My buddies old valiant I mentioned in a different thread sure seemed like it had all and more of 230 lol
skewing the dyno??
- Thread starter 318willrun
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Lol***BREAKING NEWS!!!***
STOP THE PRESSES!!!
UT learns there's "shenanigans" going on (GASP! Who'd a thunk it?), and spews his Breaking Story across the entire Spamiverse!!!
STAY TUNED for those single cylinder engine tests, folks! You don't want to miss it!!!
I never took my best running "stone-stock" 318 2bbl to the track. It was a '72 Demon with about 39k actual miles. I did run a B-body with a 318 2bbl /auto/2.94's (i believe) and it went 15.9's @ 84 mph. My Demon was a faster car. I think 15.6's or 7's for sure.
That's funny, I had a 73 charger 400 2 bbl with I think 2.94s it ran 15.9s
I have toyed with the thought (pretty strongly) to do a project using a LA 318 and see what I could get it to do only using factory stuff unmodified. So any factory LA 318 intake, heads, cam, etc but cannot modify it. Only replacement parts (from like rock auto allowed). Use the factory torque converter, and the best gears a 318 car ever came with (3.23's??). See what I could actually get it to do in the 1/4 mile. Slow? Yes. Fun?? Definitely!
And I thought my 73 340 Challenger was a sled. 9.75's figures to 15.22 in the 1/4. That 318 Demon running 15.60's isn't bad.
well, that's a guess at 15.6's/7's. I know it was faster than my B-body that went 15.9's so...
That would be fun !
33IMP
Well-Known Member
Saw an article in a car mag (don't remember which one, I had so many!) that chassis dyno-ed a stock blown Shelby mustang. Went to five local chassis dynos in one day: results varied by over a hundred horspower.
Scody21
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That is for sure. There is 4 dynos in the Bay Area that we have ran motors on. 2 of them we ran the same motor on the same day and had the same numbers within 1 HP. We ran it on ours first and thought we were having problems with the brake. Turns out we were have cavitation issues at 6000 RPM which is barely on the cams when it spins to 10,5. We still got in a solid power pull on ours, before taking to the other shop. There is one more shop with a dyno that built a motor, and then we got the motor. Their dyno lies by about 50 HP, as we ran the motor at “end of life” on the known good dyno and the motor was way down from their dyno sheet. We ran a leak down a motor was all above 90% and look fine on tear down…
That’s why you need to see ALL the numbers.
There are two types of guys that ***** about the numbers.
The guys who ***** that every number off every dyno ever is high.
And the guys who ***** that it’s just a number.
Uncle Tony is the LAST guy who should ever talk about dyno’s and how they work or anything else.
There are certain times when a chassis dyno has an advantage over an engine dyno.
They are few.
If the dyno operator knows how to develop a timing curve with the dyno its about the most valuable tool you can use.
It’s difficult to do that with a chassis dyno if it’s an eddy current type. If it’s an inertia type it’s near impossible to develop a timing curve with it.
Sadly, most guys don’t know how to tune with an engine dyno.
I’m fortunate to have a mentor who has shortened my learning curve by miles.
Plus, when we run into issues my mentor is friends with a guy who, if I named him many would know who is that he can call and sort out the issue.
When was the last time you heard a guy say hey, my dyno is a bit hot? You never hear that.
If you want to know if the dyno is producing correct numbers you look at fuel flow and OBSERVED horsepower.
It’s simple math. Then you’ll know.
If you want to know if the dyno is producing correct numbers you look at fuel flow and OBSERVED horsepower.
It’s simple math. Then you’ll know.
I wonder about Nick's Garage dyno. His numbers seem low to me for the builds and what other people's dyno shows for the same type of build. Then again, maybe his is accurate and not inflated.
The only way to know for sure is to see the observed (uncorrected) numbers and fuel flow.
Then we’d know.
True, but Don't think it's as much of an issue as some make it out to be.
Scody21
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when you get into repeated builds like BP crate motors or like the racings my brother does, you have build history and specs of hundreds, along with Cosworth factory specs and there were only so many cam specs like 25 so it’s predictable, if you use these cams, C/R and has this fuel flow / AFR the HP/TQ should be this. That’s why when you see all the data and something looks fishy it usually stinks…. Figures don’t lie, but liars sure do figure…
StreetSleeper
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Please direct me to your input regarding humidifier sir, thank you!
StreetSleeper
Well-Known Member
Fudge or correction factors? Altitude, temp, barometric pressure???
StreetSleeper
Well-Known Member
When Freiburger was attempting to explain carbs having greater dyno results than fuel injection, he suggested that the extra fuel from carbs could cool the induction-wouldn’t that change your fuel flow standard?
No. You look at how many pound per hour of fuel you burn to make 1 horsepower. It’s called:
Brake
Specific
Fuel
Consumption
The standard is it takes .5 pounds of fuel to make 1 horsepower for 1 minute.
Your BSFC would be .5.
Today, even decent engines have BSFC rates of .45ish and at one time I heard nascar was dipping into the .39ish range.
At any rate, if the engine is burning enough fuel to make 400 hp and the dyno says it’s making 500 hp you know there is an issue.
When NHRA pencil whipped the Dodge out of competition with the fuel and rpm rules, Chris McGaha did some testing of a Dodge on his dyno and after a few pulls he saw how much fuel it was using and he said it would never be competitive as the rules stood.
That’s how critical fuel flow numbers on the dyno are.
They should be looking at the observed numbers.
That’s exactly how much power the engine made on that day, in those conditions.
The corrected numbers are so you can test at various times of the year and have comparable data.
I believe you can add into the engine parameters, like flywheel weight and some other things that can alter the numbers.
yes correction factors set those to near perfect world scenario and sea level
A couple of things come to mind one, dyno's are a great tool for recording horsepower and torque but they also are great tools for advertising !!
Skewed numbers oh yeah! I for one l totally miss the pre-dyno everywhere days when there was so much more mystery and intrigue to how a person built their motor.
Was the six pack better than the dual quad or was the tunnel ram superior to the large single plane etc,and or was it just the driver? It was to be determined either on Friday night or Saturday somewhere at the track or on some back road. Now you just get to listen to some self-proclaimed expert on how you could get more horsepower if you went cookie cutter says the dyno God
in the latest article. Blah blah blah!
Skewed numbers oh yeah! I for one l totally miss the pre-dyno everywhere days when there was so much more mystery and intrigue to how a person built their motor. Was the six pack better than the dual quad or was the tunnel ram superior to the large single plane etc,and or was it just the driver? It was to be determined either on Friday night or Saturday somewhere at the track or on some back road. Now you just get to listen to some self-proclaimed expert on how you could get more horsepower if you went cookie cutter says the dyno God
in the latest article. Blah blah blah! -
