Tuning Injectors..Marine Truck Injectors

[gofish7]

Their you go! Trust me I don't like let me rephrase that I HATE tuning with unknown injector data but with trucks being mainly what I tune and a guy comes to me and is using the Delphi Marine injectors I am not going to turn him away. I just do the very best that I can with it, will it be spot on perfect? No but I've got some customers out there running the marines and their trucks are very quick with no drivability issues.

Now we are getting somewhere. I take it your only fix too is shorten pw and set the flow rate as well and try to adjust accordingly to wha the truck wants and if you have a higher VE than normal..just run with it and lower the VE down in the 400-1200 cells from 80-105 kpa so the startups aren't so rich.

DSteck....yes....data is golden in this day and age of tuning where when I tuned TPI stuff....you can get away without all of this data.

[KLUG'S SS]

Now we are getting somewhere. I take it your only fix too is shorten pw and set the flow rate as well and try to adjust accordingly to wha the truck wants and if you have a higher VE than normal..just run with it and lower the VE down in the 400-1200 cells from 80-105 kpa so the startups aren't so rich.

DSteck....yes....data is golden in this day and age of tuning where when I tuned TPI stuff....you can get away without all of this data.

Well I have even gone further than that so that the ve and maf tables aren't all jacked up with really false values I actually have gone and swapped in some stock or injectors that I absolutely knew I had good data if I had to and made sure the ve/maf were dialed in well with those and
then swapped back and played with offsets, short pulse adder etc.... to get stuff looking decent. It can be a real bitch and time consuming but worth it. But still at the end of the day I'd prefer
obviously to go with an injector with the solid well known data in place already.


I know it sounds like alot of BS to go thru but better than having a guy call me up about some drivability issues he is having a few days later

[eficalibrator]

...I'm a Math person...there is always a solution to the problem and the solution of swapping injectors is just not plausible.

If you don't believe Dave, let me put it in math terms then:

You have more unknowns than equations. Have fun sorting through an infinite set of multiple answers. Even a blind squirrel occasionally finds a nut.

[gofish7]

If you don't believe Dave, let me put it in math terms then:

You have more unknowns than equations. Have fun sorting through an infinite set of multiple answers. Even a blind squirrel occasionally finds a nut.

I never said I didn't believe him with all of the differential equations....just find it frustrating like everyone else does on here with the lack of information on those injectors. That is all.

[smithers]

I never said I didn't believe him with all of the differential equations....just find it frustrating like everyone else does on here with the lack of information on those injectors. That is all.

so know you know why not to buy injectors with little data available.
And tell your friend, if $$ for new injectors is a problem, they should find a cheaper hobby or start practicing data digging for info before making a purchase.

[murphinator]

just advise him to sell them back to the market they came from and buy some injecotrs with full characterization.

I would suggest offshore only forum for selling marine injectors ( been in the boat bizz 15 years)

[detroit]

42 marine injector data is the bigfoot of fueling...they dont really exist

I have seen some pretty awsome sharing of info on some other user type forums, its kind of wierd that people here have not figured them out...I would chip in and pay to find the offsets and make the available?

ok I am back to reality...buy some 60's with info, dont waste your time with bigfoots

[DSteck]

I have seen some pretty awsome sharing of info on some other user type forums, its kind of wierd that people here have not figured them out...I would chip in and pay to find the offsets and make the available?

There's one guy (that isn't an OEM) who could do it, and he won't.

[Alvin]

That doesn't make it right. I've made cars work with mystery injectors, but having all the correct data just makes everything so much cleaner and easier. Pridictability is a great thing in tuning.

You do not have to have the data to tune the data. If you think the data handed to you in a DVD is the be all end all than your sadly mistaken. Build a histogram biased on the tables you wish to tune then look at trends that follow that table, fit you data to a bell curve and see what you got.

BTW. You math people should do a sensitivity analysis on injector offsets and how much they can help/hurt you and where.

[DSteck]

You do not have to have the data to tune the data. If you think the data handed to you in a DVD is the be all end all than your sadly mistaken. Build a histogram biased on the tables you wish to tune then look at trends that follow that table, fit you data to a bell curve and see what you got.

BTW. You math people should do a sensitivity analysis on injector offsets and how much they can help/hurt you and where.

I stick to OEM GM injectors and Injector Dynamics (which I trust more than the OEM GM stuff). I'm not even considering the Banish data.

[Injector Dynamics]

BTW. You math people should do a sensitivity analysis on injector offsets and how much they can help/hurt you and where.

No need for sensitivity analysis. The fueling error due to incorrect offset values is completely predictable.

A .2msec offset error would result in a 2% fueling error with a 10msec pulsewidth.

The same .2 msec error would result in a 13.3% error with a 1.5msec pulsewidth. (.2/1.5=.133)

As you can see, the error increases as pulsewidth decreases.

[Alvin]

No need for sensitivity analysis. The fueling error due to incorrect offset values is completely predictable.

A .2msec offset error would result in a 2% fueling error with a 10msec pulsewidth.

The same .2 msec error would result in a 13.3% error with a 1.5msec pulsewidth. (.2/1.5=.133)

As you can see, the error increases as pulsewidth decreases.

That's exactly my point! 2% error is nothing major at all, hell its well within our error of uncertainty. 13.3% obviously is! Know that injector offset and short pulse adders are only really critical at and around idle and decel. Most of it will work itself out in the rest of the tune, the other bit.. like that is dependent of other variables not normally even looked at while tuning like like battery voltage can be fixed if you plot the error on a histogram that looks like your battery offset table. Know that you can't just take 13% away from that table should you see a 13% error but you can slowly work it out by taking a little out at a time.

[DSteck]

I'll stick to just buying characterized injectors that work off the bat.

[Alvin]

Whats next? Demanding intake companies to provide MAF calibration tables?

[DSteck]

Halltech does. Haha.

Calibrating the MAF and comparing that to calibrating injectors is fruit and you know it. To truly calibrate injectors, you'd need a 100% solid airflow model (MAF/VE). Rarely does this exist. You're robbing Peter to pay Paul when trying to dial in both aspects simultaneously.

[Alvin]

If you have a problem getting injectors dialed in leave them stock until you have the low throttle ve and maf dialed in. It's not rocket science.

[DSteck]

I don't get that liberty since I don't build the cars... I just tune them.

[smithers]

Im with DSTeck

[Alvin]

Well don't know what to say. I guess tell the OP to take the injectors out and throw them in the trash since no one has data for them and your not willing to try to find the data empirically. If it was me, I would try to get them dial in with the method I described earlier.

[NicD]

I understand the push to use injectors that have available data for them, hell I push everybody in that direction as well but let's not pretend that you can't make the car drive correctly and even fuel nicely without it.

I'll even give a hint on these injectors, take the voltage offset table from an 01-02 f-body for starters then multiply the whole thing by 1.20-1.25 and it gets it awfully close and will prevent you from having those higher VE numbers around the idle and high vacuum areas. What you set the IFR table to looks appropriate for a return style system.