So, I have been working with someone who built a machine to flow test injectors. He has been working on writing a special program that gets the numbers for the fuel tables that HPTuners uses for our cars. I sent him my stage 2 injectors to help. I will be getting the numbers back from him in a couple of days or sooner.

I need someone who has the stage 2 siemens 42s and HPTuners to beta test these numbers for me. You will need to know a bit about tuning MAF at least and have a wideband. I expect that these fuel maps will run better than GMs. Your payoff is that you will have these maps to keep at no charge, and tuning your MAF and VE tables should be a breeze. If you tune other peoples cars, you already know how valuable this info really is.

Any takers?

On a side note, I also bought a new set of matched 60s for my car and all the numbers for them. I will be testing those numbers on my old 60s to see how they act, before I sell them.

 

Okay, I got the numbers for the 42s. I'll be putting together the fuel tables tomorrow at work. Someone on the HPT forum offerd their help, but I need more people. The payout on your end is that you will be one of the first to be able to tune your stage 2 with the ACTUAL CORRECT fueling tables. I have looked at these numbers and GM is WAY off. The offsets are off, the adders are off (actually according to GM there are no low PW errors), the IFRs are off... I am predicting people will start opening doors with these numbers.

The numbers were derived by an actual flow bench, flowing with actual gasoline at 120*f. Custom algorithms were written to map injector dead times, actual flow rates, low PW errors, everything. These algorithms were checked, double checked, triple checked and checked some more against actual known values to verify the accuracy of these numbers. Keep in mind that the same brand of injectors will still have some variation from injector to injector, but this is as close as you can get without sending your injectors in to get tested.

60s numbers coming soon!

 

I know Area47 is big on the 42* injectors, maybe he would like to help out...

 

Thanks for the response. I have talked to Bryan and he is going to help with both the 60s and the 42s. Since he's running 60s now, the only way that he can help with the 42s is if he is tuning another persons car. I was kinda hoping to be able to let him know how much MAF and VE work will be needed before he does this tune to a customers car. I have a hunch that there will be quite a bit of work on the MAF at least.

 

Wouldn't the tolerances from the factory affect the numbers from each set of 42lb injector? Do you think that maybe the GM numbers were a conservative estimate based on the standard deviation of the tolerances from the factory? To get the correct numbers, everyone should get their injectors flow tested so that they can get the correct number (for optimal results). Otherwise, one guy might be way off and another dead on. I think that's why we have some factory freak 2.0s and some slow(er) 2.0s.

 

You are correct in that there is factory tolerances between injectors (which I did say above). The problem is that it is obvious from looking at the stage 2 tunes that GM did not base these numbers on flow characteristics of any injectors. GM uses MAF and VE to make up for the fact that they never completely flow tested these injectors. That explains why people have a bouncing idle with stage 2 when the AC is on and the trims are upwards of 17% in areas. Not to mention that they put out 3 versions of the stage 2 tune, all for the same injectors (one of which was to "fix rough idle issues"). Factory tolerances are not 17%. They are less than 10%. Even though the flow rates may be a bit off, the dead time, linear ranges, and recovery characteristics should be really really close. In short, yes it is better to send your injectors in to be flow tested, but how many are going to remove their injectors, send them in, pay $140 to get them flowed and be without a car untill they get them back? Not only that, but untill I am done with my testing, the ONLY man that is doing all of these tests is not going to offer this service to the general public. Once he offers these tests to the public, I hope that a lot of people send their injectors to him for testing, as well as by new injectors from him that have all of the info. He deserves to make some money off of all his hard work. Untill that happens, I still need help from people who are willing to load these fueling tables into their cars and tune with them, so I know what having these numbers does to the air tables. I will be doing the testing with the numbers for the 60s, but I do not have the ability to easily test the 42s.

 

im going to go sit in the corner and play with my timing tables now

 

lol

I just sent you the 42 maps.

 

i just don't understand the fuel side of it to be honest with you. i have tried to wrap my head around it, and i just can't seem to get it. then again, i was never good at math.

some people understand fuel tables, some understand timing tables. i just do timing and everything else around fuel, just not a direct playing with that said section.

 

Yep, and I suck at timing. To me, fuel is easy. MAF is easy too. VE can be a little tricky. Here is some great reading material for you, if you want:

http://www.yawpower.com/injectordeadtimesarticle.html