Am i getting the HPT concept right here?

[Elderas]

Im having a rough time understanding how you go about knowing how and what you need to tune with HPT. I dont have the program yet, im planning on getting it sometime within the next month. Ive read quite a bit on the HPT forums, but either im not reading the right material or im just a complete ****ing idiot but I give up. From what i understand this is the process.

I plan on running 7 PSI of boost which would be .. 0.5 bar somewhere in that neighbourhood. now because the car only reads boost that is above atmospheric pressure you would need a 1.5 bar sensor. They dont make them so id have a 2bar MAP sensor. Now this is the part im stressing on.. kPa. If i remeber high school chem (and i dont) ~105kpa is 1 bar which is ~14.7 psi. now does that mean that for every ~105kpa i see in the VE thats 1bar? thus if i was tuning for 7psi i should change the values up to ~150kpa? that would mean that the pressure in my manifold would be 7psi above atmospheric pressure which is 1bar, thus 1.5bars are entering the engine which would be an increase of .5 bar (7psi) above the stock NA pressure of 1bar.

now... the yellow and green squares that have numbers.. are those the % of air going in to the engine at a certain RPM? so at 6800RPM i would want 100% of that 150Kpa to enter the engine? is that the concept? Like using this dummy reading that i got from one of their demos.

http://i121.photobucket.com/albums/o229/Elderas/untitled-2.jpg

looking at the red line -- if I pinned it.. pedal to the metal. That would be the way id be allowing air into my throttle body. So at 6800RPM i would have 92% of 1bar worth of air in my intake manifold. ( im guessing the same concept applies to 150kpa)
now if i took it nice and easy and reved at 2000RPM, i would have 73% of 1bar in my intake manifold. What im having a hard time grasping is why the graph is in 3D
Does it assume all forms of acceleration and deceleration. so say i stepped on it off the line the gradually took my foot off. Would the graph need to be tuned to compansate for that? (quite obviously you dont mash it everytime)

Now, my computer is tuned for 105kpa. I want to add 50 extra kpa. so i would have to increase the kPa to 210 to accomodate the 2 bar sensor, then gradually interlink the % so from 10 - 200 it would be a nice smooth accension in percent. Now im guessing because the manifold will never see more than 150kpa i would need to adjust the percents in order to have the highest percent at or slightly below 150kpa. so at 150, which is my 7psi im pushing, i would need the graph to end, and be completly flat. Everything higher that 150 would be the same value as the previous 150. Is this the basic concept?

i havent gotten around to fuel and spark timing yet but i imagine its probably more of the same.

countless people have learned this i know i can learn it too. Ill start reading on spark timing and all taht stuff tomorow.

As always any info is greatly apreciated.

[Sprucegagt]

First off, does HPT allow you to change from a 1 to 2 bar MAP sensor? The last I heard, they don't do that for any of there V6 applications. Now I don't know if that applies to you (i.e. 4 or 6 cyl).

The regular air that we breathe is already pressurized so to speak, to 14.7 PSI ~ 1 Bar ~ 100 kPa.

[Shock24Z]

If i remeber high school chem (and i dont) ~105kpa is 1 bar which is ~14.7 psi. now does that mean that for every ~105kpa i see in the VE thats 1bar? thus if i was tuning for 7psi i should change the values up to ~150kpa?

Right, but its not as simple as "changing values" to accomodate for the higher pressure values. IF you were able to get a 2 bar map to function, the pressure values in that table would need to cover a wider range and would have to chart out VE's over those new pressure vs rpms. It should be noted that some have tried to run 2 bars in the past and had trouble with it. I'm not sure if anyone ever got one to work at all.


now... the yellow and green squares that have numbers.. are those the % of air going in to the engine at a certain RPM? so at 6800RPM i would want 100% of that 150Kpa to enter the engine? is that the concept? Like using this dummy reading that i got from one of their demos.


Thats a table of volumetric efficiency.
Wikipedia quote:


Volumetric efficiency in internal combustion engine design refers to the efficiency with which the engine can move the charge into and out of the cylinders. More correctly, volumetric efficiency is a ratio (or percentage) of what volume of fuel and air actually enters the cylinder during induction to the actual capacity of the cylinder under static conditions. Therefore, those engines that can create higher induction manifold pressures - above ambient - will have efficiencies greater than 100%. Volumetric efficiencies can be improved in a number of ways, but most notably the size of the valve openings compared to the volume of the cylinder and streamlining the ports.


looking at the red line -- if I pinned it.. pedal to the metal. That would be the way id be allowing air into my throttle body. So at 6800RPM i would have 92% of 1bar worth of air in my intake manifold. ( im guessing the same concept applies to 150kpa)
now if i took it nice and easy and reved at 2000RPM, i would have 73% of 1bar in my intake manifold. What im having a hard time grasping is why the graph is in 3D
Does it assume all forms of acceleration and deceleration. so say i stepped on it off the line the gradually took my foot off. Would the graph need to be tuned to compansate for that? (quite obviously you dont mash it everytime)


If you floored it (in an N/A car), I'm pretty sure the graph would shoot up to the 105kpa values (much like the far left orangish line) and hold there across the board. Somewhat the same for a turbo car but maybe a slightly slower ramp up to 105 and then into boost (105+).

If you gradually eased out of throttle then the MAP values will decrease and inherently your rpms won't go as high. But essentially the right efficiency will be looked up for that pressure/rpm. The only reason for tuning those values is because you are changing the VE of the engine at those points.


Now, my computer is tuned for 105kpa. I want to add 50 extra kpa. so i would have to increase the kPa to 210 to accomodate the 2 bar sensor, then gradually interlink the % so from 10 - 200 it would be a nice smooth accension in percent. Now im guessing because the manifold will never see more than 150kpa i would need to adjust the percents in order to have the highest percent at or slightly below 150kpa. so at 150, which is my 7psi im pushing, i would need the graph to end, and be completly flat. Everything higher that 150 would be the same value as the previous 150. Is this the basic concept?

i havent gotten around to fuel and spark timing yet but i imagine its probably more of the same.

countless people have learned this i know i can learn it too. Ill start reading on spark timing and all taht stuff tomorow.

As always any info is greatly apreciated.

I'm not sure how you would go about adding 50kpa to that table, but then again I haven't used an HPtuner.

I would like to bring up the point that these cars have a MAF as well as a MAP. It may be a little more crude for properly tuning boosted cars but I've found that it works just fine. It reads the mass of air coming into the engine and commands a fuel to meet the commanded ratio.

[Sprucegagt]

It should be noted that the VE table mentioned here is not the actual VE of the engine. This table, in regards to GAs, is used more as a modifier to the MAF table and backup incase of MAF failure. The term "VE" for it is really a misnomer.

[Elderas]

Ok so if the program doesnt support a 2 bar map sensor i would have to fake it. I herd it can be done and i even saw a how to on it. how does the maf sensor affect the VE and pressure. I have no idea. maybe i dont know what a MAF is.

and how does it come into play when it comes to tuning. Like how would u tune around it.

also my original plans were to get the GM reflash, but apperntly they lock the ECU after they do it which would mean the car couldnt be tuned afterwards, and they wont do it unless u have a supercharger installed

now i have a buddy whos dads uncles girlfriends brother works for GM so he might hook it up with a reflash, but its very unlikely.

[SpyhunteR]

If your car has a 2.2 ecotec you're screwed and can't do the 2bar becuase once it goes 2bar t he ecu is locked. With enough time and coercing I'm sure HPT could crack it and modify that 2bar tune so that it is "unlocked", but they're *******s to the 4cyl guys.

now if you had a 2.4L you can get the 2bar reflash as it is UNLOCKED right from the get go. How do i know? I was using it on my car and look at the wonderful things it helped me achieve.

You don't have to know anybody at the dealership to have them flash your computer if you have or don't have the supercharger.

[Elderas]

So basically I'm ****ed for the time being, and my only option is to get the GM reflash. Now the reflash is geared towards the SC guys so how well would my car handle the fact that boost doesnt gradually build up with the RPMs like it does with a SC.

would i need to piggy back additional **** to the ecu to have proper spark timings and fuel delivery and all that, or would the reflash work well enough and i wouldnt have to worry about tuning.
ie once i get the reflash just bolt all the parts on and go?

[Sprucegagt]

The reason why you get tuning equipment is to have the ability to change to the proper spark and fuel delivery points. Spy recommended to get the reflash because that file already has 2 Bar support.

[Elderas]

Ya but once u get the reflash GM locks your Ecu so you can't tune it whats o ever. It wont even read it. ( i dont think anyways, thats what ive been hearing)

[Shock24Z]

Ok so if the program doesnt support a 2 bar map sensor i would have to fake it. I herd it can be done and i even saw a how to on it. how does the maf sensor affect the VE and pressure. I have no idea. maybe i dont know what a MAF is.

and how does it come into play when it comes to tuning. Like how would u tune around it.


What exactly do you mean by "fake it"? Running boost with a 1 bar will just peg it at 105kpa. I don't see where the faking needs to be done.

The MAF (mass air flow) sensor reads the mass of air coming through the engine.
Knowing the mass of air coming in, the computer calculates how much fuel to use to reach the desired air/fuel ratio. The MAF sensor/values don't affect your VE table... Rather the VE table is a modifier of MAF values.

[Sprucegagt]

Ya but once u get the reflash GM locks your Ecu so you can't tune it whats o ever. It wont even read it. ( i dont think anyways, thats what ive been hearing)

You can't lock a PCM. What is happening is the OSID of the reflash file does not match any of the files that HPT has mapped. That's why you can't open the file. Sounds like you guys need to start complaining to HPT about getting that OSID mapped for the next software update.

[Elderas]

What exactly do you mean by "fake it"? Running boost with a 1 bar will just peg it at 105kpa. I don't see where the faking needs to be done.

The MAF (mass air flow) sensor reads the mass of air coming through the engine.
Knowing the mass of air coming in, the computer calculates how much fuel to use to reach the desired air/fuel ratio. The MAF sensor/values don't affect your VE table... Rather the VE table is a modifier of MAF values.

I belive what they mean by faking it means that HPT doesnt support 2bar maps for the ecotec. so you cant load any VE tables for 2 bar support. Rather you would have to make your own values for 210 kpa. Atleast thats what i think. So if the MAF was reading values for 150kpa but the VE tables were only set to 105 it wouldnt know how to use the extra air, and it would run really lean. Thats what im guessing. Im just relaying info from waht ive been reading, though i dont neccesarly know the reasons or explications.

also.

spruce your right. HPT doesnt know how to read the file so you cant get any tables off of it.

apperently alot of boosted guys said the reflash works fine in terms of VE and spark timing, its limited for boost because the injectors are set at the 36lb/h SS injectors. so you cant run anything beyond that. I think the only way people have gotten past it is with standalones. (again speculation. im a noob)