CARNAGE MX5.7 IN TASSIE
‘Carnage’ being the operative word! Scotty fangs the twin-turbo MX-5 at Powercruise 70
LAST year we built MX5.7 – our twin-turbo Ls1-powered Mazda MX-5 – to take to Red Centrenats. The little roadster was a big hit in Alice Springs, but a trip to the drag strip revealed some problems with the plastic idler pulleys and the boost control. Normally two 45mm wastegates would be plenty, but the design of our turbo headers limited where the wastegates could be placed; the exhaust energy took the path of least resistance straight past the gates and spiked the boost. Even without wastegates, we were making 10psi. So we grabbed a pair of 60mm Turbosmart Pro-gates and had Adam at MPW modify the pipes to suit.
All this was done in the lead-up to Summernats 31; with no time to sort things, the guys put a basic low-boost tune into the computer before Christmas. Next the car was sent to Damien at Bling Designs for a new Valvoline-inspired wrap, which he knocked out the day after Boxing Day. Once back at my house, I sanded back the car’s bare-metal chrome-moly rollcage and gave the barwork a fresh coating of black. I also gave the passenger area and footwell a coating of some hard-wearing ‘spray-on’ tray liner to tidy up the interior.
Summernats was a blast with MX5.7; everyone loved the little Mazda, and other than a melted thermo fan the car ran flawlessly. This made us realise that our little hairdresser’s convertible was the perfect event car. So after I fixed the thermo fans and took the car back to MPW for a 520rwhp tune-up, I started looking for events and found that Powercruise Tasmania was only weeks away, on Australia Day weekend! What could be more Aussie than burnouts in Tasmania on Australia Day?
So on sailing day we jammed ourselves into a Ford Everest, towing the MX-5 behind us, and headed down to Port Melbourne, where we were ushered onto the Spirit of Tasmania.
The ship is almost 200m long and features 11 decks; six of these are for cars. There are bars, restaurants, two small movie theatres, and even a video game arcade, and if all that fails to spark your interest you can head back to your cabin and have a sleep.
In the morning we were up early as the ship pulled into Devonport on the Tasmanian north coast. After a short stop to pick up a hire car we headed south-east to Launceston. In no time at all we were in the countryside and motoring through the rolling hills of Tasmania.
We hooked up with former Drag Challenge winner Bubba Medlyn at our accommodation 10 minutes outside of Launceston. Bubba was in Tassie for business and looking for something to do on the weekend, so he decided to come out to Powercruise with us.
Even though Symmons Plains didn’t open until 5pm we decided to head down early and get things sorted, and that worked out perfectly. As with all things ‘car’, we unloaded the Mazda and naturally the alternator died immediately. A short drive around the pits was enough to run the battery flat, so we went from having plenty of time to scrabbling for parts. Being Australia Day, the parts stores had already closed and none of the entrants had a spare, although many promised to bring one the next day. However, we wanted to put the Mazda into burnout practice that afternoon, so we put the battery on charge via some jumper cables and cabledtied our jump pack into position. We decided that would work until we had time to fix things properly the next day. It was Australia Day, dammit, and we wanted to do skids!
Driving out to the burnouts, I was pretty nervous; it had been a long time since I’d been on a pad. Most of the competitors had already been through, so I didn’t even have time to check things out before I was ushered to the startline.
There are two things you need to know about the burnout pad at Symmons Plains: It’s really small, and the entry chute is pointed downhill at the wall. I used the transbrake to start building boost, held my breath and let go of the button.
The Mazda fired into the pad as I hit top gear with both tyres smoking, and I suddenly realised that maybe this wasn’t the best idea. Heading straight at the wall, I got off the throttle and nailed the brakes for a moment, then cranking the wheel to the left I got back on the gas again and the MX-5 whipped around. With the engine smashing the limiter I tried to modulate the accelerator and get the Mazda swinging around the other direction, and the cabin filled with tyre smoke. How can a convertible fill with tyre smoke? I’m not sure, but all the smoke seemed to fire forward into the cabin and up through the engine bay. I knew the wall was close, so I backed
off and reversed to the other end of the pad and tried again… and again… and again. For a little car, it was hard to get it pointed in the right direction.
In the end I decided to back the car up to one side of the pad and do a burnout across to the exit. All up the smoke show was 90 seconds, but it felt like a lifetime. I was happy to finish Australia Day with the car in one piece, and we put the Mazda away for the night.
None of the promised alternators arrived the next day, and by 10.30 we were starting to consider a drive back into town, until Jezz Gearman lunched his six-litre R31 Skyline in the first laps of the day and offered to pull the unit from his car. Thankfully it was the right type, and we had MX5.7 up and firing in time for the off-street drags.
Fearing for my safety, Telf bought me a full Sfi-approved multilayer racesuit to wear during competition. Despite the searing temps, I put it all on and lined up for the drags. My first run was against a Harrop-blown HSV sedan with some serious grunt, and the Mazda blacktracked all the way up the track. I backed off and nailed the throttle again, and with more traction the MX-5 surged past the HSV and took the win.
Feeling good, I pulled back around for another pass, and the officials directed me next to Powercruise promoter Gup’s P90D Tesla, MEGAWAT. This was going to be a good match-up if I could get traction. Unfortunately, as soon as I tried to bring the LS1 up on boost, the Mazda started missing. Knowing the engine wasn’t right, I didn’t even give it full throttle, and watched as Gup’s Tesla accelerated away. I lapped around to the start again, where Bubba heard the tapping engine noise and had me shut the car off. The safety crew towed us back to the pits, and at this point we were thinking our weekend might be over.
With everything too hot to touch, Bubba and I headed into town to grab a drain pan and some sparkplugs. When we got back, I pulled the passenger-side rocker cover first and spotted the problem straight away. A pushrod was looking at me with the rocker arm sitting loose. “Ah, it’s an easy fix,” I thought, and after checking the pushrod for damage I put it back in and tightened the rocker back down. But when I refired the engine, there was still a noise, so I shut it off and pulled the rocker cover again. Everything looked normal until we started it with rockers exposed; the rocker next to the one I tightened wasn’t doing any work. At the time we suspected a collapsed lifter.
I contacted Tassie local David Best to see if he had any spare LS1 parts. David is a past Drag Challenge entrant, and his twin-turbo VY is currently getting prepared for the 2018 event by MPW. David packed the wife and kids back in the car and headed home to grab us the parts we needed, returning with a couple of pushrods, some lifters and a lifter guide tray.
In the meantime I set myself the task of pulling the engine down. The Plazmaman intake is a breeze to work with and I flicked it upside down, resting it on the windscreen with all the injectors and lines still connected. Because our engine has head studs and Cometic gaskets, the passenger-side head wasn’t a major chore to remove, but once we did we found the pushrod in question was bent like a lazy ‘S’.
Viewed from the outside, things looked bad. One guy walked up
and commented: “Oh, so you guys are out for the weekend!” To which I replied: “Nah, I’ll have this running in two hours.”
Sure enough, David arrived with the parts, and I decided to just use two pushrods and the lifter guide. With the engine back together, I hit the key and the LS1 fired into life. Success!
We were done in time to compete in the Saturday burnouts, but as epic as that would have been, I decided to save the car for Sunday. So the next morning I had the team up early, ready for a whole day of mayhem and carnage. When the floodgates opened for the first cruise session I was right in there with the MX-5, with Bubba in the passenger seat. The Mazda was running sweet, and on the first decent straight I opened the taps. I already knew MX5.7 was fast, but 400rwkw in a such a light car made it just hilarious to stomp the pedal and drift up the track. This car is just ridiculously fun.
To pull up beside someone and then just leave them for dead with the tyres smoking is a lot of fun, and you can certainly see why Powercruise is so popular. This was my first time at Powercruise as a driver, and after a few laps I decided to put Bubba behind the wheel. Bubba has a history of driving like a maniac at events like this; Easternats, Powercruise, Performance Car Mania – he’s done them all over the past 15 years.
Sitting beside Bubba in the Mazda was as much fun as driving the car myself. He was doing things I would not even attempt in that car, and it was amazing to just sit there and watch the master at work. Bubba would have the Mazda sideways coming onto the main straight and then drift it all crossed up with the
CRESTING THE RISE, EVERYTHING FELT GOOD UNTIL THE REAR END STEPPED OUT. I TRIED TO CORRECT, BUT THE MAZDA STARTED TO HEAD STRAIGHT FOR THE GUARD RAIL
tyres billowing smoke. Then he started doing the bottom corner and drifting the monster Miata over the crest and under the bridge towards the bottom hairpin. We wailed on that car lap after lap, and it never got hot. The boys took turns riding with Bubba and everyone stepped out with a grin from ear to ear.
Then it was time to get ready for the powerskids, so with a fresh tank of E85 I climbed into my racesuit and got ready. Now, other than drag-strip burnouts, I’ve never done a full-on powerskid, so I was both excited and nervous. I was surprised to see that we were starting before a crest in the track, and wondered how that would affect things – with good reason as it turns out.
When it was my turn I hit the transbrake button and brought the boost up, then let loose. As soon as the back tyres erupted I hit top gear and we were on our way, with a large plume of smoke behind. Cresting the rise, everything felt good until the rear end stepped out. I tried to correct, but the Mazda started to head straight for the guard rail. The natural reaction was to back off, but that just made things worse. In hindsight, I should have cranked the wheel hard right and stayed with it. Maybe I would have hit the opposite wall at a higher speed, or maybe I could have saved it, but as the rear end came around 180 degrees I jumped back on the gas to try and arrest the Mazda’s backwards progress towards the rail. It didn’t work; I hit the rail with the back quarter just as the power started to come in. Feeling a little foolish, I turned the car around, pointed it down the track, and gave it another hit with the tyres boiling away for 50m or more, before letting off and cruising back around to the pits.
The damage wasn’t too bad; the plastic bumper was a bit misshapen, the tail-light was smashed and the quarter panel a little crinkled, but at least it didn’t go in front-first. We taped up the rear bumper and quarter panel and headed back out for the next cruise session for more tyre-melting fun.
The MX-5 still ran as crazy as ever, but my confidence was a bit shot so I let Bubba handle the driving. We lent on that little beast hard and had the best time as Bubba pushed the performance envelope further and further. After polishing off a tank of fuel and another set of tyres, we got the car ready for the final event of the afternoon, the off-street drags.
This was where we thought the Mazda would shine. Bubba felt we should stay with the street rubber, but given the lack of traction they provided I wanted to use the drag radials. However, we made the mistake of not checking under the car properly before putting the big tyres back on. As it turns out, the collision with the guard rail bent the lower edge of the wheel tub 90 degrees, and it was poised above the tyre like a knife.
The Mazda cruised out to the track with no issues and we joined the line-up for racing. For a while it felt like people were avoiding the line beside us, until a tough V8 Cortina pulled up. It looked and sounded serious, but I was confident the Mazda had the goods. The starter’s hands came down and I let go of the red button. Both cars lit the tyres at the startline and the Cortina had a slight advantage, but the Mazda was already pulling back the difference when the rear tyre blew. The edge of the wheel tub had scythed into the tyre on the launch and sliced the sidewall open. From the outside it looked like the Mazda tried to turn sideways into the Cortina, but it didn’t even feel close from inside the car. I pulled over to the side of the track and waited for the tow vehicle.
That was it for our Tassie adventure. It wasn’t really the result we were looking for, but the whole weekend had been so fantastic that even the bits where everything went pear-shaped weren’t so bad.
The next morning we were back on the Spirit of Tasmania and back to the mainland, but that was a weekend that will stay for us forever. Thanks Powercruise, and thank you Tasmania.