to have a "perfect" swap, but I think you have already figured out, a highly modded car is never done, so just get it on the road so you can make your choices from a much better frame of mind and information.

Pat
Pat
 

lews930

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Thanks Pat. I did try Kennedy. I even talked with the man him self. he has never done a water cooled VW according to our conversation but he like the idea of a fuel efficient diesel in the rx7

as you said I would just like to get it going first then modify the thing along the way. I know it's not going to be perfect at first but I'll workon it

thanks again

lewis
 

12MPGHWY

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IMO, your probably going to pay quite a bit for the machining to adapt the trans to then engine (that is if your not doing it yourself), why not spend the extra money up front (if you have it) and go for perhaps a T56 6speed or other 6 speed with a uber high OD. You could kill 2 birds with one stone, that is get the right gearing and get the trans adapted at the same time.

Another observation, the Rx7 stock radiator has got to be at least 3 times the capacity of the TDI radiator. You could use a shorter radiator maybe a sciraco unit which are comonly used for dragsters of all makes, they are cheap new, with the extra space you could fit a plenty large intercooler. Also the local earls shop, so I am assuming all earls retailers carry oil filter adapters that have A/N bosses for intercepting oil coolers, this would be perfect for adapting the stock rx7 oil cooler, which has a nice variable thermostat.

lews930 said:
Thanks Pat. I did try Kennedy. I even talked with the man him self. he has never done a water cooled VW according to our conversation but he like the idea of a fuel efficient diesel in the rx7

as you said I would just like to get it going first then modify the thing along the way. I know it's not going to be perfect at first but I'll workon it

thanks again

lewis
 

lews930

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what is this t56 you are speaking of. And why not just call it what it isie: camaro tranny, mustang tranny, etc.... would make things so simple. And who do you think would carry the adapter for this engine/tranny combo? I have a intercooler from a supra and I think it will fit nicely in front of the radiator. The oil cooler will work too.
 

terry_01vw

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01 jetta tdi
lews930 said:
what is this t56 you are speaking of. And why not just call it what it isie: camaro tranny, mustang tranny, etc.... would make things so simple. .
Well said!! I am often interested in conversions going on here but i don't understand half the things people are saying!
 

12MPGHWY

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Because camaro's or corvettes may come with different trans options, T56 is a specific transmission (the 6 speed) used in a number of cars.

Besides I don't know the full list of cars and trucks its used in.

The list includes at a minimum camaro's (and their pontiac clones), corvettes, and several others, I think mustangs too.

There may be other cheaper trans's available with desirable gearing also, I would stick with something domestic and available easily for a custom job like this.

15 seconds on the web

http://en.wikipedia.org/wiki/Borg-Warner_T-56
 

12MPGHWY

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An easy to fit intercooler is the issuzu NPR intercooler, I'm not sure which supra cooler you have but the ones I remember would be the wrong shape.

lews930 said:
what is this t56 you are speaking of. And why not just call it what it isie: camaro tranny, mustang tranny, etc.... would make things so simple. And who do you think would carry the adapter for this engine/tranny combo? I have a intercooler from a supra and I think it will fit nicely in front of the radiator. The oil cooler will work too.
 

lews930

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Well I spent more than 15 minutes and still couldnt find the dimensions of the tremec tranny. I'm supposed to meet with a machinist on Tuesday the 15th to discuss making an adapter to fit my Mazda tranny. I'll post when he's done with my wallet:)

lewis
 

lews930

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wow. your knowledge of cars continues to astound me. For the record, the i/c from the 88 supra is, from a quick test fit, about as good as it gets. And how could it be the wrong shape? If it fits, it fits. even the inlet and outlet will be perfect for the location of the air cleaner and the high mount turbo.
 

12MPGHWY

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Hey smart ass there where at least 2 different supra turbo models imported into the states, I am thinking of the Mk4 or just for you the one featured in the worst movie ever the fast and the furios.

Most toyota intercoolers are shaped like a sinder block.

lews930 said:
wow. your knowledge of cars continues to astound me. For the record, the i/c from the 88 supra is, from a quick test fit, about as good as it gets. And how could it be the wrong shape? If it fits, it fits. even the inlet and outlet will be perfect for the location of the air cleaner and the high mount turbo.
 

bigblue

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I used to have an early 4th gen f-body t56 transmission (still made by borgwarner 1994-1997) that I chose to put into my monte carlo because of the .62 5th gear and .50 6th gear to go along with the 3.73 rear axle. It was overkill for my rev-happy 350 engine but might just be about perfectly geared for a diesel application with rear axle gearing like that. I rarely used 6th gear since 80mph had it taching around 2200rpm, well below the power range of the engine.

It's a very strong transmission, though heavy and I have yet to hear of it being used with a diesel. That particular application (1993-1997 LT1 fbodies) used a pull style clutch (like the MKIII turbo supra) which is a bit less common and possibly harder to fab up a bellhousing adapter. Probably expensive and almost certainly would require massaging the trans tunnel to fit the mazda chassis (is it FC?)

I'm under the impression you're hoping to get the project rolling on your budget and timeframe before you are completely concerned with a well matched set of gears for your application so you can worry about that later.

Since the toyota w-5x series transmissions are abundant and cheap, have you considered getting one with the acme adapter? It seems to be a bolt on solution and probably cheaper and less headache than couping your original mazda 5spd.
 

12MPGHWY

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An LSX T56 will bold into any Rx7 without touching the trans tunnel.

the t56 even gets used by some of the high power rotary owners as an adapter plate to the rotary bell housing is available.

bigblue said:
Probably expensive and almost certainly would require massaging the trans tunnel to fit the mazda chassis (is it FC?)
 

lews930

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Blue, yes I have considered the toyota tranny and acme adapter. the problem is the length of the tranny and shifter location. To make the thing work I would have to bend the shifter into a "S" shape or the shifter would hit the dash. I havent given up on it though. The appointment with the machinist will determine which route. The upside of the toyota tranny, other than off the shelf parts, is it has a speedo cable like the rx7. i just want to avoid spending $$$$ to determine that the toyota trans and adapter arent going to work. In using the mazda trans I was hoping to avaoid having to make new tranny mounts, drive shaft alterations, etc.. the car is FC

As for the T56 tranny. I'm still waiting for 12mpg to tell me where to find this adapter.

Blue you are correct in getting it together first then massaging it.

Anyone have a rpm number while driving in 5th gear at 70 mph?

Sorry I couldnt stay away.

lewis
 

12MPGHWY

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The same place you would find the "adapter" for the TDI to RX7 transmission.

That is of course at the machine shop after handing them a wad of cash.
 

lews930

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So that's what you call available? :confused: Gees, I guess if the price is right I could just have Mazda build me a rx7 with a Vw diesel. If I cant afford the adapter to my mazda box I will attempt to use the toyota tranny as I know without a doubt that it will hold up against the VW diesel.

12mpg, thanks for the lead on the adapter for the t56
 

bigblue

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The engine/trans would sit that far forward where it could interfere with the dash? The factory toyota shifter is one of those 2 part rubber damped units which probably couldn't be "s"'d but rigging up a bent solid steel one shouldn't be so hard if you desired. The crossmember is an issue but not probably the easiest element to make work.

There is the "aftermarket" t56 that has a speedo cable drive and bolts to a standard pull clutch and bellhousing. People often use this variant with those steel haywood bellhousings that can be drilled to multiple engine bolt patterns.

I think I remember it being geared with a 1:1 5th gear and a .62:1 6th. Not quite as high as the .5:1 but still probably good for your application. I can't figure your rpm at 70mph without knowing your axle, tire diameter and top gear ratio, but I think you konw that.
 

lews930

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Th emazda tranny and toyota shifter locations are 8" apart. to get the shifter throught the hole in the tunne would require either moving the motor/tranny rearwards or "s" shaped shifter. I dont think either will work and I dont want to gamble $375 plus the cost of the tranny.

I wanted to know the rpm of your cars at 70mph so I could get an idea of how fast the vw would trun with the mazda tranny used behind it

lewis
 
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