Hi Guys,
Does anyone know if the FD has knock retard capability on the standard ECU (or for that matter, the APC ecu)?
Also, i coming from a piston engined car where 0 degrees of knock retard is preferable, but i seem to recall reading that FD cars always seem to read some level of knock at high boost levels?
Cheers, Paul.
i dont think there is knock retard..most modern ecus have timing retard when knock is sensed and also adds fuel but apexi doesnt have knock retard u have to rely on the mapping
Quote from: rx7veilsidei dont think there is knock retard..most modern ecus have timing retard when knock is sensed and also adds fuel but apexi doesnt have knock retard u have to rely on the mapping
Wow... So if you put the wrong fuel in (i.e. too low octane - like 98 on a stock ecu), you risk damaging the engine? :(
Cheers, Paul.
simple fix to that - dont put the wrong fuel in! :Giggle (or remap for 95ron fuel and then you can do no worse!)
All engines will expearience some degree of knock
Quote from: Ricco_04simple fix to that - dont put the wrong fuel in! :Giggle (or remap for 95ron fuel and then you can do no worse!)
Well, if you\'re running a stock ECU (on an imported car) you can\'t help but put the wrong fuel in, since there is no 100 octane fuel in the UK :2eek
QuoteAll engines will expearience some degree of knock
Well, the idea with a turbo car usually (i\'ve no experience with rotory engines) is to map it so that there is no knock whatsoever even at high boost. Obviously knock is pretty bad for the engine so any mapper would be remiss if they didn\'t attend to it? :3Confused
Cheers, Paul.
As one of the 1st and most important mods to do is a remappable ECU then you can have a choice. 101 ron fuel has never existed in the UK so this is not a problem that has just come about.
Most people want extra performance out of a remap and all of their money spent on mods which means pushing it further to the edge. I have always been lead to belive that you will always get some form of pre-ignition but the severity (sp?) of which will be different.
People who post up here asking \'is x amount of knock ok\' are met with the usuall reply of your safe up to x and in danger above if you go above this - not you should be zero at all times.
Quote from: Ricco_04People who post up here asking \'is x amount of knock ok\' are met with the usuall reply of your safe up to x and in danger above if you go above this - not you should be zero at all times.
Yes, indeed - this is the reason for this thread :Thumbs-up I was confused because, on a piston engine, you want 0 degrees of knock at all times. Yet i have read similar things as you on this forum and fduk... :confused:
Cheers, Paul.
I think (and I use the word think very strongly! :King ) that id depends on what internals you have. For example on a piston engine : arp bolts, forge pistons, sleaved block etc and then these stronger components can withstand more force too.
Think we need a exp tuner to help us here! :D
I thought piston engines advanced the ignition as much as they could, then when the knock sensor identies knock starting to happen, the ignition is retard a tad, this is then repeated so as to be effictively running as much timing advance as possible. Therefore piston engines do get knock.
Or am i wrong?
Quote from: nikpI thought piston engines advanced the ignition as much as they could, then when the knock sensor identies knock starting to happen, the ignition is retard a tad, this is then repeated so as to be effictively running as much timing advance as possible. Therefore piston engines do get knock.
Or am i wrong?
Well, the mapper will write the map with as advanced timing as he can
before the engine starts knocking*. Then after the mapping is complete, when driving around and whatnot, if the ECU detects any knock from the sensor**, it will retard the timing until there is none.
Cheers, Paul.
*) Actually, you want to advance the timing for best power output, which might not be just below the knock threshold.
**) Knock after mapping could be caused by the wrong fuel being used, or really hot air intake temperatures etc.
on piston cars they can withstand knock slightly more but most ecus will retard the ingintion and add more fuel as soon as unsafe knock is detected..u do have to be more carefull with rotarys as the tips can pop
AFAIK The Apexi PFC can only alert the driver of knock and is not able to retard ignition further - is this so?
the apexi does not have ign retard as auto ign is set at mapping stage
Stock ecu will retard timing when knock is detected.
Apexi ecu has the ability to retard timing based on preset condition, i.e certain intake temps, water temps etc, but not active retard depending on knock level. I don\'t know how the knock level works on other cars but the fd has a pretty sensitive mic that pics up noise that has nothing to do with engine knock. So you may have a knock reading of 40 or so and you are no where near detonation. So the knock sensor readings has to be taken with a pinch of salt sometimes. Stock ecu on stock cars that were run on 100octane jap fuel, run perfectly fine on 98 octane here. Your only concern is if the car is modded, if so ideally you want a standalone ecu that has been mapped properly over here.
Quote from: rotaryimports.comStock ecu will retard timing when knock is detected.
Apexi ecu has the ability to retard timing based on preset condition, i.e certain intake temps, water temps etc, but not active retard depending on knock level. I don\'t know how the knock level works on other cars but the fd has a pretty sensitive mic that pics up noise that has nothing to do with engine knock. So you may have a knock reading of 40 or so and you are no where near detonation. So the knock sensor readings has to be taken with a pinch of salt sometimes. Stock ecu on stock cars that were run on 100octane jap fuel, run perfectly fine on 98 octane here. Your only concern is if the car is modded, if so ideally you want a standalone ecu that has been mapped properly over here.
Thanks Brian, thats helpfull stuff!
Btw, \'normal\' cars have the same setup with a piezoelectric microphone stuck on the engine which listens for the sound of knock, but can sometimes be fooled by other noises too! :rolleyes:
I\'m going to look at a rx7 over the weekend which has a full decat exhaust running a stock ECU (i think) - should i be worried?
Cheers, Paul.
Generally speaking, most people on here would say to get a re-mappable ECU asap with a full de-cat and Apexi PFC being the weapon of choice at the mo.
Quote from: vxerThanks Brian, thats helpfull stuff!
Btw, \'normal\' cars have the same setup with a piezoelectric microphone stuck on the engine which listens for the sound of knock, but can sometimes be fooled by other noises too! :rolleyes:
I\'m going to look at a rx7 over the weekend which has a full decat exhaust running a stock ECU (i think) - should i be worried?
Cheers, Paul.
If the car is sound and your happy with it, buy it but don\'t give it wot until you get a standalone ecu fitted and mapped.
Is there a ECU on the level of quality and price with the APC which does have active knock retard?
I\'m wary of not having that feature... :eek
Those with the PFC, do you get it mapped on 95 or 98 octane?
Cheers, Paul.
I will get mine mapped for 98RON. My car will take 95RON being UK but as I always use the good stuff then I may as well take the advantages of it too :mmmm
Quote from: Ricco_04I will get mine mapped for 98RON. My car will take 95RON being UK but as I always use the good stuff then I may as well take the advantages of it too :mmmm
I was just thinking if theres no knock retard on the PFC and you get it mapped for 98, what happens if you are unable to find 98 one day when you need to fill up? You\'d have to be very careful otherwise you risk frying the engine! :2eek
Ta, Paul.
As long as you try to lay off the boost then you should be ok. You could always keep a bottle of booster juce behind the seat should this happen.
Quote from: Ricco_04As long as you try to lay off the boost then you should be ok. You could always keep a bottle of booster juce behind the seat should this happen.
If you got it mapped for 95 would it be able to adjust for the better if you put 98 in? I\'m guessing not...
Ta, Paul.
map to 98 and keep one bottle of booster for emergency..off boost will be no problem will lower octane
You will probably find that the tuner won\'t tune it too lean. They will always have a safety limit where you to get a bad batch of fuel (even with 98 ron) and the knock reading is higher it won\'t kill the engine as easily.
Shaun
You\'ll probably have broken an apex seal before your ecu retards the ignition :P
i ran my import type R (with induction & exhaust mods) for 2 years on the std ECU and i must admit the i used 95 and 98 octane fuel.
I never abused the car (except a regular once a week WOT).
Maybe i have been lucky (touch wood) my engine is still in one piece and compression is still very high.
i fitted an apexi PFC, ran it on th base map and found it was running nice and rich (popping on overrun and off throttle) then had it mapped (by one of the reputabel companys) and i\'ve noticed my knock levels are alot higher now and when i have gone WOT my heat light flashes with occasional fuel cut (as it feels like it bogs down), so i\'m resetting to the base map cause i\'m worried about it going pop.
I have been lucky....................alot of others havn\'t.........be careful
Quote from: andyrosei\'ve noticed my knock levels are alot higher now and when i have gone WOT my heat light flashes with occasional fuel cut
The \'knock\' level on the commander and heat light goin I wouldnt have necessarily said was a big deal (I get huge readings and lots of flashing flogging it round the nurburgring - but theres no audible detonation and never is on the numerous times te car is on the dyno; besides it wouldve **** it self long ago if the readings were \'proper\') BUT - theres no reason that you should be hitting any kind of cut...
Speak to whomever mapped it dude, and get it back there to get checked out. I wouldnt necessarily reset it, unless you can save the map first with datalogit (which I assume u dont own). Just use gentle throttle esp around peak torque in th emean time :(
cheers for the info 20B boy
my mapper did ask what i wanted it set up for. i told him everthing except going pop. it was mapped (injectors maxing out @ top end) so boost was turned down to suit but even then my mapper said \'its ok for occassional bursts but nothing too prolonged\'.
on the drive home (3hr trip) it was ok in short burts but now i can\'t even do that without it \'bogging down\'.
Your right i don\'t own a datalogit and as i\'m in the middle of the \'fens\' i\'m kinda stuck with regard to dyno/mappers so reset to base it will be (until i buy an uprated pump & injectors then its going to be mapped again)
don\'t worry i always drive with gentle throttle (girls blouse me)
Quote from: andyrose...was running nice and rich (popping on overrun and off throttle)
I\'m gonna pull you up on this (i\'ve heard a couple of other ppl say that as well) :):
On the overrun unused fuel is dumped into the exhaust which causes the pop. Its nothing to do with you running rich or lean, it simply that the engine doesn\'t need to burn the fuel because you\'ve lifted off, so it goes into the exhaust.
Can an expert confirm..? :confused:
Cheers, Paul.
it does make a difference whether car is running rich or lean..a properly mapped car not really pop on overun as amount of unused fuel is small..but a car that is running rich on lift off will have more fuel left to throw out the exhaust which will ignite on the way..
Quote from: andyrosemy mapper did ask what i wanted it set up for. i told him everthing except going pop. it was mapped (injectors maxing out @ top end) so boost was turned down to suit but even then my mapper said \'its ok for occassional bursts but nothing too prolonged\'.
on the drive home (3hr trip) it was ok in short burts but now i can\'t even do that without it \'bogging down\'.
That doesn\'t sound great! Max (re:worx) generally maps the car to be very safe under normal conditions so under extremes there\'s plenty of safety in place. I wouldn\'t expect a decent tuner to map that close to the edge and certainly not maxing out the injectors - there\'s no headroom left and that\'s asking for trouble.
Bogging down might be a problem with the plugs being fouled or spark not being strong enough under peak boost. Change the plugs and leads as a first port of call.
Iain
You could buy a J & S knock sensor if you are that worried about knock levels.
Norris do a new ECU which they swear by (I think its AED or something, not to sure) was contemplating getting one when my Apexi PFC died but wasn\'t sure if many rotary tuners would have the software or confidence to map it.
Costs £1000 and has the following features built in as standard:
Traction Control
Anit Lag
Launch Control
Knock retard
and a few others too.
Any tuners / vendors thoughts on this would be cool. Apparently they have been so impressed by it that they use to swear by Apexi but now on their drag car and high powered cars they say this new ECU is the way forward!!
QuoteYou could buy a J & S knock sensor if you are that worried about knock levels.
The standard car has a knock sensor already, its just that the apexi doesn\'t retard based on the readings...
QuoteNorris do a new ECU which they swear by (I think its AED or something, not to sure) was contemplating getting one when my Apexi PFC died but wasn\'t sure if many rotary tuners would have the software or confidence to map it.
Sounds interesting, but £1000 is a little on the steep side...
Ta, Paul.
Quote from: dreNorris do a new ECU which they swear by (I think its AED or something, not to sure) was contemplating getting one when my Apexi PFC died but wasn\'t sure if many rotary tuners would have the software or confidence to map it.
Very much doubt it has all the correct controls to manage the rotary though...
i am dubious about the knock sensor and its readings..on newly rebuilt engine i have had spikes of 80-90 at idle and higher on lift off.i have ported engine and external wastegate and fueling system is totally uprated and running water injection.on wot i get low readings in the 20s but as stated on lift off and even revving when stationary some silly readings.the wire to the sensor is very thin and subject to 10yrs worth extreme heat.quite poss when dealing with such small voltages for problem to occur..on a impreza i had a knocklink
and on rolling road no reading but tuner could hear the det.but those ecus have a retard facility and are very good.i am by no means an expert but if the mapper cant detect knock with datalog then its unlikely u have any.no reputable mapper will map to the point of det and then pull back by anything less than a safe margin.
thatsaid mine went pop due badly flowing secondary and hole in vac pipe feeding fuel pressure regulator.even then that was after 5 hard runs at high speed
You gotta remember that the knock sensor is just a micropohne - it could be picking up all sorts off sounds that it wasn\'t designed to expect.
I ran my PFC on standard car and was getting silly readings - Like 148 when I lifted off the throttle - which would have ment bye bye engine if it was a true reading. Had the sensor checked out only to be told out it was fine.
Kinda leaving me stood there thinking......well can\'t you fix what other noises it\'s picking up so I can have a proper reading! :3Confused I\'m not a fan of turning the reading off cause it picks up other noises. I have the facility so I want to use it! :Grrr :D