Lets revive an old thread shall we?
Before you flame, I was going to post a new thread, but found this one so I want to add to it.
I am about to buy an s4 turbo II coupe with a **** body and an s5 vert with compression issues.
My plan is to swap the turbo II motor into the vert but was seeking some clarity on the differences.
I'm not worried about weight, mainly I'm interested in the breaks/suspension differences and the wiring differences. It was stated that the vert and turbo II share the same 4 piston brakes, is this true? I have a set of Tein hr coilovers from a coupe, will these work on a vert? Lastly, the wiring between the s4 turbo II harness and the s5 vert harness are different. I am aware of that, but could I adapt the s5 vert harness to work with the s4 motor and ECU and all the sensors? The wiring on the s4 harness is totally hacked together to the point where I'm hoping the car doesn't catch on fire on the drive home so I am trying to avoid using the s4 harness at all costs. The wiring is what concerns me the most because I've never worked with car wiring before and I'm afraid it will be over my head.

Thanks in advance for your insight,

Alex

 

Never noticed your post till now.. Not offended I'm happy to reweigh it the next time I'm somewhere with a scale..
It's a super base model - no options[PS/PM/PW/Sunroof/RearWiper/etc].. Removed A/C, was down to probably 5 or 6gal of gas at the time, I think I had a stock catback and a RB header/presilencer.. Or a stock manifold/single aftermarket cat.

The brake systems are the same save for the booster on the T][ which is bigger.

The suspension will bolt up as far as I know [though RB and Mazda have different springs for the 'vert so that's something to consider]

Here's something to get you started: http://www.rotaryresurrection.com/2n...o_s5_swap.html
You want to retain the S5 wiring harness - look up the NA-Turbo writeup on the forum. You'll want to source an N370 ECU, Pressure Sensor, and AFM. Oh and probably S5 Turbo fuel injectors [or you can adapt the connectors to fit your S4's]...

 

The spring rate is different between the coupe and convertible. RBs coupe springs have a slightly higher rate than the convertible springs.

 

So if the spring rates are different would it be a bad idea to swap in tein hr coilovers? I mean the spring rates in the coilovers are different than the stock spring rates anyways. Would it be harmful to be stiffer?

Also as an alternative for the wiring situation. I have found a few threads I didn't see earlier and it looks like I would be needing more s5 parts than I expected. Would it be possible to replace the entire s5 vert harness with a s4 vert harness and be able to retain my stock s4 ecu injectors omp tps tb ect...? Or would that cause other problems?

Thanks again guys!

 

No, not harmful. But you might need to adjust the coilovers differently for optimal handling.

The problem is that the body/dash/ECU harnesses all interconnect... So you'd have to adapt a few different connectors or swap ALL the harnesses. So it's generally much easier to source the parts.

Not to say it hasn't been done.. Search repin ECU or something like that and it should turn up.

 

these under barcing u guys talk about on the vert can they be mounted on my 88 gxl hartop?

 

Hmmmm, my '86 FC tips the scales @ 2,660 lbs with just over half a tank of gas....its a 5spd, 5 lug (big brakes), has sunroof, manual windows & mirrors, A/C, and FULL INTERIOR + spare tire, jack, lug wrench & jack handle. I weighed it on a truck scale too, w/me in it = 2,820 lbs, which is fairly accurate b'cuz I weigh 155 lbs. (it only added 5 lbs)

 

Forgot, I also have power-steering. (YUCK!!)

 

My reg papers say 1400 kilos for my vert, which would be approx 3090lbs. But how accurate that is... I dont know. I would guess it is about 100lbs lighter than the papers, this is with a 75kg person in (double up for approx lbs, that is 150lbs).

With A/C and power steering removed, but with TII engine, I weighed it at 2950lbs with me in (weighing in at 170lbs). The weight is well.. 0.1 second more from 0-60 with same engine and same spec except hard/soft top. And as people say, they are almost equal in rigidity.

However, the parts that are added for more rigidity, are all these welded? Or are some of these bolted in place? Thinking, what if these were swapped for some aluminum or titanium parts? If these parts add, lets say 200lbs of the 300lbs, alu or titanium would probably get that down to half. And the rigidity wouldnt suffer too much, add some RB uprated sway bars, a strut bar in front (rear would be hard, but is also VERY rigid due to having a separate trunk), maybe x-member bars under to stiffen the driveshaft tunnel.

Would still come out way lighter than it was, and just as rigid, if not more?

 

Not easily. There are a couple extra mounting points added to the vert chassis to attach the extra subframe.

Something else I didn't see mentioned, the entire floor and rockers on a vert are made from steel that is twice as thick as the coupe's. There is also extra layers of metal in the door posts that reach forward to the strut tower area.

 

That is correct. I didnt know that years ago when I got fender braces for my 88 hatch(which I ended up selling) and tried to put them on my vert.

The K-member COULD be adapted to the hatch backs, but would require welding.

The floor pans and seat mounting are slightly different. On the front of hatch backs there is a brace running horizontally across the pan that the seat bolts to, and two tabs(one per side) on the rear for the seat to bolt to. On the verts there is a horizonal brace for both the front and rear seat mounts.

 

verts also have a really sweet aluminum hood.

If you're worried about performance i'd remove the top motors. I think the top works better in manual mode anyway. Also the seats are very heavy, if you're going to drift if you'll want something that'll hold you in place better anyway.

My last vert was 3250 with a half a tank of gas, that was a turbo vert with NO a/c.
MY current vert should weigh even more

 

my last FC is an 87 GXL, totally stock, iron hood, iron spare, ABS, 2880lbs with a full tank.

the new FC is an S5 vert, also totally stock, 3020lbs.

my last T2 was no ac/no ps and with the 20B it was 2860, and the 13BT was 2820.

all with a full tank on the same scale.

the 83 limited was 2330 in showroom trim and the 79 was 2410....

 

has anyone ever tried fitting vert doors to a coupe car? just wondering for fun

 

I'd like to apologize, I don't know what the heck I was thinking. Here is an 86 manual with a curb weight of 2625 lbs. I was off by 75 lbs., which means the truck scale weighing Derekcat may not have been too far off considering its calibration for much more massive loads.