Datsun Roadster Forum-311s.org

As Daryl noted, he is correct that the MS controller samples air at start up and calculates from there until it is restarted. It has a provision for a baro sensor however that will constantly calculate from real time pressure, just three more wires. Thanks again Daryl, will add that soon.

So excited for this Greg! Those Jenvey Heritage TBs are wonderful looking.

Thanks Simon! I'm kinda frustrated at the moment as I'm having some weird sensor issues. I was very careful in doing my wiring, but it has been a learning process, and I hate electrical stuff. Gonna start with the basics and check for good grounds and rewire some things so I can take them off line more easily to check for interferences. And I thought I was close to trying it...

It RUNS! Finally got things wired up, checked for leaks, had some software trouble (needing to download the latest software version... thanks Daryl, our conversation made that much clearer!), got family responsibilities taken care of after getting through the holidays, went into the garage and TADA! She fired right up, second crank. The ITBs were out of balance of course, it idled high (mechanical adjustments) and ran rich at times, but I could not believe it. There are a lot of bugs to work out and hours of learning and tuning, but we're on our way. Unfortunately my play opportunities were cut short today when the so called "super industrial glue" that was holding together a part my linkage failed, so tomorrow I'll be finding a welder to do it right before I can do anything more. Still, couldn't be happier!

I tried to upload a video but it says I have an invalid file extension. I compressed it down to 10mbs, is that still too big?

Congratulations Greg!!
Now the fun begins....take your time, you'll be referring back to the manual quite a bit till you get it sorted. Use Autotune and also MegaLogviewer to help you get there. I used to do 20 - 30 minute easy drives, then run it through Megalogviewer for adjustments, gradually increasing rpm/load. Worked very well. It's too bad it doesn't do ignition - no way around dyno time for that - Good luck in your search for MBT (maximum brake torque, minimum best timing...whatever interpretation )!

Congratulations Greg, that must feel great. Interested to see how much difference it makes when you get it sorted.

P.S. I think your pic has to be under 500 somethings. Megabytes, kilobytes? Of course this is coming from someone who can barely turn a computer on!

Big step forward Greg. Congratulations.
Dan

Daryl, this is the second time you've led the way for me... first with the crank fired Mega jolt conversation, and now EFI! Your input and example has been very helpful to the progression of this car and all the fun I have with it, so thank YOU!

Thanks to all my well Wishers! More to come as I get things sorted, both with EFI and computers!

Today I got my (now welded) linkage back. I cleaned it up and reinstalled it back on the TBs, so I was ready to do a second start. Once again it fired right up dead cold in 40 degree temps, and after some adjustments to the fuel table (it was way rich!) I got it to idle at a good ratio as I learned what did what pretty quickly. Then, once the water temp went above 160, Autotune was allowed to start to analyze the air/fuel ratio vs the target and make adjustments. So, I just reved it up slowly, working through as many rpms and manifold pressure "loads" as I could (without driving the car of course) and watched as Autotune made changes to the numbers. After some time you could find table cells that were clearly off compared to others right next to it that Autotune didn't have enough info on, and you could manually adjust those for now. The more stable it became in light loads, the more aggressively I could hit the throttle to help with some higher and lower (engine deceleration) loads. My initial table was so off that the numbers were needing to be reduced by more than half, so I have some work to do. It's no where NEAR tuned, but I am really amazed at how easily it has started and run even when way off. I've reved it up pretty hard (I have a video, but again probably can't post it without help... pics for now) and it sounds better than with my Dellortos on it. Pretty darn cool. I need some dry weather to drive it and let Autotune do its thing, and that doesn't look likely to happen any time soon around here, but I'm super psyched. I haven't cleaned up the wiring etc yet, but this is pretty much how it will look, stacks and with socks. The intake air temperature sensor is inside the filter, works perfect.

Love it!

Shannon

So cool; glad you are blazing the trail!

It's really nice how period correct they look in there!

notoptoy wrote: ↑Fri Jan 01, 2021 12:47 am It's really nice how period correct they look in there!

Thank you All! Ya, unless you were to look closely you would think they were Webers. Clearly my installs and everything else on this car is somewhat "amateur does stuff in his garage with what he can find in a hardware store" so it's nowhere nice and clean like what Spriso and others can do, but I like the look over the Dellortos. Most important to me is, it works! This switch was made a lot more easy with my having already gone to the crank fired system before. However, those of you with an EI or 123 dizzy (points too i think) should be able to run EFI as the Microsquirt will accept tach signals if anyone ever wants to try a conversion. If the sound it makes when reved up is any indication, I expect a good result. With carbs, there was always just a slight delay when you snapped open the throttles; now it just sucks in without hesitation. Bring on the summer weather!

Just a "quick" ( ) update... things are progressing very well with the EFI conversion. So far my only issues have been of my own doing and learning process. I've had limited opportunities to do a lot of auto tuning due to weather. It's been cold enough that it will stop tuning because the engine temp drops below minimal threshold for auto tune to engage, so I've put a bit of cardboard in front of the rad and that's keeping the engine warm enough. Then I had to throw out a nice bunch of data during a drive as a set screw loosened up and caused the TBs to go out of balance and really messed things up! Just like with carbs, the engine does not tolerate unbalanced airflow.

So, with teething issues going away, I'm starting to get some good tuning happening. I'm a total novice but I've come to understand that there are several different ways you can tune based on what sensor(s) you choose or have (I don't have a MAF of course). "Speed Density" tuning uses the manifold pressure to determine load on the engine and how much fuel to provide based on a target air/fuel ratio and rpm. I was previously set up to use that as I used manifold pressure to determine load for spark timing with the old Mega jolt EI system. "Alpha-N" tuning uses the throttle positioning sensor and rpm to determine fuel for a desired AFR. In both cases this relates to a look up table for a target AFR at any given rpm and load and the controller adjusts accordingly based on what the wideband O2 sensor is reporting. Each has its pros and cons, but most engines run on SD because they have a plenum and a single throttle plate, not individual throttle bodies, and SD is really good at doing certain things. However, ITBs have characteristics that make them better tuned in Alpha-N at higher engine demands, but Alpha-N tuning has to do with a percentage of how open the throttle plate is and the relation to manifold pressure and rpm... it's not linear or just how much the plate is open but also at what rpm (it's a little more complex than that but I haven't dug into it that much).

Now, the tuning software, Tuner Studio, also has what's called ITB mode which allows you to blend the two so you can have the best of both worlds with ITBs. But before you can do so you have to have it running well in one or the other as there are data points that are very engine specific and requires formulas that will identify the point at which the controller switches from one to the other. Once you have these so called "switch points" you set the controller to do so and then let auto tune do its adjusting through drives... at least, that's the plan! Oh, and then there's adjusting your enrichment (think accelerator pump) but that's fine tuning further down the road.

Right now I'm just happy to be driving on SD. It starts in a few cranks dead cold (I always crank it over a dozen times to prime the motor with the EFI system off to get the oil pumping) and after a couple minutes it's bouncing around 950rpm. Once the cold start enrichment is off it idles and dances around within a couple of tenths of the 14.1 AFR I have set for it at idle... pretty cool, especially considering the cam. On drives I've heard no knocks or pings, and given the high compression ratio I am always on guard, but before long my confidence that things were/are safe increased, even though I've had to limp it home a couple of times! That was due to 1) a poor electrical connection to the throttle positioning sensor making the controller think that I was stabbing the throttle over and over, and 2) the aforementioned set screw/balance issue. The engine sounds great, no problems with bogging or low speed operation with the 40s, in fact it's already better than it was with carbs and there's a lot to learn. So far so good, and pretty fun.
Bring on some good weather!

Greg loving the update! Hoping for some warm weather!