Very High AutoVE values... Injector Size Identification?

[dc_justin]

Here's the background information. I bought a used Magnacharger Radix kit for my 2003 Silverado SS that was pulled at a dealership off of a trade-in vehicle. The kit come new with 42lb injectors.

I've set up the IFR table to 5.29 to account for this, as that is what I have read is approximately the proper size for these injectors.

Everything seemed fine until I picked up a WBO2 and hooked it up yesterday. I've got a 2 bar MAP and VE scaled accordingly (haven't gotten around to upgrading to custom OS yet). I followed the Auto Tune guide, disabling the MAF, Trims and Closed Loop operation, and scaled the VE up 30% rather than 15%, just to be on the safe side.

My problem is that even with this 30% increase, I have BEN factor values greater than 1 for most cells that I hit, and this results in VE % greater than 100% while I am still at 10" of vaccum. Intuition tells me that it's not possible for the VE values to be that high, and that one possible solution is that my IFR values are too high... I'm wondering if perhaps the dealership that removed this radix swapped out the injectors at the same time, but I don't know how to visibly identify stock injectors.

Any ideas on this or how to identify what injectors I have?

[Tordne]

Do you know what sort of 42lb injectors they are (brand - part #)?

To scale them we need to know at what pressure they are rated at 42lb, often times this is 43.5 psi, unless they are Ford Motor Sport injectors in which case they are rated at 40 psi.

Then you can use this spreadsheet to calculate what they should be on an LS1 at around the 58 psi mark.

Cheers,

[dc_justin]

I'm pretty sure that they are GM Marine 8.1L injectors. Not certain what this equates to at 48psi. Fuel pressure is vaccum referenced from 48psi to 62-64psi under boost.

[Tordne]

I missed the last line in your original post :oops:

There is usually a part number visible on the injector towards the top (connection to fuel rail). The number might be formatted similar to "0 280 155 931" which from memory is a common stock injector used in Corvette, Camaro and Holden vehicles.

Once you have found that part number you can probably search on LS1TECH or Google and find out brand and perhaps more information about the rating etc.

Good luck.

[Texas Terminator]

do you know what your actual fuel pressure is at the injectors?

[DrX]

I spoke to Magnuson today re: my crazy injector duty cycle values(my FP drops from 60 to 51 psi at full boost). They mentioned that their injectors are, "36(or so) lb/ hr injectors but 42 lb/hr at GM pressure."

So the flow rate depends what they mean by "GM pressure". My factory FP is 60 psi but this varies with model year/application. My tune from Mag has IFR set to 5.0 across the board(I think it should actually be ramped for my setup). I have a returnless non boost-referenced fuel system.

[caver]

The VE table is not actual Volumetric effiency it is predicted airflow and can easily exceed 100% the maximum value is 500%.
If you change the display to the default (Grams*Kelvin/kPa)it might make more sense.

[dc_justin]

do you know what your actual fuel pressure is at the injectors?

My fuel pressure gauge is tapped into the driver's side fuel rail and reads 48psi at idle, 62-64 under boost.

[dc_justin]

The VE table is not actual Volumetric effiency it is predicted airflow and can easily exceed 100% the maximum value is 500%.
If you change the display to the default (Grams*Kelvin/kPa)it might make more sense.

I understand that it can easily exceed 100%, and definitely should when in boost, however my values seem ridiculously high... EG. before I hit boost, my VE % are upwards of 120% and showing a BEN Factor of greater than 1 at that point

[SinisterSS]

Are the MAF and long term/short term fuel trims disabled in your AutoVE/speed density version?