cartuning 42lb injectors

[jimmyschimmies]

okay i am in the process of totally revamping my PCM and am having problems. what is the Flow rate and PW that i need to be running for these injectors (42lb)? i am going nuts here trying to find this because everyone has diffrent numbers in the tune repository?!!!

This is for a 2000 Pontiac Grand Prix with the Cartuning turbo kit and 42lb injectors

Please help!

[TDCRacing]

There is no ONE perfect table for all cars, but here are a few tips... Stock injectors? STOCK IFR! You have a GTP and are moving from 36 to 42.5 injectors? Math is your friend... divide your old injector size by the new injector size to get the variance. For example: 36 / 42.5 = 0.847. So... your new IFR table shall be 84.7% of the old table (highlight all cells in the IFR table, right-click, select CUSTOM, click on PERCENT, enter 84.7, click ok... Voila, your new IFR table near perfectly matched in a few seconds!). It may or may not need to be touched up. It depends on your car.

[jimmyschimmies]

See the problem is i already have been running the injectors for some time but i just wanted to make sure i get the as close as possible! and now i have swapped #'s around so much i'm not sure exaclty where i need to be

[TDCRacing]

Just out of curosity why did you switch the numbers around? You should be able to use the above formula to find out where your IFR table should be set at.


Do you not have the stock .bin file for your car? Just a tip always keep that.

[TDCRacing]

Here is a stock 2000 .bin file from the repository. This should contain the starting point IFR table that you need. Then just use the formula in my above post to find the finial table you need for your bigger injectors.

[jimmyschimmies]

Oh, damn i didn't think about that, yes i do have a stock file. i will definately use that formula thank you very much!

[TDCRacing]

no problem man glad i could help. i could give you a IFR table for 42.5's but i dont belive that is the kind of injectors you have. mine are lucas 42.5's

[joebaldie]

tdc i can use that i have the lucas 42.5's thanks

[murphinator]

There is no ONE perfect table for all cars, but here are a few tips... Stock injectors? STOCK IFR! You have a GTP and are moving from 36 to 42.5 injectors? Math is your friend... divide your old injector size by the new injector size to get the variance. For example: 36 / 42.5 = 0.847. So... your new IFR table shall be 84.7% of the old table (highlight all cells in the IFR table, right-click, select CUSTOM, click on PERCENT, enter 84.7, click ok... Voila, your new IFR table near perfectly matched in a few seconds!). It may or may not need to be touched up. It depends on your car.

I know us 3800 guys dont get all the good stuff like pulse adders etc.. but I am 99% sure its not linear math like dividing old size by new - I am no expert but when one chimes in I will have the popcorn ready

[RWTD]

Well, as murphinator was alluding to, you guys need to champion Chris to add in the rest of the injector parameters, like he has for the LSx vehicles. Every V6 owner who are using aftermarket injectors, guess what, you're raping your tune!

It's time you guys push for this! It's been too long.

[murphinator]

Well, as murphinator was alluding to, you guys need to champion Chris to add in the rest of the injector parameters, like he has for the LSx vehicles. Every V6 owner who are using aftermarket injectors, guess what, you're raping your tune!

It's time you guys push for this! It's been too long.

until (IF/when?) that happens what should the original poster do to be able to run larger injectors ?

plenty of people run 42.5's in 3800's and I understand that there isnt a perfect scenario but he asked a question - so what is the lesser of the evils approach ?

[RWTD]

I didn't come into this thread to help him "rape" his tune. I instead came here hoping that some of you would start a cause of championing Chris and the HPT gang to add in the necessary parameters so they do not have to continue raping their tunes.

In regards to injector raping (scaling for larger injectors), there's plenty of writeups that explain how to do this, and those can be found via the search feature here).

[Bill@HPTuners]

Sorry James to be blunt its likely not going to happen.

[murphinator]

Sorry James to be blunt its likely not going to happen.

Bill , we know that you know how much it would be appreciated if it were at least under consideration being a 3800 guy yourself.

with so many posts since gregs dvd release advising that you cant tune unless you can start with proper injector data the problem is not going to go away............

[passingpower]

Time will tell if I'm correct when I say the consensus will end up being:

"To solve your table issues, let your 3800 burn it's garage to the ground and use the settlement to buy a rear wheel V8."

[Bill@HPTuners]

with so many posts since gregs dvd release advising that you cant tune unless you can start with proper injector data the problem is not going to go away............

You can blame the dvd for when we go out of business for spending thousands of hours on tables for a pcm no longer in production for applications that are no longer in production.

Unrealistic IMO to do it on a large scale...MAYBE...MAYBE on a case by case basis but even that likely isn't feasible.

You guys should see the list of table requests we get...theres only so many hours in the day to add them & expanding supported vehicles line which ultimately is what drives sales for us, moreso than adding one or two tables to hundreds of operating systems that will likely never need or use larger injectors.

My guess would be theres lets say 100 people that care about this nuance, and only 10 of those v6 guys would probably buy the dvd.

If you really NEED them for your specific operating system like you are going to die without the injector offset table email your file & serial number to support with the subject injector offset for v6 OS and I'll see if our engineer can add it. Just don't be suprised if someone waiting on dodge or extended ford or gm vehicle support punches you in the arm the next time you see them lol

I promise nothing but its the most organized way to do it...it would be interesting to see how many v6 guys actually NEED & request this table.

[Programmer]

In some cases you'll find there are no differences in the stock offset and larger injector offset when the injector resistance is the same as stock--you can 'pattern check' with a labscope to verify it.

"Offset added to desired fuel pulse width to compensate for the differences in injector turn-on characteristics as a function of battery voltage."

What about low pulse offset ? What about end of injection based on valve timing ? How much extra fuel should be scaled back on an A.I.R. event ? What about wall wetting comp for an injector pattern change ? What table will you want added next when this one thing doesn't make you happy ?

To have everything added, it'd take a full team more time than feasible. My two cents...I'll dig up some 3800 cal offsets to prove my point.

Be thankful for what is available, as there's only a fraction of available tuning info in any of these editors--so lighten up. They'll add more info when there's time. So lay off the rape this and rape that crap...that's very unprofessional.

[murphinator]

Bill , thanks for your thorough explanation and leaving the door open on the case by case basis. I have a couple cars I am parting out that have 42.5's and my primary car is maxing out duty cycles badly (with a new filter in place) I have a walbro on order but otherwise I will be one of the people asking so thanks.

not to change the direction of the thread but I see TDC Racing trying to be helpful and I have seen him come into another forum I frequent doing the same , it didnt turn out so well there and I am throwing out the flag to make sure the same doesnt happen here

read the link about him from the other forum here:

http://www.nepontiac.org/forum/viewtopic.php?t=2986

[Bill@HPTuners]

not to change the direction of the thread but I see TDC Racing trying to be helpful and I have seen him come into another forum I frequent doing the same , it didnt turn out so well there and I am throwing out the flag to make sure the same doesnt happen here

read the link about him from the other forum here:

http://www.nepontiac.org/forum/viewtopic.php?t=2986

This thread is from 2008 so.....

[murphinator]

In some cases you'll find there are no differences in the stock offset and larger injector offset when the injector resistance is the same as stock

so reading between the lines here a bit when looking to change injectors on a vehicle where all you have to tune for size with is the kpa vs. flow rate should one be looking for larger injectors that have similar offset data ?

so Gregs dvd could be used to reference which injectors would require the least amount of changes outside the kpa vs flow rate ?

I installed a larger pump today and am still hovering around going static