Have you measured when the injectors...

[psychophyr]

Originally Posted by 06Speed6 ... ~800cc/min @ 1000 net psi, more or less.

If this is true we have a ton of headroom, but I was under the impression that noone has actually tested our injectors at thier normal operatiing pressures.

[djuosnteisn]

i'm not trying to flow test injectors here, simply showing you when mine are opening. I have no clue what the difference in flow would be from 1000psi to 1500psi, but i have to think there is marginal returns after a certain point. Not like typical PI injectors where you double the pressure, you double the flow.

Plus haven't we always suspected fueling? I'm showing some potential proof and we just jump right back onto the speculation train, lol.

Like i say, i can't tell you how much they flow, but i can say my injector is open for a significant amount of time, i'm fairly modded, and i run mid 11 afr's at wot.

[psychophyr]

I wasn't asking you to flow test them, I was referring to the number given by 06Speed6. with the proof you have given us though is that, even if we could adjust when the injectors sprayed, we dont have any room for it. So if fueling is the problem then its the amount sprayed in that time that is the reason for the problem.

[djuosnteisn]

Just want to throw this out for darksun:

Say our injectors are 800cc/min @ 1000psi. And we run at 1500psi, so let's even give them the benefit of the doubt, and say the flow increases by 50%. Thats 1200cc/min @ 1500psi.

We have half that time, so cut it in half. That's 600cc/min in our application. A 600cc/min injector, running at 80% dutycycle on a PI motor is good for about 400hp tops.

Is it too hard to imagine we may be reaching the limits of our injectors?

[psychophyr]

Originally Posted by djuosnteisn Just want to throw this out for darksun: Say our injectors are 800cc/min @ 1000psi. And we run at 1500psi, so let's even give them the benefit of the doubt, and say the flow increases by 50%. Thats 1200cc/min @ 1500psi. We have half that time, so cut it in half. That's 600cc/min in our application. A 600cc/min injector, running at 80% dutycycle on a PI motor is good for about 400hp tops. Is it too hard to imagine we may be reaching the limits of our injectors?

I know it was meant for someone else, but considering our pump puts out around 1500 psi (seems to vary between cars) that doesn't mean that each injector gets 1500 psi does it?

[Darksun280]

Originally Posted by djuosnteisn Just want to throw this out for darksun: Say our injectors are 800cc/min @ 1000psi. And we run at 1500psi, so let's even give them the benefit of the doubt, and say the flow increases by 50%. Thats 1200cc/min @ 1500psi. We have half that time, so cut it in half. That's 600cc/min in our application. A 600cc/min injector, running at 80% dutycycle on a PI motor is good for about 400hp tops. Is it too hard to imagine we may be reaching the limits of our injectors?

roar.

but get this. on my 2.0 liter ss/sc cobalt on a 3.0 pulley and had 32/lb injectors and ran them at 148% DC shits should have went static a long time ago but car could still consistently hit a power wall of 260whp for me at 13.5 a/f's. So that means my injectors gave all they could and as the mixture leaned out and made power till the mixture did not have enough fuel to keep going up . I was no where near a flow limit at that point. Ive seen a power wall limited by fuel this is not the shit we are getting cause our injectors aren't anywhere near max. I bet you they can't hit commanded properly when forced but they can flood you out. thats not the same as running out of fuel its more like a lack of control IMO.

[djuosnteisn]

Or a lack of time, hence 06speed6's analogy of a redline on our injectors.

Okay, i figured out how the injector control circuitry works, and it explains why you see a double pulse on the actual injector line, i drew a pic to save any loss in translation:



There are 2 + source voltages shared between injectors 1-4 & 2-3. This way the current gets divide evenly between two rails.

The injector only opens if there is both a positive source voltage, and a 0 volt return.

On the scope (because the injector control is just a coil), you could see when the positive source voltage was switching between the groups 1-4 & 2-3, but only when the other paired injector was firing.

[06Speed6]

Originally Posted by djuosnteisn Don't forget you only have half the time to inject compared to a PI car though. So 800cc/min = 400cc/min in DISI.

Using that logic we actually have a 1600cc/min injector.

Originally Posted by djuosnteisn Just want to throw this out for darksun: Say our injectors are 800cc/min @ 1000psi. And we run at 1500psi, so let's even give them the benefit of the doubt, and say the flow increases by 50%. Thats 1200cc/min @ 1500psi. We have half that time, so cut it in half. That's 600cc/min in our application. A 600cc/min injector, running at 80% dutycycle on a PI motor is good for about 400hp tops. Is it too hard to imagine we may be reaching the limits of our injectors?

You should go reread my post, I said ~800cc/min at 1000 net psi, the injectors begin to missfire at net pressures higher than 1000psi and cant even open past 1250 net psi. Net psi is rail pressure - chamber pressure.

Originally Posted by psychophyr I know it was meant for someone else, but considering our pump puts out around 1500 psi (seems to vary between cars) that doesn't mean that each injector gets 1500 psi does it?

Each injector sees the full rail pressure, whatever that happens to be.

[djuosnteisn]

Here is where my injector knowledge left off:

[quote name='whoosh']

update~! David tested the injectors at a few different pressure levels but the pressure indicated on the report is industry standard for injectors, that is for conventional injectors but obviously not GDI's there is no equipment available at the moment to test at the rail pressures the MS3/MS6 operates with that being said I applauded his work and dedication to the cause regardless of the pressure the injectors were tested at, we have a baseline flow rating and can move on improvements from there he tested this set for free and is sending me a beta set of "balanced 20% increase injectors" I asked if he would explain the method as to how he's gaining the 20% and all I got was a chuckle and the fact that's it's proprietary he did mention that increasing the flow on injectors can usually be done up to 50% but the hardness of the metal and the methods are completely different on the GDI's vs. conventional injectors he assured me that the reliability and spray pattern would remain as OEM quality but 20% more flow.............nice! so basically we are calling the MS3/MS6 injectors 220cc @ 3bar the higher flow units will be 250cc @ 3bar although he didn't want to put himself out there, David thinks that the power levels being hit right now on the OEM injectors indicate a 600-650cc flow if they were conventional injectors safe to say as nobody has been in the situation of being lean due to lack of fuel from the injectors unless there was a failing injector either way, the bad news is (as you can see on the data sheet) the injectors tested were 3.2% off in terms of matching flow to one another this was after they were cleaned!!!! he also said the MS3 injectors tested were the same amount % off from one another he likes to see no more than 2% difference between injectors, anything more can cause AFR differences between cylinders

[quote name='whoosh']

thanks guys! I have recd the equation to figure out the "cc/min" @ our high rail pressure but there are some factors that don't allow the equation to be accurate meaning, duty cycle is 80% max and our GDI's have a pulse width of about 5 miliseconds compared to conventional injectors duty cycle of 35 to 40miliseconds with these differences, the numbers just don't make sense I have a call into Corpus_speed6's contact in Canada to try make sense of all this I'm not too concerned with a calculated number though like said before we have hard data of our injectors at 3bar we will have the same data of our modded injectors to prove a flow gain which means we can potentially squeeze out some more HP :drool: usiung the OEM "modded" injectors

Can you explain to me how that equates to 800cc/min in a 5ms window? Also you can notice that my timescale on the scope in the vids is 5ms per division, so 8m/s ish seems realistic enough.



Also at this point i think i'm done with this. First of all i'd like to see some big brains (get a general consensus from the community) either confirm or deny the testing i'm doing. I don't want to bicker about injectors. I've done alot of work on this shit and i need to know if it's valid or not.

Here's a post i came across back in 2007 from cp-e on this exact subject. I didn't even own my car back then lol:
[quote name='www.cp-e.com']

There have been a lot of questions about when the injectors fire, so I thought you guys might enjoy hearing about our data logs last night. We're still tweaking on oupiggyback, but we're also exploring the MS6 at the same time. Believe it or not, we finally figured out what the hell the injectors are doing. At first, we thought we got our cycles wrong, or made some computational error because the results didn't make a whole lot of sense. It turns out that at wide open throttle the injectors open towards the end of the compression stroke, and stop firing either just before, or just after ignition depending on the engine load. :wacko: So the next obvious question is, "What is the duty cycle then?" There isn't a whole lot of published data on the operation of direct injectors, althought knowing what we know now, there is probably a lot to learn from diesel injectors. But we need to figure out how the fuel pressure changes while the injector fires. If the pressure stays relatively constant, then we may be able to stretch the pulse-width further into the compression cycle if we need to add a lot more fuel. The tricky part is that the fuel pressure is linked to a feedback loop, so the car is constantly changing the pressure. So, Lou is working on collecting the requisite data and we should have some answers soon. With this info we can calculate a duty cycle, but in a best-case scenario we're only using about half of what the injectors are capable of firing. Again, if you want any charts of the data let me know what info you'd like to see and I'll post it up. So I think this is good news as far as how much injector we have left. We're closer to getting a definitive answer, but the data looks good so far! More to come... Jordan

So who's right?

[Darksun280]

Mazda: 1 Guys on forum: 0

[06Speed6]

There is no duty cycle for DI injectors, it is assumed 100% duty cycle.

The Corpus_Speed6 that whoosh was referencing is me, I worked with him on those logs and we determined that we couldnt compute a valid cc/min from his injector logs.

The CPE article also appears to be wrong based on your data since in your logs the injectors open at the beginning of the intake stroke and not the end of the compression stroke.

Bottom line is that if CPE is saying we have 5ms of injection time from near the top of the compression stroke to the point of ignition then we should be looking at alot more time on your logs.

Someone isnt reading the data right.

[FreeFlyFreak]

Originally Posted by djuosnteisn Can you explain to me how that equates to 800cc/min in a 5ms window? Also you can notice that my timescale on the scope in the vids is 5ms per division, so 8m/s ish seems realistic enough.

Originally Posted by 06Speed6 The CPE article also appears to be wrong based on your data since in your logs the injectors open at the beginning of the intake stroke and not the end of the compression stroke. Bottom line is that if CPE is saying we have 5ms of injection time from near the top of the compression stroke to the point of ignition then we should be looking at alot more time on your logs. Someone isnt reading the data right.

For what it is worth the Cobb fueling calculator shows a 9ms maximum injection window at 6700 rpm.
10ms at 6000rpm and 12ms at 5000 rpm.

[djuosnteisn]

And the cobb calculator allows for complete intake and compression stroke AFAIK:

Here's Christian's $.02 on the injector discussion:

[quote=Christian.;191493]

First off, please take my posts as me simply trying to help. I have most likely tuned the greatest number of these vehicles across the world...nothing I am trying to brag about, I am simply stating facts. I would like to help and I have a pretty good understanding about what questions you all will ask concerning these issues that will need to be dealt with, or at least understood. Simply put, DI engines have approximately 1/2 the injection time available as Lex stated. The below picture and data should demonstrate this for you all. I have this information on a spreadsheet if you are interested in looking at it in detail? I do not have any information about ATR, so please do not ask. If the conversation does not maintain some civility, then I will simply step out and let you all try to speculate as much as you desire. I would describe this as the logic that switches between or blends from stratified fueling to homogeneous. This is the ECU literally switching fueling strategies back and forth as the engine constantly runs. I don't believe this to be the case. I have already tuned a few MS vehicles that a CDFP from a predominant vendor and I ran out of fuel flow on those vehicle. I had plenty of pressure, but not enough flow. This is something that should be able to be worked out with proper DI high pressure fuel lines and orifice sizing. Not a problem, we had that since day 1...maybe day 2. These vehicles have 2 additional injectors and additional displacement so you will have to analyze the torque output/displacement ratio in order to get apples to oranges. Most estimates are based on flow of the stock fuel injectors. We can discuss this in greater detail later. One of my objective was to complete all the R&D for this community so I could give you guys some good information about how to go about making various things work properly. I have already tuned for larger MAF housings, larger fuel injectors, larger turbos, EWG, etc. and I have all of this information ready to release after some final reviews. Is PT Performance purchasing the ATP software? I would appreciate having the ability to discuss various things with a trusted tuner in this community. I hope this information is helpful, Christian.

[quote=Christian.;192304]

That is not the case in any way shape or form. Please verify with me prior to posting any speculation about the capabilities of the AccessTUNER software. If we can modify MAF calibrations, fuel tables, etc. then we obviously have control of the injector pulse width output (or injector duration). These engines still only have the window of DI injection that will need to be addressed for turbos that flow over 40lbs/min (approximately). Both John and I are on the same page...DI injection duration window is approximately 1/2 the time available of a Port Injection engine. No matter what EMS, this will eventually be something that needs to be dealt with. Larger fuel injectors with additional fueling capacity will be able to provide these engines with additional fueling. I wish it were that simple...the ECU constantly has system checks to verify the intake camshaft phasing is approximately what it should be for the given conditions. The car will pull MIL codes if the variable camshaft control system sees the camshaft is not within expected parameters. Please remember that the ECU checks intake camshaft phasing as well so it knows how to calculate its fuel stratification strategies. Christian.

I'm pretty damn sure my data and measurements are sound.

Originally Posted by 06Speed6 Bottom line is that if CPE is saying we have 5ms of injection time from near the top of the compression stroke to the point of ignition then we should be looking at alot more time on your logs. Someone isnt reading the data right.

If we had 5ms from near top of compression stroke to ignition, we'd be at a ridiculously low rpm. Look at my scope logs, your looking at like a max of 10ms for 1 crank rotation, 20ms total for 1 cam rotation.

[Lex]

The first clue to what is going on doesn't require the understanding gained from the scope.

Exhibit A below shows you the commanded fueling (in mg/stroke) as the engine is accelerating in 3rd and 4th. You will notice 2 things:



1. The amount of fuel (opening time in milliseconds) of the injectors stays constant for most of the WOT run in each gear from a very low RPM until it gets past 6000 RPM. However, the engine DOES not ingest the same amount of air throughout the RPM range as shown below in a dyno run of Dustin's car (check the MAF reading). Yet, the AFR stays constant indicating the same amount of air versus fuel is found in the exhaust gas stream.



Another clue that something is off is that the volumetric efficiency of the motor decreases from mid to high RPM, which means the motor is able to breathe less (shown by a decline in torque) but at the same time fuel injected is the same to keep the same AFR. I have attached a picture below of what my port injected car does. In order to keep AFRs constant, the amount of fuel (PW) decreases as the volumetric efficiency drops (Gve).

2. As the RPM reaches 6000 or so, the amount of fuel requested goes up quite a bit. However, the AFR remains relatively constant once again. As you watch the videos you will see the same phenomenon. The green pulse indicating injection duration starts to really get wide as he passes 6000RPM and is often associate with a shift.

Coincidentally, the DISI motor starts to lose a substantial amount of torque around the 6000RPM point again shown in the dyno plot below

[djuosnteisn]

In the logs, i'm pretty sure the widening of the injecton trace corresponds to shifts.

Also, could we be losing some fuel during overlap? Thus needing to inject more? I'm not sure. Lastly how does the tumble and mixture play into all this?

[Lex]

Before speculating what has been before, it is important to put 2 things to rest:

1. Injectors tested at 43.5 psi means nothing when the injector runs at 1500 psi. You can't correlate flow with pressure without mapping the flow at all pressure readings.

2. In spite of what COBB and CPE have said, the ECU pushes the injection window closer to the beginning of the intake stroke first. It then pushes the opening window into the compression stroke. As the RPM increases and 6000RPM is exceeded the ECU really widens the injection window pushing it well into the compression stroke.

Power gains are however very minimal at this point and AFRs do not increase to show the increase in fueling that is occurring.

Originally Posted by djuosnteisn In the logs, i'm pretty sure the widening of the injecton trace corresponds to shifts. Also, could we be losing some fuel during overlap? Thus needing to inject more? I'm not sure. Lastly how does the tumble and mixture play into all this?

Have you tried running the car to redline and measuring mg/st and not shifting but simply letting off? I am leaning towards you seeing the same increase in fueling past 6000RPM even without the shift.

[Darksun280]

Originally Posted by 06Speed6 There is no duty cycle for DI injectors, it is assumed 100% duty cycle. The Corpus_Speed6 that whoosh was referencing is me, I worked with him on those logs and we determined that we couldnt compute a valid cc/min from his injector logs. The CPE article also appears to be wrong based on your data since in your logs the injectors open at the beginning of the intake stroke and not the end of the compression stroke. Bottom line is that if CPE is saying we have 5ms of injection time from near the top of the compression stroke to the point of ignition then we should be looking at alot more time on your logs. Someone isnt reading the data right.

I hate to side with CPE but the Cobalt guys report the same thing but they have like a 7-8ms window to fire in something like that.

[Lex]

AT 6000 RPM, the engine takes around 10ms to complete a revolution, so one stroke is around 5ms.

Past 6000RPM the injector is firing for almost 2 strokes. So around 8-9ms. The entire intake stroke and part of compression. However before that the pw is kept fairly constant from when you start the pull to around 6000 RPM. Since the pulse is kept constant with respect to time, it moves from just being in the intake stroke to being in the compression stroke.

Every injector has a duty cycle with respect to crank rotation. We are limited to 50% duty cycle in DI applications

[Darksun280]

I have noticed that cobalts rev range is just like ours aswell where over 5500 rpms everything starts to fall off. don't know if that helps any.

[06Speed6]

I gotta agree, something isnt right about someones logs, the torque on on the MZR DISI dynos I have seen goes down past 4000rpm or so which indicates that the engine CFM for any given intake stroke is less at 6000rpm than 4000rpm. This lower air flow should require less fuel and if the scale of the graph on the scope remains the same.

The graph should show a shorter injection period as measured in real time and not crank degrees between 4000rpm and 6000rpm when maf voltage and A/F is a constant. We need to determine if that is actually what the scope is showing.

Can we all agree to throw the whoosh, CPE, and Cobb stuff in the trash and focus on these hard numbers that dj is busting his butt to get us? If they are right we should be able to prove it with what he is getting us.

[djuosnteisn]

I'll do a much much closer "zoomed in" log of just the injection pulse on the way home. My suspicion is that this:

I agree torque falls off quite a bit near redline, and have been stating the fixed width looks odd, but attributed it to my boost creep. I didn't have creep on the dyno lex posted, and if you look at my recent maf logs, it parallels rpms (indicating same amount of air in cylinders) much more closely.
Here's one from a couple weeks ago when i was fooling with my vvt. This log was taking with the exact same VVT values i'm running right now


so I do think there is a similar amount of air in the cylinders.

Regardless a "zoomed in" injection vid is one we don't have.

[jmhinkle]

Keep going with this. The COBB info seems to go along with what we've seen from DJ's logs, at least to me. The CPE stuff was just guessing and stated as such by themselves. The injector info was also a lot of speculation based on the inability to properly test them. We have some good data to work from here, just need to figure out what to do with it.

[Lex]

What we are dealing with is diminishing return on fuel-air mixing.

When the engine is moving slowly and torque is high (say 4000RPM) and the injector is spraying only during intake, there is a lot more TIME for air and fuel to mix.

When the engine is at 6000RPM, less fuel is required to mix with the air because there is less air PER STROKE. However, the ECU is injecting the same amount of fuel as it did at 4000RPM. Moreso, it has to now inject during the compression stroke. A smaller percentage of the fuel injected actually mixes with the air present because it has LESS TIME to do so.

So injecting during the compression stroke has diminishing returns in terms of what will actually combust and what will be thrown out the pipe as soot.

The soot does not make anyone any power.

[djuosnteisn]

also lex, look at my recent maf curve like 2 posts up. Would you agree that the boost creep and linear maf curve would indeed indicate a similar amount of air in the cylinders, as opposed to the maf curve you posted from my dyno?

[jmhinkle]

So basically we are just at a detrimental time limit and pressure with our DI then? If we had more pressure we'd have better atomization and mixing? Isn't the BMW system running a lot more pressure than us? Up to 3000 psi or something?

[Darksun280]

I'm with lex's theory

[Lex]

Originally Posted by djuosnteisn also lex, look at my recent maf curve like 2 posts up. Would you agree that the boost creep and linear maf curve would indeed indicate a similar amount of air in the cylinders, as opposed to the maf curve you posted from my dyno?

If boost is constant (ie no creep) you will see a decline in the MAF derivative (rate of change) as RPMs climb. Simply put, the engine won't breathe as well at 6500 as it does at 4000.

[djuosnteisn]

Originally Posted by Lex If boost is constant (ie no creep) you will see a decline in the MAF derivative (rate of change) as RPMs climb. Simply put, the engine won't breathe as well at 6500 as it does at 4000.

I agree 100%, and the latest log i showed has a linear maf curve, thus the derivative (rate of change) is constant, thus the increase in boost is offsetting the decrease in VE.

[06Speed6]

Your maf log only looks flat over a 500rpm window and only after the shift, unless you guys are looking at a different log than me.

Basically, can we agree that the injection duration in real time should follow in a linear fashion the maf flow?

If I got some points I bet I could graph it and we could find our max hp for a given rpm for X degrees max of crank duration.

[djuosnteisn]

Originally Posted by 06Speed6 Your maf log only looks flat over a 500rpm window and only after the shift, unless you guys are looking at a different log than me. Basically, can we agree that the injection duration in real time should follow in a linear fashion the maf flow? If I got some points I bet I could graph it and we could find our max hp for a given rpm for X degrees max of crank duration.

If you could divide the maf g/s down to get the amount of air entering a single cylinder, then yes, the injection width would linearly follow that amount of air in the cylinder. What kind of points would you need?

[Lex]

Originally Posted by djuosnteisn I agree 100%, and the latest log i showed has a linear maf curve, thus the derivative (rate of change) is constant, thus the increase in boost is offsetting the decrease in VE.

Yes.

I have made 2 diagrams to illustrate what I mean.

They are from your videos. I have used the scale on the scope to infer approximate RPM in each.

What you will note is that the lower RPM graph has a much smaller percentage of fueling in the compression stroke.



The higher RPM saturates the intake stroke and moves further into compression as shown in the second diagram



If you continue holding RPM and boost up, the compression stroke fueling fills up the entire stroke time VERY FAST. Why? Because the further to the right you inject (to closer to the end of the compression stroke) the less that fuel will mix with the air. So what this means is that you will have to inject more and more fuel. However, this will quickly mean you run out of compression stroke.

This is also not helped that the combustion chamber pressure goes up as you compress the mixture meaning the pressure differential between the fuel rail and where you are injecting it into decreases meaning less fuel will be injected.

Remember how I mentioned turbulence? Well once you've closed the intake valves, air movement into the chamber has stopped. Which means less turbulence. Which means poorer mixing. Which means once again injecting during compression does very little in terms of generating a good mixture that will burn.

So, if the fueling is not addressed, the motor won't make power past 6000RPM no matter how much air flow it has. That's why no one is making "power" with this car and DI.

And that's it.

[djuosnteisn]

Originally Posted by Lex .... This is also not helped that the combustion chamber pressure goes up as you compress the mixture meaning the pressure differential between the fuel rail and where you are injecting it into decreases meaning less fuel will be injected....

HUGE POINT RIGHT HERE!


And i agree, i think that's it.

[Lex]

I would like to add:

The way to address off the top of my head - I see 3 possible solutions:

1. Add port injection. Some companies already doing this

2. Increase fuel pressure to deliver more fuel during the intake stroke. We would need to figure out if the car takes pressure into account when calculating opening time and if the hardware can handle more pressure. Ideally we would have access to the fuel pressure and injection time tables in the ECU. I have asked Christian about these and COBB does not have access to them.

3. Higher flowing injectors to deliver more fuel during intake stroke. Again, we'd need to recalibrate the system for this. The VW guys are doing this but they have a parts bin to choose from because of the R8 and RS4.

[djuosnteisn]

It makes sense on so many levels. As rpm increases, the injection cycle is necessarily pushed further into the compression stroke, thus seeing more and more cylinder pressure, and flowing less and less fuel for a given amount of time.


Thanks so much lex for this insight. Fucking driving me nuts.

[Lex]

Originally Posted by djuosnteisn HUGE POINT RIGHT HERE! And i agree, i think that's it.

Thanks again for all these logs and time put in. The community now I hope knows the limitation of power on this and any other DI motor.

My next question is to see if there are any issues with running this motor leaner than Mazda had intended at WOT.

[SSinstaller]

Originally Posted by Lex I would like to add: The way to address off the top of my head - I see 3 possible solutions: 1. Add port injection. Some companies already doing this 2. Increase fuel pressure to deliver more fuel during the intake stroke. We would need to figure out if the car takes pressure into account when calculating opening time and if the hardware can handle more pressure. Ideally we would have access to the fuel pressure and injection time tables in the ECU. I have asked Christian about these and COBB does not have access to them. 3. Higher flowing injectors to deliver more fuel during intake stroke. Again, we'd need to recalibrate the system for this. The VW guys are doing this but they have a parts bin to choose from because of the R8 and RS4.

A combination of #1 and #2 will be the most cost effective.. We just need an IM with some injector bosses, and an injector controller.

[Scatt Nasty]

does this have anything to do with blown motors ?

[djuosnteisn]

If we're getting a new intake mani, might as well put some hooks in place for a new throttle body:
BBK 80mm Throttle Body (99-02 GM 4.8, 5.3, 6.0 Truck (Drive By Wire), BBK 1756
Here's an 80mm option that should be doable with ATR.

[Lex]

This thread should become a sticky btw, the info in here gathered by Dustin shouldn't be lost.

[djuosnteisn]

In fact later tonight i'll try to summarize everything learned at the beginning of the OP, and make as many edits as you guys feel necessary till it represents exactly what we want as a whole.