Startup 08

It’s definitely the finishing straight now, barring some horrific problem. First up is that I finished re-installing the transmission. As a consequence of careful design and planning, cough, it all fitted fine and will hopefully work OK.

Luckily, the gearchange lever on the ’08 engine is in almost exactly the same position as on the ’07 engine so no change was necessary here. You can see my super-long gearchange cable snaking around the engine in the photo here.

So, it was time to start up the engine. As usual this took me some time to work up to but after faffing around for rather too long I put my ear defenders on (there’s no exhaust, remember?) and pressed the start switch. Gratifyingly, the engine burst into life with pretty blue flames blasting out of the exhaust ports. What’s more, later examination of the data logs showed that the oil pressure had come up OK (you can see the reflected light from the oil pressure lights on the video of this momentous occurrence below) as also did the battery voltage meaning the charging system was working.

So, that was gratifying! What’s more, the neighbours didn’t complain even though the noise must have been horrendous.

Along the way while doing all this I’ve been sorting the car for the next race. So at about this point I got distracted by the rear brakes. So, I took a few minutes out to deglaze them and remove the little lips that appear on the outer edges of the pads, as you can see. I think the rear brakes of the J15 are wearing more than the equivalent ones on the Fury did, which is what you’d expect with the modified weight distribution.

One of the reasons I was looking at the brakes was because I was adding a bit of heat insulation to the handbrake cables which had suffered slightly. On the way past I noticed the pads and thought they’d appreciate a trip into the light.

Back on the engine it was time to sort out the air inlet. I’ve been musing about this for some time, wondering how best to do it. In the end I’ve done something similar to that which I did on the ’07 engine. It does have to be slightly different because the ’08 airbox has a panel filter in it rather than the cylindrical ones on the older engine. It became clear that I was going to have to replace the filter entirely so the first thing was to just get some air into the airbox. This would have to be through the top so I did something similar to what I did before and bonded a lump of tubing into a specially cut hole in the top of the airbox cover, as in the photo.

The tubing is actually 100mm PVC soil pipe. I only had to buy 3 metres of this so I’ve got about 2.8 metres left. 🙂 Since I did this I’ve been wondering if I could get the whole pipe hot enough to just bend it around to face the breeze. Before I thought of that, though, I did what I did before and used some 100mm flexible ducting that I had (in that case because I had to buy 4 metres of it!) and made a mount for a spun aluminium inlet duct.

Obviously, I’d need an air filter. A while ago I’d bought some proper filter foam and I cut some of that to the size of the airbox cover and I’ve held it in place with some large size mesh, as in the photo. The curious colouration in the photo is the filter oil which I’ve since spread out properly in the foam; at this point it was sitting in some pools…

The end result of all this can be seen in the next photo, along with a cover that I fabricated over the secondary fuel rail and injectors so as to stop the odd scrute having a heart attack. I’ve also trimmed the rear bodywork to fit around the new airbox which is, of course, a slightly different shape from the old one.

Along the way about this, I’ve been wondering about how well the airbox actually works. So, as a start to looking at this I’ve wired the output of the MAP sensor into the data logger. I started the engine again to check what this did and it said that when I turned on the ignition the pressure in the inlet ducts was just under 1 bar (no surprise there, it was raining cats and dogs at the time). Once the engine was started the pressure dropped to about 0.75 bar. Again, as the throttles were closed that’s probably reasonable. What will be interesting is to see what the pressure is at WOT (wide open throttle) in race situations, especially at speed with the air inlet pointing into 100mph breeze. If it works well I might try putting another MAP sensor actually inside the airbox, and upstream of the throttles.

With all that done there’s just a couple of things to do (apart from the usual, of course). These are the exhaust, and I’m taking the car up to Andy’s tomorrow to see about sorting that, and the clutch. The clutch release on this engine is cable, unlike the hydraulic actuation on the old engine. I spent a while deciding whether to use a cable or modify the engine so as to fit a slave cylinder. Eventually I decided to do it as Mr Honda intended so I’m getting a decent clutch cable of the right length. Hopefully this won’t be too difficult to fit. I did try making a cable using some cable components (inner, outer, etc) that I had around, but it was horrible, with just too much internal friction. Hopefully the proper cable won’t suffer from that. I’m going to have to modify the clutch pedal to link the cable to it, but that shouldn’t be too difficult. It’d better work because I’ve removed most of the hydraulic stuff…

With those two details done the car will be ready for the next race at Snetterton, apart from mapping, alignment, testing, etc., etc…

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