July 14, 2016

Some additional photos from Imola.

Look at that body-roll! Needs to be addressed.

Splitter Aftermath

June 25, 2016

I thought it would be interesting to show the results of the problems I encountered with the new splitter at Imola. As posted earlier I had some serious chattering of the front splitter above 200km/h which was a bit disconcerting at those speeds.

The chattering was caused by the low stiffness of the front mounts which when air passed over the splitter at 200km/h it excited some natural frequency of the assembly, is what I’m guessing. Due to no straight passage to the frame I decided to mount the front supports directly to the bumper, which is clearly not stiff enough.

Luckily the splitter simply skimmed off the tarmac and didn’t decide to catch on to something, otherwise I would have been a pretty big explosion. Some scrapes under the splitter.

The front supports got battered pretty hard; I should probably go up in thickness. What I was very surprised by is the rear mounts; they bent backwards despite them being made out of 2mm steel which I thought would be more that sufficient for the location. Most likely they rearward force of the splitter hitting the ground caused them to bend.

Another interesting one are the canards which have bent downwards. These were never a problem, even at Monza I didn’t have any issues, but most likely this is again caused by the chattering of the splitter causing the entire bumper to rock up and down. The rocking in addition to the downforce obviously was too much for the brackets.

So the next move, as soon as the fuelling issue is sorted, is to address these issues and beef-up the entire mounting strategy, but it has been a great learning experience.

After finally completing (sort of) the Great Danton I was finally able to attend a round of the Time Attack Italian Championship, my first one this year and round 3 of the championship. This was always going to be a shakedown event to actually make sure the car runs ok and to ensure that all the new components are fitted and working correctly.

The day before the event I had quite a few things to sort out, most importantly a large water leak from the left side of the engine which ended up being one of the water heater coolant lines. I also had to drive the car down from Bergamo all the way to Imola so I was quite careful as it was all unknown, and I stopped a couple of times during the 3 hour trip to check fluids and so on.

This first image sums up my day quite nicely; a lot of time waiting for a session after fixing the car. I had some sort of problem during every session which meant that my actual running time on track was very limited. I would usually go out for about 2-3 laps and then find out I needed to come back in to fix it, by which point it was too late to reenter the session.

The first session I went out for about 5 laps and came back in thinking everything was ok but I had lost a nut from the power-steering pump and the belt was slipping.
In the second session all the water that was available in the sky decided to fall and the session was quickly red flagged. We were able to redo the session after it cleared but I quickly found out that I had lost a bolt on the exhaust and it was dragging.
On the third and final session before the Superlap I decided to actually push the car a bit now as I hadn’t had any chance to actually test the limits of the car and get to know the track a bit better. But at the end of the main straight on my first full power pass the splitter simply couldn’t hold on :D. At around 230km/h it ripped through the bumper and hit the ground. Luckily it had only a few grazes and was able to secure it again to the bumper with an improved mounting strategy but this wasn’t to be enough.

During the superlap on the first lap it once again came loose and started chattering. So I had to take it very cautiously around the lap and then on the second lap my car decided to have a fuelling issue, and that was the end of the day. My pace during the day wasn’t too far off the pack but at not point during the weekend was I pushing the car (posted a similar time to last year); hopefully I can get these issues sorted and hit the track again to actually see the improvements over last year.

Overall I’m actually very pleased with the day because all the issues were fairly minor and can be worked upon and the engine really went without a hitch. An engine I built completely from the ground up actually went pretty well, so it has been a huge learning experience.

GD V2 – Part 23

May 18, 2016

It’s almost over, just a couple of things to finish up. Finally took the car out for a drive today after 6 months of working on it, and it was great to be back in this hard, uncomfortable and ridiculously loud car. The exhaust note has changed drastically from before; I’m not sure if it’s the cams or the tubular manifold or a bit of both but it’s high pitch and raspy, oh and so much louder. It’s almost embarrassingly loud when above 3000 rpm.

The splitter is on, but needs some additional mounting and refinement. I’ve already scraped it, and I haven’t got my scrape plates on it yet.

GD V2 – Part 22

May 15, 2016

The final preparations are being carried out on the car before I can give it a test drive, so in the meantime I thought I would highlight all the engine specs and parts for those interested (parts not mentioned are OE, and I’m sure I’ve missed things):

ACL Race crank bearings
ACL Race big-end bearings
Apex Performance conrods
Wossner 86.5mm 8:1 pistons

Tomei 256 Poncams intake and exhaust
Custom rocker shims
Cometic 1.1mm head gasket
Apex Performance rocker arm stoppers

Front mount intercooler with custom piping
Apexi Power Intake filter

Garrett GT2871R turbo 0.64AR
XS Power tubular manifold
Japspeed downpipe
3.5″ catback with decat

Walbro 255 fuel pump
Nismo 740cc (JECS) injectors
AEM fuel pressure regulator

Billet oil sandwich plate
Thermostatic oil filter relocation block
Mocal oil cooler
Driftworks Supercool alu radiator

Apex Performance alu pulley kit
ACT Performance clutch kit
AH Fabrications oil catch tank
Apex Performance short shifter

After the mapping session I also checked the valve clearances again as everything has bedded in a bit and should have settled. Unfortunately the clearances are a bit higher than I would like which explains the elevated valvetrain noise, and will no doubt cause accelerated wear on the cams. Valvetrain is something that I have limited experience with and have a lot to learn; I assumed that the clearances would close up a bit after the valves have set in their seats but instead the clearances opened up a bit which means other parts have settled.

Also, I had to change the fuel pressure regulator to an AEM unit, as the “Aeromotive” unit started leaking. It was probably some Chinese knock-off unit, despite it not being that cheap. The good thing is that AEM unit is much smaller and nicer.

GD V2 – Part 21

May 14, 2016

I didn’t really think there would be so many parts to this, but it’s getting close. After running the engine for a bit I took it to a tuner to get it mapped properly. Luckily I found Preparazioni Soretti, which had worked with the SR20, the Apexi PowerFC and D-Jetro version before, despite being a Subaru specialist.

There were a couple of things he wanted to sort out before mapping the car; these were mainly vacuum and oil lines. With the new tubular manifold, it gets very close to the intake tube and vacuum lines so he recommended moving the rubber joint on the intake pipe and the vacuum line away. The intercooler piping was cut and welded to the turbo outlet and an additional joint added (in blue). Then the vacuum line on the turbo inlet was completely moved away and under the tube, meaning it clears the manifolds completely.

The final result from the mapping session was 343hp (at the crank) and 428 Nm at 1.3bar. I quite happy with the result considering that the pressure isn’t too high and it will be a big difference to my previous setup.