American Dynos

Hummm.... Dyno thread. I'm now watching for the fluffing of feathers.

 

:rofl:

Now now, I didn't link to the previous brawl :rofl:

 

*snort* *gulps air and opens eyes* Dynos..... *cough cough* Hey... Ive got a dyno!!!!! ZZZZZZzzzzzzzzzz...............

 

Yeah you have too.
Have you got that up and running yet?

 

I've heard he's on the lookout for a couple of old washing machines so he can use the tubs for rollers

 

Simply put, 1/4 mile MPH is CONSISTENT no matter how much traction or driver error there is. Drag racing with my own car, it never mattered how much wheelspin, screw ups i made, different weather or anything else because MPH was always consistent within a MPH or two. Its known and accepted around the world by everyone(well i guess not in NZ) especially those in drag racing who own 6/7/8/9 second cars that MPH never lies but dyno's are easily manipulated

Oh and don't go talking about gearing, i know of several high powered fords and holdens here that have gone from 2.79 gearing all the way to 4.11 and guess what, cars ran quicker but MPH was THE SAME.


Can't wait till the "Drag racing is boring anyway" excuse comes out




. If someone had dyno'd their car and made 400rwkw, trapped 125-130mph then fair enough. If someone else made the same power and trapped 110, then its obvious the car isnt making 400rwkw.

Simply put, LAY DOWN THE MPH AND BACK UP THE POWER YOU CLAIM

 

Show me the formula that uses trap speed from a qtr mile to provide ACCURATE information on what RPM peak horsepower and torque are provided.

Trap speed IS NOT consistent regardless of driver error or wheel spin, if the driver should miss a gear he looses acceleration for that moment & without acceleration you have no increase in trap speed. If you make a hash of the start you loose the increase in speed that was potentially available for those moments while you bog down or wheel spin.

You can't change the laws of physics chap & what you are trying to say simply does not stack up.

I've proven myself that changing tyres changes trap speed, if you think these critical areas do not effect the trap speed then you clearly need to school up on the science involved.

Changing diff ratios DOES EFFECT TRAP SPEED, it's absolute madness to argue otherwise.
Does your car accelerate faster in second than in third? (rhetorical question!)

Acceleration is the increase in speed over time, if you can accelerate more in a given period of time then you will have a faster speed at the end of that time period.

Your mad if you can't see how that plays out in a qtr mile situation.

Why are you telling me to "LAY DOWN THE MPH AND BACK UP THE POWER YOU CLAIM" ?

A few people disagree with the worlds most accurate dyno & claim some dodgy calculation full of error is more accurate - I'm just giving smarter forum members the chance to see the real world logic involved here & make up their own minds.

The worlds not flat guys, times have moved on from the fifties & sixties, calculations used to guess HP of USDM V8s based on trap speed etc DO NOT come even close to the accuracy of a DECENT dyno.

I'll not reply any further the point has been made & IMO it's impossible to take anyone who would go for a hit n miss calculation over the worlds best gear seriously.

 

more to come later

 

That's the first ruffling of feathers.

 

I personally have done more drag racing runs than I care to remember and have developed products using the strip as proof of concept.

I've increased trap speed and increased ET, reduced trap speed and reduced ET, hashed the start, missed gears etc so please DO NOT treat me as if I am wet behind the ears.

I've been through your points of view (there are plenty who think the same way until one day they wake up to the real world) in discussions with many of the top drag racers here in NZ.

I've raced guys with cars run on the exact same dyno that have run very similar power outputs with very similar cars and seen much better trap speeds - why? slicks not road tyres.

You want to prove you are correct & you want to prove I am incorrect - I get that, you wont do that by trying to downsize me, all you will do is prove lack of substance in your case.

Those who know the facts are laughing at you, those who don't know will make a choice as to who they believe but at the end of the day anyone who did well in science at school will know for certain who is full of it.

It's only very simple stuff here & I'm sure you are embarrassed by your lack of understanding so please try to be the bigger man & educate yourself rather than trying to fight the truth via having a go at myself personally.

 

*ruffle ruffle* hehehehe.

Nah Brezz. Not got it home yet. Still gotta sort a place useful to site it as well...

 

Engine dynos measure engine power directly.

Hub dynos measure engine power after powertrain loss.

Roller dynos measure engine power after powertrain loss and tyre loss.

Therefore if all three types of dyno were correctly calibrated then a engine dyno will read higher than a hub dyno which will read higher than a roller dyno.

A hub dyno will give a more accurate and consistent measurement of engine power than a roller dyno as it eliminates one of the biggest variables in chassis dyno power measurement, the tyres. Even if there is no slippage the power loss due to tyre rolling resistance is significant.

Example of factors that influence the friction and rolling resistance of a tyre



http://rototest-research.eu/index.php?DN=39&Menu=38&ID=11

A hub dyno would give you an accurate comparison of engine power between too cars with the same powertrain. A roller dyno will give you a rough comparison of engine power between too cars with the same powertrain and different tyres.

Some dyno's just appear to be used to measure the gullibility of consumers.

 

Saying mph doesnt prove hp is a classic cop out used predominantly by bench racers or people who own slow cars lol [TIS]

 

Actually using the typical generic MPH to HP calculator the estimate provided is around 400hp for my own car. given this is not really anything to laugh about I'm fairly happy with the size of my penis - sorry HP of my car so feel no need to defend it at all.

What does need to be pointed out is the vastly different ways power is delivered in cars these days.
The performance of a 400hp supercharged V8 is considerably different to a naturally aspirated 400HP V8, hugely different to a 400HP 4cylinder etc etc etc

Yet we still have a team of people here who stand by calculations invented years ago based on the typical American V8s of old (mostly auto I will add) when we are discussing the differences between dyno machines.

In the context of discussing dyno machines the results obtained from Jurassic MPH calculations are completely redundant as demonstrated by one of the fans admitting these calculations can not provide even basic information like torque output or what RPM the peak HP is at.

If they are not able to do this how are they able to provide anything even close as an engine could make less than 300hp for the first 6000RPM then develop ~1200HP in the last 3000RPM. This is vastly different to an old V8 tank that might make a very linear power delivery (250hp per 1000RPM for example).

Obviously some people simply refuse to learn & choose to fight forever over something they simply do not understand so this is only posted for those with an open mind willing to learn and grow.

 

I personally have no problem with any dyno. Hub dynos are a great diagnostic tool and tuning tool.

My only gripe is when people compare their hub dyno reading to somebodies roller dyno reading and then think they 'beat' them. It's just silly. 2 totally different tools and placement of measure. Apples and Oranges.

Just remember

'IT DOESN'T MATTER IF YOU WIN BY AN INCH OR A MILE'

'WINNING IS WINNING'

And always...

'IT'S NOT HOW YOU STAND BY YOUR CAR'

 

Dyno power really does mean bugger all as mentioned above. Sure they are a great measurement and tuning tool and will give a figure to work from (give or take 100rwhp) but when it comes down to it, there are too many variables.

When going for a few runs on the dyno a while back, the guy asked me if I wanted to have the runs as a baseline to work from or a piece of paper to brag about. Pretty much saying it could be fudged if i so desired...

Meh, 1/4 mile times are where its at. Doesnt matter how fast/how much power ur car has, if u cant drive it properly it means nothing. ;-)

 

Ok let's leave it at that.
There are people that prefer dyno, and those that prefer track.
Its a car forum, not an engineering forum.
Anymore bickering and I'll lock this puppy.

 

im running 505hp at 18psi street tune with hks2530s

 

Keeping the above shenannigans aside, how do we think the dyno, as a performance measuring tool, compares to the drag strip - IN RESPECT TO ACCURACY AND REPEATABILITY?

http://en.wikipedia.org/wiki/Accuracy_and_precision