My ongoing struggle - 1977 Porsche 924 w/megasquirt

Well, the reason I ended up on GRM in the first place was because of my buddy Turboswede. I came along him and many others from the 924board.org forums when I purchased my first project, a 1977 Porsche 924. I was learning cars a lot more back then, very new and steep learning curve, and the car taught me a lot.

I figured I'd share this since it's the car that really got me hooked and started me on my auto adventures.

The car started as intentions to restore, but got vandalized, the motor got ruined and I ended up rebuilding it. I decided to say "screw it" and gutted it out and decided to go with the intentions of building it as a trackday car.

I figured, "Well, since I'm rebuilding the motor, and since the CIS system is ancient... I may as well just go megasquirt." So I did.

The car was a mess when I got it, it sat in the valley for 10 years. Looking back, I'm actually amazed that I got it to start and run for a little while.

It was a sad story. I bought it from the original owner. The car had sat in this same place in the valley. The husband bought the car for the wife. He passed away, she parked the car on the property where it happened, and she never drove the car again. Years later she met a new guy and decided it was time to let the car go. I wanted a project, she wanted it gone. We put it on a trailer and then I had no idea what I was getting myself into. (I guess that's why a project is an adventure eh?)

Some pics of the car when I first got it (a sight for sore eyes):

I cleaned it up a little and replaced the core parts it needed to run so I could see if it was worth saving. Went through the throttle body, cleaned up the metering plate, did a tune up... surprisingly, it ran. For a while.

First gas station visit in over 10 years.

Then... It got hit by a drunk driver.

Then it got fixed.

Then eventually, I moved. In that process, it got vandalized.

I debated doing anything at all with it for a while, went back and forth over it. I eventually said, "Enough is enough. I won't let it get the best of me, I'm just going to build this car the way I want it." and said goodbye to attempting to restore it.

I began the process of gutting it out.

The interior eventually finally got gutted, and I started making things out of CF. Gas tank cover, dash, pillars, etc. It was a steep learning curve. My first attempt (on the right) was E36 M3ty. After a while I got better (left). The top has drain tubes that are exposed, so I wanted something to cover them up with, and it was much lighter and easier to protect them.

Since the dash was no longer stock, and a much smaller version, I started using my arduino kit to work on making a little prototype for basic temps with some standard thermistors (demo below, not actual thermistor values) - I wanted to have something near the megasquirt sensors to test and be able to verify they stay accurate.

last thermistor active in this photo

I finally started rebuilding the engine. When I took the head to the machine shop, it was bad news. The head was completely warped with no hope of fixing it unless I wanted to spend a ton of money on it. The cam was ground down from running dry.

A donor car came along through a friend of my father's, who used to work with him. His son had one and said as long as the car would go to good use as a parts car it was all mine. So we parted it out, and turned two cars into one good car. The bad news was, his car had a blown head gasket too. It was a mess. A complete mess. I once again was starting to feel fed up. Either way... it was a better candidate than my motor.

I wanted to keep the original engine as much as possible. So I put my block together with the donor car's head. I took it to the local machine shop, we cleaned the E36 M3 out of everything and rebuild it from top to bottom. I tracked down a set of Euro pistons since the stock compression was something like 8:1 and euro was 9.3:1. King bearings, ARP hardware for the rods and head. Modern materials for the guides and fresh gaskets all around. (yes, I'm aware 2 of the bearings are upside down in this pic, it didn't go together that way, I was just happy to get new parts)

Finally, after a lot of reading and careful assembly, a whole motor.

I told my dad, "Hey, I got my crappy Porsche motor finished before you finished your camaro. Wanna come help me put it in the car?" and he came right over and helped me put it in. We don't share too much in common, but we both love cars.

During this process I had started building megasquirt components for it. I wanted to do something a little bit different though since most people who had done megasquirt on these cars had generally just got rid of CIS and kept the stock intake manifold and throttle body. I really wanted to go with ITBs. A friend of mine owns a composites shop, so getting CF was easy. I didn't feel confident making a set of runners though, so I gave him some gaskets to play with, my warped head, a set of GSXR 1000 throttle bodies I bought, he dabbled in cad for a while and came up with this for me.

See ya, heavy, giant, heavy CIS system.

I decided that the most efficient way for me to do it with readily accessible parts would be to go for some common fuel system. One day I visited a friend of mine who owns a honda repair shop. He had a giant bin full of sorted injectors and rails. I brought my old head in and started matching up. Within a few minutes, we found a rail that fit fairly well from a mid 90s accord. He had a set of injectors to match. Didn't cost me much. I bought a new fuel pump while I was there, adjustable fuel regulator, new fuel lines, filter, and mounted everything in pretty much the same locations as the stock bits went.

Everything matched up and mounted well.

I eventually ditched the old drum setup, did a 5 lug conversion, with 4 wheel disc conversion, as well as got rid of the booster and converted to a VW Rabbit manual brake setup.

A local and member of 924board.org had a set of freshly rebuilt brakes with SS lines. He was moving to better brakes, sold them to me and I installed them.

I had sold my 944 a while before and kept the BBS wheels that I loved so much. Now I had a reason to use them again.

Since I had already lost weight, I decided to take it a step further and get rid of the GTS lights. There was a really nice writeup (part 1 | part 2) on making your own GT lights. Benefit is losing the weight of the motor, linkage, the heavy assembly etc. Downside is that most of the GT lights use halogens, which I tried and hated. So I bought some buckets and made my own lenses and put projectors in it.

My first attempt was with some spare CF I had. I hated the halogens though because they weren't well positioned and didn't really do good visibility wise.

My second attempt was to buy some premade buckets. I found a focus nearby with a projector conversion, tore those apart and added those. The car got hit (again), so I ended up replacing the fender (again).

Covered those puppies in felt.

Cut some acrylic from home depot

Put them in the oven when my wife at the time wasn't home.

The result was much better.

The old exhaust was rusting into a pit of nothing. A full Bursch system was purchased with a Bursch header.

I also began the process of stripping it to put down some basic paint so that I can do a wrap on the car. By basic paint, I mean a glorious rustoleum paint job sanded down smooth enough to put vinyl wrap on it lol. Because race car.

No recent pics since it's been black. I'll try and get some this week.

Fastforward to today. The megasquirt was being a pain in my butt. I tried doing squirt and spark only to find out that MS1 v2.2 doesn't do that all that great. I installed an MSD 6AL and blaster 2, new wires, ran the megasquirt with fuel only on Alpha-N from the tacho signal from the MSD and the car is FINALLY running and driving at last.

In this pic, cap is off so I could set timing.

I'm on the last bit of wiring for the tail lights, turn signals so I can finally go drive it legally. Schroth harness installed along with a decent harness bar and sparco seat. Comfy, still a tight fit in such a small car.

Some days I still look and it and go, "There's still so much more to do." but I have to remind myself with what I started with, and then I feel much better.

Corse;

How hard was it to setup the mega squirt on the 924? Did you notice better drivability, fuel consumption is not a worry as these cars get super mileage. Also does it feel more powerful?

My little car has the Eurospec engine so it has better oomph than the strangled North American version. But more is always better.

Thanks and your car is looking great.

Mike924 wrote: Corse; How hard was it to setup the mega squirt on the 924? Did you notice better drivability, fuel consumption is not a worry as these cars get super mileage. Also does it feel more powerful? My little car has the Eurospec engine so it has better oomph than the strangled North American version. But more is always better. Thanks and your car is looking great.

That's a difficult question to answer. The engine is no longer stock, and is now an ITB car, and just tuning it with basic drivability the car seems to be a bit of a gas hog, though I'm not entirely sure what the mileage is. I don't have hardly any instruments aside from basics in the car right now (oil pressure, voltage, temperature, etc).

Now that the fuel map is better than it was, drivability is nice. It is certainly more peppy than before. I had the old compression pistons in the car which I believe on the old 95hp motors was around 7 or 8:1. The euro pistons are 9.3:1, and with the intake setup, itbs, headers and exhaust and megasquirt, I would expect better than the euro motor numbers (which were around 125hp).

I plan on taking it to the dyno soon and getting it dyno tuned.

My adventure in setting up megasquirt started as incredibly difficult because I started the hard way. If I knew then what I knew now, the car would be in a completely different state.

My best recommendations if you decide to go with megasquirt, as recommended to me by many other megasquirt gurus is to do one thing at a time. Starting over with a new ignition and fuel system is a pain to tune.

I did squirt AND spark at the same time, and I never could get it to work right. The trigger system was primitive and unecessary (HEI module driven, really bad, should have used a trigger wheel), the ignition system was undesirable, and it made it hard to get a base map.

I've since gone away from that, put an MSD 6AL on it to run ignition off of a stock dizzy, and the megasquirt now does ONLY fuel. Which fuel only is far far far easier to tune. In my opinion, the stock ignition system is really not that bad as it is, and is therefore really not totally necessary to get rid of and move to megasquirt, at least not until you get fuel right.

That's just my $.02. The car doesn't weigh much, so compared to what it was, it moves a whole lot better. I'll be sure to report back though once I've actually got a dyno tune on it with some dyno numbers and can get the AFR consistent across the board. I can tell you though that it has the capability of being a hell of a lot more efficient than the CIS system.

The weight savings were nice as well. The intake manifold, throttle bodies, fuel injectors and rail altogether weigh almost exactly 7lbs. The CIS system weighed a lot more than that when you consider the big intake manifold, the throttle body, the metering plate, all the lines, the warmup regulator, the accumulator setup, etc etc etc. Freed up a ton of space under the hood as well.

In reply to Mike924:

I also run MegaSquirt on my 924. The wiring and physical conversion isn't that bad. It can be tricky gathering all the parts and pieces and not going into the poor house.

Before you go to far into it, you have to start with a solid base and develop a good plan of attack.

Both Corse and I fell into the same trap of making too many changes at once.

I switched to distributor less ignition and fuel injection, both controlled by the MegaSquirt as well as a larger cam and ITB's. I eventually was able to get it running well enough to limp through the local emissions testing. It was not enjoyable to drive.

Once I switched back to the stock intake and a single throttle body, it was much more drivable and easier to tune.

The initial startup is the hardest part. That is just trial and error and requires patience. Once it is started and idling you can start fine tuning the base fuel map to get it drivable and slowly drive around at different throttle positions, allowing the auto-tune feature in the TunerStudio software to bring the fuel map closer to a working solution.

Cool build! I've always liked the old water porches, Someday I'll fall into one. It's great to see that old 8v getting rebuilt to euro spec. Everyone is LSX swap crazy these days but I prefer to see the old cool engines getting all the potential they can on a modernized management like ms. Currently running a few old cars on MS and I will never go back. So much better and easier to work on.

In reply to 2K4Kcsq:

If you wanna have an interesting engine swap:

http://www.944-20v.nl/

Gotta love the fact that the 2.0L in the 924 is the fore bearer of the mighty inline 5 used in your car and others. In fact a ChumpCar/Rally buddy of mine is swapping a 10VT into an old 944 for Rally use. It will be interesting to see if the intake clears the strut tower.

There was a inline 6 version of that engine that someone in Europe swapped into their 924. Of course the early V8's used the same bellhousing pattern, but the oil pan and oil pickup creates problems with swaps into these cars, not insurmountable, but its challenging.

I'm slowly collecting parts on my own to swap to 20V, but I'm going to have some fun with and probably blow up the little 2.0L before that happens :)

So... I got this car up and going years ago and haven't really done too much with it.  The Lambo took up a lot of time and since the Lambo is basically nearly back on the road entirely I figured I'd bring this back.  The megasquirt is happy, car runs great, has a fuel cell now, which I plan on changing how it's laid out.  I really haven't updated too much on it though and I really should have, but the Jalpa has really kind of taken my majority of interest.

I also figured I'd add that I may or may not have purchased an eaton m90 for it and stuff to change to wasted spark.  So.... we'll consider this my new covid project once the Jalpa is happy where it's at.

Alright, update.  Ordered a bunch of stuff to convert the ignition over to EDIS-4 because this old ignition setup isn't gonna work for what I want to do.  Excited to move the ms2 over to a more modern ignition setup.  Looks like the parts shipped today (ordered them last night) so looking forward to poking at it in a week or two.  Gonna work on the jalpa this weekend though.

If you leverage the stock distributor (or a pickup on the cam gear) as a pickup in combination with a crank pickup, you could run full sequential:

https://www.msextra.com/doc/pdf/html/MS2V30_Hardware-3.4.pdf/MS2V30_Hardware-3.4-127.html

Plus you could ditch the EDIS module and drive the coil/pickups directly.

In reply to corsepervita :

My 924 is kicking my ass right now. I bought it with Megasquirt. It used to be able to start and drive some, but now I can't get it to start for anything. Just turns over and backfires (I think at the intake) 

I approve of this thread's rebirth.

yupididit said:

In reply to corsepervita :

My 924 is kicking my ass right now. I bought it with Megasquirt. It used to be able to start and drive some, but now I can't get it to start for anything. Just turns over and backfires (I think at the intake) 

Make sure the timing belt is correct and that the plug wires are in the proper order. 

Pull the plugs and change them (mine loves to foul them like crazy). 

Verify fuel pressure and that the injectors are firing (they can stick if they sit).

Ensure there is good, fresh fuel in the system (my 951S had really, really old fuel and it took forever to start when cold, finally got fresh fuel in it and everyone was much happier).

Then save the original tune file somewhere safe. 

Now make sure the battery and starter are in good shape and work through setting the constants, etc. described here:

http://www.megamanual.com/v22manual/mtune.htm#constants

Once you can get it started, let it sit overnight and try it again, adjust the amount of fuel for that temp range if it won't start.  Rinse, repeat for the various temp ranges (this is what OEMs do and it just sucks up so much time for them).

Between adjusting cold start settings, you can work on getting idle tuning set correctly.

Alright, so.  Went to take the supercharger out today to see just how much of a pain this will be to do.  I have a /lot/ of room underneath my itbs, so finding room in the engine bay, not an issue.  However, I do have one small problem.  The nose is way too damn long.  Is anyone aware of a shorter snout for the eaton M90?  I suppose my options are:

- Find another snout that is much much shorter

- Have a machine shop make me one custom (but that seems I could find another supercharger for that money)

Also I got all the wiring stuff for the ignition system.  It's cold as balls outside so I'm done for the day but I can tell you that the snout needs to be pretty close to the end.

Currently:

Needs to be more like this:

The good news is, the engine block has some open spots where there's no longer stuff in there so there's plenty of room and I think ease of being able to make a plenum this thing can hook up to.  I also think that if I make an adapter that comes off the back at 90 degrees, I can free up some more space.  The big challenge here is the stock throttle body that came with it is huge, very long, and probably a good 8", the snout measures (from where it bolts on to end of pulley) 9" total.  If I can get that down, she'll fit.  Looks like if I got the throttle body adapter going around and was around say 5" and got the nose down to about 3-4" tops, we might be in business.

I do also have the option of making a custom pulley for the engine that could extend out a bit more I suppose if push came to shove.

Open to ideas.

Dherr had some eaton mix/match combos he had figured out via experimenting that might help there. Can't recall a thread title, but might have been started by frenchy.

Quick search turned up discussion on an MR2 owners group, which suggested '95-97 Jag XJ6 M90, which apparently looks like this:

In reply to Stefan (Forum Supporter) :

Thank you!  I'm going to give it a go on Sunday. 

In reply to corsepervita :

There's a guy on the 924 forum who uses a m45 from a minicooper s to supercharge his na 924. He has a thread on it and plans to make a kit. 

Jesse Ransom (FFS) said:

Quick search turned up discussion on an MR2 owners group, which suggested '95-97 Jag XJ6 M90, which apparently looks like this:

I saw that but the only parts I could find are overseas for that, sadly.  And the cheapest i saw was like 450 euros.  I guess i need to keep my eyes peeled for one.

bluej (Forum Supporter) said:

Dherr had some eaton mix/match combos he had figured out via experimenting that might help there. Can't recall a thread title, but might have been started by frenchy.

Found it!

https://grassrootsmotorsports.com/forum/grm/eaton-superchargers-prices-sources/176367/page3/

Now the real question is how can I get myself the nose drive portion without having to buy an entire M62 off of a C230 lol.

I put a shout out on my fb for my car friends to see if I can find either an M62 from a C230 or a shortened jag m90.  I think this project may be one of those things I may need to just be patient on and wait for the right parts to surface and become available.  It seems unreasonably silly for me to go buy an entire m62 off of a c230 just for the nose drive.  And an M45 looks like it'd fit great but I'm after more power than that longterm.  So alas, I shall wait.

Good news is in the mean time I can get this new rad EDIS-4 ignition system all setup.  If anyone finds themselves at a U-Pull it and finds an old jag with a shortened M90, or a C230 with an early M62, let me know, would happily pay you for the part and shipping.

A certain someone apparently has an entire m62 setup and offered to sell it to me who also has a 924 so I think i'm going to go that route, hang onto the m90, piece it as parts come available and save the m90 for another day.  Looking at the layout of the M62, it looks much easier to work with in regards to the inlet and outlet ports being on one side.  It'll definitely fit.

This thing should scoot quite nicely with a SC engine under the hood!  Very interesting.

My experience with the MS1 is very limited to my friends setup on his Audi 5000 avant with a 10vt engine.  It worked well, except it definitely was harder to tune then my original MS2 setup was on my 80q 10vt swapped car.  After running batch fire and dizzy ignition for a while, we couldn't get things tuned in as nicely as I liked, so I went for the MS3X setup.  Night and day tuning difference.  The jumpy dizzy only timing reference is gone, and now have a 60-2 wheel and use the original 1 window dizzy as a cam sensor.  Works extremely well, and fully sequential is much nicer.