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-   -   Hi and low slop for modified injectors (http://www.focusfanatics.com/forum/showthread.php?t=311150)

Fernando_221 03-07-2013 09:05 PM

Hi and low slop for modified injectors
 
Hi all,

I'm starting a turbo build, injectors are a modified (TLF Performance, anyone know about it?) for 58lbs.
What values of hi slop, low slop e breakpoint I can use for it?
Can I use the FR 60lbs setting?

Thanks

1turbofocus 03-08-2013 05:17 PM

I would ask your tuner LOL there is far more to do then just change the slopes

Tom

iminhell 03-08-2013 09:00 PM

Get a data sheet from the MFG. of the injectors.
If they don't have one available, return the injectors and buy some reputable ones. It's very tough (next to impossible) for a novice to tune injector slopes. Even some pro's have difficulty. It is possible, just not easy or quick by any means.

1turbofocus 03-08-2013 11:30 PM

He is doing blowthrough and 3 inch MAF so even if he had the data sheet it wouldnt help him

Tom

paulg127 03-09-2013 02:06 AM

High slope is calculated from injector flow, ( lb flow/3600 ) to get in the ballpark, but the 58lb rating does not seem too accurate. The low slope and breakpoints are very hardware specific, but you can use the adaptive fuel terms of the, what is commonly called short term fuel trim, and the long term fuel trim to dial it in.
Typically the idle adaptive (long term fuel trim, lowest air mass) will show if the low slope may not be correct. If the other (higher air mass) adaptive values are close to nominal, most likely the high slope is pretty close, leaving the low slope to correct the idle adaptive cell, provided you do not have an air leak.
If you don't have either the MAF transfer function or the injectors accurately characterized, you really have no way of knowing which, if either is correct.
I'm sure someone has a 3" maf transfer function out there somewhere....

Fernando_221 03-09-2013 10:36 AM

Quote:

Originally Posted by 1turbofocus (Post 4626796)
I would ask your tuner LOL there is far more to do then just change the slopes

Tom

Agree. I'll contact you by email. [:D]

Fernando_221 03-09-2013 10:37 AM

Quote:

Originally Posted by 1turbofocus (Post 4627353)
He is doing blowthrough and 3 inch MAF so even if he had the data sheet it wouldnt help him

Tom

Tom, remember my ecu is map/speed density based.

Fernando_221 03-09-2013 10:44 AM

Quote:

Originally Posted by iminhell (Post 4627090)
Get a data sheet from the MFG. of the injectors.
If they don't have one available, return the injectors and buy some reputable ones. It's very tough (next to impossible) for a novice to tune injector slopes. Even some pro's have difficulty. It is possible, just not easy or quick by any means.

Asked the guys from TLF Performance and they said this:

"never heard of that we do lactency and dead time here.
Thanks

- tlfperformanceparts"


The injectors came with a flow sheet:

http://img845.imageshack.us/img845/1...wsheet58lb.jpg

1turbofocus 03-09-2013 12:31 PM

Quote:

Originally Posted by paulg127 (Post 4627468)
High slope is calculated from injector flow, ( lb flow/3600 ) to get in the ballpark, but the 58lb rating does not seem too accurate. The low slope and breakpoints are very hardware specific, but you can use the adaptive fuel terms of the, what is commonly called short term fuel trim, and the long term fuel trim to dial it in.
Typically the idle adaptive (long term fuel trim, lowest air mass) will show if the low slope may not be correct. If the other (higher air mass) adaptive values are close to nominal, most likely the high slope is pretty close, leaving the low slope to correct the idle adaptive cell, provided you do not have an air leak.
If you don't have either the MAF transfer function or the injectors accurately characterized, you really have no way of knowing which, if either is correct.
I'm sure someone has a 3" maf transfer function out there somewhere....

You should never use long turm fuel trim for tuning anything and never use short turm fuel trim or either for setting the high or low slopes

LTFT should be turned off in my opinion and STFT1 should be adjusted in the MTF , what about WOT and the high slope ? what about when he changes to blowthrough , adds a MAFia , you can throw out any MTF any one can give you and and injector settings on paper , then what does he do ?

Why does everyone approach tuning engines the hard way

Tom

paulg127 03-09-2013 01:49 PM

I'm approaching it from 20 yrs at FMC as a calibrator. There is a right way to do a calibration and a wrong way. The right way is to have the MAF and injectors flowed and characterized. The entire calibration is based on the MAF being correct, right or wrong, and adaptive changes the fueling from there. You are wasting valuable correction info if you turn off adaptive (long term fuel trim). There are many ways to change the adaptive to use it to help you from smoking a piston and helping drivability and verifying MAF and injector slope. The adaptive tells you at a given air mass that the stoich point is shifted the adapted amount.
Why would you not use this information? What do you think the adaptive is there for?


I have not used a mafia so I do not know how it functions.
I do know the calculations, tables, functions, scalars and entire strategy that use the MAF transfer function as a basis and have a hard time relating that the ENTIRE calibration is shifted if the MAF is going through a 'correction' from the mafia.

That would shift the normalizers (load) input to every table (spark, fuel, air) and that seems to be a mess to sort out.


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