This is a warning to all those with electronic boost controllers. Some may know this, some may not. In this weather you will probably find that you are hitting higher peak boost in this cold weather. This could be problematic, and potentially fatal for your engine.
I went out yesterday and hit 1.1 bar boost when it\'s only mapped to 1 bar. That\'s 10% extra boost!! I\'m told it hit fuel cut as I heard a big \'pop\' simialr to that of a hose popping off, but very loud! So, this is a warning to those people that may find themselves in a similar position! Turn your boost down, or run on the lower setting.
Apologies if everyone already knew this!!
This cold weather is certainly an eye-opener - on-boost intake temps of < 10C will see our cars performing well but your word of warning is timely!
This goes to anybody with the car in general, :wiggle
Well, not really: most cars can retard ignition to stop knock. The FD\'s (and probably other rotaries too) can\'t.
jah thats why i said the car as in rx7\'s :) should have made it clearer but ive been up since 5am today :driving
ah, yeah, just re-read your post! Sorry, my bad just as much! You deserve some sleep! :D
Im at work now :mad: Droped parents off at airport so im home alone for 2 weeks woe is me.... :guinness
Quote from: nikpWell, not really: most cars can retard ignition to stop knock. The FD\'s (and probably other rotaries too) can\'t.
It does if you have a Apexi power FC pro....i\'ll let you know how mine performs once installed.:guinness
PFC Pro? Oh do tell!
you need to tweek the gain on the controller, plus most decent controllers will self learn and stop the boost spikes
Quote from: nikpWell, not really: most cars can retard ignition to stop knock. The FD\'s (and probably other rotaries too) can\'t.
I thought the stock ECU could do this? Just the power FC doesn\'t...
Wouldn\'t have thought so, but maybe. I thought most ECU advance ignition to the point of starting to get a bit of knock, then retard it again. The FD surely can\'t do that becuase even a teeny bit of knock is dangerous. Answers on a postcard please?
I always thought that you\'d have the base map which would be retarded in the event of knock on most cars, with knock sensors that is!
I\'d have thought the stock ECU could otherwise why have a knock sensor at all?
Pretty much all NA engines (that I know) never have a knock sensor and so run on a fixed map with adjustments for coolant temp and intake temp (and alt if not like a Lotus and mapped in a cabbage field) and that\'s ya lot!
But I stand to be corrected ;)
Plus the thing to remember if the car is tuned on a dyno the temps will be higher than when its on the road. There are corrections built into the software for temps of air and stuff. As long as these figures are good then you should be ok. Although if the air temp is low then you will need more fuel and if your on the limit of the fuel system it could damage stuff.
Shaun
Could this explain why I got the warning light flickering (very briefly) when on track a couple of weeks ago? It was damn cold and wet!
If the PFC doesn\'t retard and I was getting super-cool air temps, maybe it was causing knock (although it was on part throttle at medium revs, not WOT). Surely we don\'t have to alter PFC settings every time it gets cold though!? :confused:
Hummm, Im probaly wrong because I dont know what im on about but....
Cold air is more dence so you can squeeze more fuel/oxygen into a set volume of air making for a better burn. Remember there is a lot of moisture in the air as well this time of year!
Is this the reason for the increased boost? as the car is running more efficently the exhaust pressures increase causing a knock on effect to boost ???? and lack of fuel to cope with this = pinking
I know with water injection is added (the same same effect) you need to increase fueling or pinking/knocking will take place! or like you say retard the ignition.
(Are there no pinking/knock sensory or the RX7?)
It effectively makes the air more dence and cool therfore more fuel is required to match. Or pop.:eek
I can sort of understand about the fuel, But I have never noticed an increase in boost pressures due to adding water injection or driving on a cold moist day? however you will always find any car will drive lovely in these conditions due to the increased burn efficiency.
Rah rah rah
Any ideas :Hammer :Hammer
Does the ECU anticipate and adjust fueling very very quickly using the AFR to prevent knock????
I dont know? Its the only way I can think how!
Quote from: adamkHummm, Im probaly wrong because I dont know what im on about but....
I know with water injection is added (the same same effect) you need to increase fueling or pinking/knocking will take place! or like you say retard the ignition.
Rah rah rah
Any ideas :Hammer :Hammer
Not true you do NOT add more fuel if you have Water injection.
When you add WI it lowers combustion temps hence lowers knock.
I actually found that AFRs got richer when WI is activated.
The fact of the matter is stock and Apexi ECUs have a temp correction map so compensates for lower temps and adds more fuel.
The only reason for boost spiking in the original post is the boost controller has not self learned or the gain control needs adjusting therefore to control the wastegate accurately to prevent spikes.
A stock Twinturbo FD on stock ECU will not overboost if working correctly.
The only cars that will overboost are ones with aftermarket controllers if the gain is not set correctly therefore spiking will occur, the engine will only go pop is the higher range of boost cells of the Apexi ECU have not been mapped correctly therefore the temp correction table will have no chance in adding all the extra fuel required if the normal fuel map is not mapped accordingly(if the fuel system is up to the job in supplying extra fuel)
how it makes sense guys
Cheers Mark, much appreciated for the reply. So i need to turn my gain down, right?
yep try 5% at first Nik
Which boost controller do you own ?
Shaun
Told you I didnt know what I was on about!!!!:rollin
Clears things up mate thanks.;)
Greddy Profec B Type 2 or whatever it\'s called!
You probably have the set too high. It needs to start at a lower level so it doesn\'t jump past the level you want. What are you running turbo wise ?
Shaun
Quote from: shaunwilYou probably have the set too high. It needs to start at a lower level so it doesn\'t jump past the level you want. What are you running turbo wise ?
Shaun
exactly Shaun
I have the same controller when setting the controller I started with 0 percent then slowly adjusted it higher. The gain controls how fast the wastegate closes and opens. If it stays shut for too long spool time of the turbo is quicker but there is a big chance it will spike above target boost before the wastegate starts to open and vent to reach target boost
As has already been alluded to: The both ECU\'s (stock and PFC) do AIT and coolant temp correction, so should not underfuel in cooler weather.
The stock ECU does also retard ignition if it detects knock, but the knock sensor itself is notoriously crap, so rely on that at your peril!