More power for the GXP
As you might remember, back at the Winter Nationals in June I managed to damage the TRE engine that I bought with the GXP back in 2010. Unfortunately the culprit was the gudgeon pins flexing at high rpm and galling in the piston bores. One piston came apart and the others were all tight in the bores and ready to let go.
After the engine damaging qualifying pass Peter Ridgeway and I were already talking about how to get the car back together again for the start of the season which was the Australian Nationals held last weekend at Sydney Dragway.
After a couple of months of hard work by Peter and Arthur from Custom Engines I brought the new bullet home to be fitted into the GXP mid October.
When I got it home it needed new plumbing for fuel and water (thanks to Motorsports Connections and Speedflow for all the hose and fittings) as it was a different layout to the old engine and being over ½" taller it needed modifications to the hood scoop as well. After spending a couple of weeks working late into the night the GXP was started and warmed up and everything ran as it was supposed to. The car had a new engine, fresh transmission and a new Dewco diff centre.
I got the GXP loaded into the trailer and Paul and I set off for Sydney early on Tuesday morning as we were heading up to test at the Wednesday Test and Tune held at Sydney Dragway. After an easy drive up (via Wangaratta to buy a ticket in the $70mil Ozlotto draw which we didn't win) we arrived in time to unload and cook dinner just as the sun was setting.
On Wednesday we woke to a beautiful day with a forecast around the 36~38°c mark! Not a pleasant day for racing, but I needed to get the car down the track as I had some things I wanted to test on the car as well as start tuning the engine.
The first pass was a throw away as the driver forgot to turn the burnout rev limiter off and turn the data logger on before going into stage. Oh hang on, I am the driver. Bugger :-). No damage done as the engine basically hit the burnout rev limiter as it launched and as soon as I realised I backed off, clicked 2nd and 3rd gear, into neutral and rolled through for a 12sec pass.
The air was really bad with a Density Altitude around 3200' and a correction factor of 1.06 on the weather station.
On the second pass Matt made sure I turned the burnout limiter off and started the data recorder with a reminder on the radio as I crept into stage. Nice a straight down the track, just a little loose in the top end and it wasn't too bad with 7.55 @ 182.6 coming up. The really disappointing thing was the slow 1.10 – 60' time. Back into the pits and a review of the RacePak data showed the engine was really rich the whole way down the track, but almost drowning rich off the line.
For the third pass I changed the small Tri-Y headers (which were on the old motor) over to a much bigger set of 4>1's. The exhaust ports on the new engine are much larger than the old engine and I was concerned the primaries weren't large enough and may have been restricting exhaust flow. I also made a jet adjustment trying to improve the engine tune. Once again straight down the track (that others were struggling to get down) and a bracket like 7.54 @ 182.7mph with the very slow 1.10 – 60' still there.
With most of the Pro Stock cars being 1.5~2 tenths off their numbers in the heat I wasn't too stressed, however the engine being so rich off the line was in the back of my mind. My PB with the old engine was 7.44 @ 182.95 in Sydney, at night in good air, so to run 182.7mph in really bad air shows the engine is making some good power, but with the rich tune off the line I am throwing away ET. Slow by 0.06sec to 60' and 7mph slow at half track shows how hard it was working burning all that ERC fuel.
Thursday was setup day for the Nationals so Paul and I had a sleep in before running up the street to do the grocery shopping and buy a new inflatable mattress for me as the one I have used for the last few years finally sprang a leak and I was sleeping on the floor by around midnight.
Thursday also meant we were off to the ANDRA Championship dinner. Paul and I attended in 2011 and wanted to go back again this year. This year was a little different as Sydney Dragway track champions weren't crowned. We sat on Ridgeway Motorsports team mate Michael Ali's table and had a great night helping Michael celebrate his 2011~2012 Pro Stock championship. I did get to bring home a champions jacket, however it was for Modified racer Ken Stewart who was unable to attend the dinner as he is holidaying in the USA.
Let's race already...
Friday morning and for Super Stock racers it meant we had 3 qualifying runs scheduled. The forecast was for more comfortable weather in the mid to low 20's°c and with a lot of sun around I was looking forward to having another crack at the track.
I made some changes to the car from Wednesday's test session with the goal of improving the mixture off the line and down track and getting that 60' time at least back to where it was with the old engine. Paul, Matt and myself agreed that I would do a 1000' pass first up as there were 15 entrants for a 16 car field and we would be in the field regardless and then decide where to go from there. With the third qualifier being Friday night I knew it would be the fastest session of the day.
Off to a good start with a decent reaction time then through the 60' timers in 1.08 seconds, a slight improvement on Wednesday's test session. Reminding myself all the way down the track that I was to get off it at 1000' (I have never done that before, every pass previously was full power to the finish line) I did exactly that and rolled through for a 7.48 @ 167mph. I threw the chutes as I crossed the line and Matt was on the radio letting me know what I ran. As you can imagine I was a bit excited in the car and ended up qualified in 4th position at the end of the session.
The most exciting for me was the ET. The old engine ran a best of 7.44 @ 182.95 in really good air, in fact the same day Peter Ridgeway went 6.99 seconds in his Monaro. For me to get off it at 1000' in 2200' DA (1.025 correction factor) and run 0.04 slower than my PB and be 16mph slower is pretty cool. For the first time in my Super Stock career I can play the Group 2 qualifying games!
You are the weakest link!
The engine was still very rich off the line and down track, so after a quick jet change and some other minor changes we pulled out for the second qualifier. One of the changes I made was to the launch rpm to try and help burn all the fuel that was being dumped into the engine on the launch. Trying to minimise the time I was on the 2-step I hit the gas on the second light (instead of the top light like usual) and then let go of the button on the bottom yellow. Unfortunately this meant I never reached the 2-step limiter off the line but not to worry, the 60' time was basically unaffected as it ran another 1.08 sec time. On the gear shift into second everything went wrong with a big bang inside the cabin and the engine going straight to the maximum rpm rev limit that is set well over 10,000rpm. Matt was straight on the radio as I had planned to do another 1000' pass and I immediately told him the transmission was blown as I rolled down the track for a 13 second pass, the slowest I have done in the car to date. To many spectators it might have looked like I was playing the Group 2 qualifying game, but I can tell you this was not the case.
At the bottom end I looked under the GXP and the signs were not good with transmission fluid dripping from the front of the Proflite. Once stationary I tried to move the shifter back into the first neutral and it got stuck halfway between first and second gear, again another bad sign. I tried moving the car and it was hard to push so we decided to take the driveshaft out and tow it back without the output shaft on the transmission spinning.
Back in the pits and up on the Pro-Jacks things continued to get worse. Paul drained the transmission pan and as he pulled the first plug out a couple of needle rollers fell out of the pan. Once the pan was off and we could see the start of the damage and broken bits of aluminium everywhere. After seeing that we got the transmission out of the car and started stripping it on the pit table. Once it was down to its bare case we found one of the planetary gears had disintegrated and in doing so took out the sun gear, high gear drum and a heap of other components at the back of the transmission. Unfortunately not an easy between round repair.
It was now obvious that the transmission was marginal in strength with the old engine in front of it, but now with a little bit more horsepower, it couldn't keep up. There are a few 500ci engines locally and in the USA running Proflites, so I know they can be built strong enough and I am in the process of ordering parts to build a much stronger transmission. While I would love to put a manual and clutch in the car, I cannot justify the large investment at the moment, especially without a sponsor. So for me the answer is to repair the Proflite and get back out there.
Paul, Matt and I stayed around for the remainder of weekend and watched Pro Stock and Super Stock eliminations in between packing up the trailer. An event free trip home and the car has been stripped and full assessment of the damage to the transmission is underway.
Next stop - South Coast Raceway
Parts will be on the way from the USA this week and I can start putting the transmission back together again. With some changes to the fuel system to cure the richness off the line I will be going to the Portland Championship Round on January 5th and 6th looking forward to seeing some improvements in the GXP and see if we can score some important points in the Australian Championship.
In my next article I will update on transmission repairs and preparations to go 1/8th mile championship drag racing in Portland on January 5th and 6th 2013.
I have been liaising with Scott Cleary down at the South Coast Raceway (Portland) for the Championship meeting in January and they have everything in place for running Group 2 at the event. There will be scales to weigh the cars and bikes and as you would know 1/8th mile Indexes and Minimums have been posted on the ANDRA website. So all the Group 2 racers who were thinking about entering or taking the family down to the coast as part of your holiday's entries close on the 22nd of December via the following link www.southcoastraceway.com/documents/sportsmanchamps.html
I would like to thank the following people for their on going support:
- Peter Ridgeway and Arthur Sagiaris (Custom Engines)
- Neil Hendry at Cryogen Industries
- Nick Xerakias (ERC Fuel)
- The A-Team crew, Paul Rogers Snr and Matt Ramsay
- Mark Bennett, Bennett Precision Tooling