Correct IFR tables for LS3/LS7 injectors in Gen III

[SweetS10V8]

Ive never seen the newer gen IV looking injectors that are the same length as the old LS1 injectors.

[mr.prick]

FIC has them.
Bosch III LS1 mini for use on LS2 manifolds

[WHYTRYZ06]

the ls9 tables are a tad different, should work tho... joe is working on an ls9 specific spread sheet tho...

STICKY INFO....

[redhardsupra]

Guys, these spreadsheets are wrong. Do not use linear interpolation on non-linear data.

The IFR spreadsheet calculations starts by treating the 400-480kpa range as a straight line of a fixed slope. It isn't, or at least Bernoulli doesn't agree. I understand that in that particular range the curve is fairly flat, but it doesn't mean it is. Besides, with the Bernoulli's formula, we can calculate the IFR values precisely, instead of (badly) interpolating them. Please don't oversimplify things. Also, in the IFR sheet the conversion from gram/sec to pound/hr is slightly off.

The minimum pulse width sheet equates the values incorrectly as well. 1600rpm cell in LS1 dataset is equated to the 2000rpm cell in the LS3 dataset.

The short pulse width table, ironically enough, since it's a nonlinear-adder by nature, is done correctly with linear interpolation.

And I left the Voltage Offset table for the end, because what a mess that it...
Where do I even start? The 50kPa MANVAC table pulls values from the 480kPa LS3-style table, which has nothing to do with it, unless your base fuel pressure is 430kPa and not the usual 400kPa. The 80kPa MANVAC gets its values from the 528kPa LS3-style table. That's completely baffling as far as the 'why?'
As far as the Voltage axis, the linear interpolation is used again, which is incorrect as the relationship between the offset value and the Voltage is something along the lines of offset=k/(V^3) for some value of k.

In general, the whole approach to reshaping this table between LS1 and LS3 styles is wrong. You could just come up with an underlying model, fit a surface to it, and then recreate the new calibration for the new set of numbers needed. It's really not that complicated.

If you're going to post some tools publicly, please make sure you understand the underlying math and physics, and not just take blind stabs in the dark with primitive mathematical tools.

Love,
--Marcin

[WHYTRYZ06]

OK, MARCIN... lets see what joe comes up with... i know he's been working on one so we will wait on him...

[SweetS10V8]

If you're going to post some tools publicly, please make sure you understand the underlying math and physics, and not just take blind stabs in the dark with primitive mathematical tools.

Love,
--Marcin

Like I said, I cant take credit for it being right or wrong, its just what I found.

Where do I even start?

So since you understand this so well, instead of telling us how wrong we are, help us fix it. Its obviously something that would help out the community in general.

Is the data so bad it wont work? Or are you speaking in terms like Greg Banish who believes ONLY FULL OEM calibration will work? The masses neither understand nor can afford to do OEM style testing, that's why we meet on forums to share what we find out. Don't get me wrong I would love to have everything 100% correct, and Greg is a great guy.

Back to my point.... Can you help us fix whats wrong?

[redhardsupra]

Like I said, I cant take credit for it being right or wrong, its just what I found.

yes, but you should at least do some common-sense checks, like seeing if you're grabbing data from the corresponding column, which were apparently not performed. since you just grabbed someone's spreadsheet and just ran with it, you are obviously aware that the moment you post something, especially when you make a tool, that others will use it mindlessly, thus putting the responsibility squarely back onto the creator of said tool.

So since you understand this so well, instead of telling us how wrong we are, help us fix it. Its obviously something that would help out the community in general.

you must be new here... i have contributed to this community; if you read more you'd find plenty of proof.

Is the data so bad it wont work? Or are you speaking in terms like Greg Banish who believes ONLY FULL OEM calibration will work? The masses neither understand nor can afford to do OEM style testing, that's why we meet on forums to share what we find out. Don't get me wrong I would love to have everything 100% correct, and Greg is a great guy.

How bad is the data? we don't know, because we don't have the correct data to compare it to. and if we knew the correct data, we'd have no reason to compare our estimated numbers.

There are tables for which OEM style testing are the prefered method (Short Pulse Adder). Other tables are translatable using simple math tricks, you just have to know which ones.

As to Greg...well, let's just say I blame him directly for giving people the horrible idea that you can use the linear interpolation on every table, as he does it repeatedly on his DVD, and it's absolutely wrong.

Back to my point.... Can you help us fix whats wrong?

I am working on a Universal IFR Generator, but that's only for IFR. Other tables, especially the voltage offset being a 3D relationship are a bit less trivial. All in time I guess...

[SweetS10V8]

So should I just sell my LS3 injectors and buy a Gen III set with a known OEM data, like the injector data Greg includes with his DVD?

[redhardsupra]

stock injectors out of some other platform for which we have data in some sort of format is best. everything else is ballpark. and since all airmass calibration is based by estimating the airmass with fuel consumption (which is calculated out of injector characteristics), the error will propagate throughout your new tune. If you can find injectors that fulfill your fueling needs, get them. If they dont exist, then you're forced to start hacking and guesstimating.

[SweetS10V8]

Thats why I got LS3 injectors in the first place. But now I just cant get the data to cross reference like I assumed it would, unfortunatly.