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Danny P and I were chatting the other day and he convinced me to re-tune the Speeduino ECU to use the throttle position sensor as the main load rather than the intake manifold pressure. The main reason is that we run individual throttle bodies and in general, Alpha-n (throttle position) gives a better fueling solution since the 4 throttle bodies open up the manifolds very quickly.

In any event, I have it a go and I'm really happy with the improvements in engine responsiveness. That said, it called for a trip up to the top of Haleakala to dial in the barometric tables that adds or subtracts fuel depending on your altitude.

Marianne agreed to man the laptop and reported the baro pressure, the target air:fuel ratios and the actual air:fuel ratios.

When the actuals drifted more than a point away from the target, she told me and I pulled over and modified the chart. After a few point changes, you could see the trend and I just filled in the best guesses down to 70 kPa (our usual reading at 10,000 ft). With just a few tweaks we made it to the top running the best ever. I'm really happy with the new settings.

A side benefit was the incredible amount of comments we got from other drivers, bicyclists, and pedestrians along the way. Somewhere around 30 folks expressed their fondness for the speedster (probably half went as far as saying they "loved" it.). Fun morning.

The trip up was fine. There was a bone chilling 40 mph wind blowing up over the ridge at the top, so we didn't stick around very long.

For the 0-1 people who might need it someday, here's the baro chart running from 100 kPa (sea level) to 70 kPa (10,000 ft) showing how much less fuel you need at each altitude.

Cheers!PXL_20220518_205531105Screenshot_20220518-154104

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That is some serious awesome! I'm stealing that!

To expound a tiny bit on WHY Alpha-N(throttle position based fueling) works better with ITBs(individual throttle bodies) than a MAP(manifold air pressure) sensor:

With ITBs, once you open the throttle plate beyond 10-20% there isn't a real good vacuum signal as it is pulsed every time the intake valve opens for that cylinder only.

The MAP sensor relies on a stable vacuum source to determine fueling. This works very well in single throttle body situations, and works better with more cylinders and especially with a big plenum in the manifold. Stable vacuum is VERY important.

Once I get mine dialed in as good as Mike, I may play with adding a second fueling map to add/subtract(blend) with the main fueling but only at small throttle openings as in cruise situations.

Mike, can I borrow Marianne? Barring that, I'll have to log the data and tweak later...

@DannyP posted:

Mike, can I borrow Marianne? Barring that, I'll have to log the data and tweak later...

We were having lunch up at Kula Lodge and marveling at how we've stuck together for 53 years (49 married).

She's NOT a computer gal, but she's been a good sport about helping me tune a number of EFI projects over the last 20 years.

I must admit the tuning help today cost me some time sitting outside a curio store while she picked out some required objects.

Good trade. I'm sure she'd be happy to help you out for the same deal 🙂

@aircooled posted:

Interesting......OK.  so how's this relate to jetting. ?  Like how much smaller would you go for instance if you were jetted for sea level ?What would you do for your injection ?.......Bruce

I'll give it a (somewhat) edumacated guess- with 8 data points from 0- 10,000 ft- a (very) rough guide would be aprox 5% reduction in fuel VOLUME every 1200-1500 foot rise in elevation.  I mentioned volume specifically because a 5% change in the diameter of a circle is an almost 10% change in it's area (or in the case of a tube, volume).                                                                                                                                        If I'm totally of base here someone with more knowledge please chime in...

@Michael Pickett- when you were correcting was it rich or lean on a regular basis or sometimes one and then the other?

Last edited by ALB

Your guess is better than mine, @ALB. I went to EFI after my kadrons told me that 5000 ft didn't agree with them. There are some real jetting wizards here and I'm not one of them.

To answer your correction question, I was always leaning out the fueling as we gained altitude. In this case, it took more throttle to fill a cylinder with a certain volume of air since the air pressure was lower. Without Baro correction the ECU looks at the throttle position and sends more fuel than matches the air in the cylinder.

The Alpha-n setup sends the matching volume of fuel based on where you set your ideal tune. I spend 90% of my driving at sea level so that's where I set my base tune. I've got a table of throttle positions and rpms that's filled with my desired air:fuel ratios (Target AFR). After getting a rough tune (you turn the TunerStudio Autotune on), the laptop will adjust your fueling map so it's close to your AFR targets.

You then just datalog your driving for a few days and use a finer grained program (MegaLogViewer - MLV) under lots of driving conditions (low speed, full throttle runs through the gears, highway cruising, etc). MLV will take the log files, exclude whatever you want (records below a certain temp, rpm range, etc) and give you a revised tune based on your AFR targets.

Rinse and repeat making the changes smaller and smaller (you can set it Easy to change, Normal, Hard, and Extra Hard to change). At the end, you've got a 95% good tune that you can do minor tweaks to.

So, I'd done that already at seal level and liked the tune. I could then just head up the mountain and tell the Baro table the percentage of fuel I wanted it to take out of the known good fuel table.

I know it's complicated, but not having to take the tops off of the kadrons and finagle the jets at the bottom of the bowl is rewarding.

Sharing your AFR targets feels a little like telling what oil you use, but here's what I like for how I use the car. RPM is at the bottom and % throttle on the left.Screenshot_20220518-184400

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Last edited by Michael Pickett
@ALB posted:

I thought you had already done elevation tuning with intake manifold vacuum as main load so I was wondering how off that was as you went up- how much correction did you have to do and how far out did you find it went when remapping at sea level?

Turns out that elevation adjustment using intake manifold pressure (MAP) works very differently than using throttle position (TPS).

Here's the logic with a MAP setup: you start with a well tuned fuel map at sea level with RPM as the X axis and MAP (engine load) as the Y axis. The contents of the fueling map are the amount of fuel needed at that RPM-MAP point.

As you gain altitude, the MAP readings drop because the air is less dense. However, for the most part, the ECU just looks up the appropriate amount of fuel for that manifold pressure and everything is fine.

However, another thing that's happening as the barometric pressure drops is your exhaust back pressure also drops. That makes your engine more efficient and means you need MORE fuel for that particular MAP reading and RPM. So, the baro compensation table needs to add a little fuel as you gain altitude.

Throttle position (Alpha-n) setups don't know nothing about manifold pressure (unless as Danny notes, you tell it to blend in a bit of compensation for MAP - hard to setup).

As you gain altitude your engine gets less and less air(oxygen) in the cylinders on each stroke making less power and you push down on the throttle to compensate. The TPS based setup sees more throttle and squirts as much fuel as it would need to match that setting at sea level. So, it runs richer and richer as you get thinner and thinner air. The exhaust back pressure drops making the volumetric efficiency a little better, but TPS tuning runs so much more rich, it still can't use all the fuel. With a TPS setup, the Barometric correction tells the ECU to squirt an appropriate percentage less fuel as you gain altitude.

Temperature impacts on fueling needs are compensated by the coolant and intake air temperature sensor tables.

The other thing that will affect fueling needs is the humidity. I don't worry about that 🙂

More than you wanted to know about how EFI controls things that our carbs don't have a chance of responding to.

Don't get me wrong, carbs are perfect for most folks who spend most of their time around the same altitude. There are some edge cases like mine where EFI is better.

Cheers

Last edited by Michael Pickett

I recall way WAY back when with my A Coupe, having to change out my air correction jets when I got to Denver.  It Was not hard to do, and I could not tell you one way or the other if it made a hill of beans difference.  But the guys said do it, and so I did before scaling the Rockies. Two little Solexes, 32s I think.

As to EFI on Type 1s: sounds like a really cool theory.  Also sounds like a whole lot of theory and somewhat less actual fine reality, rather too hard to nail down.

I know you guys want me to really get into the EFI "package" deal. I am not sure that is going to be my focus. I really enjoy mechanical and wiring fabrication, routing, installation. I like the challenge of making things fit AND work well together. Packaging and problem solving are my thing.

Perhaps Mike and I can team up, as I REALLY enjoy building and fitting, and he likes the programming, debugging, and tuning. This might work, as I've emailed my tune and datalogs to Mike for analysis. And he's been really helpful to me, an EFI tuning neophyte.

Last edited by DannyP

Are you even serious, Ray?

I'll take a valve adjustment ANY day of the week over coolant, hoses, radiators, water pumps, and yes, COOLANT LEAKS!

To get no valve adjustments, you have two choices: hydraulic lifters(which are an option, but not for me) or a watercooled engine with no adjustments needed.

Not to mention all the extra weight you're carrying for all that crap. And don't forget air bubbles and bleeding...

I'm going with air cooling in my clown cars, thank you.

Last edited by DannyP

Now that's a good idea. If you'd get off your butt and go EFI we'd have a REALLY interesting project. Seriously, if you do want to go, I'd be happy to share what works for me.

It's true that I've made no progress either on the EFI or even getting the 2234 into the car, but In my defense - I've not really been "on my butt" (as you say) for the past couple of years.

I'll get to the EFI when I can.

Last edited by Stan Galat

I know it. I'm old, retired and can't wait too long, though. I need intellectual stimulation to stay sharp - like captioning flying baby pictures. Good luck on your projects.

Pfft. You're not old - you're just getting started. I've made my choices and I'm living with the consequences, but I really, really, really want to get this setup done. You have forgotten more than I'll ever know about setting up EFI on an ancient engine, and I want your expertise when my schedule finally thins out again.

I very much look forward to that day.

Oh, Stan-of-many-ailments (and suddenly I feel like I'm doing pretty darn well, health-wise):

Look on the bright side (at least for the house across the street).   You've only had some minor foundation problems to overcome.

There is a vein of the mineral Pyrrhotite running widely north/south through the middle of Massachusetts.  What is Pyrrhotite, you ask?  I had never heard of it either but it is a naturally occurring mineral that, when exposed to oxygen and water, crystalizes and expands over a long time to many times it's original size.  It was included, unknowingly, in the gravel used by some companies to make concrete for home and business foundations in some Connecticut and Massachusetts towns starting in the 1980s up until about 2015.  It causes the concrete footing, foundation, floors or slabs to literally crumble after about 20 years.  It's become a big deal here as more and more people are finding their house foundations just falling apart.

The only solution to this problem is lifting the entire house up off the ground, digging out the crumbling foundation, filling it back in with good concrete, then setting the house back down. This is an extremely expensive process, with quotes starting around $200K and quickly climbing.

Here's an article on it from one of the local TV news feeds in western Mass:

https://www.wwlp.com/news/i-te...ng-local-homeowners/

@DannyP posted:

Are you even serious, Ray?

I'll take a valve adjustment ANY day of the week over coolant, hoses, radiators, water pumps, and yes, COOLANT LEAKS!

To get no valve adjustments, you have two choices: hydraulic lifters(which are an option, but not for me) or a watercooled engine with no adjustments needed.

Not to mention all the extra weight you're carrying for all that crap. And don't forget air bubbles and bleeding...

I'm going with air cooling in my clown cars, thank you.

I was simply trying to point out different reasons for not going with AC .  



Your right and I get it with the bleeding and radiators two in my case so I went with evans coolant so I could pause on fluid changes.

The really nice torque band on a subie is pretty awesome.

" Old " is knowing what curb feelers sound like, penny candy, a .02 pretzel stick, Dot paper candy, flying a kite, lighting punks, steel roller skates, 3 cent Micky Mantle & Roger Maris baseball cards flapping against your spokes, .25 gas,  going to the neighborhood grocery with a note - list from your mom, a pitcher of Kool Aid was a supreme summer surprise.

Last edited by Alan Merklin
@Stan Galat posted:

May I suggest you meet "halfway" (between Maui and NY) in the People's Republic? We have corn AND beans.

Not so much on the elevation changes.

Wait, I thought the yearly meetings were going to be in Galax

The meetings can be wherever you'd like. Either or both of you are always welcome here(NY or VA), wherever that may be.

Once you decide to start in on it, I'll be happy to help, Stan.

" Old " is knowing what curb feelers sound like, penny candy, a .02 pretzel stick, Dot paper candy, flying a kite, lighting punks, steel roller skates, 3 cent Micky Mantle & Roger Maris baseball cards flapping against your spokes, .25 gas,  going to the neighborhood grocery with a note - list from your mom, a pitcher of Kool Aid was a supreme summer surprise.

I never collected baseball cards, but I do remember all the rest of those things.

Gas was 38 cents when I was a lad. I'm sure it was less a few years before but I never noticed until we bought some for my buddy's go-kart.

@Gordon Nichols - I deleted my list 'o woes at about the 59th minute of my allotted 60 because I feel pretty grateful to be still vertical (if a little beat up and bent). Nobody wants to hear it, regardless. Everybody's got something, and I've got nobody to blame but myself.

As far as the foundation issues out there - yikes. Our concrete gets "flyash" which is a byproduct of burning coal in a powerplant. The way they have gotten rid of it is to put it in concrete. This will not be an issue going forward (as we're headed into the brave new world) so they've decommissioned the nearby coal plants.

For about 30 years, there's been a real problem with "spalling", where the surface of concrete pops and pocks. It's been my contention that this was a result of flyash, but concrete guys disagree. I've always paid extra for concrete with no flyash, and fiberglass strands added. I've not had the kinds of problems some guys have had, but I've got a section of sidewalk poured last fall that is starting to spall. It's maddening.

Out here, old houses have brick foundations, which is how they fail. Mr. Homebuilder in the 1870s (when this town was platted) would work his day-job, then come home at night and hand dig his foundation. When he got through the topsoil and into clay (3- 4 ft), he'd stop digging and start laying the foundation bricks - 2 courses thick (8"). He would go about 2 -3 ft proud of grade, then start framing. The basements were between 5 and 6 ft deep, with brick floors, as built.

Generally, at some point later, somebody would want a deeper basement and a concrete floor. Typically, they would dig down another couple of feet, leaving a ledge around the wall so that the house wouldn't cave. My guy was braver, and dug straight down from the walls, formed a concrete lip, and poured a 4"-6" thick concrete "cripple" wall just inside the brick. The guts of that guy cannot be understated, nor can the quality of the concrete (now at least 100 years old). He went probably 18" down, then poured a 4" floor, which is mostly without a crack or a joint. The floor and the little cripple walls seem to be monolithic, and they are not the weak part of the setup.

The weak part is the brick, which while made from good clay and fired right here in Morton, IL, were never glazed in any way, and therefore have gotten a bit soft in 150 years, especially in the mortar joints. Parging the walls helps hold the whole thing together, but we had one outside (bearing) wall that had bowed inward at least 4". I jacked the house up (off the floor) and dug down on the outside with a mini-hoe. We knocked out the bricks and poured a new footer, then laid up a block wall. It was easily the skippiest part of the entire project (so far), and that includes when we dug a new foundation up next to a bearing wall, then poured a new concrete wall for a small bathroom/laundry addition.

The house leans about 1" in two directions, which cannot be rectified. We're hoping that stripping the plaster and lath will not further rack the house.

"They don't build them like they used to", and for that I'm grateful. The average old house in this part of the world is complete garbage.

Last edited by Stan Galat

Re Stan's old house and basement: About 15-20 years ago, during the fat part of the housing bubble, basement "underpinning" jobs got so think on the ground in Baltimore City that crackheads were doing most of them, directed by an alcoholic "engineer" and unsupervised by any building officials. This in rowhomes that were built much as Stan describes, except with "salmon brick" on oyster shell foundations.

Added to the dozens of long-abandoned houses that collapsed each year from pure neglect, the basement boom resulted in so many collapses in "nice neighborhoods" you would have thought—well, I thought—city residents and then officials would have taken notice. In a civilized society houses do not just fall down!  Alas. This phenomenon was taken as perfectly normal. Just part of city life.

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