Injector Flow Rate Question
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From: South Florida
Injector Flow Rate Question I've got the SVO 42# injectors in my car. I had custom programming done by Superchips. I've recently purchased LS1Edit to try and correct a VERY lean condition since my cam install (verified by a wideband). I was looking at the Injector flow rate tables. Here is what Superchips had compare to what I thought they should be for the SVO 42# injectors.
Superchips 5.55 5.55 5.55 5.43 5.44 5.43 5.45 5.47 5.49 5.51 5.53 5.55 5.57 5.59 5.6 5.63 5.64
39.15psi 6.44 6.48 6.52 6.56 6.6 6.64 6.68 6.72 6.76 6.79 6.83 6.87 6.91 6.95 6.98 7.02 7.06
I've got positive lTrims and am running about lean all the way thru the RPM range.
If I understand correctly the lower values in the flow rate table should produce a rich condition. So if I am right on what the flow rate tables should be, do you think I should adjust them to the correct numbers and start there. Or since I'm lean already just use the numbers that are there and tune from there?
Superchips 5.55 5.55 5.55 5.43 5.44 5.43 5.45 5.47 5.49 5.51 5.53 5.55 5.57 5.59 5.6 5.63 5.64
39.15psi 6.44 6.48 6.52 6.56 6.6 6.64 6.68 6.72 6.76 6.79 6.83 6.87 6.91 6.95 6.98 7.02 7.06
I've got positive lTrims and am running about lean all the way thru the RPM range.
If I understand correctly the lower values in the flow rate table should produce a rich condition. So if I am right on what the flow rate tables should be, do you think I should adjust them to the correct numbers and start there. Or since I'm lean already just use the numbers that are there and tune from there?
Re: Injector Flow Rate Question I have a handful of superchips programs, and it appears as though they do their injector flow calculations a little different. Additionally, they always seem to reduce the curve by 10%.
They use a rated psi of 43 psi rather than the SVO 39 psi.
They then multiply it by 90% probably for safety reasons to ensure they don't burn anybodys car down with a mail tune.
So according to your numbers.
Actual Flow = Rated Flow * SQRT(Actual PSI / Rated PSI)
Actual Flow = 42 lb/hr * SQRT(58 / 43)
Actual Flow = 48.7 lb/hr
Adjusted 90% = 48.8 * .9
Adjusted 90% = 43.9
Convert to g/sec = 43.9 * .126
Convert to g/sec = 5.54 g/sec
There is a little bit of rounding error (5.54 instead of 5.55) but you see where the number comes from.
Good Luck,
Kevin
They use a rated psi of 43 psi rather than the SVO 39 psi.
They then multiply it by 90% probably for safety reasons to ensure they don't burn anybodys car down with a mail tune.
So according to your numbers.
Actual Flow = Rated Flow * SQRT(Actual PSI / Rated PSI)
Actual Flow = 42 lb/hr * SQRT(58 / 43)
Actual Flow = 48.7 lb/hr
Adjusted 90% = 48.8 * .9
Adjusted 90% = 43.9
Convert to g/sec = 43.9 * .126
Convert to g/sec = 5.54 g/sec
There is a little bit of rounding error (5.54 instead of 5.55) but you see where the number comes from.
Good Luck,
Kevin
Re: Injector Flow Rate Question First, ensure that your lean condition isn't being caused by something mechanical (vacuum leak ect...)
Once you've done that then correcting it with your injector flow table should be a sinch. You already have it correct. Just lower the table in steps until your lean condition cleans up.
Once you've done that then correcting it with your injector flow table should be a sinch. You already have it correct. Just lower the table in steps until your lean condition cleans up.
Re: Injector Flow Rate Question SVO injectors are rated at 39psi. A 42# SVO injector in our LS1 fuel system will flow about 51.2#/hr... So, you should go into the injector table with LS1Edit and multiply the each cell by 197%.
That sounds like alot but I believe that is correct.
I have the stock '99 injector flow rate table,, the first entry is 3.33, that value should be changed to 6.56 (3.33*197%). This is close to your 6.44 value. But its the wrong direction to richen your engine up.
However, if you have made changes to the MAF sensor (any change at all), the MAF table is way out of balance and that could be your source of the lean condition.
<small>[ November 27, 2002, 12:40 PM: Message edited by: Doc99SS ]</small>
That sounds like alot but I believe that is correct.
I have the stock '99 injector flow rate table,, the first entry is 3.33, that value should be changed to 6.56 (3.33*197%). This is close to your 6.44 value. But its the wrong direction to richen your engine up.
However, if you have made changes to the MAF sensor (any change at all), the MAF table is way out of balance and that could be your source of the lean condition.
<small>[ November 27, 2002, 12:40 PM: Message edited by: Doc99SS ]</small>
