TECH TORQUE

POWER TOOLS

STORY ANDREW BROADLEY PHOTOS PETER BATEMAN & SM ARCHIVES

> MAINLINE’S NEW MEGA-HORSEPOWER PROHUB DYNOS ARE MAKING WAVES IN THE RACING AND TUNING INDUSTRY

REMEMBER when a 500rwhp pull in the Summernats Horsepower Heroes competition was enough to win the thing outright and bring the crowd to their feet? It wasn’t all that long ago, but a lot has changed in the years since. These days you’re nobody unless your street car is good for a horsepower figure in the four-digit range, and fetching accurate, repeatable numbers out of a 1000rwhp car on a traditional roller dyno is problematic to say the very least.

But dyno manufacturers are catching up, and Aussie mob Mainline DynoLog Dynamometers has brought a range of hub dynos to market that sidesteps many of the common issues associated with roller dynos.

“Hub dynos have been around for 20 years, and there have been some systems designed overseas that are really quite portable,” says Mainline’s Craig Mahoney.

“But the challenge in designing a hub dyno is that they need to be able to capture three times more torque than a roller dyno, due to roller diameter relative to tyre diameter. As a result, early hub dynos were very limited in terms of torque-handling capabilities.”

The Mainline ProHub range has come about due to Mainline identifying a gap in the market for a range of hub dynos capable of handling mega-horsepower street cars and even Pro Mod-style drag cars – the kind of vehicle that you couldn’t even dream of running up on a roller dyno.

We had the opportunity to witness the base-model ProHub – the 2000hp-rated PH2000 – being put through the wringer by Sam Fenech’s 3500hp JSS Racing Megatilt Doorslammer, with interesting results. But first, let’s take a look at the relative pros and cons of engine, roller and hub dynos.

ENGINE DYNOS

ENGINE dynos are great tools for testing, tuning, evaluating and running in freshly built engines. If any issues with things like cam timing, oil pressure or fluid leaks present while dyno testing, these can be easily identified and rectified then and there on the dyno, before the engine goes anywhere near a car. This gives you the peace of mind of knowing that your engine is healthy and ready to run before you fit it.

Components such as carburettors, intake manifolds, camshafts and cylinder heads manifolds, camshafts and cylinder heads can be quickly and easily changed on an engine dyno, and with the variable of drivetrain loss removed from the equation, it’s an ideal scenario for back-to-back testing and development of components and engine combinations.

The main drawback of an engine dyno is that using one to tune an engine already fitted to a vehicle means removing the engine. In this scenario, chassis dynos are generally favoured.

“One of the main advantages of engine dynos is that they can be used for a lot of high-end research and development, because in a well set up engine dyno room you can control the environment,” Craig says. “Air temperature, exhaust extraction, even coolant and oil temperature can ell e ue”r ,t be digitally controlled trolled be digitally controlled to simulate different environments. But that artificial environment can also be a disadvantage because those ideal conditions don’t exist in the real world.”

From a workshop’s perspective, setting up an engine dyno correctly is expensive and requires a lot of dedicated infrastructure and a good chunk of real estate. There are limitations around the type of engines that can be run on a typical engine dyno; for example, a Pro Mod engine will make more power than most engine dynos will handle. There are also complexities involved in setting up EFI trolled engines on an engine dyno, because whole engine management system needs to be lifted from the car and set up in the dyno room. In these instances, set-up time will far exceed the actual run time, but it still needs to be paid for and that ends up being expensive for the customer.

“Engine dynos definitely have their place, though,” Craig says. “In a research and development application where the engine doesn’t have to be changed often – for example, fuel testing – an engine dyno is ideal. They are also great from an operator safety perspective.” the

Sam Fenech WESTEND PERFORMANCE

SAM Fenech is the driver and engine builder for the JSS Racing Megatilt Doorslammer being dyno-tested here.

He also happens to be the proprietor of one of Sydney’s leading engine shops, Westend Performance, which has its own engine dyno. We asked Sam about how valuable the Mainline ProHub dyno was from a testing and tuning perspective, and how it compared to the engine dyno he used at his shop.

“This is a car that we would normally only be able to track-tune. We’ve been running this combo for a long time so we’re very much on top of it, but if you were looking to try something new like a camshaft, fuel pump or blower, the cost involved in getting your entire race operation to the track to test is significant. You’ve got to get the car, the transporter, your spares and all the people involved to the track, and once you’re there we budget for $2000 a pass, so it’s a massive cost.

“We saw around 2100hp at less than 7000rpm on the hub dyno. The motor probably makes around 3500hp [at peak revs], and I can’t engine dyno a Pro Mod engine like that. There’s no chance you’d ever get a car like this to hold on a roller dyno; you’ll even struggle with a Holden V8 with a nitrous kit, so I can definitely see the value in a big hub dyno like this, although I don’t know that I’m quite ready to buy one myself.

“I think it would be difficult to convert some of the older guys in the sport to a hub dyno, but you could definitely use it to develop a new combination very quickly. The DynoLog software is great, and it all plugs into the Racepak and logs EGTs, pressures and everything else. It’s pretty cool; I was impressed.

“An engine dyno won’t tell you if there’s a problem with your fuel system, ignition system or driveline, and ultimately the real-world number is the number it makes after it’s travelled through the ’box, clutch and diff. That’s the number that counts at the track.”

Rob Herrod HERROD MOTORSPORT

ROB’S Herrod Motorsport outfit has been developing performance products and upgrade packs for modern performance vehicles for years, and his ADR-compliant Mustang packages are receiving rave reviews and selling like hotcakes. After becoming frustrated with the lack of repeatability his previous roller dyno offered during R&D and tuning work, Rob traded it in for a Mainline ProHub dyno.

“It’s the best thing ever, and one of the main things is its repeatability. Going back a couple of years we did a comparo with Wheels magazine between an HSV GTS and an FPV GT-F on our old roller dyno. We always found that different tyres resulted in different power levels and it was doing my head in.

“Our Mainline roller dyno was great; the software was second to none, but no matter what you’d always have issues with the variables of strapping and tyres. I knew I needed a hub dyno so I sold the roller dyno and bought one, and I’ve never looked back.

“We’ve built around 70 of our Mustangs now, and when Dave Morley did a story about them for MOTOR, they asked us to send them a dyno graph. When the cars arrive, we pump out the fuel and fill them with BP Ultimate, we do the modifications and then the tune, so you’d expect the cars to be relatively consistent.

“We went back through and looked at eight different automatic Mustangs that we dynotested over the course of a couple of months, and they were all between 438 and 439kW.

You’d just never get that sort of repeatability on a rolling road. The Mainline hub dyno takes all the variables and guesswork out of it; it’s just like an engine dyno. It is, I believe, the best dyno in the world today. I couldn’t do what I’m doing now with a roller dyno, and to be able to get the repeatability I now have has taken a real weight off my shoulders.”

ROLLER DYNOS

“WHAT you’re essentially doing with a roller dyno is putting the car on a treadmill,” Craig says. “They work well in low-tomedium horsepower and diesel applications, transferring energy through the tyres to the rollers.”

Placing a vehicle on a roller dyno is a quick and straightforward process, which is why they are most often favoured for dyno competitions, where dozens of vehicles can go on and off a dyno in a single day.

Roller dynos have traditionally been widely favoured by tuning workshops, and while the power and torque figures they provide are subject to the variable of drivetrain loss, j , one major advantage a chassis dyno has over an engine dyno is that the engine is being run in its real-world environment. In other words, it’s being tested with the very same fuel system, exhaust system, cooling system and accessories it will be used with in the long term, rather than the ‘generic’ fuel pumps and regulators, headers and radiators that are often used on an engine dyno. Not only will a chassis dyno allow the engine to be tuned to suit these components, but it will potentially show up any inadequacies or problems that may exist with the engine’s ancillary systems, and allow for troubleshooting.

The major limitation encountered with a roller is tyre loss, and it’s a big one.

Strapping today’s modern, highj dyno Stra horsepower street and drag cars difficult and often fruitless task. only does loss of traction on dyno rollers provide inaccurate data, but it also makes a mess of tyres in a big hurry.

Tyres are the biggest killer from drivetrain loss perspective,” Craig says. “Repeatability is essential for tuning, because the tuner could be increasing the performance of the engine, but the gains are not making their way through the driveline to the tyres and onto the rollers. For example, you’ll add one degree ignition timing and see it straight away on an engine y e of str hors is a Not dyn dat tyre “T a Cr es tu pe th w pt t wwt ty o s dyno, but not necessarily on a roller dyno.

“They don’t work particularly well with soft tyres, and slicks in particular will heat up quickly and increase losses dramatically with each pull,” he continues. “As tyres heat up they absorb energy that isn’t being transferred to the roller. Tyres distort, the circumference of the tyre changes and the contact patch is reduced, resulting in traction loss. All tyres slip a little on a roller dyno, but as long as the tyre slip is consistent and repeatable, it’s fine from a tuning perspective. But the more horsepower you’re dealing with, the greater tyre loss becomes. You can add retarders to a dyno but it won’t help traction, and with anything over 1000hp, you’re generally wasting your time on a roller dyno.”

In a logistical sense, roller dynos are a great thing. They can be configured to be quite portable, require next to no infrastructure, and only require one bay worth of space. You can even park a car on them when they’re not in use.

“You need to bear in mind with roller dynos there are a lot of rotating parts, and there is always a risk of tyre failures or wheel weights coming loose,” Craig says. “Strapping cars to roller dynos is no problem for lower power applications, but a lot more attention needs to be paid to strapping to overcome tyre loss issues in higher power applications, and correctly positioning the car so it transfers energy to the forward rollers.

“Again, the key thing to aim for is repeatability for tuning purposes.”

HUB DYNOS

HUB dynos make traction loss an absolute impossibility, with the vehicle’s driving wheels removed and the dyno physically bolting to the hubs for a positive connection between the car and the dyno.

All the benefits of a traditional roller-type chassis dyno are maintained, without the drawback of traction loss. It can, however, take slightly longer during set-up to mount the vehicle to the dyno, depending on the car.

“The big advantage of hub dynos is that they remove variables created by wheels and tyres, and make for a safer environment for the operator,” Craig says. “Mainline’s hub dynos are fixed to the floor and require no strapping, except for one frontal strap to prevent wheelstanding in extreme horsepower applications. Hub dynos alleviate issues with cars moving around on the rollers, and the repeatability is unbelievable. We’ve seen variation of less than 10hp at around the 3000hp mark with our products.”

With the extra steps involved in jacking the car up, removing wheels, bolting on hub adapters and adjusting the position of the modules to suit, one would assume that setting a car up on a hub dyno would take longer than a roller dyno. Craig argues that by the time you factor in strapping the vehicle down and adjusting the straps during testing, it’s much of a muchness.

“It’s relatively easy to connect most street cars,” he says. “A typical street car can be up and running on a hub dyno in 10 minutes.

We took a dyno to Sandown to test the V8 Utes field, because they run a control engine.

With two staff and one electric rattle gun, we managed to jack a ute up, get the wheels off, connect it to the dyno, do two power runs, then get it back off the dyno and the wheels back on in six minutes. It’s pretty comparable to a roller dyno in most situations.”

The only exception to that rule exists when you’re running a high-end drag car on a dyno.

Sometimes removing the wheels means you have to deflate the tyres in order to get the wheels out from under the body, and it can take up to 30 minutes to get the car mounted to the hub dyno. That being said, you’d stand very little chance of running such a car on a roller dyno anyway.

Anthony Maatouk MAATOUK'S RACING & MECHANICAL

THE Maatouk’s Racing name has long been synonymous with crazyfast Nissan RB-powered street and race cars. Starting out years ago with single-cam three-litre VL Commodores, Anthony is now the man behind some of the quickest and fastest GT-R Skylines on the planet, claiming the record for the world’s quickest street GT-R with a stonking 7.70@183mph pass on radials just as we went to print. Having made the switch from a roller dyno to a Mainline ProHub, we dropped him a line to get his thoughts on it.

“With the amount of power we were making on the old roller it was starting to get really dangerous, and that was the main reason behind buying a hub dyno. You’d always have trouble with wheelspin and you’d be worried about straps breaking.

“It’s made it much easier to tune cars too, because you can really see what you’re doing with timing. You add timing in and you know straight away whether it’s going in the right direction; you’re not mucking around wasting your time.

“It’s made a big difference because it’s saved us a lot of track time. It’s much cheaper and easier than tuning at the track, which is what we used to have to do with all the big cars. We’ve seen 1680hp on our shop dyno so far.

“It’s been killer so far for us; I don’t know why every shop doesn’t have one.”

Adam Rogash MPW PERFORMANCE

MPW Performance is the shop behind some of Victoria’s most bad-arse street cars, and plenty of mega-horsepower rides have graced its dyno over the years. Adam ran Horsepower Heroes at Summernats 30, and his own car, an HSV ClubSport by the name of NOSHOW, is a genuine seven-second streeter that’s good for over 1200hp at the tyres. All that makes him well-placed to weigh in on the relative merits of hub and roller dynos.

“We run a brand new, top-of-the-line Mainline twin retarder-roller dyno that’s rated to 2400hp.

It’s been great; we haven’t had any dramas with any cars at the shop or Summernats, and a lot of that comes down to how you strap the cars.

“We went for a roller dyno because on top of the bigger cars like NOSHOW and Luke Foley’s VH, we also do a lot of lowerpowered stuff in the 200-300rwkW range. In my experience, hub dynos read between five and 15 per cent higher than roller dynos, and the last thing we want in the industry is for the shop to develop a reputation of having a happy dyno.

“For example, I had a car in the dyno comp at Summernats that had come straight off a hub dyno where it made 1050hp, but on my roller dyno it only made 750-800hp. I’d rather that my dyno reads conservatively and the cars run great numbers at the track.

“If a 3200lb car comes off my dyno making 650rwkW, we know it’s going into the eights.

If it makes 550rwkW, it’ll run low nines. If a 3800lb car like NOSHOW makes 1270hp, we know it’ll dip into the sevens. When a car makes a number on our dyno, it will show at the track every time. On a hub dyno you don’t have the power loss through the wheels and tyres, but at the track, all those forces are in action.

“For our big stuff, I can definitely see the advantage in a hub dyno because it’s easier from a tuning perspective, but in saying that, we generally get everything to a certain point and then finish up the tune at the track anyway, because of the ram air effect, different pressures and all the other variables. That’s why we datalog everything.

“But you can’t go past hub dynos for tuning big-power cars. It’s so much easier on the car and the person in it. On a roller dyno it can be a bit of a wild ride! I’d favour a hub dyno for tuning a dedicated race car or a street car with more than 1000hp at the tyres. It’s horses for courses, really.”

John Pilla POWERHOUSE ENGINES

POWERHOUSE Engines is the engine builder of choice for some of Australia’s foremost burnout competitors. Johnny also builds his fair share of killer street and race engines, and has both an engine dyno and a roller dyno at his shop. We spoke to him about how he uses each, and what his thoughts are on hub dynos.

“I have a Superflow SF-902 engine dyno and a Dyno Dynamics roller dyno in my shop, and after doing serious engine development work on the engine dyno I’ve found that chassis dynos are good for making money, but not much else! The repeatability just isn’t there compared to the engine dyno.

“You need to be able to monitor and control water, oil and air temperatures to lay lines over lines on the graph, and then know how the changes you’re making are affecting performance. Forty degrees in engine oil temperature can mean a 5hp difference on my engine dyno. With a chassis dyno you’ve got engine, transmission and diff oil to contend with, which are all different weights and heat up at different rates. How do you stabilise all three to get the repeatability you need? It’s much easier to monitor and control that stuff on an engine dyno.

“Most chassis dynos only have an intake air temp sensor and an O2 sensor that goes in the tailpipe as standard. When I’m doing big stuff I like to see an EGT for every cylinder. Having said that, the engine dyno isn’t the be all and end all.

“I like to run engines on the engine dyno first, then put them in the car and check that they make what they should at the wheels. It varies from one car to another, but generally a 600hp street engine will make 450-460hp at the wheels on my roller dyno. I’ve had engines that were mint on the engine dyno, but they go into the car and they’re all wrong. A classic is that the water pump is spinning the wrong way, or the alternator or fuel system isn’t up to the task. You can’t check that stuff on the engine dyno.

“Roller dynos are good for tuning diesels too, because they don’t make enough power for anything to slip or spin. I believe that if you’re serious, you have to have both an engine dyno and a chassis dyno.

“I probably wouldn’t put a hub dyno in personally, because I like the ease of set-up on the conventional roller dyno, especially if you’re doing a wide variety of cars. And to me, if you’re building an engine that needs a hub dyno over a roller dyno, you should be doing 90 per cent of the tuning on an engine dyno, where you have so much more control, before it goes in the car.

“I also much prefer the operator safety that an engine dyno offers. Something simple like a tailshaft failure on a chassis dyno can be fatal.”

MAINLINE PROHUB DYNOS

GIVEN the advantages hub dynos have over roller dynos in terms of tyre loss and operator safety, Mainline set about designing a hub dyno that was better equipped to meet the demands of high-powered street and race cars than what was on offer at the time.

The range kicks off with the PH2000 (rated at 2000hp), moving through to the PH3000, PH4000, and the 5000hp-rated PH5000 model. The 2000 and 3000 models are the same physical size, but the big-hitting 4000 and 5000 have twin retarders on either side of car. Four retarders effectively provides them with double the capacity of a traditional twin-retarder roller dyno.

“On our system, the dyno is fixed to the “On our system, the dyno is fixed to the ground,” Craig says. “The modules slide outwards, then you reverse the car in and put a floor jack under it, take the wheels off, slide in the modules, attach the adapter with the vehicle’s wheel nuts, and mate it up with the flange on the dyno. Three dowels and three heavy-duty bolts secure the module to the vehicle. The modules can be pushed in and out by one person. The dyno is a fixture in the workshop; you have to have a dedicated position for it.”

For racers, the real benefit of the ProHub dyno is it allows a tuner to confidently creep up on ignition timing. It’s something that’s very difficult to do with real accuracy at the track because the load the engine changes all the time as the car moves in and out of traction and the suspension loads and unloads.

“With a hub dyno the operator can dial up the desired load and acceleration rate, and creep up on the timing in a controlled way,” Craig explains. “You can really shoot for optimum ignition timing without risking the engine like you would at mum ki cy on me ut n e e n e ” n the track. We’re seeing drag cars the track. We’re seeing drag per cent power increases purely by tuning, and that’s where the gains are made. It’s like getting 200hp for free.”

Cost-wise, the smallest PH2000 retails for AU$70,000, compared to a twinretarder roller dyno, which will set you back $60,000. So they are more expensive, but they’re also decidedly more capable. And there’s no better way to prove it than to bolt a 35000hp Pro Mod to it and pull the string. We tagged along as Mainline put their PH2000 under the pump, running up the JSS Racing Doorslammer at their facility in Western Sydney. cars making 10 car, we were basically trying to top the dyno out,” Craig says. “One of our customers, RotorMaster, has had its PH2000 dyno to 2400hp already, and we’ve had several other customers go over 2000hp.

“The car and the dyno performed perfectly, but unfortunately the lights in the dyno room shattered due to the force created by the upward-facing headers!

We made 2117hp, but unfortunately had to get off the throttle and abort the run. It’s important to note that while you can run up cars like this, you can still test a 100hp car if you need to, as well.” s “The car is a 3000hp+ car and