13b swap assistance
 

hello all,

I own a fc and a sa. my little 12a needs a break and my fc is looking to donate its heart to my sa. with that being said i plan on street porting my 13b and using a pair of twin itbs to help with throttle response. im not looking for crazy power so im thinking itbs is the way to go. now for the meat and potatoes of the post.

im looking for suggestions regarding longivity of the motor. like fuel system, oil coolers, e85, premix or non premix. i have access to e85 as there is a pump near my home, id like to get rid of my omp pump but i dont know how the e85 will react to the oil. money really isnt an issue and the winters where im from are long and cold so time isnt an issue either.

again, if anyone can make any suggestions on brands, cooler sizes, fuel pumps or anything you feel i should keep in mind. id greatly appreciate it.

thank you,
Nick

Welcome to the board, Nick. :)

Longevity really rests on a few key things ....
1. a solid build (spec'd clearances, modest oil mods, new MAZDA springs, etc.). Balancing shouldn't be required, but with your "money isn't an issue"-situation, it certainly would be a good move. A light flywheel would be a nice touch, too - your choice on how light you want to go. RB has a lightweight steel one that's good, but there's also aluminum. I used to live in Seattle, so I know there are some hills there, so I don't know how light you'd feel comfortable with.
2. stay up on maintenance after the engine is running. Once broken in, don't be afraid to put the RPM up there, but at the same time understand that if you find the need to beat on it everytime you get in the driver's seat, then maintenance schedules need to be adjusted accordingly. Use good, sensible oils and the best filters that you can. Maybe get a couple of gauges to monitor vitals. See? Nothing complicated. No black magic. :)

Oil coolers - you shouldn't need to go aftermarket unless you just want to. Without a turbo, I can't see why you would need more than the stock FC cooler with some quality lines. Get the cooler cleaned and tested, then install and use it. If you want to get fancy, maybe you can go for an Rx-8 dual cooler system. Same thing there: clean, check, get good lines made and use.

Premix - I think of premix as insurance. I don't think you should delete your MOP. I don't know what year FC you have, but I'm not a huge fan of the electronic ones, so if that's what you have, then maybe you can acquire a mechanical one for your project.

Streetporting is nice! I'm a believer, especially on the 6-port engines. Just don't mess with the auxiliary ports too much. Offhand, I can't think of any "twin" systems available, so that will either have to be custom made or just go for a nice-sized single (48 or 50). Sidedraft might be better for your overall powerband, but downdrafts are good, too. You're injected, so many of the old-school headaches won't really apply to you. Converting to a T2/FD pump should give you all the fuel you need for a streetport. If you want to go fancy, then the choice really is yours. I like Bosch (I don't mind the noise), but I have recently started appreciating Walbro. I'm sure there are other brand-name pumps that are equally good.

I don't consider myself qualified to speak on E85 much, so I'll keep it simple and vague. :) As I understand it, you'll have to tackle anything that the fuel will have regular contact with (tank, lines, pump, rails and injectors). However, I've seen where people have converted and said they didn't do THAT much, so there's conflicting info out there.

That's a lot for now, so I will stop there.

Here are a few E85 threads that might help:

https://www.rx7club.com/alternative-...ctors-1105465/

https://www.rx7club.com/alternative-...up-s5-1108100/

https://www.rx7club.com/alternative-...premix-903060/

thank you for all the information. It's greatly appreciated. although i do enjoy playing with my cars, i dont plan on beating on the car.
the motor is out of a 1986 fc so its a s4 6 port. supposedly the motor was rebuilt but i have no documentation of it, so im going to choose to believe that the motor needs to be rebuilt.

Why? If it seems to visually be in otherwise good health (no oil leaks, little to no carbon buildup on the rotors, etc.), then why not just do a compression test and see where you are? It obviously wouldn't tell you anything about the supposed rebuild, but if it's a known working engine, then you can use it to put the SA together and get your setup initialized, then you can move on to porting. One less variable when the time comes, know what I mean? I mean it's another thing if the engine is in questionable shape, then by all means, port and rebuild first.

youre right and i know that the motor is good because i've been driving the fc for a few months. id just like to get it rebuilt because i dont know the history of the motor, past the few months that ive owned the car.

Hi Nick!

Welcome to the club. It's great to see another owner in WA!

All of the information diabolical1 stated is spot on. In regards to running individual throttle bodies, feel free to shoot me a message or ask here. I've been running ITB's on my 13b for several years, both on a stock port motor and most recently, a peripheral port.

In regards to the rebuild, I'd say do it if you have the funds and time. Otherwise, compression and leak down test it. If it passes, just throw the sucker in as is.

-D

glad to find another person from the state of Washington. my main question djSL is what can i expect power wise? im hoping for 200 to the wheels but im not going to get my hopes up.

All of my experience is related to itb's with a standalone efi system (haltech), but I put down 178whp on my stock port 90k mile motor with a leaking coolant seal. Porting will net you more power, and so will a good tune.

I'm heading to the dyno this next weekend to complete the tune on my peripheral port, but I'm aiming above the 250 mark.

i plan on running a haltach 1500 ecu with a street port. i figured if im going to tear the motor apart to port it i might as well rebuild it at the same time.

You should be able to hit that mark with a street port.