Eric's 4KTQ project part II: the AAN motor

[itjstagame]

Hey, just wanted to say thank you for the read. As a procrastinating, over-booked lurker it gives me hope that my sad 4kq project that has been sitting uncovered in woods for 5 years, and recently noticed has been leaking and is molding.... could somehow, someday be a nice, respectable car.

I hate to hear about your rust, somehow mine still has none, there is one place about a quarter sized with surface rust starting where the factory undercoat got scraped off by a previous owner, but that factory undercoat seems pretty serious and has been good to me.

Also, I've been out of the loop for a while so maybe other builds have been doing this, but taking the engine out through the bottom looked very neat, I had only seen the cutting the front off method about 3 years ago when I was acquiring stuff for the build. I'm guessing you just dropped the subframe members from the frame itself and then removed them from the engine later? Was a tranny jack enough to help the engine come out or did you need to use the lift to set it down coming out as well?

Lastly, your indash display looks amazing, as a software engineer I'm not phased by the coding just have been slowly reading up about electrical signals and components and how to work them all. I even bought a pic programmer but never did get to play with it much with 2 kids. If you don't mind sharing when completed I'm sure a lot of people would be interested and I'm sure there are lots of knowledgeable people that could help maintain it. I had always intended to play with megaview and the ilk but it just didn't seem as common of a pursuit and megasquirt itself, harder to find good right ups without knowing your way around fully.

[elaw]

Oh man... if you're in NY and have a more or less rust-free car, get that thing covered up! That's quite a rare item in these parts.

Re pulling the engine... it's been a while and I have a crummy memory so I don't remember exactly what I did! Keep in mind I pulled the engine + trans together - separating them in the car is not a lot of fun plus I was replacing both anyway. Also a very important issue: I had good luck on my side! When you go to remove the bolts holding the subframe to the car, one of two things will happen: either they'll screw out, or the nuts inside the frame will spin and prevent removing the bolts - usually after you've unscrewed the bolts 1/2 or maybe 1 turn so they're a bit loose. If the bolts screw out, great, you get to continue the job. If even 1 nut spins, congratulations you've got a nightmare! With the bolt somewhat loose it's a bad idea to drive the car, and of course the spinning nut prevents removing the subframe so now you've got a difficult and mandatory fix on your hands. Luckily I got my subframe off with no problems! :-)

Anyhow back to your question what I *think* I did was 1) remove the bolts holding the transmission brackets to the mounts and the nuts holding the engine brackets to their mounts, 2) support the engine/trans with a hoist, 3) remove the subframe, 4) unbolt the engine mounts from the car and remove them and 5) lower the engine/trans to the ground. Plus of course little stuff like disconnecting the driveshafts, shift linkage, wiring, and every other thing connected to the engine, tranny, and subframe! But having done it, I still think it was the easiest option, and I didn't have to cut up the car.

On the display thingy, now that the 4K is getting replaced with the 80, I think the scope of the project may shift again. I'm toying with the idea of removing the 3 gauges from the console and installing the computer there with a much larger display. The alternative is to use it to replace the auto-check display in the instrument cluster, which wouldn't be too hard, I could just code the auto-check functions into the computer. It's a tough decision - a small display very close to your line of sight while driving, or a much larger display in a location that's harder to see.

The other cool thing I might try to do is have the computer linearize the gas gauge. Imagine... when the gauge says 3/4, the tank is actually 3/4 full, and when it says 1/4, it's actually 1/4 full!

[reckless1]

I like this thread, and you have a good sence of humor.

[elaw]

Hey thanks!

With this kind of project, one needs a good sense of humor because otherwise you're likely to end up institutionalized...

[90mtl]

Hey Eric, have you received that TB roller?

[elaw]

Yes I did receive it... a couple of days ago. Sorry, I should have let you know!

[elaw]

Okay we're not quite to the end of the road... I just made 3 very cool upgrades to the Megasquirt system.

The first two there aren't any photos for, but they're add-on boards developed by one of the developers of the MS3 software. One is a real-time clock which sounds pretty useless until you remember the MS3 features SD card datalogging. So with the RTC, the datalogs can now be timestamped with the correct date and time - a great feature when you want to compare logs with dated tune files.

Upgrade #2 is knock sensing! The same guy has produced a neat little board that interfaces to up to 2 knock sensors. There is still a hiccup or two in the software but generally the thing works like a champ.

And here's thing #3 for which I do have a photo:

...yes I know it may not be obvious but that's a kludge I made myself. :tard: It's a Bluetooth interface! For the whopping total of about $18.00 plus some cheap parts I had lying around, I can now talk to the MS from my laptop via wireless instead of a cable. Other than neatening up the passenger's footwell, it's really nice when I want to tweak stuff under the hood and have the computer right there to see (or change) what's going on.

[reckless1]

where do I get the knock sensor interface?

[reckless1]

by the way that's cool you made that your self.

[elaw]

where do I get the knock sensor interface?

Well... at the moment you can't! :(

It's made by James Murray, one of the guys that develops the MS3 code. The thread on the MS forums is here: http://www.msextra.com/forums/viewtopic ... 25&t=43766.

Right now he considers it in "beta testing" and he only had a limited number made. But other than one hiccup which I think is in the code and not the board (every now and then when you start the engine the knock reading is about 2x normal), they have been working well for people. So hopefully he'll be making more soon.

[reckless1]

cool deal. How does it work? some sort of amp for the pezo signal that converts to a 0-5 volt?

[elaw]

It actually uses a pretty sophisticated chip made by TI that's made specifically for knock-sensing applications. Datasheet is here if you're interested: http://www.ti.com/lit/ds/symlink/tpic8101.pdf

The board itself is very small (maybe 1.5" by 0.5") and solders onto the CPU board, and communicates digitally with the processor. It has a built in 10-bit A-to-D so it can measure knock level to 0.1% accuracy. That's probably more than necessary, but better to have more accuracy than not enough!

[reckless1]

definetely, I know any d to a converta takes some time . Do you know what the proccessing time is? I'm sure it's not a big deal but I'm kinda getting into this stuff.

[reckless1]

sorry a to d

[reckless1]

very cool . So it will store info and change timing map? I haven't read the whole thing yet but I will. Thanks.

[elaw]

definetely, I know any d to a converta takes some time . Do you know what the proccessing time is? I'm sure it's not a big deal but I'm kinda getting into this stuff.

I don't specifically, the datasheet may say.

What it does is take the amplified and rectified output from the sensor and feed it into an integrator that's gated by a "knock window" signal that controls when the chip "listens" for knock. At the end of the window the integrator's value is sampled and sent on to the processor. So the sampling only happens once per spark event.

Right now the code is relatively crude - it doesn't do per-cylinder retard and doesn't store values. But it's still a lot better than nothing. Actually I don't know if I'd want it to actually modify the timing table as you could end up with a circumstance like a tank of bad gas that would cause it to retard timing all over the table, then when you put better gas in the car it would never go back. My preference would be to have a good base map and have it retard timing only when it actually senses knock.

But some more advanced features like per-cylinder retard and boost control via knock sensing would definitely be welcome.

[reckless1]

This is basically audio hardware I think. I bet if you were into digital recording you could come up with some stuff.

[40v4kq]

Nice job with the home-brew style AAN swap. This thread makes for a good read. Sad to see a 4kq that runs and drives is going to have it's guts ripped out. I hope it's parts get used to save others, and at least it's guts will get to live on. Make sure to clean the snot out of your B3 once you have the motor and trans out of it, and clean all the parts before you install them. It makes working so much more enjoyable with a clean engine bay. Best of luck to you, and I'll be keeping my eye on this one.

[elaw]

Demolition begins in 3... 2... 1... :(

Well it looks like today's the day. It's 70 degrees out and is forecast to be warm all week, so I'm going to begin tearing apart The Red Bomber to make room for... what should we call the 80? The marshmallow?

For those of you that have expressed an interest in parts, I'm not as young as I used to be and this is not going to be a 1- or 2-day project. Maybe I'll have it mostly apart by the end of this week, maybe not. But fear not, I'll be in touch!

[elaw]

Well the ol' girl is well on her way to becoming a pile of parts. :(

Thought I'd toss up this amusing image though:

That is the ENTIRE Megasquirt harness - intact!

One of my nightmares with moving the AAN to the 80 was that I'd have to cut the MS harness and reassemble it in the other car. Turns out I didn't have to do that - those DB-37 connectors that everyone hates on the Megasquirt fit through the hole in the firewall (sideways) so I was able to pull the harness without taking the cutters to it. Me = very happy camper!

[savagerocco]

This is a perfect time to rebuild and shrink wrap the harness..... Does that include your msx harness? Doesn't look like it.

[elaw]

But then I wouldn't be able to change stuff! Seriously, the way I'm constantly reconfiguring this setup, I would never want the harness covered up so I couldn't modify it.

The fun part now is figuring out where the MS and its wiring will go in the new car. I was spoiled with the huge open space under the 4K's dash due to the PO removing the A/C... no such luck with the 80.

[savagerocco]

I had plenty of room under the dash in the passenger footwell. I'm guessing that your harness went thru the firewall on the passenger side, so that would be a good spot. I still have my ac, even working, but you are going to have some fun with the AAN belt and accessory setup, the compressor is on the opposite side and you'll have to make some lines if you want ac.

[elaw]

Oh you don't know the half of it! Not only is my A/C compressor going to be on the wrong side, it's going to be from the wrong brand of car!

It turns out that 2nd-generation Saab 900 A/C compressors are not only about 1.5" shorter than the AAN compressor (leaving more room in front of the radiator) but they're dirt cheap used. I got one that appears to be in good shape for $40 shipped on ebay! Of course the mounting locations are all different, but I think I can make up an adapter plate to connect the two.

[elaw]

I had plenty of room under the dash in the passenger footwell.

This is with MS3, right? What exactly did you attach it to (and does it matter that the CQ has auto climate control and mine is manual)?

One semi-obvious place I saw was the bottom of the HVAC case, but I'm going to guess it would end up right below the evaporator where there's condensate present so probably not the best place to be drilling holes. The MS box can get a little warm at times but I don't think water-cooling is the answer!

I hate the fact the MS3 case is so tall - if they could have made it 3/4" shorter it would fit in the space of most stock ECUs. But nooooo...