Inector flow rates

[maudyZ28]

hi all,

currently i have a 99 camaro. with the lowest rated injectors 26.2lb/hr @58 psi.

I have got a set from a 2002 commadore UTE that are the better 28.6lb/hr ones so i'm installing these. My prolem is that If I use the IRF table the values are different to the UTE 2002 table (and monaro etc for that matter) the spreadsheet shows linear injectors the stcok tunes don't.

However I have a tune from a 2002 corvette that has the same 28.6lb/hr injectors and these have the linear characteristics in the stock tune, so shall I use these?

On a final note, I must say that the spreadsheet (unless im doing something wrong) doesn't perfectly agree with the stock tunes anyway. For example putting in my ratings of 26.2lb/hr stock injectors at 58 psi rated. with a 58 psi fuel rail, the flows are 0.03g/s down everywhere. I assume maybe out fuel rail pressure should be 60 psi? in this case to make numbers agree

[odd boy]

plug these numbers into B4001

29.142278
29.328292
29.514307
29.700321
29.886336
30.010345
30.196360
30.382375
30.568389
30.754404
30.940418
31.064428
31.250442
31.436457
31.560467
31.746481
31.932496

[maudyZ28]

thanks dude, those are the same as the corvette ones I have so i'll copy that :D

what about table B3701 for voltage adjustments? copy from z06 too as they are slightly lower values than my camaro ones (presumeably dont have to open as much due to large injectors?)

[joecar]

Yes, I found that some stock tune IFR tables agree with the spreadsheet calculation when rail pressure is assumed to be 60 psi.

According to GM service manuals, rail pressure is supposed to be 58 psi (with a small amount of tolerance which allows 60 psi).

[LinearX]

What you find in real world testing is that the spreadsheet only gets you close. From personal experience, if you flow a set of 42lb injectors at 43.5psi and at 58psi, you're likely to have more real world flow than the spreadsheets will calculate for you.

http://redhardsupra.blogspot.com/2010/01/svo-greentop-42-testing-at-3-and-4bar.html#links

[maudyZ28]

thanks guys,

Joe car - does it seem strange to you that the 2002 camaro/TA/corvette tunes have the above posted flows (match sheet if rail is 60psi). And the HSV/HOLDEN ute, commadore and monaro have totally different ones for the same injectors!!! I think GM did some 'fudging'???

LinearX - good read thanks but hopefully the quoted values are ok as GM rated at 58 PSI so must have tested? Not as much problems with the scaling up stuff from 43.5 PSI. Either way the small difference from real and theory would be taken up by the LTFT I think.

[joecar]

yes, it is strange... make you wonder what their reasoning is.

[5.7ute]

Different Fuels ?????????
Also the commodore ute runs a variable voltage fuel pump. I would think that they would have added in some fudge factor for safety.

[maudyZ28]

I did notice that the O2 switch points are a lot higher too for these tunes. Oh well i'm not going to worry about wondering why they are different. I'll just concentrate on mine. However a problem may arise when my pal wants his monaro tuning !!!