CFerrari

hi,

Im new to this board and I have a couple questions regarding rotaries. I am hoping to do a swap into my 69 510 and I was wondering the best route to go.

I will be using this car for a little road racing as well as street driven with a goal of approximately 275 engine hp.

Which year/model of engine would best suit what I would like to do and what mods would be recommended to get to my goal?

All info is greatly appreciated.

Thanx in advance,

Chris

CFerrari

I guess I should add that rotaries are a completely new area of knowledge for me so treat me as a complete newby when responding. I am learning as I go along and I do appologize for the ignorance my questions may show.

thanx

diabolical1

iTrader: (3)

with a goal of having a street-driven car with 275 HP, i'm assuming that you're planning a forced induction setup, right?

you'll hear debates on this topic, but my opinion is that the N/A rotaries that will yield 275 are not truly streetable. keep in mind that i'm not considering the 20B when i say this - just the 12A's and 13B's. so i'd vote that you go for a 13BT.

RotaryRevn

Yes, its gotta be a 13bt. Use either an 87-88 or 89-91 turbo motor. The 89-91 is a better motor, a little more power and the rotors are a little higher compression but they are really hard to find. I am going to be doing the same swap. I already have the motor, now I just need to find a clean 510 for a reasonable price. I was originally going to put this motor into my 85 rx7 gslse...that was before I totalled it. Since then I have owned a 72 rx2 which I sold because the body had alot of bondo work, and I have also owned a 75 rx-3 that I sold because it wouldnt pass a California smog check. I debated putting this engine into a 73 rx3 (no smog check) but I got annoyed with not being able to find parts for the old mazdas. Also, a 510 has independent rear suspension which I like since I want to make the car a street/track car, and parts are still pretty plentifull for the datsuns. Let me know how you fit the engine and trans into your 510. I don't yet know what exactly is needed to make it fit/and or who can do it for a reasonable price. Hopefully I will find a car soon so I can start my project.

You can check http://www.risingsunengines.com
thats where i bought my engine 3 yrs ago

CFerrari

cool, nice to see some1 else doing this swap in the near future. I was wonderring if any1 had some power figures for me on the 13b and 13bt. The numbers I have found are 147 for the NA and about 185 for the T. I have no idea which model/year these numbers are from, but the 13b has been used since the 70's right? and numbers must have changed significantly over that time.

I was doing some power to weight calculations and it looks like I will really only need around 225-240, any suggestions on how to bring the stock engine to this level?

Felix Wankel

A 13BT with a full 3" exhaust, good fuel pump, and a front mount intercooler (stuff that is pretty much mandatory for an engine swap) and boost set at about 9-10 psi should get you in the 250 bhp neighborhood.

If you use an 87-88 engine, pull the turbo off and port the wastegate if you plan to do anything I mentioned. The later ones have a much better design and don't really need it as badly.

CFerrari

wow, pretty easy to hit my numbers then... excellent.

would I stick with the stock turbo or should it be upgraded? If so, what would be a good option? Go with a larger turbo such as a T3 and slightly under work it or something smaller for a quicker spool time? I do not mind a small bit of turbo lag as this will mainly be used on the road course.

Felix Wankel

Stock turbo is fine for what you need.

RotaryRevn

I believe the 84-85 13b from a gsl-se rx-7 had 135 hp, the 86-88 n/a rx-7 had about 145 and the 89-91 n/a 13b had 160. The 86-88 13bt motors out of a turbo2 rx-7 had 180 hp, and the 89-91 13bt motors had 200 hp. I believe that the main differences between the 86-88 13bt and the 89-91 13bt was that the 89-91 had higher compression rotors, lighter rotors, different turbocharger, and slightly different intake manifold. Someone help me out here but I think the Japanease Spec (j-spec) motors had about 20 more hp than us motors. ( I hope thats right because I have a jspec motor ) Felix Wankel is dead on with the mods needed to get this motor to your desired power level. It doesn't take much. If you plan on using the stock ecu, you will need a fuel cut defenser before you do any mods (even exhaust). I think I am gonna use an aftermarket fuel management system. I know I don't need it, but someday if I want to upgrade it will be nice, and it looks cleaner. I will either go with a Microtech system from Australia or maybe a haltech. Dont really know much about haltech but an inside source tells me that they are gonna have 2 drastic price drops in the near future. I think my motor is a 86-88 13bt (jspec) although some of the components look like the 89-91. Anyways I am gonna stick with the stock turbo as I am also looking for about 250 which is easy with the stock turbo. If you can get your hands on an 89-91 rx-7 turbo motor grab it! If not, the 86-88 will be just as good for our purposes. I am still looking for a trans out of a 86-91 turbo rx-7. I am borrowing a fast fours mag from my friend right now that has a dime with the 13bt motor in it. Let me know if you want me to scan it and email it to you. It doesn't say what was needed to make the motor fit though but it is interesting reading. Maybe if I get a little time, I will post a few pics of the motor I have since you are not yet that familiar with the rotaries.

RotaryRevn

Hopefully you can pick up a good motor that is ready to go. If you need a rebuild for some reason, you might as well replace the 2mm apex seals with 3mm seals for greater strength. They aren't really needed for 250hp, but its always a good thing just incase of detonation during tuning. You also may consider a streetport if the motors apart but you don't need it for 250 hp. My motor is supposedly "brand new" and was held at Mazda Japan for warranty reasons for so many years, then rising sun engines bought a batch of them when Mazda didn't need them any more. My motor sure looks brand spankin new (except for the wiring harness being cut off). even the turbo exhaust housing is clean! Anyways I plan to run it internally as it sits now and when it needs a rebuild, I will replace the stock 2mm apex seals with the 3mm seals, and streetport the motor. Steetporting the motor will give you better mid and top end power but you may or may not loose a little bottom end. I am not really sure how a streetport affects a turbo 13b on the bottom end but I think the positives out weigh the negatives. Anyone who has some knowledge in this area please respond.

RotaryRevn

Felix Wankel,

Do you think a Mitsubishi Starion front mount intercooler will be sufficient for 250-275 hp? I hear they are pretty good for a stock intercooler. I was originallly gonna go with a spearco but that was when I was thinkin 400hp! Then I came to my senses and decided I didnt want to over power this light weight 510.

Felix Wankel

Lots of people have good luck with them, if you cut off the stock inlet/oulet tubes and have new ones welded on.

diabolical1

iTrader: (3)

This is still a point of debate, and I'm not trying to start one here or flame or anything like that - so don't get me wrong.
However, since CFerrari sounds like he's new to all of this, why don't we just stick to the turbo and ancillaries. If he gets a motor that needs a rebuild, just build it back with the 2 mm seals instead of having the rotors modified. Concentrate on reliability, and I know you can argue that the 3 mm seals lend to that, but I mean more along the lines of temperature control by oil and coolant flow, and getting the rotating assembly balanced.
Let's face it ... 250 HP is modest when compared to the absolute potential of the 13B, so I really don't think he needs to worry about apex seals as long as he spends his time getting his fuel and timing right.

diabolical1

iTrader: (3)

By the way CFerrari, since you've lowered your goals to this range, you now have some non-turbo options available to you like a nice streetport or a fairly mild/mid half-bridge - both of which are streetable in my opinion.

Felix Wankel

I'd like to know the budget for the swap.

RotaryRevn

True about the seals, there has been great debate on this topic. i know last time I talked with Ray Lockhead at shane racing, he prefers the 2mm seals as long as the engine is tuned properly and has no chance of detonation(that was a few years ago at famoso raceway in Bakersfield CA don't know what he uses today). However most all of the Aussie Tuners ( rocky @ pac performance, Maz-tech ect.) recommend the 3mm seals in a modified engine. My personal opinion, for 250 hp, 3mm seals are not needed however if there are any plans of going over 12psi of boost in the future, and you are going to have the engine apart, you may as well change them over for the added safety barrier. Once again, my personal opinion and not necessarily the right way. I just know how reliable my gslse was with the 3mm seals. That is one strong engine. When I crashed my se I had 150k miles on it and it didnt even smoke when it was cold on start up. All I ever did to that motor was change the oil. Now that motor lives on in the rx3 that I used to own and it still hasnt been rebuilt. Not quite sure how many miles are on it now but it still doesnt smoke! I have heard stories of se motors which came with the 3mm seals stock going 250k miles before a rebuild was needed. 10 guys will give 10 different answers so there is no right or wrong answer to the seal question.

RotaryRevn

C Ferrari,

I'm sure you have seen this website. But just incase you haven't it makes for interesting reading. There is info on several rotary 510's here:

http://www.bryanf.com/mycars/yf/engine.htm

CFerrari

thanx guys... this is a lot of positive feedback and good stuff for me to learn on. I do appreciate all the considerations such as thought towards rebuilds, stock turbos, seal sizes, reliablility issues etc.

Right now I think I will stick with 250hp and focus more on tunring the chassis/brakes and work hard on weight reduction. I am seeing some outrageous numbers coming from 13b and 20b turbo engines and depending on the outcome of this swap I might just start on another project of greater power somewhere in the range of 450hp in an FC perhaps. I'll definately wait to see if I can master the art of the turbo rotary =)

thanx again guys.

Chris

CFerrari

btw RotaryRevn, that is the whole basis behind my build, I love bryans car. WHAT A MACHINE!!!!

RotaryRevn

Do you plan on cutting the firewall to slide the motor back? That is what I originally had planned but I have been finding out that most don't cut the firewall. I think the handling benefits would be awesome getting the engine that far back in there but I have talked with about 5 people who have done the swap and they didn't feel it was needed. I am not quite sure what I will do with it yet. I have a few pictures of rotary 510's on my website under the rotary conversions in the pics department. Unfortunately though, my website has alot of dead links right now because it has been down for about a year and I havent done anything to it. The links to look at the big pictures of the engine compartments won't work (I need to find time to fix them) but you can see small ones. Also, My friend is supposed to change the dns settings so my site address will go back to rotarymazda.com because right now that address doesn't work. Anyways if you want to check out the pics (tiny ones) just go to my profile and click on my website address.

CFerrari

ok cool. And yeah, if you could email any of the stuff from the fast fours that would be great. I have some old FF's mags laying around somewhere I just need to dig them up.

About cutting the firewall, I dont think I will be doing this on this swap as its one less thing to worry about. Although it might help a bit, I dont see it making a massive difference as I will be relocating the fuel tank and battery to where the rear seat use to be so that will balance the car off quite a bit. For my second dime I think I will try as I will be more familiar and it would be a learning experience as to how much it helps.

diabolical1

iTrader: (3)

sounds like a good plan. i'm just curious which road you decided to take for the 250 ... turbo or N/A?

CFerrari

looks like I will go for the 13bt and just get the car running will the new driveline. Then after a few events when Im more familiar with the brakes and chassis dynamics I will up the ponies to around 250 and if thats not enough, purchase a 2nd engine, tear it down and build it strong for around 325. Hopefully the chassis will be done by late january early feb so I can order the engine and get it fitted for some testing in april.

diabolical1

iTrader: (3)

cool