FB Tuning

iTrader: (30)

Not wanting to disagree with you Dunc, but shouldn't you be mapping all parameters to where the engine is happiest (not the driver) and performing at it's best.

Obviously i understand that it's always a case of prioritising and balancing Power, Reliability and Economy for the application in hand.

Many years ago, i had a remap done by a well known tuner (on here)
My girlfriend drove the car during the remap on the road. - When i drove the car home from the mapping session and gave it a bit of stick, it proceeded to det it's b0ll0cks off - I phoned the tuner, only to be told that maybe i should have driven it for the remap! WTF! - I ended up buying a datalogit and sorting the problem out myself
It wasn't Dunc BTW!

dynamix

iTrader: (3)

Point taken Rich but I was talking the other way around where the driver has a distinct delight at bouncing it off the limiter (mainly those that ride bike where they are used to high revs ).

It would also be where they take it on track a lot or tow or whatever - these would mean a slightly different map IMO.

FB Tuning

iTrader: (30)

Ahhh - Understood - Isn't the limiter there for a reason?

Back on topic.....

apalmer

iTrader: (8)

I should have used that one earlier (MBT) yes, its fact though that MBT can only really be found using a torque measurement, unless your just plain lucky, or your engine starts to det and you pull back. By virtue of this (this goes someway to answer Zens post too) unless you are able to view the exact moment that torque increase enters a null increasing state or starts to trough, you cannot see the point at which to stop increasing ignition and back off. Truth be told no-one would run absolute maximum timing anyway given that this wouldn't allow for compensations and adders so.. Road mapping has a place, certainly for transient conditions, things that certainly can't be replicated on the dyno, but isn't timing the name of the game here chaps?

Well it was for me the first time round, perhaps economy would be another completely different setup where ign advance really wasn't as vital.

As for whether an engine can be tuned without a knock detection, i've said before (not on this thread) that it would be foolish to do so (given that any non accounted for condition (weak voltage from battery, faulty injector, bad electrical contacts etc etc) but in theory, absolutely, you shouldn't be detonating when tuning ignition, if you are, your already damaging your engine! simple as that!

I appreciate also what JB said about not using the tractive effort feedback for higher load cells, in fact it would be pretty darn impossible to hold each site, especially since you'd probably never visit each one.

Horses for courses i suppose, not going to cross swords with guys who do it for a living, have many happy customers, and have found a system that works

ZEN Performance

And therein lies the problem...

You're assuming that you can always tune for MBT, like you can often do on many N/A engines. In reality if you tuned for example an EVO, then you would run into detonation LONG before hitting MBT, especially in the midrange at high boost. It really is that simple and I guess every EFI University graduate will just have to be shown these situations to make them believe there is life beyond MBT.

I would add that not every EFI University graduate remains so confined by the MBT method, and it's still a very important concept.

scoobiewrx555

Dumb question but in what context are you reffering to 'MBT'?? Minimum Best Timing, Minimum spark for Best Torque, or Maximum Brake Torque??

ZEN Performance

The standard notation: "Minimum timing for Best Torque"

scoobiewrx555

Ta

apalmer

iTrader: (8)

Yes Maximum Brake Torque.

I agree that a turbo charged engine likely to det far more easily than a NA engine, that said there would be other factors to consider which i would be monitoring with equal attention, egt's, coolant temp, charge temp, mixture ratios etc. I would therefore hopefully back my timing long before seeing the numbers idle, it's not always a numbers game agreed, and MBT chasing most certainly isn't the be all and end all of engine tuning.

An accelerometer is a clever tool for guestimation, but not for calculation. A peizo fitted spark plug would be a far more accurate way of measuring engine loads, chamber pressure calucaltions is the ultimate holy grail for measurement. Not sure the NGK sell these off the shelf though at $2000 piece.

EFI students not quite as blinkered as you'd have others believe!

-a

Andy.F

Ecutek Roaddyno does not use an accelerometer, it actually calculates the torque produced by monitoring the rate of increase in engine RPM whilst driving. If you know the cars weight, frontal area, drag coefficient, gear ratios and tyre size then it will take 'x' lbft of torque to accelerate at 'y' ms2 at any particular moment in time.

So a bit more than a guestimate and all done under real life conditions with a continually variable acceleration rate, as dictated by the torque produced.

I think people have different prioritys regards what the desired outcome of tuning is, bigger numbers on the dyno or a faster car ? They don't always go hand in hand.

I have raced cars (straight line stuff so no skill involved ) claiming over 100 dyno proven bhp more than my own, yet my car was faster.....why.... it was tuned during acceleration, to maximise acceleration, on the road, for the road ! (WRX, Spec C and type R)

Andy

john banks

Zen has said it, forget about MBT in the performance areas of the map on pump fuel with these engines.

Why use expensive cylinder pressure measurement for consumer aftermarket tuning? You can safely tune to the knock threshold without, and good closed loop knock control will safely keep it there for high specific outputs for longer than the economic life of most cars. I can see the academic interest value in calculating BMEP, but what is the point in working out the position of peak cylinder pressure when you can't decide a priori what exact position you're targeting? Has it been proven that its use can beat a car tuned to the knock limit? Do I care if I'm running 14 deg ATDC Pk cyl pressure or 16 deg? No I care about best acceleration whilst avoiding significant knock.

Even then, this is far removed from trying to find MBT on a chassis dyno on a high specific output port injection turbocharged engine in the performance areas of the map on pump petrol where it will run best with good knock control constantly retuning your timing using cheap microcontrollers with easy integer math, not even DSP, and sensors that are readily available on all modern cars. Done this way engines perform best and last well.

I would think again about your statements about knock/detonation. Is it an on/off phenomenon? Does it cause damage in all cases? Is it impossible to use a simple knock sensor to actively keep the engine around the knock threshold to maximise output whilst not doing any damage? Can you show any evidence of dangerous cylinder pressure spikes on an engine running a traditional knock sensor with closed loop control? Can you demonstrate shortened engine life from doing so? I would argue that the answer to all of these (unless I've worded one wrong ) is no.

The only race where I ever beat (or could ever hope to beat) Andy Forrest was when he was driving an Evo that had been dyno tuned by someone else, weighed similar to my Impreza that I had tuned on the road for best acceleration and the Evo had just done 80 BHP more on the dyno. Taken to the airfield I think 8 car lengths was my advantage and it was repeated when drivers were swapped around. I think few people will ever have the privilege of seeing Andy Forrest in their mirrors for long, and it is very unlikely indeed if he had tuned it. The dyno had produced a dyno queen that didn't deliver on tarmac. The road tune had produced something that maximised its potential.

ZEN Performance

You can see detonation in AFR traces depending on how you get them, but you're claiming you can accurate tune/map the engine for best power and not blow the engine up without taking into account detonation. Specific intake temperatures, or AFRs, or coolant temps are not a not accurate ways of determining how close to MBT or engine threatening detonation you are.

I do agree that you don't need to reach the point of detonation to obtain a happy figure for ignition timing for some loads. But preaching a method of tuning that leaves detecting detonation as a failsafe will lead to a great number of blown engines by those that take such advise literally and without using experience.

The blinkers may be lifted but they haven't yet been cast off!

dynamix

iTrader: (3)

Agreed ... unless running rather special fuel.

apalmer

iTrader: (8)

Your reputations precede you all, and i simply don't have enough first hand experience to reel off scenarios to clearly and objectively solidy my points. Only to say that this is what i have been taught, and to some degree, discovered whilst tuning a number of cars that i have owned on different systems.

I therefore shan't wave my text book in the air anymore, damn those paperbased tuners ay? LOL

What was this thread about again? Who was that plasticine character on the tony hart show.

P20SPD

iTrader: (1)

As with most professions, theory doesn't always deal with real world scenarios.

Tidgy

i think it started off with openmap vs ecutek,,,, pmsl.

tbh its become rather clear that theres a few points that can be made

1. software makes no difference, it's the mapper that realy important.
2. open source means that all folks, experianced or not, can adjust the map settings on a car
3. some, not all, open source software has been ripped off
4. open source mappers can, again not always, have little to no support behind the scenes to aid with issues or if things go wrong.
5. Ecutek require specific criterior to be nmet to be allowed the software and license.



did i miss anything? lol

bigarf

iTrader: (67)

morf.

Andy.F

Hmmm, I remember a time with a 2.0sti5 vs a 2.5UK although I did have a fat farmer with me ! (hope he's not still on here )
That was Ecutek taking the lead 8 - 9 yrs ago

Not always, I've witnessed det on 128 octane fuel in a scoob, so has Paul

dynamix

iTrader: (3)

had you already gone past MBT though ?

King Eric

An interesting debate this is turning into, one of the better threads on SN for a while

I've booked my car in with Duncan in Feb. Looking forward to seeing what he can get out of her

scoobiewrx555

Was that running neat Toluene?

john banks

Both 20G, that was an interesting one, you were boost braking too according to the farmer, the 2.0 did well with the rev limit and better matched gearing though.

That day with the GT35R on your 2.3 running 2 bar in the rain will last in my memory for some time though

Alan Jeffery

Andy, it pains me to see you talking tosh. If you record a gain in engine power by whatever means, either shown on the dyno, or via a measured distance/time it'll be faster.
And another thing, please define "real world" as I'm wondering which one you live in...

john banks

Why does the wastegate duty cycle for a given boost at a given engine speed and gear vary between dyno and road?

Why does the knock threshold vary between dyno and road?

Why does the airflow measurement and AFR vary between dyno and road?

Why do the charge temperatures (and virtually every other temperature you can measure) vary between dyno and road?

Since these variations are commonly seen, how can you be sure that the combination of fuel, timing and boost in that cell that gives you best power or torque on your dyno is going to give you best acceleration in different conditions on the road?

Apart from convenience, safety and MBT tuning in the non-knock limited areas, why would I want to make my engine give the best performance figures on a dyno when it is such an inaccurate simulation? Why not use it to get 90% of it done for safety and convenience and then finish it properly on the road?

Alan Jeffery

We use the dyno for safety, convenience, and excellent feedback for 90% of the time when tuning cars.
We don't only tune Subarus!
We then check them out on the road, and make any corrections as necessary. Of course .. I thought that was a given.
As I've said before until I'm blue, if you don't own a dyno, you don't have the options we have. We can CHOOSE to use it or not, it isn't cast in stone with us, I've only a passing interest in how other people do what they do.

dynamix

iTrader: (3)

Or, if you don't own a dyno you can rent someone's to tune on that

Andy.F

Do you then re-dyno the car to see what numbers it gives after all the changes

How many times have we heard of the car that has run perfectly on the road but dets on the rollers, should you retune it for the rollers ?

I live in the same real world as JB where we tune on the road for the road, yet have an abundance of rolling roads to choose from should the customer prefer that option

Andy.F

No, I think it was VP or Sunoco Nos+ race fuel but it blew out the window the theory that super high octane fuel doesn't det !

Ohhhhh yes ! lol

john banks

If it flies, floats or *****, hire it

Sorry, a dyno doesn't do any of those things, best find £80k

dynamix

iTrader: (3)

It is a big investment in a tuning tool and it does have its place and definite advantages in some ways.

Lots of them around the country as Andy said so if someone has a track only car or they prefer that option, it is easy to arrange.