Stock Fuel Injector Specs for Tuning

[thehemi]

Okay, I need a couple of the stock specs so I can start my tuning.

What is the factory flow rating and fuel pressure on a stock SyTy?
My understanding from searching around would be 29# @ 43.5psi?

And how about the injector offset multiplier vs volts for the stockers?

I'm running stock SyTy injectors in my '99 and need to know the fuel
injector specs so I can start on tuning the VE tables accordingly.

Thanks!

 

[thehemi]

Re: Stock Fuel Injector Specs for Tuning

Maybe I'm posting in the wrong category?

 

[dgoodhue]

Re: Stock Fuel Injector Specs for Tuning

Maybe I'm posting in the wrong category?

This is the best category. No need to make multiple posts on the same topic. This is a small forum.

I flowed my stock injectors, they were 32# @ 43.5psi.

Anyways for your tuning, the best way to do what your trying accomplish what your doing is get a Wideband and adjust you injector constant while idling to reasonable AFR. In theory the rest of your VE table should be in the ballpark of where its needs to be, however injectors don't have a linear flow rates, and every different brand/size tends to be different in how linear their flow rates, some even vary with the part number of injector (50# are notrious for this). So you will most likely need to adjust your VE table accordingly to what your engine wants.

 

[thehemi]

Re: Stock Fuel Injector Specs for Tuning

I flowed my stock injectors, they were 32# @ 43.5psi.

Excellent, thanks.

Anyways for your tuning, the best way to do what your trying accomplish what your doing is get a Wideband and adjust you injector constant while idling to reasonable AFR.

I'm assuming my injector constant is calculated from the flow rate
that I enter into the tune. I can adjust that, however, I think I need
to have the Offset table correct, too, since it seems like the Offset
is always applied to the calculated PW, if I understand it correctly.
Unless I leave my Offset table as-is and adjust the flow rate to get
the overall PW where it needs to be?

I have a wideband, but when I'm at idle the PCM is using the stock
o2 sensors and the AFR does not appear to remain stable. As far as
I'm aware, this is normal due to the narrowband o2s jumping around
trying to correct the AFR.

I definitely plan to tune my VE tables, but I'm trying to make sure I
have the appropriate fuel injector settings first. They're more static
(for lack of a better word) than the VE tables, so I'm trying to tweak
them as close as possible so my VE tuning is not for nothing.

I'm new and trying to learn, so bear with me if I seem naive...

 

[turbodig]

Re: Stock Fuel Injector Specs for Tuning

Excellent, thanks.



I'm assuming my injector constant is calculated from the flow rate
that I enter into the tune. I can adjust that, however, I think I need
to have the Offset table correct, too, since it seems like the Offset
is always applied to the calculated PW, if I understand it correctly.
Unless I leave my Offset table as-is and adjust the flow rate to get
the overall PW where it needs to be?

I have a wideband, but when I'm at idle the PCM is using the stock
o2 sensors and the AFR does not appear to remain stable. As far as
I'm aware, this is normal due to the narrowband o2s jumping around
trying to correct the AFR.

I definitely plan to tune my VE tables, but I'm trying to make sure I
have the appropriate fuel injector settings first. They're more static
(for lack of a better word) than the VE tables, so I'm trying to tweak
them as close as possible so my VE tuning is not for nothing.

I'm new and trying to learn, so bear with me if I seem naive...

What PCM/ECM are you running?

I don't think you'll get particularly good results messing with the Offset table... it never seems to work out that well in our application. Furthermore, it would require some linearity information that you'd probably have to get from your specific injectors. It would also assume the that table it currently has, was calibrated to match the linearity of the original injectors. (Often, that isn't the case)

Generally, you're better off turning narrowband closed loop off, and adjusting whatever your system has for an injector constant until you have a warmed-up idle AFr in the 14.5 area. Then tweak VE tables from there. If your ve table numbers start to get up in the high 90s, you may have to lower that injector constant.

 

[thehemi]

Re: Stock Fuel Injector Specs for Tuning

What PCM/ECM are you running?

Stock PCM in my '99 S10. Marine MPFI intake with Syclone injectors.
It drives great, the only real issue is a bog right off of idle. When I turn
down the injector constant until the bog is gone, its too rich. So I think
I need to setup the injectors and give it a good VE tune.

I don't think you'll get particularly good results messing with the Offset table... it never seems to work out that well in our application.

I understand that it is not going to be perfect based on my actual injectors,
but I'm hoping to have it roughly close so that I'm not way off base trying to
get the VE tables correct.

Generally, you're better off turning narrowband closed loop off, and adjusting whatever your system has for an injector constant until you have a warmed-up idle AFr in the 14.5 area. Then tweak VE tables from there.

I have not heard of that method from anyone, but it sounds pretty interesting.
I might give that a try and see where it ends up putting my injector constant.

 

[thehemi]

Re: Stock Fuel Injector Specs for Tuning

Generally, you're better off turning narrowband closed loop off, and adjusting whatever your system has for an injector constant until you have a warmed-up idle AFr in the 14.5 area.

Between VE, Inj Offset and Inj Constant, that constant seems to be the only
variable that I know. Would there be any logic behind entering the flow rate
and using the open loop tuning to adjust the Offset table until the AFR is ok?

Rochester 15637677
Bosch 280150756

Is the Offset table included in the tune on the SyTy trucks? I'm not sure how
you guys tune the PCMs?

 

[thehemi]

Re: Stock Fuel Injector Specs for Tuning

The majority of the specs online said 32# @ 45psi, so assuming
that was accurate I went with 36# since my rail pressure is 58psi.

After adjusting the Offset Table until my idle AFR was 14.5-14.7,
I ended up with these values in my table (80% higher than stock).

Labels 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5 15.5 16.5 17.5
Injector Offset Multiplier 4.36377 4.02100 2.62256 2.09961 1.84326 1.66748 1.50293 1.36914 1.26221 1.17529 1.10059 1.03955 0.98535 0.98779

1.175 to 1.100 are the values for the 13.5 to 14.5 voltage range.
Hopefully those values don't seem too high. I'm told injectors in
an LT1 are even slower, so maybe they could be close to correct.

I'm still amazed no SyTy owners have stock Offset Table values?

Time to work on the VE tuning to see if my bog will go away...

 

[thehemi]

Re: Stock Fuel Injector Specs for Tuning

FYI

Bosch 280150756 are proprietary injectors they made for Ford
so Bosch won't disclose a spec sheet. I suppose I could ask
Ford to see if they will provide specs for their E9SE 9F593 B1B
injectors. I think they came in Thunderbird SuperCoupes.