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View Full Version : Boost controllers and factory map?



Dom B
01-05-2009, 10:55 AM
Do any of the boost controllers also plug into the original boost solenoid plug to read the signal from the ecu as a reference just in case there are any knock events that need boost reduction to save the engine after crap fuel for example.

The factory ecu maps the boost and ignition curves to avoid knock, sometimes raising the boost then lowering it then raising it again at various load and rpm points. in quite an intricate map that has had a lot of research money thrown at it.

Letting an aftermarket boost controller just maintain a boost level with no reference to this original map could be costly??

Any thoughts?:inquisiti

orionn2o
01-05-2009, 11:36 AM
I didn't think any of the standard boost controllers do this, however the engine will still retard the ignition after knock events which should be protection enough I would have thought?

Dom B
01-05-2009, 02:43 PM
Yeah i that would save things in most situations, but the reason for the map for the boost rather than just a linear pressure is to avoid those trouble knock areas from happening in the first place. In some ways if the knock is happening already then damage is being done already too. Prevention is better than cure and all that. It would be nice to be able to pay lip service to the original boost map work that mitsi did as well as being able to let it pull back the boost in emergencys.

Maybe what i need to do is to read the factory map with a sensor and then translate this into the same graph but just higher up on the boost scale. I know air is the most non linear substance ever lol but it may be a start.

Do any of the boost controllers have a knock sensor input to do their own boost retard??

Nutter_John
01-05-2009, 02:53 PM
Dom step back for 30 seconds and remember kiss is the secret to life

' Keep It Simple Stupid '

The wheel has been invented so why try and create it again

There are 1000's of cars out there using a boost controller and none of them will have knock control , infact I do not know of any main stream boost controller that includes the feature . Not saying it is not a good idea but the reality is what value does it add when your normal ecu will pull timing on knock and if you blow you engine up with a boost controller then you have set it up wrong and it's your own fault .

Dom B
01-05-2009, 03:41 PM
The point is that most people don't know how to set up a boost controller the only sensor they use is the seat of their pants and most of the boost curves i have seen people set are just a flat topped line. I am yet to see someone using an EGT probe or spark plug plasma to detect what's really happening in the cylinders.

Mitsi spend probably hundreds of thousands of pounds mapping the 6a13tt as they do with every one of their engines for all of their cars. Why did they decide on the boost map that they came to and why is a guy in a garage with a pair of pliers able to bypass all the work they did and just plonk on more boost in almost any curve. How much of their boost curve was made by the engineers and how much was done by the accountants telling them they could only have a simple boost solenoid and limited testing time.

I know some cars limit torque peaks with boost like the early 1.8t vw audi engines as they admit themselves that they had a serious problem with the gearbox strength so they introduces a boost and throttle delay which made the car annoying to drive. A remap could soon sort this and loads of people were offering it but no one strengthened their gearboxes.

You might set your boost controller up perfectly and know everything there is to know about automotive engineering but one day you go to a filling station and the tanker driver has filled the super tank up with 90ron by accident. It has happened and when people talk about getting a tank of s#1t fuel, this is often what has happened. We burnt out an exhaust valve in a jag on the may-fireball high compression head in the south of france and had to drive back on 5 cylinders due to s#1t fuel.

There is nothing simple about a VR4, it does so many things over and above what we control with piggyback ecu's etc. For instance i bet a lot of people didn't realise that the abs sends a signal to the ecu under braking to fully open the idle air motor to reduce engine braking and avoid a spin. This also works in conjunction with the AYC. the lancia delta integralle and alfa 155 Q4 also does this for the same reason. It is only an effect you get with 4wd cars. As opposed to awd or 2wd cars.

Does anyone have a proven map with boost pressures against rpm and load that has been seriously tested instead of just wiggling the line up and down a bit and gritting your teeth. Most of the older greddy controllers i have seen fitted only seem to have a knob not even a map. I assume they have a few points of a graph to adjust but are you almost doing it blindly.

There is nothing wrong with discussing all aspects of a problem.

scientist
01-05-2009, 05:08 PM
The point is that most people don't know how to set up a boost controller the only sensor they use is the seat of their pants and most of the boost curves i have seen people set are just a flat topped line. I am yet to see someone using an EGT probe or spark plug plasma to detect what's really happening in the cylinders.

Mitsi spend probably hundreds of thousands of pounds mapping the 6a13tt as they do with every one of their engines for all of their cars. Why did they decide on the boost map that they came to and why is a guy in a garage with a pair of pliers able to bypass all the work they did and just plonk on more boost in almost any curve. How much of their boost curve was made by the engineers and how much was done by the accountants telling them they could only have a simple boost solenoid and limited testing time.

I know some cars limit torque peaks with boost like the early 1.8t vw audi engines as they admit themselves that they had a serious problem with the gearbox strength so they introduces a boost and throttle delay which made the car annoying to drive. A remap could soon sort this and loads of people were offering it but no one strengthened their gearboxes.

You might set your boost controller up perfectly and know everything there is to know about automotive engineering but one day you go to a filling station and the tanker driver has filled the super tank up with 90ron by accident. It has happened and when people talk about getting a tank of s#1t fuel, this is often what has happened. We burnt out an exhaust valve in a jag on the may-fireball high compression head in the south of france and had to drive back on 5 cylinders due to s#1t fuel.

There is nothing simple about a VR4, it does so many things over and above what we control with piggyback ecu's etc. For instance i bet a lot of people didn't realise that the abs sends a signal to the ecu under braking to fully open the idle air motor to reduce engine braking and avoid a spin. This also works in conjunction with the AYC. the lancia delta integralle and alfa 155 Q4 also does this for the same reason. It is only an effect you get with 4wd cars. As opposed to awd or 2wd cars.

Does anyone have a proven map with boost pressures against rpm and load that has been seriously tested instead of just wiggling the line up and down a bit and gritting your teeth. Most of the older greddy controllers i have seen fitted only seem to have a knob not even a map. I assume they have a few points of a graph to adjust but are you almost doing it blindly.

There is nothing wrong with discussing all aspects of a problem.
Has anyone every needed to be that concerned? Mitsubishi built a very conservative map for warranty issues. Not performance. We tinker with it because we want more performance. Most of us will not sit there and tune a boost curve...we are more concerned with getting it to spool quicker and maintaining the SET boost. That's also the reason standalones don't control that many parameters.

Turbo_Steve
01-05-2009, 11:21 PM
Pretty much agree with Scientist here: most standalone ECUs only offer limited 2D boost mapping, and I can only think of one which allows boost level compensation for any kind of feedback other than the MAP sensor.

Quite a few vehicles limit boost in lower gears, it's true. But a lot of that seems to be down to maintaining a degree of driveability: you change what you will and live with the consequences.

On the Factory ECU, there is something of a catch all: Fuel Cut.
This represents the "edge of what we know" in terms of the 6a13tt: within the bounds of the factory map (and knock control, fuel compensation etc etc etc) you're limited to how much damage you can do. Taking it on a track at 1Bar is liable to decrease your service interval, and will cook your gearbox if you're insensitive. But then a std VR4 on a track can kills it's gearbox anyway, and is liable to destroy it's brakes too.

If going beyond the bounds of fuel cut, I will always monitor EGTs, AFRs and knock for any modification. In fact, I generally will not go past this point without proper engine management. Whether this is dyno mapped or road mapped depends on what the destination state of tune is likely to be.
My preference is for standalones, as once you get past a certain point, I feel you need BETTER knock control than factory.

Things like gearbox damage at something of a risk of tuning. Tuning has never been risk free, as very few of us have the Formula 1 team budgets required to do it without incident. Bearing in mind I am very close to an F1 engineer, and know for a fact that they destroy countless engines, gearsets, casings testing everything from the metallurgy the engineering.....none of us can afford to do that. So you try and stay under the risk curve.

A degree of common sense, and observation of what has been achieved before, is sufficient to have an idea what results specific actions will achieve.
If you can think of a better way of finding out how far we can go without tuning it until it breaks, I'd be dead keen to hear it! The last time I tried to get metallurical analysis on a set of rods, I was pretty much laughed out of the lab: getting anyone to commit to a definite set of tolerances without ridiculous "bet hedging" is impossible.

We get this time and time again building aluminium staging: Bars and structures rated to 5 tonnes in a 75mph crosswind. You start talking ot the people who engineer this stuff, and each person in the process looks at the rated strength of the metal, and halves it. So the aluminium company halves it. Then the reseller halves it. Then the engineer who designs it halves it. Then the manufacturing company halve it. So a constructed stage, which we can load test at 35 tonnes in a measured 60mph wind, without showing even the slightest signs of stress or load (less than a 5mm deflection at the structure peak!) tells you that you can't count on anyone to give you accurate info anyway.

I think this can be further evidenced by the state of the 4g63 tuning scene, where engines are regularly being tracked at nearly twice their "designated" output without issue...where the margins were so big that a tuning company was able to build a number of tuned "specials" (the FQ series) that surpass the original specifcation by over 25% with a full warranty...including track usage!
I think this tells us that depsite all the testing, the bean counters rule the roost when it comes to car production.

This is bourne out yet further on the INVECSII gearbox, which lacks a proper cooling system. The fact that it can be destroyed by heavy usage on a standard car rather smacks of spoiling the ship for a ha'penny of tar.

Wodjno
01-05-2009, 11:38 PM
My preference is for standalones, as once you get past a certain point, I feel you need BETTER knock control than factory.



You can control knock with a Piggy also /yes

Dom B
02-05-2009, 02:25 AM
What does removing the 'pill' do for boost figures as opposed to binning the factory mapped boost curve and using an aftermarket controller.

Turbo_Steve
02-05-2009, 02:57 AM
You can control knock with a Piggy also
Sorry..yes, I meant "aftermarket" rather than standalone. Though I'd wager a standalone does it better :P :D :iloveyou:


What does removing the 'pill' do for boost figures
Not sure if I am being thick here...what's the 'pill'?
Are we talking about the inline restrictor? Or the MAF screw thingy?

Dom B
02-05-2009, 02:09 PM
No the pill is the little rubber restrictor that sits in the standard boost controller solenoid and limits the bleed rate. I think it is this part that is sized to make the Japanese voluntary limit of 280bhp. It looks like you can just hook it out to let more bleed air flow. Someone did some testing in might have been rpw.

Turbo_Steve
02-05-2009, 03:00 PM
Hmm..dunno about the VR4, but every other car I have tried this on (I've always heard it called the inline restrictor before!? but that was on 3-port solenoids) it's been very bad: the ECU struggles to cope with the increased bleed, resulting in very spikey boost. The 'pill' is usually there to smooth the PWM pulses of the solenoid. Without it, a couple of pulses can completely empty the actuator lines of any pressure, and the fixed boost control maps overshoot the targets heinously: you end up bouncing between max & min duty, and inevitably the cycle is only broken when fuel cut occurs.

That's the trouble with any closed loop system: if there is infinite gain, it will always result in 100%.