Summer fun

After spending a couple of weeks in Syria at the start of the month, it was great to get back home and have the opportunity to drive to work everyday in the Ghibli. Without fail, I step out of the car with a big grin on my face and I'm simply loving driving it!

Following on from the discoveries in my last post, I've trimmed back the sensitivity setting on the E-Boost controller and voila... the stuttering during hard acceleration has stopped! I've now increased the gain setting slightly to compensate and to set the boost pressure right at the end of the amber section on the dash boost gauge (I need to check but this should be just over 1.20 bar).

I'm also now slowly increasing the gate pressure setting, which is the pressure at which the controller starts to open the wastegates. It's currently set at 1.05 bar, but in third gear at least there's scope to increase this. Since my 3200 GT turbos don't spool up very quickly, there's less risk of over boost so the gate pressure can be set reasonably close to the desired boost pressure.

I'm really happy with the way that the car is performing now. Acceleration is nice and steady, with a kick in the arse coming around 4000 rpm. Keep the revs below this and the car is very civilised, above this and its nice and aggressive with a quick throttle response.

The warm weather is testing the new oil cooler. Now that I'm driving it more I'm noticing how it performs. It's obvious that when being driven with decent speed, the oil temp is being kept pretty low as the water temp is maintained below 80 deg C and the oil pressure stays just below 5 bar.

Slowing down or stopping when driving through town, the water temp is elevated and stays between 80-90 deg C with the fan coming on alot. Also, the oil pressure drops to 2.5 bar. But as soon as you get some speed up and get air flowing across the radiator, the temp is straight back below 80 deg C and the oil pressure to just below 5 bar.

So my conclusion is that the oil cooler is working well. It has no problem keeping the oil temp low when driving at speed (with good flow across the radiator) and it manages to take the edge off the heat when the car is stationary, which is where the problems occurred on the track.

There's some noticeable additional load on the engine at idle though, particularly when the engine is cold. It's only small, but the engine is more prone to stalling now and a dab of revs is required to prevent stall when reversing with full steering lock. I will get this sorted though when the car is dropped off at the garge next week end... the idle needs setting a fraction higher I think.

The car is going for the annual APK (road test) next weekend and also to have a few things done:

1. Re-fit the original distributor; it was replaced with a new one to check whether this was the cause of the stuttering, but since it isn't then the original can be refitted.
2. The volt meter has stopped working completely, so the wiring needs to be checked.
3. The idle needs resetting.
4. Maybe fit the new springs. I'm in two minds about this though as the ground clearance around town is good at the moment.
5. See if it's possible to modify the left wheel arch to increase the clearance a little and prevent the tire from rubbing on fast or tight right hand corners.
6. Perform small service (oil change).

I'll try and capture some log data to show the changes in the boost pressure... I expect that the boost curve will be much flatter now at the top end instead of oscillating up and down. I think the top end is now performing much better as a result. Feels like the car is back at 330 hp, but I'd need to take it back onto the dyno to check this...

Rubber Pads

My car is getting to the age where the rubber parts are needing replacement. Unfortunately, some of these parts are becoming increasingly difficult to source.


The latest parts requiring replacement are part of the suspension set-up and are labelled number 45 in the drawing above and Maserati refer to them as RUBBER PAD Part No. 396650021. The effect of these wearing is primarily felt when braking... the front suspension feels to move a little before, which can be a little un-nerving!

It seems that the non-ABS Ghibli was the only Maserati fitted with these parts, since the group of parts were changed for the ABS and later variants. Although the drawing looks identical for the 2.24v, it has a different part number (BUFFER Part No. 316620110 (Supercedes To Part No. 396650110)).

If the part I need is no longer available, I have a couple of options. First, I need to check whether the 2.24v part and the Ghibli part is actually physically different. If they're the same then I can just get one of those. Another alternative is to upgrade to the ABS parts, but this may not be straight forward and may require changing out some other components such as the subframe, which will turn out to be expensive. Another alternative is to fit some polyurethane generic replacement from Powerflex and then machine some adapter spacers. At least these generic parts will be easier to source in future plus they're stiffer and much tougher wearing, so shouldn't require replacing as frequently!