Nicks Garage 383 build

-
FWIW I think Nick's dyno is spot on and maybe even on the "tight" side. J.Rob
From what I've watched, I agree. But I'd rather have it that way, than a happy dyno.
 
Whatever the correction factor is, The time slip at the big end will tell you how much HP you got
 
Depac Dave's thoughts on correction factors. For what it's worth. Hope this is readable.

20240624_115228.jpg


20240624_115351.jpg
 
The more you have to correct the more likely your correction is not accurate. Correcting to the standard that is closer to the actual conditions increases the likelihood of it being accurate. A correction factor of 1 is ideal.


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.
 
Btw, in case some didn’t catch it earlier……..

I still really like my 383 :)

I mean, this is a 383 thread, right?
 
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...
 
Depac Dave's thoughts on correction factors. For what it's worth. Hope this is readable.

View attachment 1716266759

View attachment 1716266765


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.
 
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.
"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?
 
"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?


All of it. Use whatever CF you want. Whatever CF you use, it’s only correct when those conditions are matched at the track.

There is no perfect correction factor.
 


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.
 
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.
 
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.

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 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
 
Last edited:
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

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.
 
I never thought I'd see the day when people tout how great a 318 is and then slam the 383 Mopar B engine...
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.
 
The program shows what changes to make to maintain the power level you had.
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.
 
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
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
 
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?
 
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
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...:)
 
-
Back
Top