Roller Chassis Dyno VS Hub Dyno - Manipulating power and test variables
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- Опубликовано: 6 сен 2024
- While at PRI Show 2019 we caught up with Todd Lewis to talk about Roller vs Hub dyno, and what variables can change the numbers when comparing between them. This also leads to talking about fudging numbers on dynos too, and how you can manipulate the dyno. The Mainline roller and hub dyno use essentially the same retarders and software, the only difference being the attachement to a hub or rollers, so can be compared "apples with apples". Todd has been designing, testing and building dynos for almost 20 years and has been involved with national elver dyno competitions, as well as installed and trained countless top level workshops.
Wealth of knowledge. I feel like theres so much buzzing around inside his head that he has a hard time getting
It all out.
Hes prob gonna forget more than most of us know 😂
Buy yourself a new couch
Great video Todd 🤘- Taz.
High Performance Academy you’re not welcome here.
@@mareksumguy1887 why?
perfectdiversion **troll face**
Awesome video. Would love to see some more explanation and testing of "ramp rates" and the differences in numbers between fast & slow ramp rates.
great video. hub dyno makes alot of sense. it's not fake power. it's just closer to actual engine power.
not only that, you can actually tune the engine like you would on an engine dyno.
all of this agreed ..... however its not the number hitting the ground. as he said there are still variables that the hub dyno removes but come into play when actually driving. A roller will give you a better idea of what is actually hitting the road and drivability. a hub is better for the engine side removing these variables as you dial in the motor, boost , timing,(ect). most ideal shop would have both.(dreamland)
I always find it hilarious when people "convert" between dyno brands. "Oh I got 400 whp on this mustang dyno so that's 460 whp on a dynojet" like that's just not how any of this works. Solid explanation on the benefits of a hub dyno. Limit the variables to get consistent and repeatable measurements to make changes from
Great explanation on the differences between the roller and hub systems. Think we need to get rid of our DynoJet AWD for a MainLine hub machine.
Like I said many times, they are not a power figure machine, it is tuning equipment.
1/4 mile is where you know your true power.
I learned a few things from this video I never thought of before 👍🏻
I'm honestly surprised it's taken so long for hub dyno's to become popular.
2023 and shi still the same lmao
2023 and shi still the same lmao
well isn’t the hub dyno basically just a dyno queen sheet? Sure you’ll make a higher number since it’s mounted straight to the car, why remove the wheels? When on the street obviously you run with tires.
@@DEATHWISHVQbecause you can't tune high power engines if the tyres are constantly slipping on a roller dyno.
@@DEATHWISHVQI'd have to disagree. Ive tuned on a dynapack, made 460whp, went to a dynojet 3 hours away, 5 months later and made 459whp with no changes to the car.
Very true about the wheel n tire affecting power 4agehilux did a great vid on this and strapping different ways, is also glorious external waste gate noises
One day people will understand that a dyno is not for measuring outright power, it is comparative tuning tool that allows you to make changes and compare the results, while monitoring af ratios, temps etc. And not crash or get arrested doing it on the street.
Even engine dynos read different from day to day due to changes in weather...
So it seems that a hub dyno gives more consistent figures for tuning high hp cars, while roller dynos are fine for most road going vehicles as long as rules are adhered to for consistency.
My only gripe with roller dynos at some shops is its inability to load up the engine properly. Got my car tuned by a popular honda race shop with a dynojet. Made 635whp. Motor didnt last 2 days on the street. Come to find out, their dyno wasnt loading up the engine anywhere near enough for the weight and torque of the car.
So Dynos are used for testing and tuning cars then getting a ball park power figure. Oh I thought they were for car guys to flex haha
I noticed this on my daily. Subaru Impreza RX 1996 Ej18 NA. I had 15" small wheels and tires then upgraded to 17" wheels and tires and it was noticeably slower..
Thanks for this video it's something I've been thinking about a bit lately after seeing Cleveland exhaust go from roller to hub.
So hub is alot more accurate for your total power potential and tuning but you are going to lose that 30 to 50 hp when rims n tyres are back on and out on the road ?
not sure how i feel about any dyno to be honest easy to say it made x of hp on either , on one veriables come from tie down and rubber and so on , and on the other you remove all those , but what happens when it hit real road is a whole other thing because you added all the veriables back to the car ..plus some (wind ,air volume ,temp.) .. the only real number is time on a track or 1/4, or whatever you fancy
In my head roller dyno more closer to true horsepower on the street hub more accurate to precise tuning.
both dead true horsepower. just in a different place
hub is way more realistic number
These are excellent videos, I really like this type of content.
Never forget my mate who asked for a 300rwkw tune on his xr6 turbo - the print out literally said 301rwkw - but the car was slow as batshit.. well not slow, but not 50rwkw faster than my 250rwkw calais, or another mates 270rwkw SS.
Tuning tool.
Then after that we go out for a road tune to set the car up properly dyno's only get it close and give a number, road tune makes it drivable.
If a roller dyno is calibrated so that power and torque cross at the correct rpm, and drive train losses are accounted for with a coast down test, then how big a gap will there be to a hub dyno?
call me stupid but what I got from this is that hub dyno gives you increased HP reading for obvious reasons but looks like more reliable tune set up for different variations?
So basically the roller dyno is wheel horsepower minus traction (WHP-T)
The hub dyno is drivetrain horsepower (DHP)
kind of. lots of variables as explained
Not to mention rolling resistance, the harder you strap it down to keep it from slipping the more rolling resistance you create sapping power.
forget about hp. which is a better tuning device? it would probably be the hub dyno??
By far a better tuning device
@@MotiveVideo ok, after my research that's what i was thinking. i got my standard s2 rb25det tuned with a haltech elite 2500, psr g30-770 6 boost etc plaz plenum... made 287kw with 250km on the motor. it drives pretty nice, but it was tuned on a roller. to get the tune right would you recommend getting it retuned on a hub at a reputable shop? cheers Andrew, love the content!
Really good information!
what about loss calcultation ? (to calcule engine hp)
What about it? Don't bother. Use an engine dtyno to measure engine HP. EWach car and drivetrain is different and it is closer to a "fixed loss" rather than "percentage loss"
very cool information that like someone below mentioned - i'd not even thought of or considered previously. more critical info to think about before buying one.
Interesting power output on the Porsche bro, what's you plans on upgrades to get it to reasonable numbers?
Great video....but can we talk about the fact that the porsche only got 226-265hp?? That's mildly tuned ford fiesta st territory! What gives, are they normally that low?
Piece Bombs rates to 245kW at engine and made 20 at hunts through an auto. Spot on in our eyes for a non happy mystical dyno
Classic example of a mind that runs faster than his mouth.
It would have been a nice comparison to throw that Porsche back on the roller Dyno with a different wheel size and weight.
Not being a smartass but if you squish the tyre for example, the outside diameter should be theoretically the same. If that doesn't change that means the circumference doesn't change either. That means the Rolling radius is the same. So the only real problem is torsional slip. I thought dyno used the equation of torque to HP/KW conversation? So how does this smp/s effect the final number?
If you squish the tyre the roller becomes closer to the axle, thus changing the lever arm, but I do understand what you mean about the circumference of the tyre. Not sure how that works
Folks, its just like you were taught in science lab. You want your methods to be the same each time. Otherwise the data can be skewed and you can't make comparisons. The hub dyno eliminates some variables and operator error compared to the roller.
Excellent video! 🤙
You can do awd?
yes - mainlinedyno.com.au/index.php/dynamometers/pro-hub-axle-shaft/portable-prohub-dynamometers-2
I feel like you should tune on both dynos and street tune pull.
Joseph Andreuccetti don’t need street if you have a good dyno cell and hub dyno
Roller is more realistic for what sticks to the road bhp, hub dyno good for tuning through the drive train, the highest hp number is the engine dyno, but for me after tuning it roller is the true number tyre slip, roll, camber is what happens on the track or road! (real world)
This is important information.
Rolling radius won't change from squash the steel belt in the tyre won't get shorter it's like tracks just because it's lower don't make it shorter but you will loose power through side wall flex Wich will show as heat in the side wall
The distance from the centre of the hub to the point he tyre touches the roller changes.
@@MotiveVideo this dose make sense thanks for the reply
I do find this part quite interesting , the argument don't phases me really it's a guide for tuning . But how the gearing doesn't change but the leverage dose is pretty interesting for me
Need to put a 600hp on a Dynolog hub vs a mainline hub to see the difference and what shows what....
This car perfectly showed the effects of just wheels and tyres.
outstanding
I don’t know shit about the exact science behind it but my car on the roller spun up 505rwkw on 20x11.5 rears and then 15min later spun up 580rwkw on the hub dyno at the same shop.
No more red bulls for old mate for at least a week
He should also cut back on the cocaine.
Yeah, right... Nice talk, about dyno which doesn't measure power loss after run.
I hate the whole my dyno makes more power thing. The hub dyno helps with consistency for the sake of tuning, that's it. That 30hp you "gained" by going to the hub is useless once the wheel goes back on. the 1/4mile tells all thing is irrelevant aswell. Tire traction, clutch slip/converter slip, gear ratios and driver can change 1/4 mile time drastically without actually "losing" or "gaining" power. I've seen a 4300lb car make 400whp and run 12.9s, watched the same car the next run do 15.0 because of traction . Some due to improper launch and some the tires being too cold.
The 1/4 time is not a good measure of power. But the trap speed is!
The time is greatly affected by launch, but the trap speed is not.
Those 12.9 and 15.0 runs - the trap speed would not be very different between them.
Hmm...can we talk about the Porsche for a moment? I'm pretty sure that there will be a whole video out sometime in the future, but man....that thing has lost a lot from its original power, hasn't it?
It's auto?
yah5o it makes what it should and ran the quarter mile time it should
Centrifigual mass is the thing.A wheel is a big flywheel and the more centrifigual mass, eg heavier tyres means it uses more power to accelerate and also stop.
Many 'bling' wheels and tyres cost power, stopping and suspension. And to me look stupid as well. A wheel that weighs 15lbs for instance and the rim is very heavy V a lighter rim and heavier centre will make a fair difference. So a 14" rim will have less centrifigual mass than a 20" with the same diameter tyre. And usually a 20" tyre will be faaaaaaar heavier than the same dia in 14"
The peak power howeve will be the same or even a fraction more as the flywheel once accelerated will help maintain power.
The hub dyno at least equalises all of these figures.
And yes different dynos give different numbers. I have done an E85 conversion and made less numbers on a different dyno.
FACTS!
What's new
The car is gonna be raced with wheels & tires on it right? So if it makes 300 on a hub dyno then 250 on a roller dyno, you tell everyone 300, then it performs like a 250hp car with the wheels and tires on it, wouldn’t that be disappointing? I feel like you would want to tune with a hub dyno and then use a roller to get the number you actually tell people.
828drifter the whole point of the video was to make people understand the difference to interpret it better
Many American and British dynos try to calculate engine Hp and give really high numbers. We’ve seen some drum inertia dynos in the USA make more “wheel horsepower” than the car is rated to at the engine.
So rally the power means nothing as every dyno is different. If you understand that you stop caring and understood it’s a tool for tuning. Rea world performance numbers are what matter.
I have a feeling the loss is due to extra friction in the roller bearings (from the high side-loading due to strapping the car down so much)... rather than the inertia of the wheels and tyres.
And it’s more likely to be the parasitic drag of the wheels n tires...rather than “inertia”, that’s robbing power.
hardened steel bearings (as long as they're not overloaded) will not appreciably affect friction in the kW range. If you put multiple kW of heat into a steel roller bearing it's fail very quickly.
manitoublack yeah true...
manitoublack i still believe it’s more parasitic drag rather than rolling inertia, though.
Geez a 2 minute video stretch out to 10 minutes. Mate you could have explained it much clearer instead of going backwards forwards. Most people are already confused i bet
So a more real world figue would be on a roller dyno as no one drives around without wheels and tyres
MPH is a real world figure. Dynos can be manipulated.
I can hear the keyboard warriors getting pissed..."Na my mate in his commodore"...
Long story short, don't bother with roller dynos and go for hub dynos.
Ultimately ultimate dyno numbers are a pissing match. Too many variables to truly compare numbers with numbers. Temperature, humidity, height above sea level, variations between the same type of dynos. Ultimately the numbers are not comparable
Remember, this guy sells hub dynos. ..but yeah, his argument is pretty solid. They didn't even mention most important part of a dyno though, the organic bit. Hub dynos have *no* give. They are extremely unforgiving of mistakes and not many tuners have a lot of seat time with them.
@@emmanuelmeris5841
The ultimate solution is to dyno straight from the driveshaft, but that's obviously too impractical most of the time. Hence, the next best things is a hub dyno that rigidly links the hub to the dyno to eliminate all tyre compliance and slippage. You still have to deal with drivetrain lossess, but it's still infinitely better than having tyre slip mess with your measurements.
Of course, atmospheric conditions will always be an issue unless you somehow have a climate controlled chamber with no lack of airflow. Short of a wind tunnel, rollers and other means to full to fool the car into believing it's actually moving, it's also nigh impossible to fully account for variables such as how modern cars are smart enough to completely turn off the radiator fan when the car is running fast enough to be better off with no radiator fan running.
What myth are you busting exactly Andrew? Put the rambling to the test I.e. same dyno and different tyres. The rambling is hardly scientific.
Bit of ramble but blokes builds dynos what hes basically saying is roller dynos have too many variables. Hub dynos eliminate some of the variables which is a genuine scientific process ,eliminating variables.
Geez he waffles on endlessly about one point. Sounds like a salesman.
Jake Elliott he’s a very smart engineer.
@@MotiveVideo I got the impression he was having to cut himself short on most of the points he was trying to make - He could have spoken for hours given the chance to expand!