ecu retard function

[bnaellis]

Hi This is a question for all but more so directed at Glen.
As you know the stock ecu on a fd will retard the timing slightly when there is knocking. Well the power fc doe snot have this capability, I have heard from knightsport in Japan that when they tune power fc's the always retard the timing slighty to compensate for the pfc inability to do what the stock ecu would in the event of knocking. I just wondered what the guy's down under think of this ?? I don't know if the pfc is popular in Austrailia
I know motec is is this reatrd function available on the motec ecu's ?? or do the guy's in Austrailia retard timing slightly when tuning a rotary just in case of any knocking ??

rgds

Brian

[Fish]

Brian, good question. I have run various types of ECU's, but am looking at running the Motec on the 7.

When mapping an engine, you should use some form of DET can's. Basic form of DET cans are a pair of headphones (the sort you see builders using, with hose pipe going into the engine bay, then bolted to somewhere on the engine itself. The is a VERY crude way, but it works.

Sophisicated ways are to use an electronic microphone and proper stereo headphones. But I have found these give too much detail. Like you can hear the fuel flowing though the rails.

Anyway, back to the subject in hand.

You should never map to run on the limit of knock, DET whatever you want to call it.

Even when mapping an engine on a bench dyno, the mapper would always pull the ignition back a little. thats unless your mapping an engine for one event.

If you where to get a bad tank of fuel, you would be DETTING all over the place, and as you knowm rotaries dont like DET. Things like octane booster helps this, but is NOT a cure for it.

Motec does not retard the ignition. Not sure about the Haltech, and as you say Apexi PFC doesnt.

Best to always pull the ignition back some.

Dan

[bnaellis]

Cheers Dan,
I am about to get pfc, intercooler, downpipe and hiflow cat
and want to keep boost to 12 psi max, I don't expect to get detonation but as you said, one can get a bad tank of fuel or something. I don't suppose you know how much the stock ecu retards under detonation do you ?? If I am going to retard it what is the recommended amount in degree's ??
I guess this is quite important as the lower/leading spark plugs spark first and these are more important than the trailing. I guess there could be a danger of retarding a bit too much and lose power because the leading is sparking when there's not yet anything or hardly anything in combustion chamber to cause a proper explosion, bad fuel consumption and loads of unburnt fuel out the exhaust. I was a mechanic for 7 years now I can't remember much technical, just a tad embarassing.:)
Oh well thaks for info.

rgds

Brian

[Fish]

Why not look at having a colder plug in the leading hole? Like going for 9's both leading and trailing. But the only issue is the type of milage that you do. TOWN!

I think the leading plugs will need changing a lot sooner than 6k miles. I think Nigel does them every 3k due to this.

I would drop a couple of degrees off full throttle, and add some on the base landing zone of higher RPM's.

I think most ECU's that do knock retardation monitor the knock sensor and decrease the ignition using this reading.

I should have an additional knock sensor and guage in mine by next week.

Dan

[bnaellis]

I think I might have a look at changing the sparks plugs then.
I'm looking forward to the extra power when I get the bits fitted though. Off subject a bit do you still own your scoob ??
I beat one 4 times round clapham junction/ wandsworth one way system where we were the other week coming back from go karting. I beat him up around 70 mph we had to keep slowing down because of traffic. I was in front at the lights when we first started and each time I kept pulling away from him until we hit more traffic, then I'd take off again and the same thing he couldn't keep up. I got a leak in my inlet manifold gasket and had two passengers also, I thought that all scoobs were sub 5 seconds 0-60 are am I wrong ??
Eventually the guy pulled up at a set of lights really excited about my car, I think he might go out and buy one the way he was going on. I didn't tell him it was an auto as I didn't want to embarass him.

rgds

Brian

[Fish]

Brian, NEVER have fear in telling someone that they have just been done by a 2 pedal. :D

Playing with a scoob around town would be very close. Go into the country lanes and wave bye bye as he goes off in the distance.

I really should come and play one night in mine. Just for scientific perposes... ;)

Dan

[t2rew]

a freind of mine with a version 5 sti just melted a piston. apparently its common, you b carful fish

[Fish]

T2, been there done that. Picture attached.

This was running a held 1.6 bar of boost, using fully uprated internals, inc. Prodrive Group A conrods.

You always learn the hard way in life. :confused:

Dan

[t2rew]

woops

[Glenn Butcher]

Originally posted by BNA_ELLIS
SNIP...I guess this is quite important as the lower/leading spark plugs spark first and these are more important than the trailing. I guess there could be a danger of retarding a bit too much and lose power because the leading is sparking when there's not yet anything or hardly anything in combustion chamber to cause a proper explosion, bad fuel consumption and loads of unburnt fuel out the exhaust.UNSNIP

Hi Brian, sorry I have not replied on this one.

I don't actually know enough about the PFC to tell you what it does when it is knocking. I am hoping that it would retard the ignition for you.

It is a difficult area, if the engine runs retarded ignition there is the potential for it to run extremely hot, as fuel is burnt after the point it should be and ends up heating up the turbo more and more (potentially bust all your oil lines, and stuff the engine/turbo).

You have probably read the Spark Plug thread? http://www.mazdarotaryclub.com/forums/showthread.php?threadid=264&referrerid=1 may help you decide on the plugs.

If you are giving it a hard time all the time, colder plugs are ok.

[Fish]

The other issue is that most of the ECU's that do retard the ignition, do so AFTER it has detted! :(

So on a rotary, as you well know det is not allowed. Unless you are running 3mm tips.

Dan

[bnaellis]

Mmmmmm now I'm not sure if I still want to retard the igniton after all.:( sulk

brian

[Glenn Butcher]

Dan you are bang on...

...with all the sensors in the world, can still detonate - and a knock sensor will only be triggered when it is knocking/pinging/detonating - by that time it could be too late!

Even with MoTeC or better you can still blow an engine (look at the F1 engines from last year).

But the good thing is, is that you have more warning through whether or not it is running lean etc. through EGT (Exhaust Gas Temp) probes, Lambda, etc.. Also Fuel Pressure which is extremely important. i.e. if something goes wrong with the pump/lift pump a Fuel Pressure sensor alert can be triggered to a warning light from the MoTeC (or to the ADL Dash). Usually can stop a melt down :)

Trick is to get someone who really knows what they are doing with the tuning, so that it wont detonate in the first place!

Old story, if you spend the money with the right people in the first place - you will save money in the long run.

[bnaellis]

Tuning I will be happy with, Tim at rxmotors does all my work. I have the greatest confidence in him when it comes to doing anything on my cars. I am just trying I guess what 1000's of other have over the years try to work out how to safely squeeze more power from a rotary. It's a bit of a parodox in the sense we do so called reliability mods which in turn gives us more power which in turn gives us less engine life than if we left it alone in the first place, but I just can't help.:rolleyes:

Brian

[Fish]

Brian, each tuner has their fav. ECU.

The general consensus ifor safety mods is a vented bonnet, to let the heat escape.

Dan