💬 Dyno Tuning Basics | TECHNICALLY SPEAKING

hi and welcome to another episode of technically speaking today we're taking a look at how our chassis dyno works and how to use it there are a few main types of dynamometer and engine dyno a hub dyno and a chassis dyno each you've got their benefits and their drawbacks an engine dyno is great for getting very consistent results in very consistent conditions your engine would be removed from the car or put straight on the engine died after being built and connected directly to the dyno load cell with no gearbox the engine Dinos water cooling supply fuel system and sometimes ignition system would be connected to the engine and it'll be ready to start and ready to tune but this is often very time consuming and better suited for engine development project programs or an engine that would be modified over several weeks or several months a chassis dyno where a cars driven straight off the street strapped down to the rollers and we're ready to tune this is certainly the fastest way to get tuning but it does have its drawbacks the idea is that the car is strapped into the rollers using a method where the heart of the car wants to pull forward the more the downwards force increases resulting in the car pulling harder down into the rollers this works really well and provides consistent results up to a point then you end up fighting the traction limit of the actual tire this normally happens around eight hundred to a thousand horsepower depending on the particular situation the chassis dynos ideal for getting cars up to around 800 horsepower on and off quickly easily minimum set-up time then we've got the hub dyno which is bolted directly to the vehicles drive hubs eliminating the wheels and tires altogether this is a great solution for high powered race and street cars and a great in the middle solution between a chassis dyno and an engine dyno you can have accurate repeatable results in cars that are making well north of 2,000 horsepower or you can fine tune a 400 horsepower street car the downside is there's a little more setup than the chassis dyno and each vehicle stud may need a different bolt adapter to get on the dyno but it's just the same as not all wheels will fit on all cars regardless of the Dino style we need to know what a diner actually does it needs to control the rate at which the retarder shaft spins and it needs to measure the load at the retarder arm from a load cell found mounted between the retarder and the Dyna Shaz II notice these mechanical connections the only thing stopping the retarder from pivoting forward and the only thing that's measuring how hard the retarder is being forced against the Danish a Z in order to control the rate of acceleration of the roller or to hold a particular role of speed there is an eddy current retarder attached to the end of the common shaft that the cars sitting on so this is what we're talking about if I open the retarder cover here we've got our eddy current retarder sitting right here this is a thing that does all of the work so we've got this is an electrical brake this is attached to a common shaft that goes the whole way through through our front or our grip rollers these are the ones that are nulled so you get the best traction for your rubber tire the back roll is here are both free spinning they're not or braked they're simply there just to roll along all the work gets done off the front or the driven roller if we move across the retarder we can see the is attached to a huge solid bracket which is then attached to this load cell this is a thing that is measuring the effort that's getting applied to that front roller the result of this effort is heat which the retarder disperses with its own internal fan like design in order to keep the retarder core temperature to a minimum now because we know the roller speed and we know the force being applied to the load cell we can calculate the amount of horsepower being generated using a fancy formula which is torque in pound foot times RPM divided by 52 52 equals horsepower keep in mind there is a bit going on here to compensate for temperatures the moment arm lengths of the mechanical connections and atmospheric conditions so what does it all mean on our chassis dyno it means I can hold a car at any consistent Road speed and any engine load in order to measure the power output and adjust the engine management system until the engine is making the most power possible at that point this is known as steady-state tuning it also means I can do a ramp test allowing the engine to go from 2,000 rpm to 7000 rpm over say 15 seconds essentially choosing how many meters or feet per second the diner will allow the engine to accelerate at this is known as a power run so what's tuning adjusting the engine management parameters at all load and rpm sites in order to make the most power at each rpm and each engine load so let's get a car onto this thing and see how we actually use it [Music] okay so let's lock into gear we're gonna cruise up through second through third we're gonna end up around fourth gear with a gear ratio or a final drive of around one to one and here we go we've got our dyno roll the speed locked at 60 kilometers an hour so as I apply more and more throttle so I'm pressing the throttle pedal in the car down now 16 18 20 we can see that our torque at the rear wheels is going up and our powering Awards bottom left-hand corner is also going up but our rpm in the car is remaining the same so far go for and more and more throttle same road speed so essentially I'm driving up the hill but I'm stuck at 60 kilometres an hour I can't I can't go any better okay so right now we're at 2,000 rpm and we're at zero manifold pressure we're not in vacuum and what I mean boost pressure air fuel ratio throughout the thirteen point eight to one at throttle position to hold here at 55 kilowatts of the wheels is 28% now if I press my foot down a little bit more we now have a boost pressure of 4 psi but the same engine rpm we've moved into a different load cell meaning that now I can tune this site here and shoot my fuel my ignition timing mi Bruce pressure at this site if I come off the throttle and reduce the throttle position same engine rpm but now I'm in vacuum so now I can come across and chinley slowed sight so essentially I would want to go through and tune all of my load sites at 2,000 rpm or as many as I can get to then once I've done that I'm gonna let more speed out on the dyno so I'm going to increase the dyno speed my rpm will go up because I'm allowing more roller speed my next load site 2250 rpm there we go I'm now at the 2250 rpm I'm at the next load side up I can go through and I can see my mixtures I can see my ignition timing I can see what my short-term Oh two Corrections are doing more throttle position up up up up up less throttle position down down down more and less if I let out more rpm I can put the trace on here in the haltech software so I'm just gonna let more and more and I'll let the dyno come up to now 125 kilometres an hour and now I'm up at nearly three and a half thousand rpm I'm gonna leave the same throttle position but I'm gonna bring the dyno speed down and down and down so let me bring up and you can hear it dragging us down sames throttle position or I'm trying I've been up and up so now I'm stuck or locked at 20 to 50 again after we've steady-state tuned as many load sites as we can we then move into our power runs these are ones everyone talks about these are the ones that make the full noise they give us the big number at the end so we set the dyno up as a start speed and a finish speed so at the moment for example we've got our start speed at 50 kilometers an hour so we would go into fourth gear or the gear that's around 1 to 150 kilometers an hour full throttle we let the dyno start releasing Road at at the moment 15 km/h per second until we get to 205 kilometers an hour which in the case of the dyno will actually us there in case of any emergency or problem and it will bring the car back down by itself or you can come off the throttle and gently brake to bring us back down to an idle speed this will then plot out the power of the wheels versus engine rpm so over here in the top left we've got power in kilowatts versus roller speed along the bottom and the corresponding engine rpm at that roller speed we've got two paragraphs shown here so this is during the tuning process so if I click along here I can see that on one power run I was making 144 kilowatts at two thousand eight hundred and ninety-five rpm but on the second run I was making 159 kilowatts nearly 15 kilowatts more this was due to the ignition timing change that got made between these two runs in the next graph below here we've got our corresponding air-to-fuel ratios so the blue runs are slightly higher power run the same fu ratio graph with the blue the lower value with the red to show us our air/fuel ratios and then if we flick across to the right hand screen here we've got our torque rear foot pants so our foot-pounds of torque at the rear tire that's getting measured by the dyno it made more torque resulting in more power as it came on from there on you'll be doing power on you to be adjusting your fueling and your ignition timing for your specific boost level to make the most power once you're happy there you'd add more boost pressure you'd then adjust your fueling and your ignition timing and telling your bet until you're making the most power at that boost level and so on and so on and so on until you run out of something and that is how the car gets tuned on the dyno so been a little bit of a technical one but thanks very much for sticking with us till the end my name's Scott and I'll see you next time [Music] you

Channel: Haltech

Views: 157,199

Keywords: haltech, efi, ecu, engine management, motorsport, mighty car mods, efi 101, hp academy, fullboost, street outlaws, skid factory, tuning, modified cars, street machine, summernats, modified, racecar, dyno tuning, tuning fork, ford falcon, how to tune, chassis dyno, engine dyno, dyno run, tech tip, tuning tips, car tuning, diy, ford barra turbo

Id: rkcYDrwaJBg

Length: 11min 35sec (695 seconds)

Published: Thu Aug 01 2019