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'99 2.5rs
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Discussion Starter #42
Yep, I got 23.5mpg around town, 25.5 on the highway. Those aren't much lower than I got with the stock engine.
 

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2001 Impreza 2.5RS
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321 Posts
holy crap this is an awesome write up/journal my friend! Six Star Motorsports is going to go for an EZ30D turbo GC swap and i just sent this thread over to Dewey just in case it has any use for him. i will be following in their's and your footsteps Dyne. awesome job! teach yourself how to TIG weld? talk about determined, thats amazing. your a gifted dude, you dont need MED school =P lol jk, good luck w/school too!
 

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1996 Subaru Impreza LX, Maroon
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I have often times wondered why no one uses the Arduino to solve problems like the ones you solved with it. Great work.
 

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IMPRESSIVE, and I agree with another poster, definitely sounds like a porsche (at least it sounds like my boxster)
 

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Hey, it's nice to see another DIY effort running on the stock ECU. I posted this on NASIOC but clearly all the talent is over here on RS25.

The major difference between our approach appears to be that I stopped merging my harness at the heater core and you carried all the way through the TCM. Maybe yours was the better approach.

Funny, I had a similar idea about the tachometer and you've already proved it to work. Great job. Maybe I can emulate my missing TCM with the same hardware. Your headers and intake deserve a lot of credit too.

A gallery chronicling most of my EZ30D-->98RS efforts here:
https://picasaweb.google.com/lbartik/H6Swap?feat=directlink

Did a wrx 5spd at the same time. Car was 4EAT.

I have pretty good schematic worked up for swapping into the earlier cars. Some of the missing info came from the 02WRX-into-98RS swap guide here at RS25.com.

It's in, it runs, it leaks oil. (That's what they do I'm told.)
It has an exedy 3 puck and fidanza Al flywheel. Yes, it dies at every stoplight and there's no such thing as slipping the clutch.

Biggest problems:
ABS dead since it was A/T before (unsuccessfully tried grounding the A/T-ABS link wire).

CELs
P1596 Automatic Transmission Diagnosis Input Signal Circuit High
P1698 Engine Torque Control Cut Signal Circuit Low Input

I think the car needs a good intake and a tune. Looks like the openECU project made some headway in the last few years. Anybody have experience?

It's running a single-outlet WRX catback, no cats, OBX headers. As it sits, it runs head-to-head with a stock 02 WRX wagon. Not enough (yet) to justify the complexity of the swap to me.

A/C - haven't even got there yet.
 

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92 SVX Pearl White/Black
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182 Posts
ABS is useless with the extra weight anyways. Better to delete and learn to control the footing.
I agree, though the new, as in less then 3 years old traction control systems can be very nice, and of course they all rely on the wheel speed sensor and abs system.

I drove an 02 bmw 330 that had a pretty damn good traction control system, loose gravel road sharp turn at way over a typical safe speed because that system kept it so stable.
 

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ABS is useless with the extra weight anyways. Better to delete and learn to control the footing.
I Beg to differ. While your manly supposition is humorous, I must disagree and ask for further explanation.

ABS delete on my winter car? Threshold brake on snow/ice better than ANY ABS? Hah. Weight distribution? The engine weighs <100lbs more, about the same as an average 12yr old kid. The car can hold 4-5 adults, 15.9gal gas and more in the trunk.

Am I missing something?
 

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92 SVX Pearl White/Black
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182 Posts
If you need to make panic stops on snow/ice and you can't do it without abs you are probably going too fast, lol
That being said I grew up in North Dakota I am very familiar with crap roads, winter and summer, the cars I grew up driving where all rear wheel V8's without abs basic 70's 80's cars stopping was never a problem, starting off sometimes was.

As far as what he was saying about weight the abs pump, control box, and valves all have weight, and they are all up front granted its not like your going to make much difference but removing that will give you a slightly better front to rear weight bias.
 

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'99 2.5rs
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195 Posts
Discussion Starter #53 (Edited)
More Awesome
Awesome! What'd you use for a radiator? I used the stock EZ30D rad, trimmed the hoses, and jammed them in.

Emulating the TCM diagnostic signal to the ECU might be tricky, I have no idea what kind of waveform it is and don't know how you'd determine it without a TCM and some logic analyzing voodoo.

The 3rd wire on the alternator goes directly to the ECU. I don't know if it's important; I just swapped the connectors on the 2.5RS's front harness and ran the wire through the firewall to the ECU.

I think I have the A/C stuff planned out so it'll work, but I have to tear out the dash to fix the wiring. The only thing I'm worried about is that, from the wiring diagrams, the 2.5RS A/C compressor appears to have a thermal overload switch, while the EZ30D compressor (which I'm using) has a rheostat.

As for the stalling at stop - do you have the ECU wired to be in gear or neutral? Mine would stall when it was wired to be in neutral, and went away when it was wired to be in gear. I don't know if that'll help if you don't have a TCM.


edit: Oh, regarding this swap vs a wrx swap: my car is much more fun to drive than my wife's '03 wrx wagon. The extra torque whenever you want is great.
 

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eBay aluminum WRX rad, hacked up the top tank to match rough dimensions of H6 inlets (dimensions from a parts catalog before I had the engine in). I did it opposite (L&R) trying to avoid interference with the filler cap. LH worked, RH ended up without enough offset to use ANY normal hose. Total mess. No expansion tank installed yet.

The diagnostic signal is probably a TTL SCI, I bet there's no handshaking or anything. Just a heartbeat or simple pulse train. Need a scope and some more intelligence to prove it.

My ALT's working well with only 2 wires. I just measured the impedance to the case through the pins on the old and new alternator to match pinouts.

So the A/C compressor has a different sensor/switch on it? What else is vastly different between the H6 and RS A/C systems? One of the two cars had a shielded wire to the compressor clutch if I remember right. Seemed out of place. I'm still stuck on the idea of keeping my RS compressor and lines by swapping the clutches. What is the ECUs job in the A/C system?

You're right, I don't have a TCM and maybe that's exacerbating the stalling or forcing it into limp mode. It' s the one thing that I left behind in the donor car. Since I bisected all wiring at the anteroposterior line, I never really planned to integrate it. I saved my 2.5RS tranny module, maybe it can fake out the H6 ECU and ABS motor, as ridiculous as it sounds.
 

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2000 impreza RS
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308 Posts
Dyne, remember those seat cushions you sold me, like 2-3 years ago? (Least I am pretty sure they were yours...). Well, they are finally going in next week :lol:
 

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'99 2.5rs
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195 Posts
Discussion Starter #56
Dyne, remember those seat cushions you sold me, like 2-3 years ago? (Least I am pretty sure they were yours...). Well, they are finally going in next week :lol:
Ha! I was wondering what ever happened with those.

So the A/C compressor has a different sensor/switch on it? What else is vastly different between the H6 and RS A/C systems? One of the two cars had a shielded wire to the compressor clutch if I remember right. Seemed out of place. I'm still stuck on the idea of keeping my RS compressor and lines by swapping the clutches. What is the ECUs job in the A/C system?
Based on the wiring diagrams, I think the EZ30D compressor has a rheostat and the 2.5RS's has a basic on/off switch. IIRC, in both cars the ECU monitors the thermal overload switch/rheostat and cuts the AC if there's a problem. I had originally planned on swapping the clutch/pulley and keeping the 2.5rs compressor, but the 2.5rs line leading back to the cabin hits the intake manifold and I'm not sure if you can simply swap the line.
 

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92 SVX Pearl White/Black
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I dont see why you can not swap the line, assuming you can adapt the ends to mate up and seal correctly.

The line should just be a path for the flow if there isnt any switches in it.
 

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1999 OBS, 1991 MR2
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Just subscribed to this thread. You have managed to work around almost all the things I've considered drawbacks to this swap (power steering, radiator support, lack of hood latch, etc...) except for the a/c. I'm am curious as to how you will get this working. Great job and major props for taking the time to do things right.
 
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