Smarty UDC!!

[dorkweed]

AH64ID...................I've had a good amount of math, geometry, pre-calculus, etc. but I still cannot figure out how to read those 3 dimensional graphs you post.:ashamed:Can you help a guy out???

[AH64ID]

They are easier to read in the demo software, since you can rotate them. But what the graph shows, timing for example, is the amount of timing BTDC in relationship to rpms and load. So on the stock timing map you can see that timing doesn't increase with rpms/load across the board. There are some very retarded points in the middle of the map where drivers spend a lot of time. In general terms what you want to see is timing increase with load/rpms so that your peak pressure is at about the same point. So as you add fuel you have to inject sooner, and as you increase piston speed you have to inject sooner.

[Rogan]

basically, his 3D maps are just a fancy one of these (this from my 500whp Subaru when I was tuning it with OpenSource..)

[AH64ID]

I haven't updated this in a while.. Here are some past updates...

From 9/10/12

So it's been a while since I really gave any update, other than the dyno graph. Truth is that I didn't adjust my tuning for 2 months. I was very happy with it. It met all of my goals for how I was using it. Last week I did some towing and realized I needed to tweak the settings in the 35-55% load area. I was towing across Idaho at 2K rpms, OD, at 18K GCW (11' tall TT) into a 20-30 mph headwind on a 90° day. I realize that sustained operation in that load range gave me slightly higher EGT's than expected. I know a few degrees comes from the manifold blankets, but I was at 1000-1150° the whole time, and may have cooled off to 900° on the few shallow down-grades. I didn't have my laptop with me, but took some mental notes. On the return trip the temp was about 15° cooler, and I didn't have a head wind and the load was lower, and the temps where where I expected them to be. I know I am not going to be able to move that weight at those speeds at 900-1000° with a headwind, but wanted to make a small tweak.

I went back to my timing tables and thought I could add a little and see what happened. I had ran more timing previously and it hazed a little too much, but this time I tried even more. Still very mild. I haven't hooked up the trailer yet, but in the 30-50% load my EGT's are down a little, boost is similar, and the haze is similar to the more retarded setting. I get some haze in the "passing" region because the EGT's are low and the turbine isn't as efficient. When towing there is zero haze at those loads because there is more heat to be retained in the turbine.

I also got to looking at my cruise section of the timing table. I think there was a little room to improve on mpgs. This morning driving to work I did some testing with the lie-o-meter. I have been using 1600 rpms as the start of my "cruise/economy" region. I set the cruise at 1400 rpms on a flat road and reset the lie-o-meter, it instantly read ±38 mpgs, and settled in the 34 range. I then accelerated to 1600 rpms and did the same thing. It instantly read ±29 mpg and settled at ±28. I realize it's not 100% accurate, but 10 mpg difference for 3-4 mph? I thought maybe I had too much timing in the cruise region and was working against myself. I retarded the timing a bit and went back out. This time the 1400 reading was ±37 and the 1600 was ±36. So I think I am on the right track. The timing is still advanced for economy, but not so much that I am working against myself.

I have my first empty highway run for about 110 miles this afternoon, so time will tell.

I am coming out of towing season, so I won't really know if I like this new 35-55% region for a while, but that's tuning for you.

I also spent last week driving around Yellowstone. The elevation is 6400-8800. I was there last year and had to be very careful not to make a LOT of smoke on the standard Smarty Jr SW3 tune. This year there was hardly any, even if I got on it (kids like to hear the turbo whistle) the smoke was no where near as think and cleared very quick. The only difference from last year to this year is the UDC and a GDP Air Boss/Grid Delete. I would guess most of the smoke, or lack thereof, is the tuning. I did get 18.9 mpg driving around Yellowstone for the week, at about 9000 lbs. I got about 18.0 last year.

From 11/17/12

Another update...

I did that 110 mile run at 70-80 and got 19.2, so I think backing the timing off a little really helped. I have since bumped it back a tiny tiny bit and the load went down, so I am happy.

I have still been messing with that 30-50% load area, trying to find a good timing for spool, but also one I can hold sustained when towing and not have too hot of EGT's. I won't hook the trailer up again for a few months but I am pretty happy with how it works now. EGT's are down a little and no increase in spool time.

I have also decided to upgrade to a Smarty Sr. I don't want/need any more power than I am making now, but I really don't like the OEM rail pressure map. I think it should be smoother, and not have peaks and valleys in the middle of it. A smoother rail pressure map means smoother timing, less rapid FCA changes, pressure changes, etc. Since I built my own timing calculator I have already got a tune ready to plug into UDC when the Sr shows up. It keeps the same duration, and relative timing that I have now, but a very different rail pressure map. I am curious how it will effect everything.

From 11/17/12

Timing is a function of pulse width (duration) and rpm. Each load %age and rpm should have a different timing value.

Looking at some of the UDC samples timing is the same from 68.9% thru 100%. In a racing application that may be okay as they go from 20% to 100%, and don't spend much time between 70% and 90%, but if you tow I don't think flat timing is good. The pulse width at 70% is a lot shorter than WOT, so the effective timing is much greater, so at 70% load you will have higher piston temps, higher cylinder pressure, etc than at 100% load. Each load needs it's own timing. As pulse width increases timing must increase to keep the same relative (% before TDC and % after TDC) timing.

On my truck that high timing from 1000-1400 really is noisy. I dropped it way back. I don't have my Dongle with me, but I recall being around -3° at 12.6% load at 1000 rpms.

Generally speaking 1000-1400 (0-50% load) is spool region , this is the only place on my timing map I run less timing than the factory. Above 50% load here isn't obtained often, but I generally advance from 50% to WOT a few degrees. 1600-2400 0-30% is the cruise region, mainly up thru 25%, I use 25.1 as a transition and am completely out of the cruise timing at 31.4%. Now you are in the acceleration/spool/hill mode. I back the timing off to reduce piston temp, increase exhaust volume for turbo spooling, and still make good power. This is the hardest part to tune (32.4-100) because what works for spool may not be good for towing a trailer at 40% load for hours on end, so you have to mess with it to find the best spot. At these rpms the entire timing map can be used, especially if you tow. 2600-redline, this is the passing, racing, playing zone. My low load timing is not increased here (but how often are you 10-50% load in these rpms, this is the zone where you will be dumping fuel and need the power. Timing is critical because of piston speed, it's easy to go too far or too little. With stock duration/pressure I would stick to about 19° max at WOT/3200 and 22° max at WOT/3500.

One last thing, on the duration map Marco has rpms/load as the labels. That should be rail pressure and volume, as the duration map has nothing to do with rpms. The ECM uses rail pressure and desired fuel (load) to determine the pulse width. So that 100% 3600 rpm block can be applied at much less than 3600 rpms. This is needed if you create your own timing calculator.

IMHO it should look like this... Load on top, pressure on left.

So at 100% load and 23,206 (peak OEM rail pressure) the injector is open for 2005 micro seconds. The way a timing calculator works is you take that 2005 micro seconds, the deg/sec of the crank, and when you want to inject the fuel (say 50% before TDC/50% after TDC) and you get the timing needed. So at 2000 rpms it take 83us to go 1°. So 1002.5/83 is 12.07, or 12.1° of timing is what you need. At 3000 rpms it only takes 56us to go 1°, so you need 17.9° to get the same 50% of fuel injected BTDC.

Obviously the duration map is not all inclusive, so you will have to do the same extrapolation the ECM does if you want to calculate all your timing. You can calculate all the timing, some of it (I would work 100% load at a minimum so you know where you should max), or none of it...

I don't think you can create a mash it without smoke tune that is reasonable on UDC, simply because we don't have access to the boost/fuel limiter table. So the base tune may allow more fuel than we can burn smoke-free, and mashing will do that. But you can play with your torque management to get it there. I also found reducing the PoD to 85 really helped and didn't effect power at all. Even aggressive driving I am black smoke free (just a haze), but if I go from 20% to 100% throttle in an instant than I roll some serious coal.

Happy tuning....

Here is a timing map I made (and have severely altered) but it gives you a GENERAL idea of flow. Numbers are irrelevant without knowing pressure/duration.

From 11/22/12

Well I got my Smarty Sr yesterday, so instead of sleeping I stared at UDC all night. I had already built a tune in the timing calculator, so I just had to copy it over (really want a copy/paste function). I made some minor tweaks once I could see it in the UDC map (Excel graphs aren't as easy to read/manipulate) and it's done.

With my new rail pressure map the timing map is smother.

Here is the timing with the stock pressure.

Here is my current timing, as you can see less minor peaks within the map, all based on pressure.

As I have said before without knowing what my pressure/duration tables look like the timing numbers are irrelevant.

[JOHNFAK]

When for 2nd gen ?

[AH64ID]

Not sure, but you will like it!

[diesel4life]

Maybe they will start thinkin about us "peons" with the dinosaurs now that big brother took their rights away with the newer toys

[AH64ID]

Okay, so this is going to be a quick lesson on checking your peak timing. The purpose in this is to make sure you don't have too much timing for your fuel. It's possible to have a low timing number, say 16° but not have enough fuel for that to be optimal. A 50:50 split (BTDC/ATDC) seems to work good for heavier fueling. A little more if you are really trying to squeeze every hp out, maybe 51-52 BTDC or a little less if you don't want quite as much piston heat, 45-48. Those are rough numbers I have played with, but motor mods will have effects as well.

With the way the stock maps are laid out it's pretty easy to check 100% load timing, a lot more difficult to check lower loads. But with some common sense you can do a lot just knowing what peak timing should be.

So lets look at a stock 04.5-07 tune. For this lesson we will leave duration and pressure stock, just messing with timing.

This is a stock duration map with additional labels. What's important to note is that rpms is really load and load is pressure. 100% load is the only one that isn't appox, it's really 100% load. The rest are for reference to an OBDII reader and not necessarily to match the load on the side of the timing/pressure table (which is why anything but 100% is harder to calculate).

When the ECM goes to calculate the desired pulse width (injector open time) it looks at 2 tables. Pressure and duration, with pressure being first. Lets calculate the desired peak timing at 4 rpms, 2000, 2400, 3000, 3200.

So we first reference the pressure table. At 2000 rpms and 100% load the pressure is 20,885 psi. We then go to the duration table (one below with labels). You will notice that 20,885 is not listed on the left column, so now we have to do some math. There is a 23,206 row and a 20,305 row, with 2,901 psi between them. 20,885 is 550 psi above 20,305 and 550/2901 is 19%.

The next thing we look at is duration at 100% load. At 20,305 the duration is 2156us and at 23,206 it's 2005us, with a 151us difference. You will notice that as pressure increases the duration decreases for a given load, this is because the pressure forces the desired fuel out faster.

So we now take our 19% difference from the pressure and multiply it by 151 for 29us difference. We subtract that 29us from 2156us. This gives us a pulse width of 2127us.

So know we know how long the injector is going to be open for we can figure out when to start the injection event. A crankshaft has 360° of rotation, and by using rpm's we can calculate how long it takes to go 1° at any given rpm. Lets start with 2000 rpms. 2000 rpms is 33.33 rotations per second, multiplied by 360° gives us 12,000 deg/sec. A microseconds (us) is 1,000,000th of a second, so 1,000,000 divided by 12,000 gives us 83us per 1° of rotation.

Next you take the total injector open time, 2127us, and divide it by 83. That gives us 25.6° of total injector open time.

Let's say we want a 50:50 split of BTDC/ATDC. Multiply 25.6 by 0.5 and you get 12.8°. Thus we would set our timing at 100% load, 2000 rpms at 12.8°.

Now lets look at 2400 rpms on the stock tables. Commanded pressure is 22,336. Since 22,336 falls between row's on the duration chart we have to do the math again. 22,336-20,305= 2031. 2031/2901=70% . At 20,305 the duration is 2156us and at 23,206 it's 2005us, with a 151us difference. .70*151= 105us. 2156-105=2051us.

At 2,400 rpms it takes 69us per 1° of rotation. 2051/69=29.7° of injector open time. Same thing 29.7*0.5=14.9° of timing.

Now lets look at 3,000 rpms. Commanded pressure is 23,207 (same as 23,206), which happens to be one of the columns on the chart so no math is needed. 23,206 and 100% load is 2005us. At 3,000 rpms it takes 56us for 1° of rotation. 2005/56=35.8°. 35.8°*.5= 17.9°.

Now lets look at 3,200 rpms. Commanded pressure is 23,207, which happens to be one of the columns on the chart so no math is needed. 23,206 and 100% load is 2005us. At 3,200 rpms it takes 52us for 1° of rotation. 2005/52=38.5°. 38.5°*.5= 19.3°.

Pay close attention to the 3,000 and 3,200.. the pulse width is the same, but the injector open time is just under 3° longer at 3,200 due to the increased speed of the crankshaft.

So now you are able to calculate what your peak timing should be based on pressure/duration tables and a given rpm. When the load is less than 100% you need to have less timing than 100% load, or you will be injecting all the fuel much sooner and that can lead to increased piston heat and cylinder pressure.

A calculator is simply a starting point, not an ending point. You may or may not have to adjust your timing values from what calc gives you. It's a reference and a guide, not a rule.

[dorkweed]

AH64ID, you should consider doing a "power point" presentation of this stuff. I'm still not totally "getting" all the stuff you're posting. Is that possible over the website or the internet????

[War Eagle]

Professor AH64ID,:smart:This is great stuff! But I am thinking we need a class to even get some of the understanding that you have mastered. :think:Or how about tutoring or cloning?:pray:Thanks for keeping this info in circulation.

[AH64ID]

Are any of you guys considering buy it?I would at least download UDC, it's free, and see what it's about.

[AH64ID]

Cruise mileage is something I have been messing with nearly the entire time. I have gone the full gammet on retarded vs advanced for cruising. With the stock rail pressure map I really had to drop my timing back from stock at 1000-1800 to keep the rattle down. Now that I have a Sr I am re-attacking my cruise timing from 1600-2400. I have smoothed and lowered the cruise rail pressure and I can now bump the timing back up and not rattle! My cruise EGT's also went up a bunch with the lower rail pressure, and I have started bringing them back down now. I'll report back when I know more, but I am excited as I think I should be able to squeak just a little better economy out of it, not to mention lower cruise EGT's.

[CSM]

Cruise mileage is something I have been messing with nearly the entire time. I have gone the full gammet on retarded vs advanced for cruising. With the stock rail pressure map I really had to drop my timing back from stock at 1000-1800 to keep the rattle down. Now that I have a Sr I am re-attacking my cruise timing from 1600-2400. I have smoothed and lowered the cruise rail pressure and I can now bump the timing back up and not rattle! My cruise EGT's also went up a bunch with the lower rail pressure, and I have started bringing them back down now. I'll report back when I know more, but I am excited as I think I should be able to squeak just a little better economy out of it, not to mention lower cruise EGT's.

So, you are saying that you are lowering rail pressure... and therefore burn rate of your fuel... which is allowing you to increase timing?

[AH64ID]

Yes in the general cruise region I lowered rail pressure. OEM rail pressure has a big spike at low load, then a big valley as load increases. I felt it would be better for power/etc to have low load rail pressure be lower and as load increases so does rail pressure.

The slower burn rate may also provide for a more even burn/pressure spike at low fueling and thus more economy.. It's all playing at this point.

I got up to about 9-9.5° of timing and am getting a slight rattle so I'll back it off again, but I know the limit with my pressure settings.

My truck doesn't like timing at low rpm like some do, like dorkweed's. I'd go insane with the rattle with stock timing and a tone ring mod.

You can see earlier in the thread what OEM rail pressure looks like, here is what I am running now. The truck seems to like it. The longer/slower burn really helped spool (not that it was an issue) below 1400rpms. Now I just have to get the timing optimized and I am sure my cruise EGT's will drop back, they went up to 700-800° with just the rail pressure mods.

[jlwelding]

[War Eagle]

Are any of you guys considering buy it? I would at least download UDC, it's free, and see what it's about.

I already have the S6 PoD. I wasn't planning on buying the SSR also, so I am still thinking I can do the UDC stuff, but I have to learn more about what and how it works and what to adjust and not adjust.

[AH64ID]

Unless you are racing/pulling there is no need for SSR. Normal driving/towing is well within the limits of the Sr on UDC. If you want to run UDC you have to come up with a list of things you would improve upon the tune you currently run. If you are happy with your current tune there is no need to get UDC, but if you want to change a few things it's great!The torque management feature is almost worth it alone!

[AH64ID]

The family and I went for a drive today and I was reminded how long it takes the entire truck to warm up. We drove about 100 miles and I bet it took 35 or so before everything was hot. During the first 20 miles I was cruising level at about 4 psi and 750* at 68 on level groung at 35-37* with less than 3 mph of wind. On the return on the same route with the same conditions I was at 2 psi and 600-650 with a few % less load too. The only difference was the temp of then trans and diff fluids, it just takes a long time to warm all that stuff up. My point is if your doing test runs in winter you need to add extra miles for temps to stabilize so you can see how the truck reacts to the changes. Many people blame the fuel for poor mileage in the winter, but I really think its only a small percentage with the cold fluids being a big one, followed shortly by cold/dense air.

[War Eagle]

I concur with your thinking on the cold temp being an extra drag on all the mechanical parts that run in oil (engine, tranny & read end)I have noticed the same thing on a cold morning. It takes a long time for me (my body) to get warmed up and moving efficiently.

[Bill Hedges]

Is that a topo of the rockies over the blue ridge? Some times i just dont know what to say about the things some of you guys post. It is so far over my head it is rediculous. I mean no disrepect to anyone and hope you keep posting this kind of info because I have learned from some of it and other things are just way over my head. I cannot believe how much i have learned and I do have the utmost respect for every one here, they all seem to contribute in what ever way they can and thats what makes this place stand out from all the others. Thanks for letting me be apart of it.

+100% for me it is VERY intimidating. i have nothing useful to add to any of these posts but i did want to say it is dumbfounding the amount of brainpower ,skill,and expertise that goes on at this website. and i thank you all. ok back to my lurking until i learn enough to ask an intelligent question.