FC_fan

iTrader: (2)

First off, I live in northern vermont and have an '86 S4 N/A. I wanted to go to an S5 tII engine and drivetrain but decided to stick with an S4 tII swap for simplicity(see question 1). car will be a daily driver and weekend warrior (I know, racing breaks **** but I have a subaru impreza RS as a backup/winter ride for down time.sadly, subie's auto though)

I have been reading through a bunch of swap threads and various info and want to confirm/ask a few more things so here they are in numerical order.

1. I was reading a thread here that said I could just plug in my N/A harness to the tII ecu and just deepen the power steering pin and maybe have to extend like 2 wires. is that true? Will that work in stock form? want to confirm that thread.

link:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/how-make-s4-na-engine-harness-work-s4-t2-ecu-491683/

2. I was reading somewhere about just taking the S5 turbo components and slapping them on the S4 tII because the turbo components are the biggest difference in S4 and S5's. I read S5 turbo systems are more efficient, make slightly more power, and generally work a lot better with fewer problems during their lifespan.

Is that possible while still using that N/A harness(if that works) and stock tII ecu? Is it really worth the trouble? (I am looking for that fine balance between reliability and performance.)

3. last, simple question. Is it easier to pull the motor and tranny together or seperate/ both are being replaced by tII's so just wondering what you guys think.

I usually check my threads once or twice a day, mostly evenings. If you need more info or clarification on what I'm asking, please just post up and I should reply by the next day. thanks guys, all info/criticism appreciated.

-Josh

RotaryRocket88

iTrader: (7)

1. Yes. The NA harness easily converts over.

2. Use the S5 turbo setup. It's better, and lets you get rid of the twin-scroll system.

3. Pull the motor & transmission together.

FC_fan

iTrader: (2)

Thanks RotaryRocket88. I would like to wait for a few more posts to see if everyone agrees. no offense to you of course. sometimes other members know some more tricks or other info that another member might not The swap won't be till spring anyway.

BTW everyone, next month I will be looking for either a $200-400 donor car for the drivetrain or cheap drivetrain parts. If anyone has anything or knows some good deals, put that in your post too! mind you, I won't have the money till next month though. thanks

FC_fan

iTrader: (2)

oh, couple questions about your post rotaryRocket88. if I switch to the S5 turbo components, do I use the S4 or S5 ecu? and will my S4 N/A harness plug right into the S5 turbo components?

FC_fan

iTrader: (2)

hey guys, found this site selling a JDM 13BT with ecu tranny, the whole shabang. its in canada close to where I am. think this sounds legit?

linky:
http://www.tokyomotorimports.com/eng...nsmission.html

arghx

iTrader: (3)

keep the s4 ECU when you switch to the s5 turbo

RotaryRocket88

iTrader: (7)

Cut the wire at pin 1R (P/S switch on NA, but knock sensor on turbo ECU). Extend the TPS and BAC wires, and you're done. All the plugs are the same within a series, with the exception of the slot in low impedance vs. high impedance injectors plugs. I used a very sharp exacto-knife to carve the slot wider to fit low imp. injectors into my high imp. plugs.

The NA harness even has plenty of length to be routed exactly where the turbo harness normally went. Looking at mine, you'd never know the difference.

Things to ditch: knock box, twin scroll solenoid, air supply valve (ASV).

The ASV plug on a turbo car is on the engine harness (not the engine management harness), so there's no way to plug it in on an NA car. I removed it and never have any issues with the engine bogging while turning the wheel.

The knock box is optional since most people feel that if your motor knocks at all, it's probably too late anyway. I didn't use one. 91 octane and a rich mixture are my anti-knock features .

FC_fan

iTrader: (2)

ok, thats what I thought on most of that rotaryrocket88. you say that the plugs are the same within a SERIES. if I put those S5 turbo components on, won't the plugs be different since they are different series parts then my harness?

Digi7ech

iTrader: (1)

Do not buy a Jspec motor from anyone other than Japan2La on here.

He's one of the few people I trust when it comes to ID'ing and sending usable motors. He's also reasonably priced.

You DO NOT want to get an S5 motor. It has higher comp rotors and will require lots of stupid work so you can get the S5 ecu to run it.
----------------------------------------------------
Follow Hailers post in that thread. It's golden.

Use S4 electronics. S5 electronics in a simple answer will not work in a S4 car.
-S4 BAC
-S4 AFM
-S4 boost sensor
-S4 TPS
-S4 injectors
-etc...

Yes, use the S4 NA harness. Extending wires is much easier than moving pins all around on the TII harness. I've done both ways multiple times.

I've personally removed ALL emissions wires and solenoids along with twin scroll and knock box.
--------------------------------------------------
Yes, use S5 manifolds and turbo if you can. They are better. Just remember to order the right gaskets from mazdatrix or who ever.

S4 and S5 turbos have different iol return lines to the front cover. Use the one for the ENGINE not turbo. So if you have a S4 engine with S5 turbo. Use the S4 oil return line.

S4 fuel rails are good for later upgrades(parallel lines or AN fittings) because they are threaded ends
S5 primary rail is good because the FPD can't fail as terribly and burn your car down like the S4.

FC_fan

iTrader: (2)

I know I need an S4 motor and just swap out for the S5 turbo components. Didn't notice that link I posted was an S5. wooops.

so what you are saying digi7ech is to use the S5 components but put the S4 sensors and electrics on the S5 stuff???

And wasn't there a fix/mod for the FPD using some kind of banjo bolt from an s4 N/A or something? I think I found a page through the FC FAQ, I'll look for it again.
thanks for all the info guys, this is good stuff.

Digi7ech

iTrader: (1)

yes, you can use a banjo BUT why not use an S5 FPD instead?

I've had 2 S4 FPD's leak on me. I've been using this S5 FPD primary rail for 3 1/2 years now with no leaks.

I tend to collect parts though. I can swap between S4 manifolds and fuels rails when ever I like. I'm running
S4 Atkins block
S5 turbo
S5 manifolds
S5 primary rail
S4 primary rail with semi AN fittings
Aeromotive FPR
Custom rewired engine harness
S4 BAC/TPS/AFM/Boost sensor
etc..


Essentially. The mechanical external parts are of no relation to the Electrical or chassis model(excluding OMP which I would personally recommend to block off and go premix).

The electrical needs to be the same as your series car though.

To simplify though....
Get a S4 longblock and then swap after and sell off the S5 parts to make some money back.
S5 turbo is highly recommended due to it's dual runner wastegate.

------------
Don't forget about drivetrain though.

You'll need a TII tranny and clutch and slave cylinder.
THen it's up to you about going with a TII rearend or using a hybrid driveshaft.

I used my stock 100k NA rearend and it lasted as an NA for about 15K before it became a one wheel wonder. Then It lasted another 60k before I swapped to TII rear end.

dawicka2

You will regret buying an engine from anyone other than japan2la or atkins....arghx is right. Swap is ***** easy. Research a lot and jump into it. Thats what i did with no issues so far with my Na harness to t2 engine swap.

One more time for the record....... no other ******* company other than Atkins or Japan2la.

john ny

FC_fan

iTrader: (2)

you mean sell off the S4 turbo components and just get the S5 ones.

I'm still not quite understanding what you are saying about the electrical. just plug the N/A harness into the S5 turbo components that will be on my S4 block and replace the S5 BAC/TPS/AFM/Boost sensor with the S4 ones? that's right isn't it?

I am doing a full drivetrain swap to a TII drivetrain from tranny back. I am hoping to find a combo deal of an S4 complete TII engine with tranny. hopefully with ecu,sensors too. I will more then likely end up sourcing the driveshaft,pumpkin and half shafts. I may try to find a roller with a tranny and rear end (or just rear end with shaft depending) but I want a good price on it so we'll see.

I'm going to try and sell some of my guitars and amps and maybe even my subaru 2.5rs to fund this project. downgrading to a cheaper subie that gets better gas mileage maybe. I don't need 2 cars with 19mpg or less after all.lol

oh ya, and I actually just purchased a drift e-brake button from Japan2La. thats coincidental that you would bring him up. whats his pricing like as I need it shipped to Vermont, I would imagine shipping would kill me!

FC_fan

iTrader: (2)

I got it on the companies. oh and dawicka2, what is that front bumper in your signature? could you send me a larger image of it? looks interesting. I'm thinking of designing my own front bumper from foam then plaster mold to fiberglass as I am going widebody and a lot of bumpers look less wide then I want. getting a set of 255 front fenders and modifying for a better line. more like the line from the tamon design kit. thanks.

BTW this is my first swap with minimal mechanical skill (brakes, calipers,exhaust, suspension work) so I am researching a hell of a lot before hand but it does seem easy enough if I take my time. I will go slow and it will probably take me 4-5 days just so I can triple check everything. I'm not gonna blow this thing up.

dawicka2

^^^^Thats the way to do it.....take your time. This swap will definately give you skills and confidence. Have all tools and parts going into it, and label everything.

To answer question...My front end started as a gpsport bootleg and i modified it to look like it does now.
Wing is kinda balanced on there for time being. Prob get on it again sunday.

https://www.rx7club.com/showthread.p...debody+scratch

john ny

FC_fan

iTrader: (2)

dude, that is a good idea for that bumper. its like old school meets new cause it is almost like an FD bumper but still retains that FC line. I might actually get an FD front and modify it wider although I think they are a little bit wider then FC's anyway.

more on topic now, I am actually having a few guys from my car club and my brother helping me with this project. my brother is a honda guy though but he knows more then me and he's younger! he has a CRX he is swapping soon as well. its got a body kit already but its getting a bit ricey. trying to keep him from being a total ricer though. another guy is a certified body guy and is technically a certified mechanic as well but never worked in a shop. he knows his **** though and especially his fiberglass fab work but is sadly another honda owner, accord. there are a couple others with general mechanical skill so I think this should go well my new place has a two car garage too so thats cool and useful.

Digi7ech

iTrader: (1)

generally Honda kids are retards and do ghetto work.

Oh, don't sell your back up car. You'll need it.....

It's not as hard as it seems. I did my first swap with no experience at all. The most I had done was change alternators. Now I know almost every bolt of my car.

Just take pics/write/label stuff and you should be fine.

Dropping in tranny+motor at once is much easier than at separate times.

racerlinkfc

i have been told the same thing im going to be using an s5 t2 motor tranny and ecu just using my s4 harness i was told to remove the omp and block it off since the omp is electric i will of course be premixing from here on just get all the s4 stuff you need to do the swap and you should be fine , but of course im sure other members will either agree or disagree, so goodluck and take pics and update us on your ongoing project !

Digi7ech

iTrader: (1)

No, your fucked.

S5 motor has higher comp rotors. A S4 motor ECU won't control it correctly.

You will need to trade for a S4 motor or get a Haltech and tune it in.

dawicka2

No one told you that on this forum......... Who ever did is full of ****. Factor in another 1,000 dollars for the stand alone to run a hopefully good compression engine.

john ny

misterstyx69

iTrader: (142)

So, you are saying that an S5 Keg won't work correctly with an S4 ECU?..

FC_fan

iTrader: (2)

hey, does japan2la have a website or anything that I could check out his pricing on?

also, here is my understanding and double check list for this thread:

buy s4 turbo long block,tranny,ecu, driveshaft,pumpkin,half shafts, full TII or aftermarket cat-back exhaust. then replace the S4 turbo components (i.e. manifolds,turbo, downpipe,etc) to S5 components. Replace the S5 components BAC/TPS/AFM/Boost sensor with S4 sensors. also buy an aftermarket boost gauge deepen the pwr steering/knock sensor(S5) wire on my S4 N/A harness. plug everything in.

anything I forgot? are there any other sensors I need to change?

wvumtnbkr

No!

Buy an S4 TII longblock with all sensors. You can use your NA harness. The only thing you may want to use that is S5 is the turbo and manifold. There are no electronic items on the turbo or manifold. THis is not a must! If you want a little more power under the curve, then get an S5 turbo and manifold.

Basically get the following: (Based on your wants)
S4 TII Longblock
S4 TII tranny
S4 TII Driveshaft
S4 TII rearend and half shafts
S5 Turbo
S5 manifold
S4 TII ECU, TPS (use the NA one), Boost Sensor, and AFM

MINIMUM list of items to get:
S4 TII Longblock (all sensors attached and all fuel injectors in place)
S4 TII tranny
S4 TII Driveshaft (from TII transmission to NA rearend)
S4 TII ECU, TPS (use the NA one), Boost Sensor(TII), and AFM (TII)

DO NOT USE A BANJO BOLT for your PD. Just get an S5 PD.
Get a wideband O2 and boost guage if possible.

Hope this clarifies!

Rob

Digi7ech

iTrader: (1)

I mention S5 turbo because the S4 one IS going to boost creep with any open exhaust.

Boost creep == motor death unless your prepared for it(rtek 1.7+720's will save you till 15psi).

I would even recommend porting the hell out of either turbo wastegate you get.

S4: Can be ported larger than S5's BUT is custom with welded new flapper
S5: widening the runners a bit more and a little back cutting will make you fine for 12-14psi.

I only creep a couple psi over in 5th gear with a ported S5.

dawicka2

no! (well a couple of things)

t2 driveshaft will not work with na rear end. Na and turbo tps are different......you should have no problems with a NEW s4 pd if installed correctly.
make sure your injectors are the correct impedence too. Just cause they're s4 doesnt mean they are right.

Minimum is actually t2 engine na clutch trans dshaft axles and rear.
^^^^What mine is.

john ny