From what I've watched, I agree. But I'd rather have it that way, than a happy dyno.
Nicks Garage 383 build
- Thread starter RAMM
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Depac Dave's thoughts on correction factors. For what it's worth. Hope this is readable.
Newbomb Turk
Well-Known Member
More accurate than what? The ONLY time an engine makes the power the dyno says it does is when you use observed numbers AND the weather at the track matches the weather like it was on the dyno OR when using corrected numbers the weather has to match.
It doesn’t matter which CF you use because IF you are going to live and die by corrected numbers any corrected number has to match weather conditions at the track.
You keep saying the higher the CF the more inaccurate it is. My question is by how much? 20%? 2%?
I don’t know but I’m doubting is more than 2% worse case scenario. If that.
Also, most flow bench software I’ve used corrects to STP.
Why not correct to 90 degrees, 80% humidity and a 29.0 barometer? You’ll see more days at the track with numbers like that than ANY CF I’ve seen.
I’d argue (and do) that the CF is not the reason why dyno numbers are all over the place. It’s shitty dyno operators that have sloppy methods or they are just outright lying crooks.
Newbomb Turk
Well-Known Member
PRH
Well-Known Member
Btw, in case some didn’t catch it earlier……..
I still really like my 383
I mean, this is a 383 thread, right?
I still really like my 383
I mean, this is a 383 thread, right?
Dartswinger70
Well-Known Member
Ok so have we decided if the 383 is a dog or what? you know rumour has it a 340 can spin 325 horse thats 10 under a 383...
Newbomb Turk
Well-Known Member
Yeah, so???? He’s not talking about CF errors using the same CF across the country or around the world. He’s talking about an inherent flaw in the CF and it’s the same error regardless.
And that error only affects the actual power the engine makes. In other words, if we both use the same CF our numbers should match. You can
test in Denver in August and out here on the west coast in October and the corrected numbers should be the same.
PRH
Well-Known Member
It depends on which CF is used.
"More accurate than what?"
The correction factor that is closer to the conditions during testing is more likely to be accurate than a correction factor that is farther away from the conditions during testing.
Edit: What part of this do you disagree with?
Newbomb Turk
Well-Known Member
Agree
Newbomb Turk
Well-Known Member
If accuracy is what you are after, the Performance Trends makes a weather station and software that uses the observed numbers and the weather at the time of the dyno and compares those conditions and numbers with the weather at the track that day.
Then it gives you the actual power the engine is making on that day at that time.
Notice it doesn’t use corrected numbers. There’s a reason for that.
They are already correcting the numbers at the dyno based off the weather at the dyno. They can correct using whatever standard you want them to. The likely most accurate numbers will come from the correction factor that is closest to the weather conditions at the dyno and racetrack.
Newbomb Turk
Well-Known Member
I guess I didn’t explain it well.
The Performance Trends Weather Wizard doesn’t correct anything.
It uses the observed numbers off the dyno and the weather for that pull and then compares the weather at the track against the weather on the dyno.
From the OBSERVED numbers it recalculates the power number to the weather conditions at the time you are going to make a pass.
It has nothing to do with any correction factor because as I said, unless the conditions are exactly the same between the dyno and the track the CF doesn’t matter.
I didn't see the estimate for torque and horsepower comparison on their web site for weather wizard. Only estimated jet changes. I called them and they said their program won't do the horsepower dyno to track estimate only jet changes. It will however calculate corrected power to multiple standards for the weather conditions at your dyno.
edit: spelling
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Newbomb Turk
Well-Known Member
I haven't bought the Weather Wiz or whatever he calls it yet. But I'm going to.
I had to go look at it again to remember what I was looking at.
You are correct in that it will not give you an estimated HP. What it does do is give you tune up changes relative to observed numbers.
For example, your weather on they dyno was 70 degrees, 29.2 Barometer and 20% humidity. And on this fictitious engine we will say it has 500 uncorrected HP.
At the track it's 90 degrees, 28.5 Barometer and 60% humidity.
The program shows what changes to make to maintain the power level you had.
While yo can toggle between different correction factors its the OBSERVED numbers that matter.
Those that slam the 383 just don't know. lol
Those are the same guys that bought the 360 from the scrap yard after we pulled them and dumped them. lol
If you watch the Engine Master competition where the do odd ball engines like the 318 Poly, Nail head, old Cadillac, Chev 307 etc... Making 500 + or whatever hp takes a similar recipe just there's little to no off the shelf part for some of those engine, if you put the right heads and cam, cr, carb etc.. Your general able to get the power most are looking for. Even a 500 hp 4 cylinder can have similar cams, cr, over all head flow etc.. As a larger V8.
If you generally put 300/400/500 etc.. Parts on whatever engine your gonna get around 300/400/500 hp out of them.
If you generally put 300/400/500 etc.. Parts on whatever engine your gonna get around 300/400/500 hp out of them.
Really it's not to maintain the power level but to maintain the air fuel ratio to get as much power as you can. Which could be more or less power depending on the weather swing. It works the same way a correction factor works.
RAMM
Well-Known Member
I'd take a 360 over a 383 any day. I've never seen 500+ft/lbs out of a stock stroke NA 383 ever, but I have seen it with a 360 more than a few times. J.Rob
how about offset grinding that 383 crank with BBC rods? You like that? Does that get enough piston speed?
Dartswinger70
Well-Known Member
I remember those days very well. I always played with small blocks but I knew 383 / Big block guys who would yank 318s and call me and say "ya want it, come and get it..." 318s were boat anchors, they were free. sometimes with a 904 still attached to them...
RAMM
Well-Known Member
I've only gone as far as 3.545" and the jury is still out on that--LOL. J.Rob
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