HPT - New Version of Hardware & Software & Purchase info

[xonelith]

HPTuners is releasing a new version of their software, which seems really cool. With the new hardware, they changed how the purchase works. There is no need to select 2 vehicles at the beginning. You basically get some credits. With those credits you can purchase other vehicles whenever you want.

Something interesting. You could get all years of the Grand Am with these credits (97-2005), if I understand it correctly.

The official info can be found here:
http://www.hptuners.com/order.php

The forum info and discussions regarding this can be found here:
http://www.hptuners.com/forum/showthread.php?t=4672

[99blackSE]

Wow that looks good, that would definately help having all the years under one thing. Thanks for the info Tim.

[SpyhunteR]

yaya... still nothing for me.

[xonelith]

Is the 2.4 J the same as the N? Seems they are adding that, aren't they?

[O1GAGT]

Is the 2.4 J the same as the N? Seems they are adding that, aren't they?

From what I understand there are several minor changes between the cavalier and the sunfire, so I would assume there would be a few differences in te N body computers as well. Hptuners has been stringing the J-body guys along for over 2 years, so when they do come out with something alot of people will be surprised.

[xonelith]

From what I understand there are several minor changes between the cavalier and the sunfire, so I would assume there would be a few differences in te N body computers as well. Hptuners has been stringing the J-body guys along for over 2 years, so when they do come out with something alot of people will be surprised.

I can understand the frustration. I didnt' realize it was 2 years!!!

I know the last year was an issue due to the merger with super chips and the addition of Ford and Chrysler.

There's also a few things I'm looking for. Apparently, on some years of GA's (V6), there is a delay for the PE. I think it is like 10 seconds stock. My issue was I was commanding PE to kick in at 35% throttle, but it wasn't kicking in until 85% sometimes. They corrected it in a bin, now I'm just waiting for the parameter (Powertuner 1.8 doesn't have the parameter either). I suspect this will take some time too:( Oh well. I don't mind waiting (as long as it's not 2 years)

[O1GAGT]

Yeah, I saw over on the HP Tuners forum that you seemed to have alot of questions that went un answered. I currently have the DHP, but am just getting started with the tuning aspect. Good luck, and I hope everything works out.

[AaronGTR]

35% is to early to activate PE mode. ;)

[GAGTS03]

I just really wish that someone would come out with something like a DHP for the Ecotec, something you could use with intake, header, few other mods, make it tunable (sp?), but still nothing, I honestly have to say they are losing tons of money by not making one or "stringing" it along for too long. The amount of 4 cylinder "tuners" out there is amazing along with cavs and sunfires, oh well...only time can tell.

[Sprucegagt]

35% is to early to activate PE mode. ;)

How so? Last I checked there was no absolute good or bad setpoint to activate PE. Then again, I have never come across a good explaination on what is a good setpoint for activating PE.

[tejohnson]

I activate PE at 45% myself. Always activates right at 45% with no hesitation...

[AaronGTR]

How so? Last I checked there was no absolute good or bad setpoint to activate PE. Then again, I have never come across a good explaination on what is a good setpoint for activating PE.


Most of the people on the powrtuner forums don't activate it that low. Of course, most of them are also superchargered GP's. A turbo car may benefit from it a little earlier since they can hit full boost at WOT before redline, but IMO 35% throttle is still way too low because you aren't going to be spooling that fast with that small an input. For a SC'd car, that small a throttle is basically like running NA, or in other words no boost yet and pretty low power output, so there's no point in switching to PE mode at that point.


Stock PE for my car is 70%. I switched mine to 60% starting at 3200rpm, basically just as a general safety precaution. I'll probably make some more changes to it but not until spring when I get the injectors switched and start driving the car again. What I set it at will depend completely on the results of my scans of course. :)

[xonelith]

As mentioned above, the reason for the 35% at that time, was the delay was not allowing it to kick in until 80% or more (If I set it higher, PE would kick in higher). Hence, causing KR. I originally had it at 55%, but was knocking like crazy. Kept lowering it until, most of the KR went away.

I didn't realize it was a problem in the bin until later. Again, their are other things that determined the delay, I'm just not sure (cylinder air? Boost would probably raise this number and remove the delay).

Right now, I'm at 55% and seems to work ok.

As for when to kick in PE, it depends on the setup and when your car needs the fuel under load. For some, at 45% throttle, if they're not commanding enough fuel, it could go lean. It also depends on the rest of the tune and depends on how you tune. I don't think there is a hard, steadfast rule.

IMHO.

[Sprucegagt]

Great this sounds more confusing to me that before. I know from checking my scans that my idle and cruise settings are good. LTFT below 6 at idle and immediately go to 0 when you touch the throttle. It is PE that I have yet to really mess with. I know at full throttle I see 5* of knock and LTFT of 8 or higher. Not sure of what the O2 mV is at that time. Think you guys could help me with the PE portion of my tune if I put some scans up? I need to readjust my MAF table before I do it. I had to turn off the EGR because its going bad and I don't really see a point in replacing it.

EDIT: I know this is all OFF TOPIC. If I can get some help I will make a new thread.

[xonelith]

It is PE that I have yet to really mess with. I know at full throttle I see 5* of knock and LTFT of 8 or higher. Not sure of what the O2 mV is at that time. Think you guys could help me with the PE portion of my tune if I put some scans up?

Post 'm up. I'll take a look.

Keep in mind, that the LTFT's actually lock-in to the last value, prior to the moment PE is engaged. So basically, just before you entered PE, you were lean. Try changing the time it enables to a lower number (ie 65% instead of the stock 70% TPS).

If that doesn't get rid of the KR, try changing the PE afr. Decrease the number (ie run richer). Take away 0.2 to start. If you still have KR, remove .1 more.

The +'ve LTFT's, are basically saying that you are running lean (hence the KR). Telling the computer to add fuel. (At least that's how I see it; not technical:)).

[Sprucegagt]

Once I get internet access at my new house then I will post up the scans. Should have something next monday. Thanks.

[MMGT1]

My problem is I'm getting WAY TOO MUCH FUEL!! How can I reduce the amount of fuel going to the combustion chamber. I'd like to reduce fuel until I see KR and then put it back up a bit until it's gone again....I am getting no kr what so ever in any rpm range or in any gear! And my LTFT's are running @ -13 or so most of the time......a lot of fuel smell from the pipes let me tell you!!!!!!!!!!

Paul

[tejohnson]

What have you changed? Any modifications to the MAF table? The IFR? The injector skew? Have you changed anything mechanically recently? Would you happen to have a Caspers AFPR?

[MMGT1]

Engine has Full Milzy stage 2 package with 36 lb injectors. Milzy set the injectors up when he did the install.

[tejohnson]

What are your IFR values?

[MMGT1]

If your asking the injector flow rate it's set to 4.30 Skew is at 1.0, so no adjustment.

[tejohnson]

Not the skew, but the flow rate. It is a rate by kPa table...

[MMGT1]

It's set to 4.3 Up from 2.68 origionaly

[tejohnson]

It's set to 4.3 Up from 2.68 origionaly

Perhaps HPTuners really changed some things around in their software since I had seen it last, so I really need some context. Is that value Grams/Sec? Is it the same value throughout the kPa range of 10-100? It used to be Lb/Hr by kPa....

As an example, see the attached spreadsheet. I used some known values to come up with your projected table. For example:

Rated fuel injector pressure: 43.5 PSI (tests are typically done at 3 bar)

Fuel pressure on your car: 52 PSI (for a 2000+)

Injector Fuel Rate: 33 PSI (your injectors are actually 33#, but due to the pressure of 52 PSI of fuel pressure, thier rate is 36#)

[MMGT1]

Yea, the scale is 4.3 Grams per second. The scale has been set across the board at 4.3

Should the conversion be done from 33 psi giving an input rating of 4.16 g/sec? Not the 4.3 it's set to now

Can the values you gave me be used in the flow table? Are they "actual" projected #'s? 4.546.... @ 0 kpa and so on...


PS thanks for the info.......this is gonna help tons!!!!!!!!!

Paul

[tejohnson]

Yea, the scale is 4.3 Grams per second. The scale has been set across the board at 4.3

Should the conversion be done from 33 psi giving an input rating of 4.16 g/sec? Not the 4.3 it's set to now

Can the values you gave me be used in the flow table? Are they "actual" projected #'s? 4.546.... @ 0 kpa and so on...


PS thanks for the info.......this is gonna help tons!!!!!!!!!

Paul


Yep... The way I would approach it is to lean it out slowly. Raise the values in increrments to the values in the spreadsheet till your trims start looking better. This will take a little while to accomplish since you have to drive a bit to get the trims settling in. For example, raise initially in small increments, flash, go out and drive for a half an hour. When you drive, start by letting the car idle for a while monitoring fuel trims, looking for knock. Then, take the car out and drive at part throttle, again, monitoring trims and for knock. Then 50% throttle... Then 70% throttle.... 90%... Then WOT. Don't go out and drive all out doing WOT runs inintially, just take your time.

The higher the Grams/Second value, you are telling the PCM the injectors are bigger... (i.e., bigger value leans it out, smaller value makes it more rich).

In the end, your values may be a tad lower than what is in the table in order to accomodate good fueling in top end power in combination with AE and PE.

Most important message to take away from this: Take baby steps...

[MMGT1]

Very good info............I will follow your advise

[MMGT1]

WOW! (did I say WOW!) I thought so..................holy crap man, what a difference!!!!! Instantally my LTFT's have come into a more acceptable range under regular driving modes. At idle the LTFT's are wacky but I have a new 02 sensor going in tommorow and a belt tensioner, then the tranny mount from "Milzy" should be in this week and I can fine tune the rest. As I said "Wholy Crap" what a difference......can tell just from the exhaust it has trimmed down quite a bit....now to fine tune it :)

[tejohnson]

Cool... Once you are on the acceptable side, start adding some timing via air temp to get some more power, back it off once you see KR. Keep in mind your tuning and the outside ambient temps. If it is colder (which I assume it is) let it stay a little rich. Then, move on to add some shift pressure and slowly rid yourself of some of the torque management settings. You may not want to go too wild removing torque management unless you want to rebuild your transmission in the near future ;) Have fun...

[MMGT1]

Torque management has already been dissabled:) If she blows, she blows.....looking foward to the 4T65E upgrade from Milzy when he gets it all together! But, as I said, GREAT INFO..........thanks a bunch!!!!!!!!!

[Sprucegagt]

Perhaps HPTuners really changed some things around in their software since I had seen it last, so I really need some context. Is that value Grams/Sec? Is it the same value throughout the kPa range of 10-100? It used to be Lb/Hr by kPa....

As an example, see the attached spreadsheet. I used some known values to come up with your projected table. For example:

Rated fuel injector pressure: 43.5 PSI (tests are typically done at 3 bar)

Fuel pressure on your car: 52 PSI (for a 2000+)

Injector Fuel Rate: 33 PSI (your injectors are actually 33#, but due to the pressure of 52 PSI of fuel pressure, thier rate is 36#)

Anyone notice the rather large error in that attached table. Fixing it will change your projected IFR table by a good amount.

[MMGT1]

What error???? I have since reverted to the 4.30 across the board that Milzy had set the car to. What do you see that can address the IFR table???

Signed,
Lost in tuner land....................

[tejohnson]

Yeah... What error? If you look at the resulting values, you will see that they are in line with the 36# injector table that you can import with Powrtuner (i.e.: Msec/Gram column)

[Sprucegagt]

Hint: look at the MAP PSI vs. kPa values

[tejohnson]

Your going to have to spell it out for me. I can't see what you are referring to...

[Sprucegagt]

Todd I expected better from a college grad not to mentioned Boosted. :nono: (jp)

No one ever noticed that the MAP PSI value generated was considerably higher than the corresponding MAP kPa value.

At 100 kPa we all know that the engine is at 0 PSI. That is the point where boost would start. Anything under 100 kPa is a vacuum. Notice in this table it says that 100 kPa is the equavilent to 14.504 PSI. Not to mention a positive PSI value for every cell. :nono:

Now for the answer.

If you took Physics in college you would know the difference between Gauge and Absolute pressure. The MAP sensor measures in absolute pressure (kPa), while the measured fuel pressure is gauge pressure. The two are not the same unit of measure. Gauge pressure takes into account atmospheric pressure while Absolute pressure does not.

The correct for this simple. Gauge pressure = Absolute pressure - Atmospheric pressure (Atmospheric pressure = 14.504 PSI). Atmospheric pressure was never accounted for in the formula in each MAP PSI cell. So, subtract 14.504 from the formula in each MAP PSI cell. See the attached table to see what I mean.

And that's your Physics lesson for the day. lol

[tejohnson]

Point taken, but did you look at the resulting IFR table? Yikes! You will need to adjust the actual formula to fix that one ;) Or, simply remove row 12 all together and merge the logic into row 25...

( there's comp sci lesson for the day ;) )

[Sprucegagt]

Point taken, but did you look at the resulting IFR table? Yikes! You will need to adjust the actual formula to fix that one ;) Or, simply remove row 12 all together and merge the logic into row 25...

( there's comp sci lesson for the day ;) )

Okay now ya lost me. If you mean the SQRT being there, I'm not for sure why.

[tejohnson]

Because the kPa -> PSI conversion factor is used. While I understand what you are pointing out, it is all based on kPa values, then the flow rate is scaled using the following:

Grams/sec = Rated_Flow * SQRT( ( MAP_PSI + Actual_Fuel_Pressure ) / Rated_Pressure ) * 453.6 / 3600

So the error is only in the display of information, which can lead to confusion about the operation of a MAP sensor, but the IFR calculation was actually correct.

[MMGT1]

injectorscale revised.zip (4.5 KB, 1 views

...............so is this a usable scale for my application?????........................

(From above by Sprucegagt)

Actually, Sprucegagt, your car is almost identical to my set up. Is the above table by you the one used on your car now? If so, how do your LTFT's look. That is what I'm trying to get under control right now. Would like to have the fuel corrected, then I can get a little more aggressive with the timing while monitoring knock.

[tejohnson]

Simplified version to avoid confusion ;)

[xonelith]

I think, in your situation MMGT1, stick with a table that is the same throughout the kpa range. IMO, your problem is not due to your IFR's, since your trims are not consistently high or low at specific MAP values.

LTFT's are not only changed by messing with IFR. If you modify any setting (like MAF), your trims will be affected.

Keep in mind, tuning via fuel trims is only a guess. These trims are primarily based on your o2 sensor readings. All these readings tell you is if you are rich or lean, not HOW rich or lean. So, trying to get 0 LTFT and STFT in an evening, I don't think is feasible (especially considering the fairly drastic weather changes we have had).

Takes time to get this stuff right. Don't give up and heed TEJ's suggestion on 'baby steps'.

[MMGT1]

Oh I hear you Tim. The tune is really close on the trims since you helped me tune!! I want to be ok to hit the timing a bit. Just being cautious before I do anything. Leaving the car the way it is for Sunday :)!!! I'll get into a bit of tuning when the mount goes in.................

[Sprucegagt]

Because the kPa -> PSI conversion factor is used. While I understand what you are pointing out, it is all based on kPa values, then the flow rate is scaled using the following:

Grams/sec = Rated_Flow * SQRT( ( MAP_PSI + Actual_Fuel_Pressure ) / Rated_Pressure ) * 453.6 / 3600

So the error is only in the display of information, which can lead to confusion about the operation of a MAP sensor, but the IFR calculation was actually correct.

That's just it. The formula does not all use absolute pressure values. MAP_PSI was calculated as a absolute value, while Actual_Fuel_Pressure and Rated_Pressure are gauge pressure values. You can't add absolute and gauge values, then divide by another gauge value and expect to get a correct conversion factor. Only thing that formula does is take your Rated_Flow multiply it by a conversion factor and then convert it to grams/sec.

Plus I used this table(in its original form) in my car with ratings for 21.5 lb/hr injectors and 55 PSI. My car ran EXTREMELY lean. It would barely come off of 25 LTFT at any rpm.

Now I know my fuel pressure was at 55 PSI because I set it there, and I know that I had the wrong lb/hr rating for the injectors. But that error should of resulted in a rich condition. Obviously that didn't happen.

[tejohnson]

Try this: Compare the values to the import tables in Powrtuner for 36#, 42#, etc. You will see that they are very close. Using negative pressure (below 1 bar) results in the fuel map being completely reversed, which is absolutely wrong.

Feel free to ask this of the Powrtuner forum folks. In short, the base of this table came from someone over there, which pulled it from an LS1Edit mailing list (or something of that nature). I only added in the mSec/Gram calculation, and noticed that it is aweful close to DHP's canned tables for different injector sizes. In fact, these calculations should even cause things to run a bit more rich.

The most importatnt thing to do is to know the actual rating of the injector, and exactly what pressure was used to test (typically 3 bar). Then, you should know your exact fuel rail pressure at 100kPa (which is pretty easy to test with a FP gauge on the schrader valve... Turn the ignition on, read, your done).

Again, if the numbers jive with what is working, can you explain why your results are the exact opposite? Never had an issue with my numbers, just running out of injector due to boost. ;)

[Sprucegagt]

Try this: Compare the values to the import tables in Powrtuner for 36#, 42#, etc. You will see that they are very close. Using negative pressure (below 1 bar) results in the fuel map being completely reversed, which is absolutely wrong.

Feel free to ask this of the Powrtuner forum folks. In short, the base of this table came from someone over there, which pulled it from an LS1Edit mailing list (or something of that nature). I only added in the mSec/Gram calculation, and noticed that it is aweful close to DHP's canned tables for different injector sizes. In fact, these calculations should even cause things to run a bit more rich.

The most importatnt thing to do is to know the actual rating of the injector, and exactly what pressure was used to test (typically 3 bar). Then, you should know your exact fuel rail pressure at 100kPa (which is pretty easy to test with a FP gauge on the schrader valve... Turn the ignition on, read, your done).

Again, if the numbers jive with what is working, can you explain why your results are the exact opposite? Never had an issue with my numbers, just running out of injector due to boost. ;)

Do we agree that 100 kPa at the fuel pressure regulator is the equivalent to pulling the vacuum line off?

If so the computed 100 kPa cell will result in whatever Injector Rated Fuel Rate you enter so long as the Injector Rated Fuel Pressure = Your Fuel Rail Pressure.

Now, plug these numbers into your table and see what you get.

Injector Rated Fuel Pressure = 43.5
Your Fuel Rail Pressure = 43.5
Injector Rated Fuel Rate = 33

[tejohnson]

43.5 for the FPR? Maybe if you are a 99. If you are seeing that low of a fuel pressure on a 2000+ than you likely have a fuel delivery issue.

Also, there is no need to remove the vacuum line from the FPR. Just turn the ignition on and prime the pump a few times without turning it over. Stock fuel pumps have a "check valve" so pressure bleeds down very slowly, but holds after you key off, where somethin like a Walbro will not. You can verify 100 kPa with the scan tool.

Now I will say that I Was Wrong about the top end of the fuel table on the calculations I gave. The numbers are a "tad" lower moving towards 100 kPa than the canned DHP tables (which I am using as reference info), which "should" make it leaner. Moving towards 0 kPa, however, they are about right on. I'm thinking they may intentionally make them a tad more rich on purpose.


EDIT: See attachments to verify correct fuel pressures for 99, then 2000+ in step #2 of each document

[AaronGTR]

At 100 kPa we all know that the engine is at 0 PSI. That is the point where boost would start. Anything under 100 kPa is a vacuum. Notice in this table it says that 100 kPa is the equavilent to 14.504 PSI. Not to mention a positive PSI value for every cell.


Actually at 100kPa you are not at 0psi. You are at 0psi of positive boost pressure yes, but atmospheric pressure is 14.5psi so thats what you are at at 100kPa. The MAP does measure absolute pressure just like you said. Absolute pressure from 0-14.5 psi for a 1bar MAP. So you get vacuum when the throttle is closed and at WOT you get 14.5psi. Above that is boost so you get positive pressure, which is really just saying higher than the outside atmosphere, but it's still a range from 14.5psi up as far as the MAP is concerned. Not 0psi to 6,9, etc for whatever boost you're running. That's of course why we need a 2bar MAP.

I think Todd's numbers where correct. (or more correct anyway lol )

[MMGT1]

Gave that table a try and the LTFT's went nuts!! Drove it for a while and fuel was pissing out the tail pipes. Hit -28 came down to -18.9 so looks like the 4.30 across the board is the only way to go.......thanks for trying for me though. I think my injectors are bigger than you realize because that is just way to much flow!!

[Sprucegagt]

43.5 for the FPR? Maybe if you are a 99. If you are seeing that low of a fuel pressure on a 2000+ than you likely have a fuel delivery issue.

Also, there is no need to remove the vacuum line from the FPR. Just turn the ignition on and prime the pump a few times without turning it over. Stock fuel pumps have a "check valve" so pressure bleeds down very slowly, but holds after you key off, where somethin like a Walbro will not. You can verify 100 kPa with the scan tool.

Now I will say that I Was Wrong about the top end of the fuel table on the calculations I gave. The numbers are a "tad" lower moving towards 100 kPa than the canned DHP tables (which I am using as reference info), which "should" make it leaner. Moving towards 0 kPa, however, they are about right on. I'm thinking they may intentionally make them a tad more rich on purpose.


EDIT: See attachments to verify correct fuel pressures for 99, then 2000+ in step #2 of each document

I posted those numbers to try and verify that the equation in the table is correct. I know not to use a 43.5 PSI setting at the FPR. What I'm getting at is, if the Injector Rated Fuel Pressure = Your Fuel Rail Pressure in the table then at 100 kPa you should have a fuel flow rated equal to the static rating of the fuel injector.

[Sprucegagt]

Actually at 100kPa you are not at 0psi. You are at 0psi of positive boost pressure yes, but atmospheric pressure is 14.5psi so thats what you are at at 100kPa. The MAP does measure absolute pressure just like you said. Absolute pressure from 0-14.5 psi for a 1bar MAP. So you get vacuum when the throttle is closed and at WOT you get 14.5psi. Above that is boost so you get positive pressure, which is really just saying higher than the outside atmosphere, but it's still a range from 14.5psi up as far as the MAP is concerned. Not 0psi to 6,9, etc for whatever boost you're running. That's of course why we need a 2bar MAP.

I think Todd's numbers where correct. (or more correct anyway lol )

Your getting things confused Aaron. I know 100 kPa is 14.5 PSI of Absolute pressure. But the equation in the table is trying to add Absolute and Gauge pressure to reach a conversion factor. The two pressures are different and can't be considered equal units of measure. Also at WOT you get 0 PSI of gauge pressure which is equal to 14.5 PSI of absolute pressure.

Please read my earlier posts where I explain the difference between Gauge and Absolute pressure.

Either way I will be my own guinea pig and test my table on my car. VE then MAP. Once this is done I will post my results. I have a feeling it won't really matter if I run stock values or this table.

MMGT1:
Which table are you using? Are you just putting it in with no adjustments to the MAF table? Any change in the IFR table requires adjusting the MAF table.

[tejohnson]

Right, I understand what you are getting at, and it is what leads to quite the confusion, but the resulting table is more in line with the tables DHP has made available. The other issue lending to the confusion is the GA specific fuel table where all the values are the same stock, regardless of kPa. In the 96 PCMs, there is only one value, and not a table sorted by kPa. Perhaps if we had a better understanding on how the IFR values are used within the calibration, it would ultimately help.

As far as the PCM is concerned, it will only anticipate seeing 0-100kPa ( actually 0 is not very likely ;) ). I'm curious of the calibrations which accomodate 2 & 3 bar map sensors in the newer PCM's and wonder if they have increased the table size above 100kPa.

[AaronGTR]

I posted those numbers to try and verify that the equation in the table is correct. I know not to use a 43.5 PSI setting at the FPR. What I'm getting at is, if the Injector Rated Fuel Pressure = Your Fuel Rail Pressure in the table then at 100 kPa you should have a fuel flow rated equal to the static rating of the fuel injector.


Ok, not sure if this is relevant to what you're saying but might be a good point to remember... you have to know what fuel pressure they are using when they rate your injectors as well. IE I'm not sure what pressure the lucas 42lb injectors are rated at but I know a lot of injector companies rate them at 43.5psi. The stock dephi injectors in the 00+ GA are rated at 55psi though. Since the 00+ GA fuel pressure is 48psi at idle and 55psi at WOT on an NA car, that rating probably makes it easy for them to calculate fuel delivery at WOT. If you are using different injectors you might need to calculate the difference in flow at the different pressures before you plug them into your tables. Just in case no one thought of that yet. If you're just taking an injectors rated flow at 43psi and plugging it in the table at a point where it's at 48psi then yes you would be running rich as hell because the injector's actually flowing more fuel than what you told the pcm it was going to, so you're LTFT's would be way in the minus like that.

[Sprucegagt]

Todd:

You may be right with the final results. I have posted this up on DHP forum and will see what we get there. I agree that learning more about how the PCM uses the IFR table would definitely help. Having one injector rating regardless of MAP just does not sound right to me.

Aaron:

The Delphi injectors have a rated operating pressure of 380 kPa (55 PSI). But a static flow rate of 23 lbs/hr. Got to watch the terminology used here. Static is not the same as operating.

Delphi Injector Ratings (http://go.delphi.com/esp.asp?sess=DCYCREC74TNBT6D0UVBY)

EDIT: You'll have to look it up. The link was supposed to go directly to the fuel injector rating page.

[AaronGTR]

I got my info directly from someone at delphi. It's not static. They are rated at 22.5lbs/hr at 55psi. That's actually just the conversion. The actual rating they use is 2.84 gram/sec @ 380Kpa. ;)


edit: I sent one out to RC engineering for flow testing along with a set of 4.2L injectors as well. They confirmed it at 209cc/min @43psi, which =236cc/min @55psi, or 22.56lb/hr.

[xonelith]

Having 1 injector rate for the entire MAP range doesn't make a whole lot of sense to me either, however it depends on the variability. In a boosted vs NA system, their is definitely more variance at different MAP values, so getting away with the same value I don't think is the best idea. However, in an NA situation, things are a little more consistent.

I ran a flat rate throughout the range and everything seems good. LTFT's are pretty even (+ or - 5). My only issue is I"m running a tad rich at idle and cruise speeds (14.3 according to my wideband). I'd feel a little better running close to 15.0, but this is minor.

Another note, I haven't adjusted my MAF (yet). It will definitely help me, but I don't feel it is required.

Note, that everything I say is more speculation. I'm still learning, so feel free to correct me or make me feel dumb...LOL

[Sprucegagt]

I got my info directly from someone at delphi. It's not static. They are rated at 22.5lbs/hr at 55psi. That's actually just the conversion. The actual rating they use is 2.84 gram/sec @ 380Kpa. ;)


edit: I sent one out to RC engineering for flow testing along with a set of 4.2L injectors as well. They confirmed it at 209cc/min @43psi, which =236cc/min @55psi, or 22.56lb/hr.

Interesting info. I appreciate it.

[AaronGTR]

lol, yeah. Some of the stuff you guys are talking about here is a little difficult for me I'll admit. I did go to a lot of trouble to confirm the injector flow rates a few years ago though. :) (I need to go read up on the DHP forum now so I understand everything you guys are saying)

[Sprucegagt]

You wouldn't happen to know the pull off rate of the Casper's AFPR? Graph or coversion of some type showing how much fuel pressure is reduced per amount of vacuum.

[tejohnson]

Never measured it... Would love to have some electronic gauges, or a 0-5v fuel pressure sender and attach it to the A/D input...