I guess I'm doing this blog post just to ease my nerves and make sure I have everything covered. I really want it to pass, or if it fails then it can be an 'easy' fail.
Last update on the fuel tank shenanigans. I am 99% sure I've now resolved the issue. The tank inlet has a jubilee clip, a spring clip and some silicon sealing tape. In an ideal world any one of those should have sealed it, but this isn't an ideal world. The silicon sealing tape was a new thing, recommended by an LCB fellow builder. I've never seen it before, but it's quoted as being fuel safe and very effective.
What I ended up doing is removing the jubilee clip and binding the end with silicon tape, with a flare butting up against the tank. I then put the clip back on. So I've got the spiral clip for the physical connection, the jubilee clip for the liquid seal, and silicon tape for the vapour seal. It's ugly but it's working. Once the car is on the road and I've emptied the tank a bit I'll rearrange things. And probably get a different filler pipe.
Out of interest I also weighed the back of the car with the full tank. The corner weight is now 158.3 Kg, which is only 12kg more than the original weight. Actually, that makes sense. The IVA gives a method of calculation that means for my 25 litre tank I was expecting an extra 20 Kg of fuel. So I'm right on the money there.
Of course, I also weighed it with me in the car and it came out as 197.5 Kg. My design weight for Axle 2 was 406 so I've only got a little left for a passenger. Then again, the passenger weight will be more on the other wheel so again that adds up.
Now the bad news. I did a noise test at the proper revs. I'd done one before at lower revs but that doesn't count. With max power at 6500, it needed to be tested at 4875. With an idle noise of 84.5, at the required revs it's 104.4. Given I need 99dB that's a little over. Oh who am I kidding, that's a lot over! I am hoping that most of that is my testing method and location. A quick Google suggests even the idle noise of 85dB is louder than a police siren and similar to a lawnmower. It really isn't that loud so I reckon it's the meter positioning and the quality of the meter itself.
If the exhaust is too loud, I am limited in what I can do. Easiest thing would be to replace the silencer with a wider one, unfortunately there's not enough space. Similarly I can't do a longer one as I've got the exhaust end one side and the cat on the other.
What I can do is repack the existing silencer, or more specifically add a DB killer with some fibreglass wadding. The problem is that I welded the exhaust together, so it's not a simple case of adding one. I guess if I'd have done the noise test a few weeks ago I could have had the time for one to arrive and for me to cut the exhaust and install it. So this particular one is in the hands of the IVA gods. I'll sacrifice a milky bar later on to see if that appeases them...
(The following day...) I've been thinking more about the exhaust again. Whether it passes or fails I will probably still add the DB killer, or do something to calm it down a bit. But at the same time I can add a flexi joint. I didn't bother initially as the consensus is a longitudinal engine doesn't bend the exhaust as much as a transverse. But it's not a huge deal to add one, I have space and it would make things that little bit more reliable.
And one more picture. I wanted to follow up on the steering angle to make sure it was sufficient. It occurred to me last night that with an overhead picture I could then draw on some lines and measure the angle;
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