Cleaned the bottom and rear of the car, though it was impossible to get at all the oil. I didn’t want to use any sort of sprayer that drives water into the wiring or chassis tubes, so I’ll wait for the oil to absorb dust and fall off…
After that, it was time to install the new exhaust, this time with a Borla muffler, mostly because it’s stainless but also to test the claims of great muffling and low back-pressure. The exhaust is set up so that it disconnects downstream of the flex coupler with a V-band for track events, and a short right angle extension can be swapped in, much like how the exhaust was before today. Both wastegate outputs are also fed in upstream of the muffler – no point cruising quiet(er) but attracting the wrong type of attention while under boost.
The muffler works really well (Borla PN 40359), I’m pretty happy with it. The picture from the rear shows how it’s leaned forward, to miss the future diffuser. This leads into something I’m working on, to solve how Midlana’s been looking a bit “unkept.” One issue (in addition to the engine cover) is the chopped off lower rear panel (crunched when the car backed off-course at Willow Springs then cut off because it wasn’t repairable). The plan is to fabricate a one-piece engine tray/diffuser of aluminum or stainless. Whatever the material, the nearly 48″-wide sheet has to be thin/soft enough that it can be curved upward to form the diffuser. At the same time, I’d like it thick enough that it can serve as structure under the engine, something of a contradiction. A middle ground might be to have a shop roll the curve into it for me.
As mentioned before, the air filter’s being changed to pick up air from the side inlet instead of sucking in hot engine compartment air (now hotter because of the muffler below it). The ducting and different air filter element is on-hand; the new filter is better suited to being enclosed and fed via ducting. After finishing the muffler, the new filter was installed without the ducting just because, the large hose clamp tightened, and I headed out for another test drive.
During the drive on my newest favorite road, I saw two Alfa Romeos GTVs (my favorite model) pulled off to the side, the owners chatting. Further on were another 3 or 4 more, one with its hood up. I stopped and asked if they needed any tools. They laughed and said “we drive Alfas, of course we have tools!” We chatted some about Midlana and then I was on my way – thankfully not trailing a stream of oil like last week!
With the muffler working so well, new sounds are detectable now, and unfortunately, one sounds like engine knock under full boost. What’s unclear is whether it’s always been there and I couldn’t hear it, or if the (assumed) added back pressure from the muffler caused it. I’ll log a drive to see what’s going on; maybe it’s just something that sounds like knock. If it’s the real deal though, boost will be dialed back a bit :).
Stopped for gas on the way home and half way through filling the tank, I saw something move out of the corner of my eye – the air filter had just fallen off the turbocharger, hah. How it managed to stay on the vibrating engine through the entire drive and only fall off right then, I don’t know, but I was happy to see it happen. The hose clamp worm screw housing had contacted the compressor housing, giving a false indication of being tight – fixed.
No oil leaks on the test drive, though there’s still oil from the original leak coming out of the woodwork. What didn’t help the oil leak situation was the engine tray being off the car. Not only did this allow the oil to be blown aft, but the open rivet holes allowed some of it into the chassis tubes, only to later drip out when it feels like it.
Lastly, alternator output remains at 14..0-14.5V during the entire drive, so no issues there.
Oh, ran across this pretty cool looking (and free!) PC application for designing mechanical linkages. I haven’t used it yet but it could be useful for future projects :).