Things seem to be heading in the right direction. After a more thorough look at the numbers and the acceleration rate and the atmospheric conditions during the pull things are making more sense. There are still a couple questions I need answers to from the builder, but it's not as bad as I thought. These engines are still going back on the dyno again and we will have a discussion about sweep rates, correction factors etc before they run.

Red Baja , machine shop did the oiler holes ( they have the fixture)and mike cut orfices and assembled everything.

Borgie would be proud of me

Piston oilers are a nice feature. Done several of those on my marine engines.

Now since the thread already veered from a carb thread to dyno to cam to pin oilers, let me ask this. Why would you set the acceleration rate of a sweep over 1k/sec. How would you expect that to effect results/info etc?

I always thought you guys were closet Borgie fans.

I agree. Sometimes super duper expensive carb isn't worth the cost.

From what I was told the slower acceleration rate will show a more accurate number. A fast sweep can fluff the number a bit.

Did the dyno operator do any steady-state pulls?

Time is always a factor, even in fractions of a second. Torque is measured and it takes time for the dyno to measure the torque. It takes time for the energy to be transmitted through the water brake to the strain gauge. It takes time for the strain gauge to react to the force, and convert the force to an electrical signal. It takes time for the signal to travel from the strain gauge to the electronics and be converted into some sort of value, and it takes time for that value to be recorded. A fast sweep gives less time at every increment of recording for all that to take place, where a slower sweep will give more time and usually be more accurate.

Well good info I figured they would push you out as they did.

Here is some info that may explain some of the low BSFC's.

Since we can see uncorrected hp by looking at fuel flow + other info , what if the fuel flow is lying to us ?

Here's where I am going,

The faster the acceleration rate, the more lag there is in things like airflow and especially fuel flow. It's not just data to computer lag, but more an actual lag of fuel going into the carburetor.

More commonly, 300rpm/sec and 600rpm/sec acc rates are used. You can see fuel flow rate differences between those tests.....so I would ASSUME (never been a part of anything higher than 600rpm/sec) that the fuel rate recorded would be way behind.

Anyone on board with this ? Or.... ?