Howard1784
Well-Known Member
What happens when you dyno an engine and it does not meet the advertised horsepower number?
Engine Question
- Thread starter Howard1784
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AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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For on an Engine-Dyno; Here are your options
1) return the product
2) check your elevations/air density
3) check/adjust your valve lash
4) Check your Compression
5) check your Leakdown
6) check/adjust your Ignition Timing and octane rating
7) check/adjust your Fueling
8) check/adjust your valve events/cam timing
9) cry?
10) that's all I got
EDIT-1
11) check your dyno sheet as to various "corrections"
1) return the product
2) check your elevations/air density
3) check/adjust your valve lash
4) Check your Compression
5) check your Leakdown
6) check/adjust your Ignition Timing and octane rating
7) check/adjust your Fueling
8) check/adjust your valve events/cam timing
9) cry?
10) that's all I got
EDIT-1
11) check your dyno sheet as to various "corrections"
Last edited:
Howard1784
Well-Known Member
Yeah, was curious if one buys a BP engine advertised at 465 hp, but the motor dyno'd at 420, 430 etc..etc. what happens then, if anything?
kdbunn
Well-Known Member
I thought blueprint engines gave you a print out of the dyno test with the engine???
Run it anyway. There's no way in HELL you'll ever match the same output from one dyno to another, and using different operators and even possibly corrected standards.
What should happen?
Ironracer
Gearhead
Well in all seriousness, you think it could be off as much as 40 horsepower?
What kinda Dyno's did Ma Mopar use? dat **** was Alway's Wrong! Lol
Ironracer
Gearhead
I think they were known to set the timing conservatively and also at a lower RPM than what some of them Motors would actually roll out at on the higher end...
dirty white boy
50 yr old Juvenal delinquent
at 7250 buck for a 465 hp stroker thats 15.59 bucks er HP, if engine down 45 HP thats 701.16 thay shorted him, supposing proper tune and dyno accountability.....DWB
Ironracer
Gearhead
I can honestly say if I knew I was just kind of numbers I'd be upset by the way wasn't that damn Engine 5 grand a couple years ago? oh wait probably 10-15 years ago.. never mind I'm living in the past... when a dollar was worth something
Demonic
Well-Known Member
A dyno is nothing more than an elaborate bathroom scale, or something like this:
If you've worked around gauges or insturments of any kind, you know that they can be off, or way off. Usually a dyno that reads high is called a "happy" dyno, etc. So if the engine reads at spec on one dyno, and lower on another, which one to believe?
However, a leakdown and compression test is way quicker than hauling it to a different dyno. Don't get stuck racing dynos.
If you've worked around gauges or insturments of any kind, you know that they can be off, or way off. Usually a dyno that reads high is called a "happy" dyno, etc. So if the engine reads at spec on one dyno, and lower on another, which one to believe?
However, a leakdown and compression test is way quicker than hauling it to a different dyno. Don't get stuck racing dynos.
It should hold together
if I ever send an engine for a dynamic test, someone shoot me, because I done went rapid 
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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EDIT to post #2
from what I (average-Joe) have gleaned;
It's been said that an engine is "just an air pump". The output of any given engine, regardless of the tune, can be changed just by varying the; temperature, pressure, humidity, etc, of the air going into the engine. The highest output would be with the lowest temp, the lowest humidity, highest pressure; which would then input the maximum amount of oxygen into the engine. If you then take that exact same engine, in the exact same tune, to a new environment, different from the first, then without fail, you will get a different output.
To solve this, the raw data of the dyno, is "corrected" to a standard (STP) that corrects it to what is believed to be normalized at that standard. IIRC that standard is something like; 77*F, @ sealevel and a certain humidity (I forget the number, maybe Zero?), don't quote me.
So after correction, all dynos should,
theoretically, read the same; and consistently from day to day...... even tho the raw data may change somewhat.
In practice, IDK, it seems this is not always the case........ It only takes a minor error in calibrations of the input sensors, or the load-device, to skew even the raw data, and so:
garbage in equals garbage out.
-------------------------------
anecdotal;
>Back in September 1970, I bought me a low-mileage 1970 Swinger 340/4speed/3.55s. During the next couple of years, I got to be very familiar with that engine. It always ran more powerfully as the air got cooler, and lost power in the heat of summer or on high-humidity days.
>In 1975, I got me a brand new Suzuki 750GT "Waterbuffalo". It was rated 70hp. But getting over the Great Divide, in the Rocky Mountains, I had to downshift as the air-density steadily declined.
Back on the Prairies, it was a rocket!........ for 1975, lol.
>I live "on the Prairies" at about 900/930 ft elevation, for at least a 50 mile radius, with minor changes; and I only run my hotrod from May to September, a daytime high temperature variation of not more than 30 degrees, so it's relatively easy to tune my engine.
> tuning snowmobiles tho..... to run from plus a few degreesC, to minus 30/35C* is a tuning range of about 3 jet sizes..... and if you forget to rejet as the temperature falls, well, lets just say I made a lotta money rebuilding melted engines; and the way snowmobiles are run, it only takes a few seconds to kiss a lean-running one goodbye.
> so once again, it's all about getting the oxygen in, and putting just the right amount of fuel, into it.
>And go easy on the ignition timing; on the street, a few degrees short of ideal is safer than a couple too many.
On the dyno; I have watched internet videos in the which the dyno-operators, gained ~7hp going from 2/3 degrees short, to gaining ~2/3hp on the last degree, at the horsepower peak. This on 360 sized engines.
On the street;
at 400hp, that just don't matter to me... lol. My butt-dyno can't tell the difference in output of my 367, anywhere from 32 to 36 degrees, so I just run 32>34* . I mean, a stout 360 will have the tires spinning thru two gears anyway, at least..... and it doesn't take 400hp to do that, not even 350, probably not even 300................ so 7hp, to me, is like, who gibsachit.
from what I (average-Joe) have gleaned;
It's been said that an engine is "just an air pump". The output of any given engine, regardless of the tune, can be changed just by varying the; temperature, pressure, humidity, etc, of the air going into the engine. The highest output would be with the lowest temp, the lowest humidity, highest pressure; which would then input the maximum amount of oxygen into the engine. If you then take that exact same engine, in the exact same tune, to a new environment, different from the first, then without fail, you will get a different output.
To solve this, the raw data of the dyno, is "corrected" to a standard (STP) that corrects it to what is believed to be normalized at that standard. IIRC that standard is something like; 77*F, @ sealevel and a certain humidity (I forget the number, maybe Zero?), don't quote me.
So after correction, all dynos should,
theoretically, read the same; and consistently from day to day...... even tho the raw data may change somewhat.
In practice, IDK, it seems this is not always the case........ It only takes a minor error in calibrations of the input sensors, or the load-device, to skew even the raw data, and so:
garbage in equals garbage out.
-------------------------------
anecdotal;
>Back in September 1970, I bought me a low-mileage 1970 Swinger 340/4speed/3.55s. During the next couple of years, I got to be very familiar with that engine. It always ran more powerfully as the air got cooler, and lost power in the heat of summer or on high-humidity days.
>In 1975, I got me a brand new Suzuki 750GT "Waterbuffalo". It was rated 70hp. But getting over the Great Divide, in the Rocky Mountains, I had to downshift as the air-density steadily declined.
Back on the Prairies, it was a rocket!........ for 1975, lol.
>I live "on the Prairies" at about 900/930 ft elevation, for at least a 50 mile radius, with minor changes; and I only run my hotrod from May to September, a daytime high temperature variation of not more than 30 degrees, so it's relatively easy to tune my engine.
> tuning snowmobiles tho..... to run from plus a few degreesC, to minus 30/35C* is a tuning range of about 3 jet sizes..... and if you forget to rejet as the temperature falls, well, lets just say I made a lotta money rebuilding melted engines; and the way snowmobiles are run, it only takes a few seconds to kiss a lean-running one goodbye.
> so once again, it's all about getting the oxygen in, and putting just the right amount of fuel, into it.
>And go easy on the ignition timing; on the street, a few degrees short of ideal is safer than a couple too many.
On the dyno; I have watched internet videos in the which the dyno-operators, gained ~7hp going from 2/3 degrees short, to gaining ~2/3hp on the last degree, at the horsepower peak. This on 360 sized engines.
On the street;
at 400hp, that just don't matter to me... lol. My butt-dyno can't tell the difference in output of my 367, anywhere from 32 to 36 degrees, so I just run 32>34* . I mean, a stout 360 will have the tires spinning thru two gears anyway, at least..... and it doesn't take 400hp to do that, not even 350, probably not even 300................ so 7hp, to me, is like, who gibsachit.
ESP47
Well-Known Member
Did you actually receive an engine with lower than the specified power or is this just a theoretical question?
Dartsun
Mopar Dude
They sent me a dyno sheet with mine in 2008.
Bluecuda340
Well-Known Member
So if it Dyno's with more HP do you send them more money? lol
Howard1784
Well-Known Member
Theoretical. It was really directed for Johnny Mac @ blueprint. For example, If I wanted to buy their 465 hp rated engine but the one they built comes in at 420, what, if anything happens?
TT5.9mag
Two atmospheres are better than one
@Johnny Mac is a guy that stands behind blueprints products. I’m sure he would have a few tests he’d like you to perform and return the results to get an idea of what would likely be going on. Every blueprint engine I’ve seen dynod (more than a few at westech) has been at or above the listed output. Hopefully Johnny chimes in.
Rest assured all BluePrint engines fans, you know I would never let you down!!
All, we would never, ever, period, ship an engine with less than advertised hp. Each engine gets countless hours of R&D, dyno testing, etc. All our cells are calibrated regularly. Every engine gets a multiple point dyno test. Including oil filter inspection. If one doesn't make advertised HP, there is something wrong with it, and it gets torn down and inspected.
Short of some crazy human error involving a misprint, or a smudge on a paper Is misread...there is literally 99.9% chance this wouldn't happen. And if it ever did, we would do whatever needed to make it right.
But again, rest assured, literally every engine ships with ITS EXACT, serial numbered, logged and scanned, dyno sheet
Hope that helps everyone that wasn't aware.
Dyno variance, from ours to someone else's would be minimal, as long as properly calibrated and adjusted for atmospheric conditions. If that was more the question, but talking minimum at best. Evident by the engine masters show, and many other examples.
Hey Jonnhy. That’s a good point to bring up. Racing dynos is generally bad. But, like you said, they all should be within a respectable read out amount of each other with the same correction factors and a properly calibrated machine. A few numbers here and there aren’t a big thing but to be expected IMO.
I looked into various correction factors use across the globe and in the various auto manufacturers across the globe and I found out there’s a bunch of them. I was actually surprised.
You also mention one of my favorite programs, engine masters. There’s a lot of people that always label someone’s dyno happy and there’s no shortage here that do that with the EM show. But yet time and again, they always come up with what you guys advertise as well as a few other shops. I guess the EM kids got a good working machine!
Seriously, it’s nice to see that a few shops come up with numbers that you (and Engine Masters) came up with on power output.
I looked into various correction factors use across the globe and in the various auto manufacturers across the globe and I found out there’s a bunch of them. I was actually surprised.
You also mention one of my favorite programs, engine masters. There’s a lot of people that always label someone’s dyno happy and there’s no shortage here that do that with the EM show. But yet time and again, they always come up with what you guys advertise as well as a few other shops. I guess the EM kids got a good working machine!
Seriously, it’s nice to see that a few shops come up with numbers that you (and Engine Masters) came up with on power output.
dirty white boy
50 yr old Juvenal delinquent
seen lots of happy blueprint customers on here and other places,..mopars chevys too,.. never seen a UNhappy blueprint customer...., anywhere!
It seems Dynos are not designed to compete against each other but to compare and tune the engine at hand.
