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...

It's not the MAP sensor

On Saturday I put the inside of my car back together (the passenger side foot well has been a mess while I've been installing the PLX R-500) in preparation for my drive to the UK this week. After doing so, I went for a drive to check that everything was connected properly and working.

Despite the boost only getting up to 1.10 bar, I'm still getting a stutter when I accellerate full throttle in third gear. However, the stutter did come later in the rev range. So, this really rules out the MAP sensor and I'm back to trying to find the cause of my problem.

It has to be somethingon the control side of the engine... I suspect it's the ignition timing but to be honest I think it could be anything on the ECU side. I think it's going to be extremely difficult to track this down and this lends more weight to me installing a new ECU, if only to be able to get a better insight into what's happening in the engine. So, I could be installing that Haltech ECU sooner rather than later, depending on how Jarle in Norway gets on with finishing his Haltech installation in his bi-turbo over the next few weeks...

Oil cooler and MAP

Well, I finally ordered the Laminova oil cooler, take off plate and remote oil filter parts from Think Automotive last week and they arrived ready for me to pick up on my trip to the UK next week. When I'm back I'll book the car in with Jorrit at Auto Forza and ask him to fit it all for me along with some custom length hoses. I'd do it myself, but I just don't have the facilities unfortunately.

Also, I think I've figured out the cause of my stutter and drop off in performance around 4000 rpm. Contrary to what I thought, the MAP sensor in my non-ABS Ghibli is the Marelli APS-03 sensor (where as I thought it was an 06 sensor). As you can see from this link, the APS-03 sensor only reads up to 2.16 bar absolute pressure, which is exactly the pressure in my plenum chamber when the car gives a stutter. So I think it's reasonable to assume that the ECU in my car is designed to set the timing "safe" when the MAP sensor reading goes out of range.

I've set the maximum inlet pressure down to just below 1.16 bar gauge pressure now, but I haven't been for a drive yet to see how it performs. But I'll be doing a lot of driving next week since I'm planning on taking the car over to the UK on the ferry, so I can get a feel for how it's performing then.

No other news other than I gave the car a wash the other weekend... it was filthy and I needed four buckets of water to clean it!

Boost contoller sensitivity

The last few drives I've been playing with the boost controller sensitivity setting. It was set to 20 (not that this means anything since it's application specific), so I tried increasing it to 30 (although I was a bit weary since this is quite a big step).

I drove to Amsterdam on Saturday evening so got a good opportunity to load up the engine on full boost on the A4, keeping a close eye on the TomTom for cameras. I noticed that sustaining full boost gave the tell tale signs of a too high sensitivity setting, since the pressure gauge needle "wobbled". Before switching off the engine when I arrived at the first port of call, I quickly checked the maximum boost attained during my journey (my boost controller records the highest achieved boost level) and noticed it was high at 1.26 bar.

On one occassion during the drive I noticed a distinct hesitation during accelleration at maximum boost. It lasted a fraction of a second and I'm pretty sure that it was the ECU cutting the fuel supply to the engine after detecting a condition that it considered a bit on the extreme side.

While driving, the boost seemed to be responding very quickly to the throttle, which was nice. However, the wobble at full boost and the pressure spike are not really sustainable if I want longevity from my engine. Therefore, I reduced the sensitivity down to 25 before my next drive. This time, I no longer observed the wobbling needle at full boost, although when I checked the maximum attained boost level at the end of the drive it was still a bit high, indicating that the car was over boosting, I think in the lower gears where the revs ramp up quickly. I've therefore trimmed a little more off the sensitivity to prevent the spike a little, down to a setting of 23.

I very much doubt that this will have an impact on my ultimate power rating from the car, but soon I will be able to get a better idea since my PLX Device R-500 data logger arrived today! I'm not exactly sure when I'll get to install it and will probably have to do so over a few weeks (after first buying a solderer... I've not done any soldering since I was at school so I'm a little anxious about tapping into the car's wiring). I'm looking forward to seeing the data though... should give quite an insight into what's happening with the car...

Chasing the performance gap

I've been thinking some more about the strange performance that I've been getting from my car. I had another read throught the manual that came with the E-Boost boost controller and figured that I might not have the sensitivity set up correct, so I'm slowly increasing it each time I drive the car until I notice some "wobble" on the boost pressure, at which point I'll knock the sensitivity back a little.

It could be that the boost controller is not responding quick enough with the wastegate control to maintain effective operation of the turbos, but I doubt this since I'd expect to see the boost pressure drop off in this scenario. But I'll try adjusting it nonetheless.

To see if my modifications make and change to performance, I've ordered a G-Meter to do some on the road diagnosis. Hopefully this should arrive in the next couple of weeks and I won't have to make frequent trips to Rica anymore.

I also had a look in the engine compartment yesterday, seeing if there would be space for charge coolers or increasing the size of the intercoolers. Looks like there's a couple of options that I could persue... including something interesting I read about candle wax... But whilst looking I noticed that the hose to the left intercooler has deteriorated quite badly with some nasty crack in the ninety degree elbow. It could be leaking, so I'll ask Jorrit to change it out when I next see him.