fiestaturbo.com

[FezzR]

As per Jim topic

[stu@mdevelopments]

Ok folks,
Why do we sometimes run a peak boost? A question im asked quite a lot in one form or another, often masquerading as "If youve set it to peak at 22 and fall off, why cant it stay at 20?"

Well, thats depends on why you are asking in many ways.
If your asking, why actually have a peak in the midrange at all, well thats simple, its because we are looking for big torque to propel us up the road and a big spike up the ass can achieve this nicely. End of story.

If however your asking why if we can run say, 22peak and 16 held, why cant we run 22 all the time if the injectors are big enough to do it for a spike, well thats where it becomes complex.

The amount of fuel we can inject is heavily reliant on one main factor, and that factor is the "Induction Stroke Time Base" This, in more english terms is simply the amount of time we have to inject the fuel whilst the inlet valve is actually OPEN. So imagine we have, on a theoretical engine, an intake valve opening time of 16MS at 7000rpm. You are revlimited to 7100, so we dont need to concern ourselves with higher rpm. OK? This 16MS is also subject to camshaft duration normally, a longer cam will give a longer opening time. So, given this info, we also know our peak power requirement is going to be 300bhp. Our chosen fuel pressure for the system, based on all requirements (See recent essay. lol) is 3.5bar. So we need to now select an injector, that can supply enough fuel in 16MS for its share of 300bhp (4 cylinders = 75bhp each) with a pressure of 3.5bar but pushing them no harder than 70% for injector reliability.

So cool, weve chosen our injector, the engine is dynod or mapped and weve got total success, 300bhp at 7000rpm, the fuel system and the engine is totally within tolerances. Game Over, home in time for tea.
Or is it..

Our intake valve thats only open for 16ms at 7000rpm is in fact open for 32MS at 3500rpm isnt it? (7000/2 so 16x2)) The same injector that can only sustain the fuel for 2bar of boost and 300bhp at 7000rpm is PERFECTLY capable of supplying the fuel for a "Theoretical" 3bar+ of boost at 3500rpm as the fuel has twice as long to get into the engine so we can hold the injector open for twice as long if need be or possible.

In reality, we would only open the injector in this theoretical engine spec for 25% longer to keep within the absolute max constraints of 95% injector duty cycle and even then, 95% is only for peaks such as described and NEVER used at high rpm. Butr im sure your now getting the picture as to why engines CAN run a nice big peak, but its not safe to hold the boost that high.

Always remember of course that BHP almost NEVER breaks things, its always the torque, and a big spike is a gearbox killer at the very least.

Hope youve found that interesting.

[Excursion]

Awesome!

[FezzR]

fankoo
most interesting

seems like a bit of catch 22 tho really, do you spec an engine for your desired spike or for you peak rpm power or a bit of both.

is fuel pressure essay on PF?

[Andy.B]

Very interesting read, i always knew torque killed boxes, but didnt realise the boost spike can kill em aswell.

So is it possible to map (on say std FRST management) a car without a boost spike, thust not causing the shock increace on torque???

May seem a stupid question but id like to know the answer.

Andy

[heeman10]

Cool little scribble Stu, one of those common sensical things we should all know but never really think about!!

Question Number 2

Injector duty cycle. How much effect, in the real world (ie not racing where you'd systematically replace injectors) does duty cycle have on an injector's life? Speaking to Karl a while ago, he said he's happy mapping to 100%. Would you suggest maybe he would only use that for a big spike, or run the injectors right up at that rate for long durations? Or do you think it's more likely he'd only do such a thing on a car that would have its injectors replaced on a frequent and regular basis? I'm not asking you to speak against his methods in a bitchy way, I'm sure you both do things differently, so feel free to be frank if you don't mind!

[FezzR]

my opinion James is that i would never go to 100% of any engine(speaking the whole package) components capabilities, UNLESS it was competition day and you need that extra power to win.
otherwise its simply not worth the risk imo.

in the "real world" i would be even less inclined to go to 100% injector duty because there are so many unpredictable or unknown factors that change from day to day or hour to hour bases; and all you have to rely on is the ecu getting the adaptions right (assuming its closed loop system)

[sailorbob]

I find it incredulous that someone would ever map for 100% injector dutycycle, too many things to go wrong, just off the top of my head:

Injectors and/or drivers overheating.
Variances in fuel temperature causing a different mass of fuel to be injected.
Variances in inlet temp and/or coolant temp needing fuel adjustments that you may not have allowed for their full cumulative effect.
Wear in components like the fuel pump or injectors that will cause the adaptive learning to increase dutycycle.
Needing extra dutycycle to compensate for low voltage.

I’m sure there are many more things.

[heeman10]

Precisely, I think 70-80% is a good top end to use them to, perhaps I've remembered it differently and it was 90%...it's possible, it was a hot day! It seemed like a high value anyway, I just wondered if that was a common figure for competition cars

[stu@mdevelopments]

fankoo
most interesting

seems like a bit of catch 22 tho really, do you spec an engine for your desired spike or for you peak rpm power or a bit of both.

is fuel pressure essay on PF?

It depends what its for.
If its a road engine its specced as an overall package to give the best "Compromise" available with maximum tractability and reliability.

A race engine is specced almost purely against desired powerband and a Rally engine with an intake restrictor is biased towards a spike of commonly 3.5bar boost. This is due to teh simple fact these engines cannot consume more than around 30lbs of air due to the inlet restriction and are thus in single boost figures at high rpm.

The fuel pressure comments are in a topic about a 165 superchip needing a setup or something i recall. Im sure someone will find it if they search my posts here on FT.

So is it possible to map (on say std FRST management) a car without a boost spike, thust not causing the shock increace on torque???

Yes, absolutely, we can essentially do as we like given the correct parts and of course the funding, but one thing to beware of is a turbocharger that is undersized for the job will usually drop boost at high rpm making the curve "Appear" like its spiking, when in fact, the engine is consuming more air than the turbo can supply. Horses for courses.

Injector duty cycle. How much effect, in the real world (ie not racing where you'd systematically replace injectors) does duty cycle have on an injector's life?

As ive said on many a topic, i dont like to indulge in "He said she said" and avoid "Tuner wars" like the plague. Its made much harder by the fact Karl is a very good personal friend of mine.

However, you have asked, and thus i will assure you that i dont agree with running an injector at 100% for any length of time at all, and i suspect you missunderstood what Karl was saying as im sure he wont either. Siemens, Rochester and Bosch all recommend 85% max to their customers and i am not in a position to argue with them either. 2 of your members here have given perfect reasons why not, so no need for me to reitterate.

[MAD_Adamski]

way over my head

[sailorbob]

Stu, in your post you referred to "Induction Stroke Time Base" and clarified this the amount of time you have to inject the fuel whilst the inlet valve is actually open. Is this for certain types of ecu as it doesn't appear to be the case for the more modern Ford ecu's that I've been looking at the code for, the end of the injector pulsewidth is timed to finish before the inlet valve opens. The reasons being that injecting neat fuel into the cylinder causes poor burning and hence poor emissions and the increased likelihood of bore wash. The actual timing of the injector pulsewidth is dependant on quite a few factors and a longer duration cam would reduce the available time for injection. (BTW quite a few A9L ecu tuners fire their injectors earlier to increase the amount of time the fuel is in the port to increase it’s heat soak).

PS I think your technical explanations are great and hopefully make clear why people should use the likes of yourself for tuning

[FezzR]

Stu, in your post you referred to "Induction Stroke Time Base" and clarified this the amount of time you have to inject the fuel whilst the inlet valve is actually open. Is this for certain types of ecu as it doesn't appear to be the case for the more modern Ford ecu's that I've been looking at the code for, the end of the injector pulsewidth is timed to finish before the inlet valve opens. The reasons being that injecting neat fuel into the cylinder causes poor burning and hence poor emissions and the increased likelihood of bore wash. The actual timing of the injector pulsewidth is dependant on quite a few factors and a longer duration cam would reduce the available time for injection. (BTW quite a few A9L ecu tuners fire their injectors earlier to increase the amount of time the fuel is in the port to increase it’s heat soak).

PS I think your technical explanations are great and hopefully make clear why people should use the likes of yourself for tuning

im thinking the timing would vary depending on air flow velocity/distance between injector and valve and a few other factor effected by and effecting them, mainly i would have thought RPM. At high RPM you are going to need to inject earlier (in terms of valve position) to give the fuel chance to get the vavle by the time its opens as it will obiously close soon.

i would think on the side of emissions it depends how long before the valve is that injection occurs

[sailorbob]

In the more recent codes I’ve looked at (eg Mondeo, Cosworth as opposed to Fiesta Turbo) I have identified two tables that affect injector timing, I’ve labelled these;

INJECTOR_TIMING_VS_ECT_TABLE - a 2d table of timing vs ect
INJECTOR_TIMING_TABLE – a 3d table of timing vs rpm and load

There are also adjustments of the timing when in neutral or drive for vehicles with auto boxes. The changes in timing are also subject to a rolling average calculation to avoid too great a step in change.

[FezzR]

ect - engine coolant temp?

[sailorbob]

ect - engine coolant temp?

Yep

[stu@mdevelopments]

Stu, in your post you referred to "Induction Stroke Time Base" and clarified this the amount of time you have to inject the fuel whilst the inlet valve is actually open. Is this for certain types of ecu as it doesn't appear to be the case for the more modern Ford ecu's that I've been looking at the code for, the end of the injector pulsewidth is timed to finish before the inlet valve opens. The reasons being that injecting neat fuel into the cylinder causes poor burning and hence poor emissions and the increased likelihood of bore wash. The actual timing of the injector pulsewidth is dependant on quite a few factors and a longer duration cam would reduce the available time for injection. (BTW quite a few A9L ecu tuners fire their injectors earlier to increase the amount of time the fuel is in the port to increase it’s heat soak).

PS I think your technical explanations are great and hopefully make clear why people should use the likes of yourself for tuning

Afternoon Bob, long time no speak pal
Whilst what you are saying is perfectly feasible for a fully sequential system, it does have its flaws, one of these being airspeed issues. Fuel puddling on valves is not commonly used in a modern system fitted to a "turbocharged" performance car as it doesnt lead to better atomisation in most cases at all, it is actually far worse. What do you think would give most bore wash? An injection of atomised fuel into a moving airstream or a lump of puddled fuel dropped into a cylinder as a valve opened?
The best place to atomise fuel is into moving, swirling air. The reason the systems code LOOKS like your injecting onto a closed valve in many cases is simply due to the finite response time of the injector itself. If the respond and open time (Time from ecu saying NOW, to it actually happening) is 2ms, then we must start at LEAST 2 milliseconds before the valve lifts. Then you add on the fuel travel time, and time to establish a fuel pattern, and you end up with a table that looks much like it will be firing on a closed valve when indeed the fuel will be arriving at the correct time when it is running dynamically. Another thing to bear in mind is that some systems place the fuel bloody miles away from the valve, these systems MUST inject the fuel before the valve opens or by the time it reaches the valve it will have closed again. SPFI is a common example of this with its single injector placed high up on the engines manifilds, literally FEET away from the valves. Some systems even fire twice, on the exhaust stroke and the intake stroke just to complicate matters somewhat further.. lol As far as the actual topic goes though, we are now starting to overcomplicate a simple system explanation into something that Joe Bloggs doesnt want to have to comprehend. The point i was making is the spike is available whilst we have plenty of time to process the air and add fuel for it compared to how long we have at 7Krpm and that point in my opinion has been explained just fine.

All this is largely by the by on a Fiesta Turbo system as its is so poor it has no way of identifying phase correctly period.

The problem with all these explanations on forums is someone always wants to look slightly too deep and complicate what was a simple essay to educate people in various methods that may help them to understand a little about what goes on in these systems, even when the method is not directly related to the car they own.. lol No offence intended of course, i am usually the first one to do that as that is how we learn new things.

[sailorbob]

The problem with all these explanations on forums is someone always wants to look slightly too deep

Guilty, as charged, and yes, if you don't ask you don't learn! I definitely appreciate the technical input from you to the forums, it helps confirm (or disprove) the theoretical stuff we read

[stu@mdevelopments]

Hows your dissasembly of COSY coming along pal, are you winning??

If you ever discover why it often spits its dummy out and tells us we need to fix the "Innoperative EGR valve" id love to know.


They dont of course actually have one, making it a Bic™ to fix

[FezzR]

The problem with all these explanations on forums is someone always wants to look slightly too deep

Guilty, as charged, and yes, if you don't ask you don't learn! I definitely appreciate the technical input from you to the forums, it helps confirm (or disprove) the theoretical stuff we read

whohoo its not such a lonely club. my opinion is tho the answer is there at the top for joe bloggs if they get bored or lost the stop reading; if they want to learn they keep reading over and over till they understand, so no reason to stop really

and just to prove the point no you've mentioned zetec "phase" im gonna ask about that too unless you feel its worthy of an entirely different thread? ( ill leave it till tomorrow before i ask though as im sure your busy unlike moe )

[sailorbob]

Hi Stu,

Getting there, slowly but surely. Just need the hardware side of things to catch up with my deciphering. Made a fair bit of advancement, and corrections, since we last spoke about this. I've come to the conclusion the ST Escort code is a bit of a bodge with the turbocharger side of things ‘tacked onto’ normally aspirated code. It also has some eec-v subroutines in it.

Regarding the EGR error, does it throw out this error all the time? I found this set of parameters recently

THERMACTOR_SWITCH, EGR and DPF_EGR present, HS_FAN and LS_FAN not present

as a word sized switch in a block of data just before the main hardware set-up routine that would explain why you get it. I’m 99.9% sure this is right because Mondeo DEWY/DEEP code is very similar, I just need the hardware to prove it’s correct by deselecting these flags in the Mondeo code and running a chip on one. Deselecting these flags in the COSY code should stop the phantom error.

Seems to be a couple of other bugs in the code too, I really need to get my hands on another ST Escort code such as ANTI/CARD/QUIK (is there a fifth TCA5 ?) to see if Ford fixed them.

Cheers.

[heeman10]

All good reading Stu, feel free to go off on tangents and explain more

My university final year project this year will be to research and compare engine management systems. I'll be running a 1.6 Fiesta Zetec S engine up on our dyno with the standard ECU, a Megasquirt and a MoTeC ECU and comparing the three (and basically spending as many hours on it in the lab as I can to learn as much as possible). So all the info I learn between now and then (late November-mid December) is handy. Shame we don't have a turbo'd engine here, but there's plenty to learn from a weedy 1.6

[FezzR]

All good reading Stu, feel free to go off on tangents and explain more

My university final year project this year will be to research and compare engine management systems. I'll be running a 1.6 Fiesta Zetec S engine up on our dyno with the standard ECU, a Megasquirt and a MoTeC ECU and comparing the three (and basically spending as many hours on it in the lab as I can to learn as much as possible). So all the info I learn between now and then (late November-mid December) is handy. Shame we don't have a turbo'd engine here, but there's plenty to learn from a weedy 1.6

are they supplying the ECUs if so that sounds wicked great project

[heeman10]

Yep, we already have a MoTeC (presuming M2 or M3) and a mostly-built Megasquirt, plus the original ECU with the 1.6

[FezzR]

Yep, we already have a MoTeC (presuming M2 or M3) and a mostly-built Megasquirt, plus the original ECU with the 1.6

cool beans sounds like great fun you could really learn alot from something like that. would be even better if they let you create your own chip for the standard ecu too to give a true comparison of how the engine / ECU responds to your input changes

[stu@mdevelopments]

Hi Stu,

Getting there, slowly but surely. Just need the hardware side of things to catch up with my deciphering. Made a fair bit of advancement, and corrections, since we last spoke about this. I've come to the conclusion the ST Escort code is a bit of a bodge with the turbocharger side of things ‘tacked onto’ normally aspirated code. It also has some eec-v subroutines in it.

Regarding the EGR error, does it throw out this error all the time? I found this set of parameters recently

THERMACTOR_SWITCH, EGR and DPF_EGR present, HS_FAN and LS_FAN not present

as a word sized switch in a block of data just before the main hardware set-up routine that would explain why you get it. I’m 99.9% sure this is right because Mondeo DEWY/DEEP code is very similar, I just need the hardware to prove it’s correct by deselecting these flags in the Mondeo code and running a chip on one. Deselecting these flags in the COSY code should stop the phantom error.

Seems to be a couple of other bugs in the code too, I really need to get my hands on another ST Escort code such as ANTI/CARD/QUIK (is there a fifth TCA5 ?) to see if Ford fixed them.

Cheers.

Excellent, sounds like that could be the issue for sure.
As you know, your deciphering work is on a totally different direction to mine where i find the maps i require 2 dimensionally and simply make the changes i require at that level, so technically you will deffo know more about that system than me, but whats always bugged me is how can it possibly be intermittent if its a software error? Seems odd to me.

As for the other tag codes, i do of course have them all if you want to trade some info, drop me a mail pal, always good talking to you.

[sailorbob]

Stu,

Is "Inoperative EGR valve" error 332? As this result is from KOER and continuous tests it does seem odd that it's intermittent. But then again the eec does strange things with error codes and clears them for various reasons e.g. if the “number of warm ups” counter associated with the error code >= 80 then the code is erased. Another thought is I wonder if Ford have left the A-D input on the 8061 electrically floating, it seems unlikely that they would make such an error but it could be an explanation and they do appear to have set the code to say EGR is present!

My programmer has gone back to the States today for repair, when it comes back I’ll be able to try switching off the EGR on a Mondeo and if that works I’ll let you know the address of the switch in the COSY code to do the same.

[stu@mdevelopments]

Stu,

Is "Inoperative EGR valve" error 332? As this result is from KOER and continuous tests it does seem odd that it's intermittent. But then again the eec does strange things with error codes and clears them for various reasons e.g. if the “number of warm ups” counter associated with the error code >= 80 then the code is erased. Another thought is I wonder if Ford have left the A-D input on the 8061 electrically floating, it seems unlikely that they would make such an error but it could be an explanation and they do appear to have set the code to say EGR is present!

My programmer has gone back to the States today for repair, when it comes back I’ll be able to try switching off the EGR on a Mondeo and if that works I’ll let you know the address of the switch in the COSY code to do the same.

Why dont we have a god smiley? :god:

Ahh.. here you are:

[FezzR]

Bob the ECU GURU

you got me into wanting to get me head round it again Bob i know its gonna end in a sore head