Hybrid motor questions

[speezly]

Bear with me, as I may ramble a bit...

I have a 255 block that came with 22t heads and manifold attached to it. From what I've gathered, the compression ratio would be too high to run reliably on a 22t Ecu. I went out and found some z20 heads that should work with the 255 block, but I'm still unclear as to what I would need to make this work. If I source an old 20g manifold, can I use the 22t harness and sensors to run a setup like this with a td04? Would I need different EM since it would be a quad cam setup? Am I stupid for even trying to figure out how to make any of this work and just go with a Wrx top end and Ecu and run the heads non-avcs? What are the benefits of the tgv setup I see on most wrxs compared to running an older style manifold with no tgv? Sorry to keep rambling, but I am just perplexed as to what direction to go in.

[mike-tracy]

The ej22t ecu and ej20g ecus and robtuned ecus will run both SOHC and DOHC engines without issue. You can't get around a too high CR with any of those however. Rob won't support an engine with >8.5:1 CR on his tune either.

I'm not familiar with z20 heads, a quick google search says that's a nissan inline head?

Consider your goals and how much you want to spend on the car. The later WRX and STI engines have a reflashable ECU, but the cost and difficulty installing those from a wiring perspective is going to be north (and likely way, way north) of $4k. Each time you change a component, such as exhaust or turbo, or (in CJ's case) fix a vacuum leak, they need to be retuned. Our "stupid" ecu's are a lot more flexible with changes to the system.

I decided I wanted a tunable ecu and modern engine myself, but I didn't want to drop the money into my SS, so I went with a 2000 RS. Still working on it, but the end result should be pretty good. Built EJ22T short block with Ej207 heads. A STI 6 speed. Twin scroll turbo. tons of other small things that really add up money wise. You DON'T want to know what I have in to it.

[Legacy777]

You DON'T want to know what I have in to it.

I don't think any of us want to know how much money we have dumped into our cars

[speezly]

The z20 heads are jdm dual avcs heads. And what is all required to update to a modern Ecu? I've heard from some that I can run the heads without avcs and it should work, but this is all so new to me. I should have just bought a jdm 20g and been done with it. I've got a 22t block fresh from the machine shop, just need to buy new pistons and rods, but while I'm working on that I figured I would try to use the other motor I have in my garage for the time being.

[speezly]

[mike-tracy]

http://forums.nasioc.com/forums/showthr ... =z20+heads

^similar to those heads, right? DOHC and dual avcs, cool. With an older engine you could have the original and donor car's wiring harnesses merged. With that engine, it uses Canbus and ignition immobilizers, meaning you will likely never be able to get it running on it's own ecu, unless you had the donor did a 100% wiring swap including the dash, and all electronics (abs, tcs, cruise, etc. They are all networked together under the canbus communications protocol).

Best bet would be to get the complete intake manifold with it's wiring harness, and wire up a standalone powerful enough to control a dual avcs engine. You'll save a lot of headache compared to everything I've read about swapping that generation motor using it's ecu.

[mike-tracy]

From personal experience of a friend's car, it's not worth bothering without avcs enabled. The engine runs almost like it's in limp mode till you are in boost. When he got it working, the car had power everywhere. AVCS is a really, really cool tech.

I agree that getting an ej20g heads and intake, or ej20k heads and an ej20g intake would give you the best bang for the buck. Runs off the stock SS electronics just fine. I ran that setup (full ej20g) with a td04, SS pink injectors, stock ecu and a top mount for a little while.

[cj91legss]

Each time you change a component, such as exhaust or turbo, or (in CJ's case) fix a vacuum leak, they need to be retuned. Our "stupid" ecu's are a lot more flexible with changes to the system.

Why ya gotta put me on blast bruh.....?

[speezly]

I was told that a jdm legacy Ecu would work and I could use an 05 lgt engine harness and run two extra wires for the exhaust avcs. I have a really good tuner here in VA(all aspects Motorsports) but I would like to get as much done on my own before paying them 70/hour to troubleshoot

[mike-tracy]

Sure, anything's possible. I recommend emailing Iwire about the feasibility of swapping a canbus engine and ecu though.

[Alphius]

You can use an 05 Legacy GT harness and add the exhaust AVCS wires and run a JDM Legacy ECU. The challenge is the immobilizer. You need to add the immobilizer, key cylinder and key from the US GT, then desolder the immobilizer chip from the US and JDM ECUs and solder the US immobilizer chip into the JDM ECU. Once you have all that taken care of, you can do a complete wiring merge so the JDM ECU and 05 harness are controlling the new engine.

The problem with running AVCS cams without the associated controls is that the cams default to full retarded timing. Mike, that's why your buddy's car was gutless. Non-AVCS cam gears with plugs in the cams restores proper cam timing and power if you can't control the AVCS.

I'd do what Mike suggests and run a 20g top end with a RobTune. That'll be a solid setup, and much cheaper and easier than the AVCS alternative you're talking about.

[Alphius]

Each time you change a component, such as exhaust or turbo, or (in CJ's case) fix a vacuum leak, they need to be retuned. Our "stupid" ecu's are a lot more flexible with changes to the system.

Why ya gotta put me on blast bruh.....?

The older ECUs may be more flexible as far as not breaking into a million pieces with small changes, but the same applies: you need tuning to get the most out of any particular setup. The problem is you can't tune the factory ECUs, so you're stuck running a setup that's fairly close to the available ECU options.