Wow, what a couple of months we’ve had! Our preparation and testing for the 2012 WTAC campaign had never been so intense and the Pulse Racing Team has stepped up to the challenge. Although, as we found out, the more you test the more you need to change! As the old saying goes ‘the more you know, the more you realise you need to know’.
We didn’t make too many changes from last year as we knew the car was good, we just needed to improve reliability (figuratively speaking). Strangely enough ‘time Attack’ and ‘reliability’ are not really two words you will hear together very often.
After our 2011 WTAC campaign we realised we clearly needed a better lubrication system and a wider scope on data logging… of course I couldn’t help myself, we had to make some more grunt while we were at it! Reviewing the minimal data we did get from 2011, though, we realised the huge drag effects of the new aerodynamics set up – going from a top speed of 265kp/h in 2010 down to 240kp/h in 2011 with the same horsepower.
So, with the dry sump lubrication system and revised engine package, it was time to delve deep into the Motec Catalogue (ouch $$$). While we were at it the whole car was re-wired and we now have a sensor for just about everything, from damper height for the aero testing and logging to a myriad of engine performance and protection sensors – no stone was left unturned.
Test Session 1 – Wakefield
During our first shakedown at Wakefield Park with Mr Glenney at the wheel, we hit the track with a fairly conservative engine tune making just over 300kw @ 15 pounds of boost. The car had really big speed considering the low(ish) power and we were seeing 170kph down the back straight.
Our two biggest areas for development was the huge amount of front end push on mid/high speed corners (which at Wakefield really only means the corner coming onto the back straight) and destroying front tyres within two laps (ouch $$$, again).
Considering the EVO was tearing tyres apart on a moderate shakedown at Wakefield, we realised we would be in big trouble when we hit the Creek in August on big grunt. The catch was, our slow speed turn-in was awesome! Steve’s comment “The best I’ve ever felt” This posed the question…was it Suspension or Aero? Hmmm… time to hit the Data!
Back at the Pulse Racing Workshop the data was scrutinised, the spanners start to spin and the fun begins. We fully customised the front cross member & geometry with all suspension points shifted, revised & adjusted. The EVO’s behaviour is now completely different now to that which we saw in 2010 WTAC guise and it would seem that every suspension set-up we had previously evaluated had now become irrelevant. In my opinion, back in 2010 we had a modified road car but now we were dealing with a fully-fledged race car!
Test Session 2 – The Creek
With a host of revisions to the suspension & aerodynamics we headed off to a Burrows Day for testing! This time I got to drive Yeehaa! First session out we were black flagged… what the? Apparently the Burrows crowd didn’t appreciate the EVO that much (what do you mean it’s not a street car?) Fortunately they allowed us to use the track during their lunch intermission and we shared the tarmac with Garth & the Tilton EVO. Our revisions on the suspension had paid off and the tyres were thanking us for it, although we still had a bit of front-end push especially through turns 4 & 5. Mind you, we were still taking it easy on the engine and only running 15 Psi of boost!
Back to shop for more suspension work, this time suspension springs – I’m sure we would have to be Eibach’s biggest one car customer, the number of different spring rates we’ve evaluated is uncanny and I would estimate we’ve been through 25-30 revisions. The Pulse Team mechanics are now the guns at tearing out the Ohlins shocks & performing lightning fast spring changes!
Test Session 3 – Back to the Creek
This time we have Steve back behind the wheel & a little more boost – 20psi – joining the Southern Sporting Car Club (my local car Club) for a Supersprint. With the competition getting closer we chose not to run a timing dorian so as not to show our hand too early ;-).
We had very positive results from this test, running a 1.32 on old shot tyres, although still with a fair bit of front-end push… hmmm. We then turned our attention to the aerodynamics.
The rear aero is so efficient we are seeing 60% more down force on the rear compared to the front as we build speed, even with the front wing set to max angle (13 deg. is stall angle). So in an effort to get some chassis balance back we kept backing off the wing angle (Steve’s idea, not mine – I want more, more, more! Something to do with my personality I think). We ended up with a zero degree wing angle on the rear however, with dual element in place (Steve wanted this gone too) we are still producing a large amount of rear down force & not so much at the front… GRRR!
Back to the aerodynamics drawing board we go! We originally compromised heavily on the front wing position as to (1) not look overly ridiculous & (2) maintain engine & intercooler cooling, when in truth the best position is up & smack in front of the bonnet (re: Chris Rado – Scion style) but I just couldn’t do it. So with all the other front end cooling vs. aero features on the car we ended up settling on slightly higher front wing position which gave much better airflow & allowed for much larger wing end plates. Now to test it…
Test Session 4 – Back to the Creek again
The Wednesday before the WTAC we ran on 85% power for our final testing, but on big power our front-end push is BAD & feels like its getting worse as the day goes on – Shit! The wing position made the front end down force numbers better so we have obviously been barking up the wrong tree.
With one day before the WTAC starts its time to check everything – it all seems fine until we try heavily backing off the centre diff preload & it starts to turn… hmmm interesting!
Going over the data with a fine tooth comb it appears we have a considerable amount of rear wheel spin, so we check front & rear diff preloads – Bingo – front diff good, rear diff BAD.
We’ve been chasing this problem for weeks & it turns out to be right in front of us (well behind us) all the time… Grrrr! The rear diff was stripped down and sure enough, worn clutch plates.
A quick rebuild later and we’re ready to race – the only catch is we’re heading into a race meeting with a totally unknown car. We will be tuning the chassis during the event so we’re lucky it runs for two days!
World Time Attack Day 1
Despite the unknowns, our extensive development on the Pulse EVO has given us an excellent understanding of what the car likes and how it will respond so we can make intuitive changes very quickly.
We operate on a very limited budget so without any tyre sponsorship, we needed to be very conservative with our tyres – we have a budget for only 10 / 295 tyres & 4 / 265 tyres & we all but exhausted all our old tyres in testing. It sounds like a lot of tyres I know but, considering they are really only at their best for 2 laps, we need to be on the money when we use them.
We chose to start the event on 265 Advans, set the swaybars, springs and shocks then hit the track! Whamo! We’ve fixed the front end push problems we had on exit, although there’s a catch – we’ve lost our beautiful initial turn in we had & are slower – don’t you just love motor cars!
Throughout the following sessions we made a series of gains in spring, shock, wheel alignment & bar changes but tore up 6 / 295 Advan AO50’s in the process. We end the day with a 1.31.8 time and, considering we’re still not 100% happy with the setup and have only been running the car to 27psi of boost, things are looking promising for Saturday… especially when we will be turning up the wick to 35psi of boost!
I’m sure both Steve & I had a rather sleepless night – brains in overdrive – as we both turned up at the track on Saturday morning with a stack of enthusiasm and some really good ideas.
We changed the brake master cylinders & bias system to aid left foot braking & carry out yet another spring change. We’re now down to one complete set of new 295’s, so we bolt on yesterday’s set & head out.
The changes work a treat, on a relatively cruisey lap and using the old tyres Steve runs quicker at 1.31.1 – clearly we’re moving in the right direction.
The boost is wound up to 30psi it, we carry yet another spring change (I told you we are Eibach’s best client) & try some centre diff changes. Talk about tyres turns into a 5 minute debate over whether to put the new tyres on or keep the old tyres on for session 3. We eventually decide on the latter & go out on now very old tyres. At this point we have the suspension setup well sorted so it’s not punishing the tyres anywhere near as bad as before. Steve heads out and reels off a very respectable 1.30.8 time. Yeehaa! Now it’s Game ON!!!!!
Here we go, we mount the new tyres, set the Tune for 35 Psi (520kw in Attack Mode). You could feel the excitement in the Pulse Racing Garage, we’re shooting for a 1.29 or possibly even a 1.28! Steve lines up in pit lane just behind the Cyber EVO – its game on – as it turns out though, it was not.
Unbeknown to Tarzan, he drove over a lap spraying oil all over the racing line. In Steve’s words “I almost slipped off the track warming up the Tyres!” Session 3 was just not meant to be and the session was red flagged. In a true display of gentlemanly professionalism, Tarzan walked down to our garage & apologized for the oil down & messing up our lap.
Session 4 (the last one!)
The questions are – how bad is the track oiled and can we still get the best out it on our now slightly oiled brand new 295’s?
After ½ hour clean-up time, Proclass 2 ran a session followed by 3 Open Class groups so maybe, just maybe, the traction will be there! The Pulse EVO heads out for the last session, driver and crew all wound up & ready for action!
On the first hot lap Steve baulked at turn 2 & aborted, then found some clear track nailed it. Watching from the pit lane roof we could see Steve was giving it everything he could, absolute balls to the wall stuff. It almost looked like he was about to take off over the hill between turns 3 & 4 but countered with an awesome 4 wheel slide through turns 4 & 5.!
With the car appearing & disappearing through the view points, we saw the car all out of shape coming around Corporate Hill & clouds of concrete dust in the air (left over from the oil clean-up). Steve takes an evasive line to keep out of it and stay on the track, finishing the lap with a time of 1.32. It’s a credit to Steve’s skill as a driver that he didn’t slide off the track, the logs show it happened at well over 160kph! (Certainly not for the faint hearted).
Looking over the logs we were definitely set for a 1.28 or 1.29 lap, the Pulse EVO was absolutely rocking with a terminal speed of 280kph down the straight & up to 2.2 G’s coming out of some corners, we had just left our run far too late!
We were far from unhappy though, our disappointing result in 2011 made our WTAC 2012 result so much sweeter. The fact that we turned a 4 cylinder road car into something that can run faster than a V8 Supercar on slick tyres is absolutely fantastic.
The car never put a foot wrong all weekend – even though we beat on her real hard & she finished the weekend just as healthy as she started it. The Pulse Racing Team had a rocking good time doing it and, as they say, there’s always next year!
Paul @ Pulse
Photo credit: Matthew Pham, Cars For Hope