Well, we didn’t blow it up. Didn’t get everything I'd hoped for, but I’ve confirmed a few hunches, dispelled a few myths, and I now have a star to steer by.
The day started later than I’d hoped – the band played last night, I slept through the alarm, and woke up a half hour late. I made coffee, hooked up the trailer, grabbed my checklist, tools, gas, fire extinguisher, camera, clipboard, then I filled the thermos, loaded the Midget, kissed Kate, stopped and bought one of those disgusting sausage/egg/cheese croissant sandwiches that they keep under the heat lamp at truck stops, and still got there before the folks who run the place did. Not an issue – I suspect we were all a little fuzzy this morning.
Offloaded the Midget, fired it up in the parking lot, and I looked to the north to see if I had awaken Les Paul – one of only 3 stars whose autograph I have - he’s buried across the street – still slumbering. Rest in peace, Lester – and thanks for the toys.
The dyno is actually a Dynojet – in an earlier post, I was thinking it was a Mustang. It’s elevated, which is fine, but when you’re trying to ascend a pair of ramps with a high strung car that won’t launch below 5K, one can start to imagine the look on the dyno tech’s face as you lurch forward.
I managed to get it on the drums, and Jeff, who I believe is the owner, and Kyle Maas, his assistant/coworker, strapped it down tight.
I invited Time Curtis and Mark Wolbrink to come along. Mark races a KX500, and owns a fistful of records at Maxton. 125+ on a dirt bike – I have no idea how he gets his balls behind the tank. A few years back, we exchanged a few PM’s, but our paths didn’t seem to cross until we met down at Maxton last month. He wanted to stop by and check out the fireworks today. The shop was cool with that, and I asked him to bring a camera. The pics in this post are courtesy of Mark, and I’m VERY thankful. Visit his site – he’s as dedicated a racer as anyone will ever meet –
http://wolbrinkrace.blogspot.com/ Tim is an electronics wizard of the first order, and has set up everything electrical on the Midget that looks impressive. The spaghetti work is mine, the groomed loom is his. He was once a keyboard tech at Paisley Park Studios in Minneapolis, and has worked for Smart Studios in Madison, so I figured an audio engineer would be a good choice for recording data – the Wintec system is a virtual tape recorder – the knock sensor, a microphone.
While Jeff and Kyle made themselves busy with another customer’s Camaro, Tim and I got to work on setting up the Wintec software. I had some issues trying to data log at Maxton, and one of the suggestions I got on line was to reinstall the software, which I did last week. Of course, the new software claimed that the old files were “corrupted”, or produced on a “newer version” of the software. I honestly couldn’t remember if I had downloaded a newer version or not, so we logged on to the website only to find the version that Electromotive had available for download wasn’t as recent as the one I had installed from the disc that came with the system.
Tim was able to upload the existing parameters from the brain box and create a BIN file that the new/old software would recognize, but a test run showed we were having difficulties recording the data. The tach worked on the laptop, but the record function would not record.
While this was going on, Jeff came over and checked his ignition hookups. He couldn’t get an accurate read on the #1 sparkplug (wasted spark, I’m thinking now, 20/20 hindsight), so he tried a few tricks – a sensor on the trigger cable, an auxiliary sender with a piece of magnetic tape on the front pulley – neither worked. Eventually, though, he put the sensor around the cables that run from the ECU to the coil packs, and with a few software adjustments, all three tachometers were working – and all within a close enough range to each other to say we were good.
I did a preliminary pull to see if all was well. Jeff’s readout looked like a spirograph drawing made by a drunken sailor balancing on a beech ball. Tim, on the other hand, got a solid data log through the first three gears, which proved what I had suspected – at 28 degrees advance, I had no knock. One baseline in place, but the recorder cut out just before the 3 to 4 shift.
And then it started to sputter.
Okay, we’ll figure this out. While I had no power readout data from the dyno, I could tell that it wanted to run, so while Jeff and Kyle sorted out the issues on the dyno, Tim and I went into the advance curve, and bumped everything up 2 degrees. We’d noted the noise threshold on the knock graph, adjusted it accordingly, and then dialed in 2 degrees of retard to pull it back if it saw a knock event.
For Tim, it was just like dialing in a compressor in an audio chain. For someone like myself, a bit of an audio geek who tends to think in analogies rather than algorithms, it made perfect sense.
But before we downloaded the new curve into the ECU, I needed to figure out what was causing the sputter. So I climbed into car, hit the starter, and no pop. I poked my head out the window, looked at the fuel pressure gauge I have located on the firewall, and yes, indeed, I had run out of gas on the dyno.
For those of you keeping track, I’ve driven this car a total of 15 miles, and have run out of fuel twice.
Gas it up, laugh it off, and fire away. This pull is the one in my previous post – I’ll reinsert it here just to maintain continuity of the documentation. Just click on the pic.
Okay, first real pull, still sorting things out. Dyno spits up a printout - A/F ratio 10:1 – at least now I know why I’m running out of gas. Tim’s data log indicated no knock, but once again, it stopped recording mid stream – not sure what’s going on there.
This number is significant – power peaks at between 7500 and 7750. According to Sumner Patterson’s spreadsheet, 4:22 gears, 22” tires and 7741 RPM gets me 120 mph. The class record is 121.779. If that’s not a bulls eye, it’s definitely a pin-high chip shot from the bunker.
Peak power, 56.84. Hmmm . . . I’ll need more.
About this time, Mr. Wolbrink showed up. He slipped away from an asbestos abatement job that his crew had well in hand, and brought his camera. The smart man knows how to delegate, and Mark is a smart man.
We chatted a bit, I introduced him to Tim, Jeff and Kyle, and he borrowed an engine stand and converted it into the heaviest rolling video camera stand you could imagine. Smart man.
Mark shot a few pics, which I’ll share here –
Tim at the computer –
Me and Jeff, reviewing data on the big screen –
Tim and me, posing – and a quick nod to the Bill Reilly team - thanks for the fashionable shirt – I told you I’d only wear it on special occasions –
Mark made a video of the final pull, which is a rather large file that he’s linking to my wife’s Facebook page. I’ll post that as soon as Kate gets back – she’s whooping it up in Chicago this weekend with her band mates.
Yeah, she plays in a band, too.
The result of the last pull, in which we advanced the timing another 2 degrees, brought in a 60.90 peak. This time, Tim waited to record until after I reached 4th gear. Still no knock.
The two pulls we were able to capture, superimposed -
Okay, here’s what I know.
First off, single pulls are snapshots at best. You want to be able to repeat the results two or three times before you hang your hat on them. You also need to balance that out with not burning it all up in the bullpen.
Right now, there is no indication of knock.
It’s running too rich.
Once the fuel delivery is brought into check, I think I can continue to dial in the ignition.
I’ll be calling Dave Anton at APT to discuss these results, and we’ll figure out some jetting changes, keeping in mind that Bonneville is at 4200.
I also need to bullyrag the folks at tech support at Electromotive to help us figure out why the recording function is cutting out.
I also know I’m going to need some more firepower, but for a 60 year old engine design with a poorly jetted carb and a 5 port head to pull 1 horsepower per cubic inch at the rear wheels, I can’t complain about my Saturday.
A huge thanks to Jeff and Kyle at Late Model Throttle.
Topic: Milwaukee Midget (Read 3277450 times)