rx7hellbent

Hello i am doing a swap, i own a 85 12a GS, im putting in a 91 13b.
please somone ANYONE, at this time i have a 13b with 55k on it, do i need a dif tranny? ( i have a 85 5spd) i know i need the fuel pump, and someone told me the gas tank as well, i have the ECU and harness, what else do i need?
i need this put into "idito" temrs as best as anyone can.
thanks

PM me or post any advice, thanks.

Whizbang

the fuel tank from a GSLSE or otherwise modify the existing tank for fuel injection.

a front cover and oil pan from a 13b GSLSE

the trans will be fine.

then just add the wiring harness for the motor and place the ECU somewheres under the dash and add the related controls.

make sure you get everything connected. s5's had a little more electircal crap than the s4's did.

youll run into some hang ups as it always happens. unless you have a S5 parts car the motor is coming from the you can basically make anything work, minus the need for the GSLSE front cover and oil pan.

rx7hellbent

Im taking the fuel tank off the 91 rx7, to put on the 85, i have the parts car, well the car is at the junkyard, what all from the engine bay do i need? i have the WHOLE 13b in tact, only thing im missing is a dis. and starter.
im taking fuel pump,gas tank,13b from the 91, ECU and harness,
what else? anything?

i need the coils and ignitor, and **** what else? im doing this ALL on LOW budget, im getting the parts, all i need is someone to give me the right list of **** to get.

Whizbang

the coil packs, the pressure sensor located on the passenger side wheel well. little black rectangle with a vac hose to it. and a four prong connector IIRC.

MAF sesnor. the black tube looking think.

wiring harness would be a god send.

Rx-7Doctor

iTrader: (13)

You do not need to change fuel tanks and the Se tank is no different than your Gs one. You can either just run a Se fuel pump which bolts on the frame rail just like your carb'd pump does or get a inline FI pump. You will need to add a FI filter and change any rubber fuel hose over to FI hose because of the increased pressure.
I am going to guess that the engine is complete with manifolds and everything?
Low impedance is correct about the Se oil pan and cover because the later 13b's engine mounts were at the oil pan area. You will have to modify the mounts because the engine is longer and needs to go further forward. I have a Se crossmember,Se pan and front cover.
Pm me if your interested in buying them. I also believe i have an extra SE fuel pump too.
Just remembered something also. You have the beehive cooler on your 85 Gs. You will need to either get an S4/S5 cooler or a Se one. The SE one is much easier to mount and i also have a non-leaking one too.

Whizbang

the biggest problem is that the S5 13b is not going to directly mount the FB. you will need the oil pan and front cover from a GSLSE

trochoid

iTrader: (6)

The FC tank will not fit in an FB chassis and there is a difference between the SE tanks and the carbed ones. The fuel supply tube is bigger and there is a sump cup in the SE tanks. If you can find a good one, use it.

I would go with a Walbro external FI fuel pump, cheaper and more output than the stock SE pump. Grab the oil cooler and lines off the S5 and read my writeup in the archives on the swap. FC fmocs have better bungs and won't leak as frequently.

For wiring and dealing with the electronic mop, read Steve84GS's posts.

A little heads up, you will spend more time doing research, than working on the car.

Rx-7Doctor

iTrader: (13)

Itwon't make one bit of difference putting in a Se tank. It is a WASTE of time.

And the stock Se oil cooler is much simpler to bolt in. Were looking at alot of work and keeping it the simpler the better

trochoid

iTrader: (6)

Doc, haven't seen you around for a while, not looking to argue, or kill a parts sale. That said.

Mazda put the sump cups in the SE tanks for the sole purpose of preventing fuel starvation, and possible detonation on the FI systems. The FC sump cups have nearly 3 times the capcity of the SE ones. So apparently these are needed. I can post pics of the FC cup. I have a thread around here somewhere, maybe in the archives, that show the differences between the SE and carbed tanks.

As far as the fmoc goes, the bungs on the 1st gens are crap, period, we all know it. It's his option if he wants to save coin and use the FC, and inccur a little more work, or buy a 1st gen one for bolt in simplicity, for more money. Either way, new oil lines are a plus.

rx7hellbent

-shakes head- i think i need to go find something GOOD for my head....

Rx-7Doctor

iTrader: (13)

There will be no fuel starvation by using the Gs tank. We are not talking about a high Hp motor here with high demands. The se pump puts out more than the stock Fc's. The turbo Fc's have about the capacity of the SE's. The Fc's tank were redesigned because of usage of an internal pump. But we are talking about an external pump.

I agree that the mounts on the Fb's coolers are crap but when you redo them per the thread somewhere in the archives they never fail again. With the Se cooler he can just use racing beats or even stock se lines. Remember this person does not have the technical or fabrication skills to modify alot of things. So the simpler it is done the less headaches he will have.

trochoid

iTrader: (6)

You will get some disagreement from others who have experienced fuel starvation using a carb tank, even with a carb.

Priced an SE pump lately, iirc, they are near $200, a Walbro can be found for $100.

rx7hellbent

well said, doc, im, trying to keep it all as low cost and low pain in my butt. ( no cussing this time)

this is already making me go HOLY F*&K! seeing how i have to be up before 9 to be at the junkyard when they take out the 13b, and i pray to god they dont mess anything up, i will just give up..

but so far ive been sitting and looking at this 7 sitting at my house, with a 98% perfect body 1 ding, and 2 keyed marks, no rust what so ever.. and its the nice factory mazda red from 85' i love it.. and i just couldnt stand it any longer..
i had a daily driver, but a SUV didnt like it i guess. and my POS ford that was my daily driver went down and i will be damn if i put any money into another ford.

and i already delt with fule pumps, i did for my 12a..

steve84GS TII

If you run the EFI engine off the GS fuel tank,you WILL experience fuel starvation problems,especially on left turns and when the fuel level is below 1/3.Ask me how I know......Ive had an FC slosh baffle and intank pump in my GS tank for 5 years now.It took me only a day of driving without the baffle,to realize that it was absolutely neccesary.

The HP output of the engine had absolutely no bearing on this,all port fuel injection systems require 40-50 psi of pressure to fire the injectors.If the fuel pickup grabs a hold of an air bubble,the fuel pressure created by the pump will momentarily be lost, and the engine will die until pressure is regained.At the least,youll get whiplash and maybe hit your head on the steering wheel....at the worst,youll blow your turbo engine when the mixture goes lean and you detonate.
The tank must be modified to accept the baffle and intank pump,or you will need to procure an SE fuel tank and run an external EFI pump.

And yea.....the S5 engine swap can be a can of worms because of the wiring and increased electronics.Not that its impossible,far from it.....but there are few that have tackled the job while retaining the stock S5 EFI.Get an FSM,youll need it to figure out the wiring on the left side,which must be custom made.If you have any specific questions during your build,feel free to post a question or PM me personally. I do have something of a claim-to-fame when it comes to S5 swaps....

Rx-7Doctor

iTrader: (13)

I appreciate the post on the fuel tank. But he is not running a turbo motor and he is on a extreme budget and does not have the fabrication skills to mod the tank. With the stock Gs tank and regular driving he is not going to experience problems. He is trying to do this as quickly and as easily as possible right now. Later on he can procure a tank or do a mod on this. I have been in contact with him by Pm that's why i know what he has to work with and how he wants to get it done.

steve84GS TII

I understand all that......but turbo or not,slow or fast,20HP or 2000HP.....when that tank gets below 1/3 and he turns left,the engine is going to cut out.
I just feel that doing it right the first time should always take precedence over hurrying up to get it done.Budget not withstanding,how many times does he want to pull the gas tank?

Mazda12AGS

I had a friend with a stock 90 GSL that cut out when you turned hard to the left, so I can just imagine that it is gonna do it if you don't do it right the first time.

vipernicus42

iTrader: (4)

The way I see it is this:

If you just want to get the damn engine *in* and spinning, yeah you can pick up a junkyard -SE pump, stick with your old tank, etc... Yes it will be cheap, yes it will be a little easier, but you're going to turn around in a short while and go "now I want those upgrades the guys were talking about". But at least it gets you on the road, for now.

Doing it right the first time costs more money, takes more time and more effort. But the result is worth it when you never have to address issues that arrive from taking shortcuts. Not everybody is as meticulous about doing it right as trochoid and I are, but even with my complete lack of fabrication skills I've managed to find ways of getting things done.

rx7doctor, I respect how you're trying to cater to the needs of rx7hellbent, and that's cool, but don't try and scare people off from giving him alternatives and educating him to problems he *may* experience if he goes your route. I mean you no disrespect, in fact I have the utmost respect for your ability to read between the lines and figure out what someone's budget and skill are aimed towards, but I don't like the way you said "I've got your solution, I can sell you the parts you need, and don't listen to these guys you don't need to go that far". Give him your option, let him decide, then when he posts saying "well I'm gonna need a this and that" offer your parts *then*.

trochoid and steve, it's good that you share your knowledge of one way versus the other, but we also have to let rx7hellbent decide which way he wants to do it. We don't have to *convince* him to go one way or the other, just provide him with our opinions and let him take what he wants.


rx7hellbent, I wish you luck on your project. Personally I'd go for the route that costs more but covers all the bases, but that's just the way I do my projects. I paid for the ISCRacing airbox ($125 including K&N filter) because I considered it an investment worth doing for my 12a w/ Sterling carb. Most people wouldn't spend $10 on their airbox, but that's just the way I do things. Don't get me wrong, I don't have money to burn, but when it's for my Rx7, I do it 115% the first time. That way I never have to rework things I've already "completed".

Jon

vipernicus42

iTrader: (4)

Oh, btw... IIRC the '84-85 tanks are *all* the same, regardless of whether they're -se or not.

I could be wrong, but it's a distinct possibility that I seem to remember.

In which case, he should be alright to stick with his 85GS tank and just get an external FI pump (either a used -SE one or a walboro, though I never trust used parts) and be set.

Jon

Rx-7Doctor

iTrader: (13)

Jon, I dont understand your commnet about scaring people off to giving him alternatives.
Or letting them educate him about problems he may or may not have if he went my way..
What you are not aware of is that i had atleast 12 pm's with him about this. I even advised him to drop the project because he would not like the results if he did not do it the right way. I offered the CORRECT parts that i had to get his job done if he was going to insist on going that route. IE; SE oil pan, SE fuel pump,SE front cover and Se oil cooler.

And your right alot of people are trying to do this as inexpensive as possible. I don't like it done halfway the 1st time either. In fact i'm very **** about doing it right the 1st time. You can get this impression from anyone that i've done work on their car for.
But being an Ex-Service manager i have learned that it is their choice at the end if they are doing it themselves. The only thing i can do is tell them how i feel and how it should be done the 1st time and what the consequences may be if not done correctly. If they wanted me to do it i would politely decline. But it is his money and his decision and that's all we can do.
And in the end he did take my advice and drop it. He pm'd me and found some 12a's and is going that route. You see i make ALL of my decisions based on COMPLETE FACTS.

Just alittle note to you guys that don't know me. I've been around the automotive scene for over 30 years. Which is longer than most of you guys have been around. So when i offer advice it's based on what i've gotten for input from that person and not some out of my *** decision making. Sorry to be so harsh but i am tired of having to explain myself to people that do not have all the FACTS at hand. I have NEVER given anyone on this Forum advice that would be deterimental.

Midwest 7's

iTrader: (4)

the efi gas tanks were different than the carb tanks.

Rx-7Doctor

iTrader: (13)

Ok lets end the **** fight shall we

The FACTORY part # for ALL 84-85 gas tanks is the SAME. fa66-42-110a. This being NO DIFFERENCE between carb'd or FI.

steve84GS TII

Thats odd because my stock 84 GS tank had no fuel pickup baffle in it when I pulled it out.Could've swore the SE tanks had a small cup in the bottom of tank that surrounded the pickup sock.
I cant imagine Mazda would just drop EFI into the 1st gen without considering the consequences of fuel slosh on an un-baffled fuel pickup...

trochoid

iTrader: (6)

There may be only part number now days due to inventory, I don't know. Here is a link to a thread, with pics, adressing the differences in the S3 tanks. They are different. If you still have doubts, I have both style tanks out of cars and in the shop and I will be happy to take and post better pics.

https://www.rx7club.com/1st-generation-specific-1979-1985-18/84-85-fuel-tanks-facts-416682/

Doc, I have not responded to your PM because I wasn't quite sure what to say about. I try not to be cynical, but the quoted post comfirmed my fears. rx7hellbent has PMed me also, so I will be keeping an eye on his progress.

Midwest 7's

iTrader: (4)

dude if all you can do is quote part #'s all the time you need to get off the ******* computer and head out to the garage. hands on work beats book work anyday.
as noted in scots pics above, and from my personal observations, the se tanks are obviously different.