Porsche 944 Megasquirt conversion

[MostMint]

Fresh from Cut ‘n Paste - IAT bung welded to CAI

[TireSmoker]

The 944 went back home to Scott's today. I was able to do a little street driving with it the past couple days and I have a rough tune in there. It starts and idles easily, I plan to do a little more tuning during our Friday practice session.

This one was a hard project to document, because I was stuck on the crank trigger issue (and being sick) for several weeks, and once it got running, it was just a mad scramble to get other details sorted.

I had Scott drive it real quick before we loaded it. The current tune only has 25* of timing at WOT. He said the part throttle was a little wonky, but WOT felt strong. When I drove it, it was only set to 21*. I don't know what the max should be on this engine. 4 valve engine with a centrally located plug should, in theory, require less timing.

This project was super frustrating at times, but it'll all be worth it if we can make some fast laps at Mid-Ohio next weekend!

-Dave

[wxo]

Give us a report after Mid-Ohio.

[TireSmoker]

Well, Mid-Ohio is in the books. Hindsight is 20/20, and we should've waited for a trackday to shake it down.

We got to the track on Friday morning for practice. While warming the car up, I noticed the alternator wasn't charging. It was a brand new alternator that Scott had installed between the time it left my house and Friday -- 6-7 days? Scott even had sent me a pic, showing his meter with 13.5 volts. Well, knowing alternators generally have an excite wire to 'turn on' charging, I figured out we needed to run a wire from the B+ terminal to the D+ terminal. In the end, an easy fix and didnt take too much time to sort out.

Once Scott took the car out, we noticed it came back with no air filter. Luckily, it was picked up by track officials perfectly intact. We used some Gorilla tape and a clamp and it stayed put the rest of the time,

The next time out looked like disaster. Joey was in the car, coming down the front straight and just TONS of smoke. When they towed him back, they took the car to the grass to let the oil drip-dry there. But it wasn't disaster. There is a single bolt that holds the oil cooler feed and return lines to the engine. It was too short and backed out. We got a longer bolt and were able to get it back together.

All 4 of us made practice laps. I went last. The car has some top-end speed! The new tires were not as grippy as hoped.

On Saturday, Scott took the green flag at 9am. At 10:30, he was towed in, car was dead and wouldn't start. The new aftermarket bracket that was a combination crankshaft-sensor-mount and alternator bracket had broken. This threw the sensor way out of alignment. With some hardware store help from Chris and Jered, we were able to MacGyver together a working solution, and I was out on track by 12:30pm.

I didn't have any issues during my stint and the last 20-30 minutes were really fun. We had a FAST car. We could out-run or run-down just about anyone in the straights and we werent terrible in the corners. Joey and I both saw 5600 RPM on the back straight, which worked out to 143 MPH.

I got out of the car at 1:50pm and went from exuberant to pissed off in about 30 seconds when I heard the car turning over and not starting. This time, the alterntor pivot bolt was missing, which again messed with our crank sensor alignment. Chris and Jered made another quick trip to the hardware store, got a bolt, and we had the car running again for Tom's stint.

Tom got towed in with the car not running, but his issue was quick. It's easy to bump either the ignition switch or fuel pump switch sometimes when shifting into 3rd (happened during my stint), and he hadn't realized he bumped it. Turned everything on and he went back out.

Joey got in the car at 3:45pm, but it would only last 20 minutes or so before he was towed in with catastrophic engine failure. We could see a hole in the block where the upper balance shaft goes.

BIG THANKS to Chris and Jered for hardware store running, and Jered for dinner on Saturday night by his trailer.

[Basement Paul]

Where's the picture of the window in the block?

-BP

[VeeDub]

Pics of the block for sure.

[MostMint]

I didn’t think to photograph the hole but Scott had this view of the inside. Bonus pic is the CPS bracket right after it cracked

[Basement Paul]

A suggestion would be to make that exact bracket out of steel.

-BP

[TireSmoker]

No, the correct answer will be to figure out how to use the factory crank sensor back by the bellhousing. That will eliminate this bracket all together. That bracket might be nice for street use, but is not positioned well for an endurance racecar, IMO.

Scott only sent me a little 10-second video of the carnage. I dont have any pics to post.

-Dave

[TireSmoker]

BTW, Scott's friend Jason, who sponsors the team via his company, has told Scott to get 2 (!!) more 3.0-S2 engines.

-Dave

[MostMint]

That bracket was in use to get a crank signal in the time that was left. Now there will be time to get the signal right from the top mount location Dave mentions. If that fails that entire bracket needs redesigned. If you look closely there is a mark just at left of photo. If that bracket went straight across instead of coming down in more of a V shape there would have been no contact and we may not have had those issues.

Also if the make had left the metal wider instead of cutting a slot that removed over half the metal there the metal may have had adequate strength. Just not a well thought out part for a real racing application. Made it possible to get the car running though so it was not a total waste.