The top line you see is the boost controller set on the highest setting (16psi) then the middle setting, then the lowest setting (7-8psi). The very bottom line was back in the NA days Look at the differences in torque! Today of all days had to be 38 degree temps. I wonder how it would have looked on a cold winter morning Hmm, can I say I have 301rwkW now or would that be cheating? Seeing as they took the wheels off that would make it rhKw (for hubs hehe). Usually on a day like this (bloody hot) it would have been around 260rwkW on a proper roller dyno, so thats an extra 40kW gain! Pity I cant go on a track without rear wheels though I could use the extra power haha. so really the 301.7kW is a little bit misleading, unless its the standard to measure power at the hubs. I'll stick with saying its 260kW when hot, and 270kW when nice and cold
how does it derive flywheel torque in the bottom left graph? Also, is the ratio of 4.40 supposed be diff gear ratios cause if it is then it should be 4.08 (4.40 would make an 8% difference in torque readings). Also the AFR of 16.31 is getting pretty dangerously lean - engine response would be slow and lazy.
They said it was on the lean side of things And if it was any leaner, they would have backed off. Wasn't lean last month at UAS, so could be something with the sniffer, or something happened with the fuel filter etc during that time. I'll be getting that checked out dont you worry Apparantly there is a stock gtir pulsar that had is AFR checked (not on EVO's dyno though) thats been running around at 16:1 under load for quite a while and cant get to the bottom of it! Weather like this anyway my engine rarly sees more than a few psi of boost. It was just this one dyno where it got floored a bit (was hoping it would go on earlier in the morning when it wasn't as hot though). I guess it could be a good thing it did go on, or wouldn't have known better. Dont know for sure if the 4.4 is meant to be for the diff, certainly sounds like it could be.
Holy crap, they've given you an even shorter diff ratio ...... if you really had a 4.40 diff you could throw away 1st & [/SIZE=18] 2nd gears :LOL: 6352rpm in 4th at 163km/h, would not be good for fuel consumption. Those AFR's are a bit scary; when it's power 'versus' safety it's always better to lean (no pun intended) toward safety. Hey Peter, now all you have to do is pull the motor & hook an engine dyno to the crank & you will "gain"[/COLOR=green] some more Kilowatts :LOL::LOL: You're not vying for that "dyno queen" crown are you ?:wacko:
I'll be 'leaning' towards richer It will be interesting to see what the problem is. Could be as simple as a blocked fuel filter or (hopefully) an odd sniffer. still, 40kW gained by taking off the wheels is quite big. I remember the arguments of the SAE vs DIN dyno charts :LOL: an engine dyno hmmm? Sounds tempting, but an expensive way to dyno. But who knows what further kW are to be had? As for the 1979Nm, divide it by the diff ratio (in this case 4.4) and it ends up around 449.77. I think thats the way to do it
nice power! I'd add you to the dyno list, but the figures on the list are all measured at the wheels. is there any way to convert power at the hub to power at the wheels?
hub power is the same as wheel power Its a measure of the same thing, force required to move a given mass to calculate torque and hence horsepower. There are no kw gained by taking off the wheels Like any dyno they are fairly useless at cross comparison between cars unless you know they are accurate and calibrated. You can adjust a dyno to read whatever horsepower you like. In Perth I could get you 2 dynos of my car on the same day with 80rwhp difference. The one I use I trust to be accurate, plus by using the same one after each mod I know the HP gained is a real measurement because any error in the calibration is repeated. If I wanted to gain 60rwhp for bragging rights then that would be easy, but worthless IMO. If you want to compare cars then really same dyno on the same day is the only way so if you do some mods shifter then keep going back to the same dyno to be more accurate.
But as much as I want to say I have 301kW at the wheels I cant really as the wheels were taken off. If I measured it at the crank i'd get a much higher reading, as it doesn't need to spin the flywheel, gears, diff, hubs, wheels, etc (but my car would not have 'gained' any kW either). I believe the one at UAS or one of the roller dynos here in Canberra to be much more realistic seeing as it really does measure at the wheels. (and I get very similar readings between them which is within a few Kw), also I know thats the power being put on the road. Around 40Kw is a big difference, but I dont want to say its 301Kw because when people think of dynos, I wonder how many think of hub dynos. You can still use it to compare mods etc though. As you can see, the difference in power and torque between what it was when NA to now, TT All in all, good to see the difference in the dynos. Wish it wasn't so hot on the day, but good to know that a leaning of AFR may have developed. Could it be because it was so booldy hot?
Dyno Well it shows our dyno does not read high. Shifters car on our dyno makes same power on our dyno with same boost, months apart and different temps etc. As long as weather station details are entered and same gear etc might vary 5 or 10 rake tops. Unless something changed with the car. The Dyno Pac dyno are very good and accurate especially for changes done on car and then retesting and quiet. Prob is though it is a pain to take wheels of cars and bolting up etc and in Australia not nearly as recognised as Dyno Dynamics. Shifter you were spot on when way back you posted that you would take your car to Dyno Pac dyno to get a comparison and predicted it would read more. Yes with NO slippage possible and less weight to turn with wheels and tyres and friction loss, then in theory and now in practice proven the car will make more power. The difference is way more than I thought it would and should be. Goes to show what power some brag about their cars rwkw may not be as much as others as difference yard stick. Also not rwkw is it? I think this is surely a record for stock turbos and engine. Maybe that extrusion hone and FMIC and Microtech etc does work. Wonder what my slot car would make 450 kw at hubs? I know it made more power when we stuck more guys in the boot.
Sorry thats not correct Hub dyno is in fact measuring a rwkw. Just because you are connected at the hub and not the actual wheel spining itself makes no difference. Less weight of the wheel and tyre also makes no difference. No slippage does make a difference but unless your making huge amounts of torque this shouldnt be a problem when comparing to a roller dyno. As I said before, any dyno just measures the force required to move a weight and calculates torque and hence HP from that. The difference between the hub and roller dyno is that the calculations to define torque are made differently to take into account the obviously different setup. The result is still the same measured rwkw. The problem shifter is having is that the dyno is simply not accurate. He could just as easily go to another dyno dynamics and record another 300rwkw or even 260rwkw as unfortunately it doesnt seem like most shops get their machines calibrated as frequently as they should. The same dyno should obviously repeat the same measurement time after time, which is why you should always use the same one, before and after, when demonstratig the power difference a mod can make.
Its still rwkw, see my reply to John The calculations made to arrive at the torque figure take into account your measuring from the hubs. They are calculated differently than roller dynos to arrive at the same numbers.
sorry nathan youre wrong on this and JP is right I believe its about a 7 percent correction between wheel and hub dyno's. Somebody can post the latest figuires. its not just the slippage in the rolling dyno thats expends energy. you got tread pattens.{noiser tread and aggressive thread pattens lose energy into sound waves.} diameter of tyres,{ higher the diameter equals more torque - less power. On the other side , less diameter equals more power - less torque.} how wide the tyre is , {the wider the tyre more drag,{see tyre pressures as well}} tyre pressures, {under inflated tyres increase the length of the foot print and increase drag and noise},{over inflated tyres... this is a good one the structure of the side walls cannot absorb the power puses of the motor the distribute them evenly back through the carcess to the rolling surface. i.e it can make the tyre rolling surface break traction.} design and weight of the tyre and rim. turning the rim creates drag {air disturbance}. unless you have some silly looking rims {or the GTR race vent rims} the loss here is small however the loss via the tread patten can be up too 0.5 percent. the heavier the rim the more the energy it consumes before the dyno. the old calculation was 1 kg on the supension is equals to 10 kg body mass, 1 kg on drive line is equal to 15 kg's of body mass. I dont know this still hold out it might have been revised shadow
Sorry Shadows, thats still incorrect Your not thinking of how the dyno works. The wheels or hub dont just spin a wheel on the dyno which equals X amount of horspeower, its more complicated than that. Why do you supose you need to enter into the dyno the figures for temp and pressure etc and not just insist all dynos only operate at 20 degrees and 1 atmosphere? The dyno will read acceleration of the mass (particluar to that dyno), then make a whole lot of adjustments, including those to standardise for temperature and pressure. Roller dynos calculate for an average wheel size or I believe this can be altered also. Hub dynos calculate for the fact they are reading from the hub. Then the reading is finalised into a torque figure and hence a HP or kw figure. Two properly calibrated and setup dynos, one hub and one roller will give the same reading on the same car. If Shifter was saying they simply took his wheels off and used his hubs to roll a roller dyno then yes I would agree with you and what youve just said, but the calculations made in a hub dyno take into account its from a hub.
but the problem is the calculations used on each manufactors dyno is different. No two standards are the same. normally the hub dyno's the calculations dont take notice of the tyre tread , tyre pressures, exact mass of the wheels and tyres, any drag from the wheel design. normally the hub dyno's only take into account the wheel size and maybe how wide and profile if your lucky. That can easly lead to a 3-4 percent over reading of rear wheel power. If you really want an extra 1-5 percent gain in power.... dont forget to push both rear calpiers apart. shadow
Every forum I read about the subject agree that Dynopacks give higher readings then roller dynos everywhere, but are really good for testing mods before/after etc. Try a search on google Dynopacks give readings that your engine delivers to the wheel. Not at the wheel. (or tyres) By the way, the figure my car makes at UAS, is very similar to the one I used in Canberra which gives very similar readings to the one they used at Autosalon. They cant all be very wrong. Have you ever put your car on a roller dyno Zisluv? If so what were the results? If not if there is one around your area that uses the latest software etc and is accurate? Why dont you give it a try and see if they do read similar?
