Gen 2.5 3.8 Swap

[Salonika]

So just to double check myself, you couldn't run the FBW throttle body from the 3.8 with the 3.5 ECU correct? Wouldn't the 3.5 need a sig from a TPS? Or does the FBW throttle setup still have a TPS with the same harness as the 3.5, that would connect up?

 

[Jeff V.]

Good to know, so what makes these ECU's reflashable vs the previous Gens without the EEPROM memory chip?

The flash memory is built into the main CPU. The big MH7202F chip on the 98-01ish ECUs. Later chips had different part numbers and different programming languages, but all Mitsus since roughly 1998 have had CPUs with integrated flash.

so what is the probability that the stock ECU can run the MIVEC Like ChargerX3 is going to attempt?

It's too early to say at this point. The MIVEC solenoids need some special circuitry to run. They're not a simple on/off switch. There's some good threads about it on Club4G.org. We don't know yet if we can re-purpose or modify an existing circuit in the 98-00 ECU to work the way we need it to.

So just to double check myself, you couldn't run the FBW throttle body from the 3.8 with the 3.5 ECU correct? Wouldn't the 3.5 need a sig from a TPS? Or does the FBW throttle setup still have a TPS with the same harness as the 3.5, that would connect up?

Correct. You can't use a DBW throttle without a matching ECU. The ECU has a whole bunch of motor control and monitoring circuitry for the throttle butterfly. It's actually got a whole separate CPU just to keep an eye on the throttle to prevent unintended acceleration. Not to make light of the injuries and deaths involved, but the Toyota fiasco from a few years ago was a very useful learning opportunity when it came to electronic throttles.

There's a few options for swapping ECUs, but it's a pain due to wiring differences and dealing with an automatic transmission. Mine and Charger's trucks have manual transmissions, and our wiring harnesses are super primitive, so we've got a lot of flexibility with what we're doing.

Once we have something that's actually proven to work, we'll talk about it a lot more.

 

[Jeff V.]

Where did you get new fuel maps for the 98 ecu, Jeff? Let alone any maps lol?!

Well, I didn't get new ones. I just dumped the existing maps with one of these: http://www.tactrix.com/index.php?op...s&flypage=flypage.tpl&product_id=17&Itemid=53

After that it's just a matter of building what's called a definition or XML file. It's like a map of the ECUs data that shows where all the maps and interesting values are located. It's not trivial, but I know how to do it. I did a lot of the early maps for the 3000GT. Some friends built on that work and took the project a lot further after I lost interest in the car.

Once you've got a definition file, you can start changing things and flashing the changes back into the ECU.

 

[Toasty]

Really digging this thread, I had given up on the idea of a MIVEC swap for my truck and started heading down the 1UZ path. I'd much rather have a Mitsu motor and a V6 at that, for me the electrical side is the difficult end of a swap. Best of luck to you guys. I really hate having a bunch of extra wires and half of them don't do anything, for me swaps have always meant the addition of an engine harness. That's fine for something stripped down like a carbureted Montero but with my '99 I really don't want the extra pain in the *** of a separate engine harness like I've done on past rigs and I'd have to do with a 1UZ.

 

[Jeff V.]

I don't really keep up on Toyota stuff. What's the benefit of the 1UZ-FE swap? I know a little about that engine, but I don't see why it's more attractive than say, an LS swap. The GM aftermarket is miles deep.

 

[Swank Force One]

I don't really keep up on Toyota stuff. What's the benefit of the 1UZ-FE swap? I know a little about that engine, but I don't see why it's more attractive than say, an LS swap. The GM aftermarket is miles deep.

Lego-like swapping allows attachment to stock trans. Much less work than LSX, ridiculously reliable motor, pretty good power.

 

[ChargerX3]

Really digging this thread, I had given up on the idea of a MIVEC swap for my truck and started heading down the 1UZ path. I'd much rather have a Mitsu motor and a V6 at that, for me the electrical side is the difficult end of a swap. Best of luck to you guys. I really hate having a bunch of extra wires and half of them don't do anything, for me swaps have always meant the addition of an engine harness. That's fine for something stripped down like a carbureted Montero but with my '99 I really don't want the extra pain in the *** of a separate engine harness like I've done on past rigs and I'd have to do with a 1UZ.

Im going to go out on a limb and tell you that a 6g75 swap with your full size Montero will be quite a bit easier than my max. I'm actually looking for a 98-99 to turn into a crawling beast 75 swap. Just haven't found a good example yet.

 

[Jeff V.]

Lego-like swapping allows attachment to stock trans. Much less work than LSX, ridiculously reliable motor, pretty good power.

It's because of the Aisin trans, isn't it? You can swap the Toyota bell housing onto the Montero trans and then it's just a matter of fabricating mounts, exhaust and a wiring harness, right? If that's the case, it's about the same amount of work as doing a 3.8. Power potential is probably better though.

I'm going to have to do some reading about that. I don't have any interest in doing it, but I'm always excited to see how other people tackle projects like this.

 

[Toasty]

Im going to go out on a limb and tell you that a 6g75 swap with your full size Montero will be quite a bit easier than my max. I'm actually looking for a 98-99 to turn into a crawling beast 75 swap. Just haven't found a good example yet.

The Mighty Max IFS is a little tighter to the engine than in a Montero for sure, the hood is lower and they are quite a bit narrower (Especially on the Gen 1). I had a 3VZE-FE in my '82 Mighty Max, very tight fit.

It's because of the Aisin trans, isn't it? You can swap the Toyota bell housing onto the Montero trans and then it's just a matter of fabricating mounts, exhaust and a wiring harness, right? If that's the case, it's about the same amount of work as doing a 3.8. Power potential is probably better though.

I'm going to have to do some reading about that. I don't have any interest in doing it, but I'm always excited to see how other people tackle projects like this.

That sums it up, the only difference is that the 1UZ has a massive amount of support comparatively. As in I can order a brand new standalone harness for it based on the exact ECU custom for my application. They don't make much more power than the Mitsu V6, so the only advantage is availability and support.

 

[ChargerX3]

I meant electronic wise. There would be very little wiring for you to mess with.

 

[Toasty]

I meant electronic wise. There would be very little wiring for you to mess with.

Ah, I thought you meant space wise. My 3.5 just passed 60k miles so if I swap it out it will be in favor of power, I wouldn't hesitate to swap a 3.8 non MIVEC if I needed an engine. For my truck 10 horsepower isn't enough to justify buying a normal 3.8 to install. Stoked to see what you come up with for the MIVEC though, are you running the variable intake as well? The pic looks like the normal intake?

 

[ChargerX3]

No variable intake. Eclipse motors didn't come with one. I would like to get one eventually but they have been difficult to source.

 

[Toasty]

The Gen 3 3.8 has the variable intake, they are kind of tall though.

 

[Jeff V.]

I bought a 3.8 intake for my 3.5. Figured I'd make it all fit now in case I ever decide to go full 3.8. I'll probably have to take a chunk out of my hood, but that's just an excuse to practice my welding. My truck is going to look like an extra from Mad Max, but it should go like hell.

 

[Toasty]

Beautiful truck by the way. Short bed v6 trucks were the coolest, that's the only Mitsu truck I haven't owned but have always wanted. Seems like the V6 trucks were a little taller than the others, did they mount the body a little higher like they did with the Gen 2 when they went to the electronic transmission? Is yours a 5 speed?





My Gen 1 pickup with the 3VZE shoehorned in, the Toy motor is quite a bit taller than the Mitsu V6. The Mitsubishi V6 is wider though, I Just barely squeezed in past the master cylinder and booster luckily it was remoter reservoir too. I imagine your Gen 2 being equipped with a V6 from the factory has more wiggle room for the larger cylinder heads?