Tuesday, June 06, 2006

BMC DIA airbox fitted to Maserati Ghibli

This weekend I fitted the BMC DIA airbox to my Maserati Ghibli (and got sunburn on my lower back in the process... a warning to all car enthusiasts working on their cars outside in the sun!).

I started on the driver's side (I have a left hand drive Italian 2.0 liter model) and removed the OEM airbox and intake system back to the compressor inlet. I reused the existing 45 degree elbow and to this connected a 50 mm hose connector (seems that the existing inlet system is actually a bit smaller than 50 mm diamter since I struggled to get the elbow to fit onto the connector). I then fitted the straight 50 to 70 mm reducer, unfortunately in blue since they were out of stock in black ones at Auto Sport Parts.

The flexible alluminium pipe that came with the BMC DIA kit was then utilised by fixing this to the reducer via a 70 mm hose connector. The flexible pipe was then shaped and trimmed and the BMC DIA airbox fixed onto the end of this. The fitting of the driver's side system went reasonably smooth, since there's a fair bit of room to maneuver on this side. I'm actually not too happy with the flexible allumium pipe, since it feels a bit too delicate and I worry that it might leak... I'm therefore planning on changing it out to a silicon 90 degree elbow (maybe this weekend). I think it's meant to be utilised as a feed pipe to the inlet of the airbox to siphon cold air from the front of the car. In this application, it doesn't really matter if it leaks, but I don't want unfiltered air making it to the compressor (let alone the engine).

To fasten the airbox I used the drilled alluminium strip that came with the kit. I'm not too keen on this stuff and there's not a lot of places in the engine bay to fix it. I used a screw that fastens the filler spout to the windscreen washer tank, but soon wished I hadn't seen the alluminium strip twisted and made a hole in the plastic spout, leaking water into the engine bay. Will have to rectify this at the weekend, but have an idea where I will fasten it... or maybe even make a dedicated fastener.

The procedure for the passenger side was identical except that there's less space here making it a bit more fiddly. This is particularly highlighted by the fact that the inlet hose passes very close to the exhaust manifold on this side... so much so (only a few millimeters clearance) that I'm concerned that the silicone restrictor may not be able to cope with the temperature. So I may need to get a longer 50 mm connector hose (which is not the preferred option, since it lengthens the amount of 50 mm hose which is what I'm trying to minimise) or maybe clad the silicone with allumium foil (not very attractive but probably sufficient to shield the silicone from the heat radiation).

As with the driver's side, I'm not too happy with the alluminium flexible pipe or the fixing bracket, so I plan to improve on these at the weekend.

Another thing that needs sorting this weekend are the oil vapour recovery filters. I've currently installed a make do, temporary solution, but the filters need fitting much better. I plan to get hold of some longer lengths of hose and have the filters located at the front of the engine block, just fore of the O rings that support the OEM oil recovery hoses.

So... the moment you've all been waiting for... how do they perform?

Well, I took it easy for the first 10 to 15 mins to let everything warm up while listening out for any strange noises. Everything seemed to be going OK so I started to open her up a little. First of all, the car feels much more torquey... even in 5th and 6th gears, the car seems a bit more enthusiast between 3000 to 4000 rpm. I can also hear the turbos spooling up with a faint whizz when I floor it at 3000 rpm.

Another nice sound is revealed when I lift off the throttle... there's now a nice throaty intake roar.

Top end performance... well... the car is now breaking traction on dry roads when I floor it in 2nd gear. So that's a good sign. Also, seems that the boost pressure is now spiking. The E-Boost boost controller appears to be venting off boost pressure when accellerating hard, since the car gives a judder and when I try and watch the E-Boost gauge I see it climbing into the mid 1.2s followed by a quick drop to 1.19 bar. This indicates that boost pressure is reaching the safety cut out level, which means it must be spiking. This is good news indeed!

I plan to take the car to Rica Engineering this week to reset the E-Boost controller and check the fuel map. I should be able to set up the E-Boost to ramp up to just over 1.2 bar and then hold it for the remainder of the gear, which should give good, safe, reliable performance. I'll also get a dyno run done and see what's happening in real terms.

I'll keep you posted...

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