Hey I'm new to the club, I've dug and dug but can't really find much help on rotary engines. I will properly introduce myself this weekend when I have a computer on hand. (Yes I'm hiding at work to post this). However on to the point. I've loved my TT 300z before a deer decided it wanted to feel an impact at 100mph. So I got another Z. I've tossed around the idea of doing a normally vg30dett swap but hell I want something different. So why not a rotary? I understand the weight difference but I think I have it figured out enough to make it work weight wise. But the main thing I cannot seem to find out is how the hell do you increase the HP on a damn rotary. All I'm trying to achieve is 400 to 500hp. the tranny I'm going to use a Chevy 400t. I've found the kit for the bolt up and I'm not worried about the rear end. The stock Z can hold up for me. No this is not a drift car or track car. Just a weekend cruiser. But I'm new to the world of the rotary, and arguing with a Nissan guy about using a smaller 13b is pointless. So here I am lol.

 

well if you've got money then anything is possible.
If you cruise some sections and look at what other have done to get their engines set up you will find that most of them are Aftermarket Turbo/Ecu/Bigger injectors/ported/pinned and WELL TUNED by someone who knows the engine.
I got good HP out of a Stock TII engine with add ons BUT I had a good tuner.
This is why I stress that without a good tuner you just got nice shiny parts.

 

Yes I agree about the tuner, it's amazing how well it'll help. I keep reading about apex seals blowing out? Is that really such a big issue on the rotary? . And to edit my OP, I thought the bolt kit was for a t400 tranny however it's for a power glide so I'll use the stock tranny.

 

That would be interesting, but expect to spend as much as as if you were buying a built FD...

 

Don't buy into the "apex seal" hype. That's primarily the only thing piston guys know about a rotary and that's what they rag on to sound informed

Yes, the apex seals are commonly a failure point, when any of the following apply:
1. The car is not properly maintained.
2. You're making 2-3x the power the original engine was designed to handle 30 years ago.
3. The engine is in need of a rebuild, but you continue to push it anyway.
4. You have a crap tune, or you tuned a piston car yourself once without blowing it up and now you're a "tuner".

The same scenario happens all the time in the piston world and its called punching a hole in the block

It takes a lot of money to get a lot of power out of these cars and keep them running. When I say a lot I'm comparing that to what's possible in the realm of RB motors and the likes. If you just want 3-400whp, you've got no problems here. If you want 500+, the pistons are starting to look better if you're a Nissan guy and don't care about the rotary and just want power.

 

I'm fine with 350hp or less/more, but due to the weight of the Z, compared to the rx7 I figured it would help out to have a little extra ump. And no it's not really about the power any more. I have a kid so it's more of a hey that will turn some heads at car shows, and I love trying new things.

I've read a little more indept on the motors last night, and it seems that a 13b- from s5 will work for what I want. Plus it's a hella lot cheaper to! I've seen one on eBay that is 1k but it's seized/no compression. If that is the route I go, if the block is rusted from sitting for a while, how hard is it to find a new block? The other option I've been leaning towards is buying a whole car so I have everything there electronic wise.

 

A seized engine for 1k is not a bargain. You should be able to pick up a running engine that needs a rebuild for 1k. Another option is to keep your eyes open to craigslist in your area and pickup a used S4 or S5 turbo. For us first gen RX-7 guys, a S4 transplant is a little better.

 

Everything I've read points that the s5 is a better engine, due to the port size and overall better dependability. Please explain why you'd say the older model is better? And I've searched near and far around my area Charlotte NC, but it's either over priced or a NA.

 

Us first gen guys convert the S4/S5 front cover to a 1984/1985 GSL-SE 13B (EFI) to retain the front engine mount. This also allows us the to use the factory 1984/1985 GSL-SE 13B oil metering pump or premix. The S5 oil metering pump is electronic and required when doing a S5 swap with factory CPU. The other option when doing a S5 swap to to keep the S5 OMP connected to the computer but disconnected from the front cover and premix. This isn't a very pretty or practical. I hear the s5 OMP isn't cheap either. Not sure if you went with an aftermarket CPU if the S5 OMP is required at that point. Of course, an aftermarket CPU isn't cheap.

I guess you have a few questions to answer is regards to how you will mount the engine. This might help you determine which version would be best for the application.

 

Yea I understand why it would be beneficial to y'all to maintain the s4 engine. It saves y'all a lot of time and money. And other than wiring the rotary to run correctly and in prime condition, my other concern is mounting the engine and transmission. I know it's all going to be custom mounts for both. I feel the tranny should be fairly simple. However the engine, I haven't yet determined the best route. I know the rotary is narrow compared to the vg30de and probably shorter as well. I've been tossing the idea and thought about doing an A frame built off of the frame where the original VG mounted. (I'll do a crued drawing when I get home.) But I'm not sure how tall the rotary is compared to the vg. So I don't know where to actually mount it to stay under a closed hood without cutting the hood and the pitch to have the A frame at to mount to the rotary block. (I have access to welders and everything else I need to fabricate it)

 

Wowww that's a unique build. Hopefully you got the time and money to work on this; don't give up anytime soon!

 

The 13B-REW block is actually the best block, most advanced chrome coatings, and good ports for forced induction use. Many people also find the REW intake the most pleasing.

Making power on a rotary is easy: well built engine (quality rebuild following clearances, especially apex seal/rotor clearances), appropriately ported (in most cases this is a street port), appropriately sized turbo (GT35R for the 400 HP level, or the fashionable BW turbos which have a bit better response due to better turbine design), and a GOOD TUNE. GOOD TUNE being the key. And coming from the piston world, you may not be aware that a full standalone is a requirement for a high HP rotary.

 

I'll post pictures in a few. I picked up the donor car today. it has a straight body, so I'm glad about that. However no I did not know it needed a stand alone unit. Any recommendations on a good tuner.

Is it really that big of a difference between the re and rew? The rew seems to be a good chunk of change more than the re?

 

 

Oh, sorry, I missed you were referring to the RE (as in, Cosmo RE). No, not much of a difference internally. The Cosmo RE uses an FC style CAS to trigger which is less reliable/accurate than the REW trigger wheel. The Cosmo RE turbo system was actually reliable.

If you didn't know a standalone was required, then stop, and start reading some of the high HP builds in the FC and FD sections of this forum.

I am partial to the Megasquirt line, particularly the MS3-Pro.

I have no tuner recommendations as I have no experience with any of the good ones (only the bad ones, most of them local).

 

Yea, I started reading on that as soon as I seen your reply. I'm still undecided on the motor though, I've been leaning towards the S-5 here lately. Mainly because I think it will be an easier platform to work on. And on the tuner I've seen some that would good in my opinion. It has the complete harness for a plug and play style.

http://www.haltech.com/mazda-13b-kit-now-available/

I got the interior on the way, it should be here Monday or Tuesday. I can continue to update this post as I progress if y'all are intrested in seeing the build up.

 

The Haltech is a good choice, lots of support in the rotary community and the plug and play harness makes it super easy.

Honestly once you are standalone, the engine series makes very little difference from an ease of use stand point. The only thing about the Cosmo/REW is that they use side feed injectors, which are a bit of a pain to upgrade. But aftermarket rails/kits are available.

S5 engines have almost all the improvements of the REW and you can port them anyway. Might be easier to mount as they mount on the center iron (though the passenger side mount is odd).

 

sorry for the delay in posting. My son turned two so been kinda focused on that, then reenlistment in the guard. Anyway. On the engine I'm going with the S5.I have plenty of room in the engine bay to play with for the swap to lol. I've been shopping around but nothing really has came up worth a damn. Or the shipping cost more than the motor! But I'm looking anyway.....Hopefully going to get the roll bar tubing next week for the half cage.























Yea it fell off my jack. :/

Kinda glad it did though. If it didn't it wouldn't have made it under the car.





















Yea needless to say, those dogs are no longer with me. (They were strays)















s.

 

speakers and amp before motor is in.......check

priorities.....lost in translation lol

I can see how that engine is crammed in there, I NEVER want to work on one, ugh

 

Sorry for the garbled sentences. I hate the iPhone with a passion. The speakers and amp aren't installed I wanted to have them placed, so I knew how to do the roll cage without interfering with them.

Priorities, getting away from the wife. So yea that's been achieved.

and yea it's a major cuss storm working on the vg30de. The Motor and tranny alone weighed in at 800pounds.

 

Cool swap! I am from the Charlotte area, there are a lot of good guys up there. You can check out the shop Eccentric Performance (Asheville) to see if Steve has any motors or knows of any motors. There is a facebook group called Upstate SC RX-7 Owners, not a ton of people but might be worth asking there. Good luck! Looking forward to seeing it on the road