Sunday, June 11, 2017

The Day of Reckoning

I had a friend in high school named Blake. Blake was one of the nicest guys you'll ever meet and also drove the most stereotypical redneck truck imaginable (1979 Chevy pickup, lifted 6 inches with 33" tires, Flowmasters, and a carburetor that was way too big). Blake also got really nervous when he went on dates. So nervous in fact that he would sometimes have to excuse himself during the date so that he could go puke. I'm not a terribly nervous person by nature, but there are a few things in life will give me the Blakes. Those things include but are not limited to: getting married, drinking the water in Mexico, and going to the dyno.

My appointment with Church Auto Testing was at 2PM on Friday, so I worked a half day. Even though Grace has run reasonably well for the past 2 years almost, that whole morning doomsday scenarios ran through my head. I was about 50% sure that the head gasket would go, or the intake manifold endcaps would pop off, or the driveshaft would rip itself in half, or... 

The time eventually came and I met my buddy Vaughn for lunch and after a good 'merican burger we drove down to Church. Church is just off the 110 freeway in the Port of Los Angeles. As a side note, I love ports. I could just hang out there for hours and watch ships come in. My wife thinks I'm crazy, but who doesn't love cargo ships and shipping containers?? I've got a friend who loves them so much, he's building a house out of one!

We arrived a little early and Shawn, the tuner, was still out to lunch, so we pulled in and looked around. Inside the shop sat more than a few performance cars. Besides the cars in storage there were just two dynos in the shop. Church has been around for 15 years and does nothing but tuning. They use DynaPack dynos which is one of the reasons I chose them to tune my car. A lot of shops use DynoJet dynos, which are an inertial dyno. This means that the dyno doesn't have the ability to hold the engine at a steady speed or load, and as such, is not useful for tuning part throttle or part load. Dynapack dynos connect directly to the hubs of the car, which meant that we had to remove the wheels to mount the car on the dyno. Unfortunately the rear wheels on my car are a huge pain in the arse to remove and even worse to re-install, so prior to going to the dyno I mounted a set of skinny trailer tires to the rear that I had borrowed from Vaughn.

Once we were mounted up, the tuning began. Shawn started tuning for with the 91 octane gas that was in the tank. First he roughed in the low load and part throttle area of the map, and then got the acceleration enrichment dialed in. This took about about 30 minutes. Now we could start some full power runs so we started at the base boost of 10 PSI. When this came out at 242 HP / 238 lb-ft, the nervousness was gone and I knew that this was going to be a good, puke free dyno day!

After a few runs we worked up to 17 PSI, this is the video for the run:

I suppose we could have kept going, but I wanted to keep the the tune conservative, and I figured 320 HP was sufficient. Vaughn and I then drained the fuel tank of all the 91 and added 12 gallons of e85. The flex fuel sensor read about 75% ethanol. This pretty normal for e85, which is rarely actually 85% ethanol.  When we restarted the engine it ran a little rough, but after a few minutes of tuning all was well.

Shawn set the boost to 20 PSI and attempted a pull. At about 4500 RPM he shut it down because it started to run out of fuel flow. This was a little strange because the fuel system should have been able to keep up. Shawn had me attach a fuel pressure gauge to the pressure regulator and watch as he made another pull. I saw that as RPMs got above about 4000 RPM, the pressure began to drop. This told us that while the injectors should be large enough, the fuel pump was not providing enough flow to keep up.

Despite the fuel flow problem, Grace made 348 HP and 378 lb-ft by about 5000, which I considered to be freaking rad. With sufficient fuel flow Shawn thinks 380 HP / 400 lb-ft is easily achievable. He dialed the boost on e85 back to avoid any damage, so at about 10 PSI, it's making 275 HP and 270 lb-ft.

But enough about the numbers, let's talk about the shape of the torque and power curves. I had initially intended on sweeping cam timing to find the best setting. After the first few runs, I got a pretty good idea of what the curve looked like.  For any given boost level, peak torque is at about 4600 RPM, and peak HP is reached right around 6000 RPM. This isn't a terribly wide spread in peaks, but once full boost is reached, the torque curve is reasonably flat. I have to also remember that this engine was designed the same time John Fogerty was hitchhiking home from Woodstock, so it's not going to have the same mesa shaped torque curve as a variable-timing twin-cam motor designed in a new-fangled CFD program. That said, I was pretty happy with the horsepower peaking at 6000 RPM, so I didn't feel a need to mess with the cam timing.

My turbo, a Borg-Warner EFR series turbo, marketed as a responsive, and early spooling turbo. I run the 6258, which is the baby of the bunch topping out at only 450 flywheel horsepower. As you can see on gasoline, it reaches full boost (17 PSI) by about 3300 RPM. On e85, the spool happens a bit quicker, but with the higher 20 PSI max boost, it is reached at about the same 3300 RPM. For a Ford 2.3L that should ultimately put down 380 HP to the wheel, I think full boost at 3300 RPM is pretty awesome.

I arrived just before 2PM, but didn't get tuning until about 2:30. We spent about an hour and a half on the dyno which cost me $550. Dyno tuning is never cheap, but with a good tuner it is money well spent. All in all, I'm very happy with the result: Grace made plenty of power, didn't leave any ventilation holes in the side of the engine block, and I didn't puke.

That face when your engine doesn't blow up on the dyno, and makes more power than you expected

Thursday, June 8, 2017

Creature from the Black Lagoon

Dyno day is approaching rapidly, in fact it's tomorrow. In preparation for dyno tuning, I thought it would be good to get my cooling system in order. Running an engine on a dyno, especially at high load steady state conditions, puts a lot of stress on a cooling system. I'd read somewhere that a significant portion of a dyno session can be cooling time and dyno time is not cheap. So not only does it make sense from a performance standpoint to have a good cooling system, but also from an economic standpoint.

Since this engine has a cast iron head and block it can accumulate a fair amount of rust inside it. In the past couple years, I've kept straight water in the system because I didn't want to deal with sticky coolant every time I had to unhook a coolant hose. Living in Southern California, it never freezes so I can get away with this. On the flip side, this created even more rust in the system.

mmm iron hydroxide!

I knew that there are a number of rust removal products but I searched for quite a while before I found a product I wanted to try. I settled on Thermocure, made by EvapoRust. They claim it dissolves the rust and suspends it in the water. I had tried standard EvapoRust on a bunch of old bolts and it worked like a charm. The evaporust turned black, and the bolts came out clean. ThermoCure seemed to have good reviews and was a reasonable price, so I ordered a bottle and added it to the radiator.

The instructions say to let the vehicle run for four hours with the product in the coolant. I'm not sure I ran it that long, but I let it go through several heat cycles and sit for a couple weeks. I drained both the radiator and the block and got this nice dark brew. 

Not quite convinced that all the gunk was out, I filled the system with pure water, heat cycled it, and drained again. This turned out to be a good idea because as you can see, there was still a bit of sediment left in the engine.

At this point I called it good and filled up with a 50/50 coolant mix.

This time tomorrow I'll be heading to the dyno. Hopefully my tuner (who is NOT Matt Happel) doesn't subscribe to the Matt Happel School of Tuning. Wish me luck!

PS: I never put in my HP bets on the last post so here goes. 91: 280HP / 300TQ  E85: 340HP / 360TQ

Sunday, June 4, 2017

Return of the Hobo

In a previous installment, you read about my glorious triumph installing a flex fuel sensor. I had taken a flex fuel sensor from an old Ford Taurus in the junk yard and fitted it to Grace, and everything was awesome. Turns out it was all a lie. 

Granted, I didn't know it was a lie at that point. I installed the sensor, built a circuit on the ECU board and it was reading the ethanol content of the fuel, or so I thought. I soon found that while out driving, the engine would suddenly run really rich, almost to the point of dying. And then with no indication, it would go back to normal. I took a couple data logs, and found that the ECU was showing a fault on the ethanol circuit and would go into a sort of limp mode, and when ethanol percentage read 1% without any fluctuation, that meant the sensor was not reading correctly.


Data logs, AKA my lifeblood. I spend most of my days at work looking at data logs not unlike this.
 I felt fairly confident that the old junkyard sensor was bad, so I set out to find a new one. After wasting half a Saturday to find one in a junkyard (a new replacement sensor costs a minimum of $300) I gave in and bought an sensor I found on eBay. I had high hopes for this new sensor, but was grateful that it came with a 30 day warranty.

New old junk: another 1st generation metal body ford flex fuel sensor

New old junk and old old junk side by side.
I installed the new old sensor and viola!, same result. By now I was suspicious that maybe I had done something wrong. I checked my ECU several times to make sure that my circuit was right, I checked my wiring, I asked on every forum that I thought might have some knowledge on these sensors. Of all the advice I got, the best piece was this: make a sound card oscilloscope. I needed to look at the signal coming from the sensor to determine if it was toast or if I had screwed something up on the ECU side. 

A sound card oscilloscope uses a bit of free software on your PC to read electrical signals coming through your sound input jack. I had to build a very simple circuit to reduce the voltage of the signal in order to protect the sound card itself, though that was a pretty quick job that cost essentially nothing. Normally a good o-scope will cost hundreds of dollars, but if you just need to check a low voltage signal occasionally, a sound card o-scope can be the perfect tool.

A couple wires, a couple diodes, a resistor and a potentiometer. Behold: the sound card oscilloscope.
I probed the circuit right at the ECU so I could make sure that I was seeing exactly what the ECU was seeing. It was a very clean signal, coming in at 39.9Hz. I had found an old Ford spec sheet for this specific sensor.  Its nominal range is 50 Hz at 0% ethanol and 115 Hz at 85% ethanol (or 125 Hz at 100%). The chart also showed a tolerance band of +/- 10 Hz, which meant that my sensor could theoretically read as low as 40 Hz and still be within range. This seemed to indicate that the sensor was dead.  I still wanted to know for sure, so I ran a small amount of denatured alcohol through the sensor. There was no response in frequency of the signal, so at that point I gave in an ordered a new GM style flex fuel sensor.

1st Generation Ford (Siemens) flex fuel sensor range

39.9 Hz signal = dead sensor

The whole reason I had avoided the GM sensor from the beginning was because of its quick release style fittings. I wanted to have -AN fittings throughout the entire system. It was kind of a silly requirement, but sometimes I get it in my head that something needs to be a certain way and then I'm unreasonably stubborn about making it that way. My wife wouldn't know anything about that... (unrelated side note: planning a house remodel is strangely like planning a wedding. You are required to have an opinion on many things, and once you finally come around to having that opinion, it's wrong ¯\_(ツ)_/¯ ) Anyway, I ended up finding a fitting that made me comfortable with using quick release style fittings in my fuel system. Russell Performance makes a fitting that is a very solid piece for adapting -AN to quick release, and it's actually pretty reasonably priced. I did what I should have from the start and picked up two adapters, a GM (made by Continental) flex fuel sensor, and a new wiring connector.

This two piece adapter fitting threads together to prevent accidental disconnection.

Ford flex fuel sensor connector on the left, GM connector on the right

After way too much fiddling around with sensor location and hose routing, I got the mounting sorted out. When I fired up the ECU and enabled the flex fuel circuit, it instantly started reading right around 14% ethanol. I then realized the Ford and GM sensors have different ranges (GM is 0% ethanol = 50Hz, 100% ethanol = 150Hz), so I  corrected that and it read 11% ethanol, which is a very reasonable value for the E10 pump gas here in California.

About a week ago, I called someone on the phone that I had been meaning to call for some time. I set an appointment with Church Auto Testing to have Grace tuned. The moment of truth is approaching. This Friday we will know how much power she's got. I'm actually far more interested in the shape of the torque curve than I am the maximum power figure but since it's a fun game to play, let me know in the comments how much power and torque you think she'll put down. I'll be doing a 91 octane pump gas tune and hopefully also an e85 tune, so be sure to specify what fuel when you add your guesses!