Boost Control via Factory ECU

[Hotwire]

Stock thermostat begins to open at 18º0F/82ºc, and is fully open by about 90ºc. My car came from Japan with a 40mm Koyo aluminium radiator, and G-Reddy hard coolant pipes, so I have a feeling they fitted at 160ºF/72ºc thermostat, which would be fully open at around 80c - which is the temps im seeing.

I could probably only check this by removing the thermostat, but given the temps i see and the modifications to my car, im 90% certain that's the case.

So my next steps are to rectify the thermostat issue (new one), get a leak test done (to ensure no leaks at high pressures) and then to get a high flow cat to ensure its not back pressure causing more boost drop at high revs....

[kinkyafro]

What is supposed to be the 'ideal' temp range then?

we unscientifically pegged it at 85 degrees C. I generally find my car runs at approx 90 degrees once warm and can hit 105 if stationary after a spirited drive.

[Nutter_John]

Sorry Rich I thought it was 84.9 degrees C

[twisted32]

So you still have not changed your thermostat Lee?
I was considering a 77deg or 72deg thermostat when I do the alloy radiator as my temps stabalise at around 93deg (new, stock 82deg themostat) in cool conditions, but quite easily pushes upto 99 deg (thermo fans switch point) in traffic.
Maybe 77 deg is the way to go (tridon)

[Hotwire]

Im still undecided as to go 77 or 82, as with the additional cooling capacity of the Al radiator, if the thermostat is fully open at 90ºc, then really the temps should be pretty stable at this temp. Hitting 99c while in traffic would have to be a result of lack of capacity of the stock radiator, not the opening point of the thermostat. It MAY have added a little heat soak initially, but I would point the finger at heat soak occuring due to lack of size.

[Shtiv]

Hmmm even with my alloy radiator mine sits around 90 degrees in cool weather, wonder when my thermostat opens.... It usually runs at 90-95degrees and i've seen it over 100 heaps.... Next question, how accurate is the stock sensor, has anyone checked?

and I know that maxxing BDEL D (to 159.4 and taking WGDC D to 80% gives almost 16psi boost from 3-4k dropping off to 13 or so.... I haven't had a chance this week to do much at all though and it's been raining most of the week and my logger involves having a window down a bit so. i'll get there early next week hopefullly. Still holds the 16 too, not just a spike and drop off at constant RPM

[Shtiv]

more info on boost control here:

http://ozvr4.com/forums/showthread.p...237#post201237

[merlin]

there wont be any fuel enrichment when the engine temp is 70-80*C, it will be running closed loop lambda control.

[Hotwire]

Removed - answered my on Q I think - PM sent

[Shtiv]

Sorry Rich I thought it was 84.9 degrees C

bahahaha! but I agree, about 85 degrees would be best....

[Shtiv]

there wont be any fuel enrichment when the engine temp is 70-80*C, it will be running closed loop lambda control.

what happens in the open loop zones though?

[Adam.Findlay]

hey so have you guys got your cars running higher stable boost yet? i have removed the restrictor pill from my solonoid and had a wee fiddle with the wgdc but the boost was very unstable ranging from 15psi to 8psi. if someone has got it working holding 15ish psi stably could you post up what duty cycles and gains you have used. if not i will hopefully spend some time getting it right this weekend

[Shtiv]

Yeah, change the BDEL as well (max is 159.4) and look here:

http://ozvr4.com/forums/showthread.p...237#post201237

[Sylwek]

Odd, when I see disassembly of auto/manual ECU it does not refer to any wgdc table in any place by the means of coolant temperature. There is only retire/downgrade of wgdc after the engine temperature exceeds predefined level. I could notice only load what is temperature related there.
And yes, you can actually set the boost however you want just the same way any other Mitsubishi car from these years.

[Hotwire]

After being rather busy leading up to Christmas finally got back to revisiting this on the way to work this morning. Attached are 2 plots, one of Temp Vs Temp Scaled in Evoscan,

and the other is WGDC Vs Temps and as can be seen, 85 on engine temp, 80 on engine temp scaled is definitely the magic mark for achieving full boost control. As such, I will ONE DAY SOON change my thermostat back to the stock 82c. I still believe 77 will result in temps that are too cool for propper boost control (and who knows what else it will affect) in cooler months.

[Nutter_John]

Yeah roughly 84 was where we first noticed the uplift in boost on the dyno , took quite a lot of runs to fully confirm properly

[Shtiv]

Wow your car runs cold Lee.... Mine is rarely below 90 and that's with the aluminium radiator

And yes, definitely less duty cycle when cold

[Hotwire]

Yeah it does run very cool - that was in 24º ambient temp too - in winter was cooler. Only time I get consistently over 80 (scaled) is when its 34+ and i'm in traffic. Intersting that with the stock 82ºc thermostat you get 90s consistently, maybe a 77º is the best compromise?

[lateshow]

I've tried searching but where can I get definitions that have those boost control parts (i'm currently using a bleed valve type of thing and it works great but just would like to try this out, not sure if there are any benefits in using the original solenoid where as the ECU doesnt actually care about "predefined boost levels". Geekmapped doesn't have new definitions with boost control (only the ones merlin did ages ago) so help me out?

[twisted32]

Yeah it does run very cool - that was in 24º ambient temp too - in winter was cooler. Only time I get consistently over 80 (scaled) is when its 34+ and i'm in traffic. Intersting that with the stock 82ºc thermostat you get 90s consistently, maybe a 77º is the best compromise?

With the alloy radiator, and new, stock 82 deg thermostat, coolant temp scaled seems to like sitting around 85deg, until you are sitting in traffic etc. I was thinking I would go for a 77deg thermostat, but I am sticking with the 82 for the moment. At least until we can adjust thermo's to come on earlier than 90odd degrees (temp scaled).