I'm sure it has been asked before, and don't worry I did a search on it and gather some information first. Alright I have right now a Turbo II with a shot rotor that needs to be replaced, probally more as well, it has 106,000 miles on it. On friday I intend to ear the engine out and find out what exactly is wrong and needs to be replaced. Here is the question I have set aside 15,000 to build a race car, after $500 for the car I'm left with $14,500. Now what should I do build up the 13b turbo that is in there, drop in a whole new 13b turbo, or do a 20b engine swap for it. Which is most likely going to give me the most gain, if I spend the 14,500 on the 13b will I get as much as if I spent around 10 on the 20b swap and then 5 on that engine? So here is a link to a site that discusses a 20b swap on a 2nd gen RX-7 http://fc3spro.com/TECH/SWAP/COSMO/20b.html check it out and you guys tell me what you think I should do?

 

i say rebuild it, start fresh ... less problems and it will handle your mods better

 

if you are good with cars and you want a race car i'd say go with the 20b swap but you wont have any money left afterwards but why not a 13b re swap you can swap in that motor and have enough money left over to get performance parts for atleast 450rwhp

 

what are the advantages of going to a 13b re?

 

less expensive of a swap more money to work with whatever your needs are wont make as much power as the 20b but it can produce some good numbers

 

once again, even with a swap (assuming its not a fresh rebuilt swap) id still reccommend rebuilding whatever you put in the car, just to make sure everything is on the level before you start doing sick mods to it. and i agree with 91mazdarx7, a 20b will hit your cash reserves so hard you might not be able to afford to put gas in it.... the 13bre is a good swap choice..

keep in mind, with a rebuild you have the options of porting while its already open. thats where the power comes from on the rotary, BREATHING MODS. intake / exhaust...

 

Well what kind of power can I expect from just dropping in a 20b? And what are some recomended mods for the 13b-re to gain some power. I'm really looking for a "10 second car" or better what is the best way to get there, and will both options get me there?

 

20b will get you there for around 20k. But if you are really into drag racing I wouldn't use a rx-7. In the v8 world 10 seconds only cost 10k. But its up to you.

 

nevermind.

 

Alright here is a new twist to the scenario, I want to be able to race the car in NOPI Race series but due to the rules I can only use a 3 rotor engine in the pro-outlaw RWD class where most cars are running seven second cars, or I can keep it as a 2 rotor engine and run in the Pro street tire class whre they run 9 and 8 sec. cars. Now which one should I do with the resources I have discussed earlier which is more likely to happen a 7 sec. 20b or a 8 sec. 13b?

 

I've already thought this out for my own self. I'm doing a 20b swap with all the works. It's not someting that you should tell everyone that you are doing because some have no clue about that motor and some know that it's a pricey job to do and will assume you're full of ****. All I can say is that you'll love it when it's done. Mine's still got 2 years before fully erected. It'll be a street car.

I don't know how a 20b will do in race only applications. Obviously you'll enjoy the larger displacement and torque. Make sure you get fat, sticky slicks.

 

If you have all the time and alot (I mean alot) of money, do the 20B. But I'm a fan of the 13BT or the 13B-RE. They're cheaper and you can more with mods to them (with the money you state you have) in my humble opinion.

 

rebuild it youself for the experience! i will probably be doing that soon. i'm looking forward to it.

 

Oh also, I did all the pricing (new AND used) for a 13B-RE and all of the little requirements. And it turned out to be between $9,000 and $13,000 thousand. But if you can get things discounted or used itll be cheaper. But overall its pretty costly there still. Just imagine with an added $2,000 to $4,000 for an engine without porting.

 

holy crappola thats a big wad to spend for a little gain over modding an aspec engine w/rebuild and port. what else did you factor in besides the engine?

 

Everything that was needed,

Upgraded clutch and pp, engine mounts, engine, fmic, turbomanifold, upgraded turbo, piping, exhaust, radiator, bigger injectors, ems, and several other things on the fc3spro list. Pretty much to get everything done without taking shortcuts. Not to mention I factored in engine rebuild and porting (the costs of the rebuild parts) and such.

 

ahh ok. basically everything you'd need to do it right with either engine with the only difference being if you paid more for the jspec block than the aspec one.

 

Im talking about the 13B-RE.

 

...right...the jspec 13b from a cosmo right? or am i confuzzled about something.

 

An 8 second 13bt will be hard to do.

SoulAssasin had a half bridge with some turbo and I think he did 9's.

Honestly there is a VERY small group of 13b's which are in the 10's and under.

A 20b will net you some immense power without completely sacrificing the engine.

so far I have seen quite a few 400-500hp FC's but nothing over that.

They were running professionally built 13bt's with huge turbos(t77 and custom T04R style).

A local guy is running a cosmo engine and is doing about 370rwhp. Can't remember what turbo he has.

The 13b-re(2 rotor Cosmo) is a good engine because it's cheaper than a FD 13B-REW and basically has the same stuff.
It has the good internals but also has a slightly larger intake port.
The throttle body is also bigger than a FC TB so that will help a bit.

 

Yeah thats right, and it does have more gains and possbilities then a 13BT. Those costs are to make it run and drive with power and efficientcy. (Taking RETeds list and all the prices involved). Which he had done already, I just wanted one just for me and to my preferences for parts.

 

So what do you think a 500hp 2nd gen would relate to in track times? and how much power would I expect just from the 20b swap?

 

Looks like I am going to go with the engine already in there. I have it out now and will be stripping the block tonight and then I will send it off to be streetported. I will put a bigger turbo on it and a bigger BOV a new intake and exhaust and a drag line suspension. What else should I put do to the engine to get some power gains?

 

man what ever happened to soul assasin? is he back in the states? he hasnt been on in a while. also he was running a t04r hks turbine. i think he put out 520 horsepower if im not mistaken with a half bridgeport.