How do you know.

[Blue71]

How do you know when your injectors are to small ?
What a good indicator.

[91chevZ71]

duty cycle % if you can read the data. ALso, when your engine hits a wall on RPM
anything over 90% on duty cycle is pushing it.
not really sure on port fuel, maybe someone can chime in

[Blue71]

Thanks for the reply 91,

I Can't tell the duty cycle with DataMaster, it only gives me inj BPW/injDC. It running lean 70 and up map, VE as high as it would go 99.9%.

Seen the thread by PFK pointing to Red94chev thread.

Quote.
from Red94chev thread.

The above formulas can also be applied to Vortec engines, except eight 19 lbs/hr injectors rated at 42-43.5 psi are used in the 350 Vortecs. Think it doesn’t work? What is the stock hp of a 5.7L Vortec? 255 hp, right? Well, hp = ((19 x 0.85)/0.5) x 8 = (16.15/0.5) x 8 = 32.3 x 8 = 258.2 hp!! Well, what do you know!?!?! It works.

end Quote

Looks like I need at least 24# injectors to support the 350HO, I also need to check to see where the fuel pressure running.

Boy, looks like DIY tuners are a rare breed around here!

[91chevZ71]

yeah, dude...you need more injector. Can you raise the FP and recalc the base pulse? Is there anyway to get a real datalogging setup with your computer? How does the MPFI computer interact with the rest of the truck? sorry about the Q's, dude

Mike

[Blue71]

Can't raise the FP with the regulator that on it, not adjustable.

Another thing to add to the list of things to get.

DataMaster not a real Datalogger ?

The computer is the 7427 running in TBI mode,
it works well with the 4L60-e, I can adjust the shift points TCC lockup ect.

Would love to get this running in PFI mode with the 7427 there is a flag for it in the OD bin, But I think theres alot more to it then just checking a flag.

Far as I know only a hand full have been able to do this, HAulnA$$ is one of them I think ? or maybe the only one.:dunno:

[pfk]

Thanks for the reply 91,

I Can't tell the duty cycle with DataMaster, it only gives me inj BPW/injDC. It running lean 70 and up map, VE as high as it would go 99.9%.



injDC is your injector duty cycle, the square on your right should show you your percentage. I have no idea how it works with the PFI mode.

[Blue71]

Thanks PFK,

I don't know how it works PFI mode either.

I think its still running in TBI mode, four injectors = one TBI injector in a bank to bank arangement:dunno:

Don't know what DC should be, the highest I've seen is 11.2

I compaired the two Bin's, Stock TBI bin BDJY and the one Eldelbrock sent me ( modded BDJY).The only changes that Eldel made that I see were to the constants, Injector flow rate from stock of 61# to 83#, Timing tables are lot more agressive, Accel enrichment vs differential tps is different, everything else remained the same.

Had a guy that was working on it and got it running a lot better then Eldel, But he is no longer around and Iam still a newbe at tuning and now this stuff all works.

Thanks again,

Mike