AH64ID

I have a Bilstien damper and like it over the OEM one, but I also have the older steering. I'm not sure what steering you have. As for shocks I run the 5100's and my truck rides great! It rides better with the LRG tires than most I have ridden in with LRE tires. I have stock springs, bushings, and a 1" spacer level kit. I've ran a lot of different shocks over the years and the 5100's I have now have been the best. Rancho 9000's were the worst, followed by Rancho 5000's. 4600's were good, but I prefer the 5100 feel. Lots of different suspensions, vehicles, etc... but I drank the Rancho kool-aid for many years on may rigs and looking back they were a horrible shock. As for the ride differences. Does the 08 have a level kit,aside from the thruen? Have you looked into body mount part number differences from 04 to 08? What about control arm bushings? I would think the softer Thuren coils would help, but the steeper control arm angle will hurt you. When I went from a 2" level down to a 1" level the ride difference was night and day. Literally like going from riding empty with 80 psi in the airbags to 5 psi.

Long story short.... yes.

I know that the CR injector test machines do this. That is my understanding. As soon as you increase the nozzle size the flow will increase above 125mm3. Without knowing the exact internal working of the VP I cannot comment as to how efficient it is... i.e. does a nozzle capable of 2x the fuel on a test stand actually flow 2x the fuel in the truck.

The volume of fuel injected is dependent on the nozzle size. If you go to bigger nozzles you are injecting more fuel, hence the more power and more smoke :-) The 125mm3 is part of the OEM calibration of the ECM/VP44. They know that at OEM power the commanded volume of fuel is 125mm3, it doesn't mean it's always 125mm3 or that it can't inject more than 125mm3.

Yeah they haven't appeared to have too many issues in the past, but don't want to find out the hard way :-)

That's some pretty dang good mileage! When I up my main timing in the cruise section too much I get a haze and don't like it. If you're getting the haze and pulling harder it's a good timing value, but about as much as I would run without strapping it to the dyno.

A lot of it is smoke driven. Often a greyish haze is seen around optimal timing/fuel when fueling heavily. This gives me an idea that I am nearing max timing and will adjust from there, usually a small retard in timing cleans it up nicely. Sounds is another big one, thou I am not sure how that applies to your noisy *** VP truck :-) If it's not smoke or noise driven then it's usually trying to improve mileage or decrease WOT EGT's. I'll be honest, a lot of my tuning is done remote so I am looking at the data I talked about above. BTDC:ATDC, degree at which the injector closes, etc. When people I am tuning for ask for revisions I like to get load, rpms, boost/EGTs, rail pressure, etc.. Usually they are looking for more power or lower smoke. One thing I have found is that every truck smokes different, but most trucks are usually happy within a degree or so of each other, relatively speaking of course. For my personal tunes I sometimes go many many months without making any tweaks, especially major ones. I think I have only done a couple of tweaks in the last year or more, and most of them deal with the adjustment tables and not the main tables. Most of this year has been spent getting the pilot where I want it. Quiet combustion was my main goal at low rpms/loads. With UDC Pro and a ComMod I am able to adjust some tables on the fly (timing being the one I normally do). I've had 3 full tune flashes since March and before March I didn't do anything after August. For pilot tuning I have to do a full flash, not just a RT (real time temporary flash). Thou I don't recall the last time I tweaked anything in the empty zone of the tune, just towing. For the first time in well over a year I redid my timing tables with a big change. This last month I tried 2 different timing profiles in the 40-60% load range from 1600-2000 rpms. The tune pulled well, ran clean, and was fairly efficient, but I was hoping to pull a little better mileage while towing heavy. I made changes from 0.2°-1.5° in this area. What I noticed was a small reduction in EGT's, about 25-50° tops, no change in boost, but about a 10-15% increase in economy (high 9's to low 11's in similar loads/driving). I then went a little further and EGT's went up and boost down so I went back. I was happy enough I made an ECM file and flashed the tune. So now I'll do some additional towing and see. I've got some trips coming up that are repeats of last year with the old tune so I'll see what happens. Since I started custom tuning my truck in 2012 I bet I have 100 ECM flashes. A lot of them deal with becoming a better tuner, some deal with experimenting, some deal with hardware changes, and some deal with tuning software changes and table availability. It took 3 flashes to get my fuel gauge reading how I wanted it to, and it took one flash just to enable my 2nd WIF sensor. So not all of them are drive ability tweaks. I'm also picky and experimental. I want to know how small changes make effects so people I tune for get the best product. Sometimes I just want to see if I can do it better even if it's working better than expected, but I'm sure none of you in here have that issue In terms of ±0.5° being too much, I try to tune on the safer side of that. To me trying to get that final ±0.5° should be left for dyno tuning a race tune. Street/Towing tunes shouldn't be at that level of timing, IMHO. That being said playing with ±0.5° in the cruise profile isn't the same. You guys are seeing what happens with too much timing and the sluggish feel. You may not feel that at WOT at 2800 rpms, but it's not a good thing. So, I guess spool, EGT's, boost, noise, exhaust color, smoke, etc should all be looked at in regard to non-cruise timing. It will take time if you're trying to get full optimization, but even that will change with elevation and seasons.

Well hell..... The OEM duration table goes up to 240 mm3 but we only ask for 115-120mm3... I was hoping we could use all of that 240.

Yes there was lots of learning going on in the early VP days. Trying to get the ECM to talk to a smart injection pump was a lot of fun from what I hear. The quad looks like a great platform for sure!! I'd like to mess more with UDC Pro on a VP truck, I just don't have access to one. It look like the VP is capable of nearly 2x the OEM fuel but it's hard to say what it will allow for.

Using my 05's tune I'll try to go into a little more depth about the timing cliff. Lets look at 2000 rpms. 30mm3/21% is close to normal cruise empty at 70 mph for me. At 2000 rpms and 30mm3 I run 7.0° of main timing, that puts all of the the fuel injected 1.4° BTDC. 100% of the fuel is injected BTDC. At 2000 rpms and 65mm3 (46% load) my timing is at it's lowest point of 1.5°. All of the fuel is injected by 9.2° ATDC, and 14% of the fuel is injected BTDC. At 2000 rpms and 145mm3 (100% load) my timing is 8.3°. All of the fuel is injected by 11.7° ATDC. 41% of the fuel is injected BTDC. You can see that there is 6.8° of timing advance from 46-100% load, but the injection events end only 2.5° apart. This keeps peak cylinder pressures at similar time for different quantities of fuel and timing. The boost/fuel numbers at 46% load will also have a longer ignition delay which pushes the peak pressure back. So if I were to run 7° of timing at 46% load the fuel would be injected by 3.7° ATDC and 65% of it would be injected BTDC which can lead to negative torque, and poor exhaust flow/spool. So at 26% we have low fuel/boost and a long ignition delay so we advance the timing to get peak cylinder pressure where we want it (12-15° ATDC optimally). At 46% load we have more fuel/boost so the ignition delay is shorter, but the injector isn't open very long so we need less timing to get that peak cylinder pressure where we want it. (Remember CR's use a pilot so the timing is too low for a CR). At 100% load we have plenty of fuel/boost to give us a short ignition dealy. We need to advance the timing here so that we get the fuel injected and ignited to create peak cylinder pressure where we want it. Too low of timing will still result in good ignition but we miss the 12-15° ATDC window and lose power with higher EGT's... but lower emissions (think 04.5-07 CR's). So it's all a balancing act of rpms, injection duration, ignition delay, peak pressure, and efficiency. Hopefully that clears up the mud just a little.... I'm trying to only discuss the stuff as we can correlate CR to VP. It almost looks like your truck is trying to defuel but the Quad is overruling the ECM.

Yes it is, and it's still aplied in the ECM, especially with CR's, but it looks much more difficult to fine tune. It doesn't appear you can adjust just 60-80% load and leave the rest alone, maybe i'm wrong thou. Same thing we've been talking about in here with the timing dip after the cruise portion of the map. It's not as deep as it looks thou. At 1800 rpms my peak cruise timing is 6.4° and my lowest timing is 1.0° and then it rises back up to 6.1° by 100% load. Here is the same view on a stock early 04 map.

I don't like the math and if/then stuff. It doesn't seem as adjustable. I'd much rather build a 3D timing map, but that's where my experience is.

It is defiantly easier to understand, but not enough variables based on my CR tuning experiences.

Haha, yep. Seems simple enough to make it more complicated :-) No wonder UDC Pro looks busy.

I can't imagine that most users need to mess with the low boost timing reduct, but it's hard to say. The max load timing offset seems odd, so with Quad do you not have a 3 axis map for setting timing? i.e. rpms, load, and timing?

Boost plays very little into timing adjustments in the CR world, even on stock tunes. Really the boost adjust table is just there for HIGH altitude going from coast to mid fuel and once boost is above 1-2 psi the boost adjust table is 0. As boost comes up the ignition delay is reduced, due to higher intake volumes and temperatures, so you get the effects of timing advance without advancing the timing.... make sense? So no, I wouldn't adjust timing based on boost unless you're running a HUGE single turbo and can't get it to spool. Which begs the question, does Quad allow for it? It's not an OEM table that exists in UDC Pro. The timing drops off because there isn't the fuel to support the timing. It works in cruise because the fuel quantity is so low that the ignition delay is longer. As fuel is increased the ignition delay is decreased and timing needs to drop to keep peak cylinder pressure at ~12-15° ATDC.

Right where it needs to be. This is where the timing would be too great if it didn't drop off and too much negative torque would develop and reduce power and increase strain inside the cylinder.

It looks like it. What year are you looking at with the UDC table listed above? 2002 shows a much bigger drop. The difference is labeled as steady state and transient. I understand that to be constant rpm vs increasing/decreasing rpms. I am not sure of the threshold to get into the difference thou.

A quick look at UDC Pro tells me that max mm3 is between 115-120mm3. That's on a 2002 SO, and HO manual trans federal tune.

That's a descent drop, and more than we are seeing in the above table. That's also a common drop area based on getting out of the cruise area and into the "spool/work" area. I'll have to dig around UDC again....

I am quite certain that 20-25% load is not ~70 mm3. 70mm3 will be closer to 50-70% load. How much timing are you seeing pulled at 20-25% load? And at what rpm? That feeling is called negative torque. Too much fuel is igniting BTDC and the other cyliders are having to work harder to get the firing cylinder from the compression stroke to the power stroke. It's also creating a TON of cylinder pressure and is very hard the head bolts/gasket. EGT's may even decrease because the cylinder has a lot more time to absorb the heat. Too little cruise timing will increase load and EGT's and decrease economy as well.

I have seen the higher MM3 reference in the some maps, but that's not going to correlate to 100% load. IIRC I have mm3 references in my tune over 200, but OEM limits fueling to 132mm3. Most of the CR tables run up to 145 mm3, which is why a stock CR will only peak at 91-92% load. There is more fuel available but the ECM is hitting a limiter. I don't have my tuning computer with me today, but I'll try to remember to bring it tomorrow and let you know what I find for load to mm3 correlation. I know we did a thread a while ago about valve cover mm3 value but I cannot find it. It may not mean that value is 100% load, but it's going to be close. Proper timing is like fuzzy math. There are different proper timing values for many things, it's why custom tuning is so popular. Box tunes use a couple (with things like Smarty Revo) timing tables and we find what works best. Custom tuning lets us tune for specific mods and use. Proper timing on a street tune will be different than proper timing on a tow tune on the same truck without any hardware changes. When I work on a timing map I look at things like the ratio of fuel BTDC:ATDC and when the injector closes ATDC. But I also have to look at rpms, load, mods, and use. This is why I can drop timing with larger injectors, but it's the secondary effect. The primary effect is that I was able to shorten duration for the same amount of fuel. With a shorter duration I don't need as much timing to have my injector close at my ATDC goal. Less timing and a shorter faster injection event are good! With modern tuning I now recommend slightly larger injectors than I would have 5 years ago. The empty cruise profile is the only place where it's a little different and we use a lot of timing, relative to quantity, to get some efficiency. If we tried that much relative timing with WOT fuel we would have some serious engine issues. If you're trying to squeeze every hp out of a motor then we dyno tune. By running the truck on the dyno we are able to advance timing until the power production peaks. Once it starts to go back down, too much timing, we back it off to peak and there is the max advance we should run. This will of course vary per rpm and fuel quantity. Way too much or too little timing should be visible in the exhaust, on the gauges, or audible.

I honestly don't think there is much R&D being put into W/M systems since we have gained so much control over the ECM and tuning. We can do a lot more with tuning today than we could in 2011.

Dyno's aren't really needed unless someone is trying to get 100% out of a setup. Many of the tables that appear overwhelming have minimal impact and/or are just for drive ability and emissions. You can make UDC Pro as simple as Quadzilla by leaving many of the tables stock, just like Quadzilla likely does or you can modify them to meet your needs/mods. I'd jump into the VP tuning but the lack of the "base" table has me wondering. Thou maybe with a custom tune the base table is zeroed and only the one table is needed. I've been doing custom tuning for 5.5 years and still learning stuff, so it's not a quick process.

The pilot's main benefit is to decrease noise and improve initial combustion, especially when the main event is at a very low timing advance (such as ATDC for OEM tunes, or certain profiles). This all has a play into emissions. At higher rpm's and loads there is enough timing, with modified tunes, that there isn't much of a benefit to a pilot. There isn't an audible difference and the pilot timing gets to be pretty far advanced when the main is advanced 15°-25° or more. I personally don't run much more than 18° of timing, but that's also becuase I get to run a failry short injection duration based on the size of my injectors and desired horsepower. When I dropped the pilot at upper loads I noticed a small decrease in EGT's for the same load and that I lost a little bit of power, but not enough that I even bothered to correct it.