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Something i did up as an idea the other day, if you have your injector flow rate and have WOT RPM points and the injector pulse via calc X/65.536 for a datalog then it can calculate an estimate dyno graph.

Here's mine with the dyno chart and the results for my injectors at the time just 777 VT injectors @ 3.5bar and data from the log that was done on the dyno at the time of the graph. Obviously transmission loss will vary but 15-20% seems to be a common estimate for auto's?

Let me know what you think.

Ive included a blank template which i will reupload and update if bugs or fixes are made.

Here's the only other one i have to compair, which is the wifes wagon, dyno is from when we bought it, logs figures inputed are after a tune, new plugs, coils, LIM Gaskets, EGR Turned off and port match inlet manifold. Note that this one was in 3rd gear with converter locked and logs are just WOT on the road

Here's the current update on my car, compared to the file in the first post ive added

Rockers 1.98
Larger Delphi MAF and intake piping with pod filter
68mm TB
40LB Fomoco injectors
New Auto Gearbox went in
Full retune again

188HP / 140kw at the wheels would seem reasonable to me for that setup on stock ecotec, could even at a guess take 5% loss out for a brand new box which would nudge it near 150kw at the wheels.

Let me know your thoughts, i think the spreadsheet is a reasonable guessing tool. You can also put the equations into tunerpro so you have the data on the fly and also input it into history tables.

going through a few logs of cars, here's some other various builds

As a note obviously this is injector based guessing so fuel tuned to Target and nothing affecting fueling must be the case for more accurate results.

Is this how they estimate the power of top fuel engines?

No idea, I just had the idea when someone asked me about a set of injectors and how much power they were good for and it rolled from there.

I put new Gorst coils on the wagon and gapped the plugs to 1.7mm, redid the WOT log and did the spreadsheet again, got a little gain in the middle, but nothing up top or down low really.

Im going on holidays next week so will see if economy picks up on the highway trip.

Its a good idea. I assume the fuel measurements can be pretty accurate, but I guess it cant take in to account the compression, AFRs, or engine/trans loss. It seem the ballpark figure gives and idea, and I also expect when someone says "these injectors are good for X HP" they are assuming optimal everything and doing calcs similar to this.. probably simpler at just amount of fuel at 80 or 100% DC though.

Well it takes into account anything that is related to fuel input changing, the injector HP is a calculation, obviously alot of injectors may not handle 80-100% duty cycle but that's really got nothing to do with calcs as under 80% the injector output is still related to the theoretical HP capacity of the injectors.

As long as the AFR's are the same then comparison from sheet to sheet should be accurate.

For more accurate results if you have a datalog while on the dyno and the dyno sheet to compair to then trans loss should be able to be calculated pretty good as the rest is known from the logs. So for both my cars changes to mods should show the increases close to what would be seen on the dyno.