Dan Shea

yeah 500-700 is a deffinately a price i would pay for a product that gives me hp gains in the teens.

JustinL

How bout 400$ for a megasquirt II and get control of spark as well?

You S2 guys have a 60-2 bosch trigger wheel which is fully supported by the current megasquirt code. All you need is someone to be the first and go for it. I've been trying to convince someone to give it a try for a while but no-one seemed too interested.

There will be a learning curve unlike just a MAF pnp kit, but the potential is there.

bleucamaro

I'm using it with my SMT-7. $50 MAP sensor, $17 IAT sensor, and SMT-7 $425 Plus you don't have to build it yourself. Works good for controlling timing and fuel.

It doesn't work so good at transforming a linear MAP sensor curve to a logarithmic AFM curve for the DME. It does however work great at translating that curve up and down the scale.

For the MAF guru's: Is the MAF output signal, linear, or logarithmic parallel to the AFM? Also, is the Analog to Digital conversion in the DME handled on the chip, or is there a transistor set on the DME board?

The problem I see with handling the logarithmic to linear transformation in the tune is that as the voltage increases with rising flow, any noise in the signal or spikes will have a more profound effect.

Fishey

Mega Squirt 2 is on my car and there are plenty of pre-built units avalible.... Now, it doesn't run but then again it has no pistons

maddydaddy

I am willing to pay up to 1G for a plug and play PROVEN deal, but I think the market drops off pretty bad above $700. I must be crazy for HP.

James Reeser
89 944 S2

rberry951

You've kind of answered your own question here. When you plot out the voltage scale of the AFM/MAF/MAP they are vastly different. So is their behavior. Certainly a device that emulates the AFM's behavior as well as its scale is a good way to go within the boundaries of AFM performance. The Promax/Scivision MAF is a good example of this. But if you have greater HP goals than the MAF can flow, you're up against another wall. So as John Vitesse has stated above, the best way to do it is to do it in the transfer function to properly align not only the scale, but the behavior of said scale so that the DME's load calculations are correct. And must be done in accordance with that particular MAF's calibration. You stick another MAF on there, the whole function changes.

The voltages go through an analog->digital converter on the board, then those digital numbers are fed through factored scales of the transfer function to calculate air flow. And it is still a metering system. Nothing more, nothing less.

People often get the wrong impression that the 'tuning' they are doing with a piggyback is just changing a fuel value. What it is changing is the air flow calculation, and if your AFR is what it should be per the chip program, then that means you are right on scale in your load calculations and the timing maps will line up as well. So when you 'add fuel' with your piggyback, you have actually added voltage that puts the scale where it should be to line up where you actually are in your flow/load calculations.

The biggest issue with a MAP as I mentioned in PM is the spikes and handling of negative pressure/vacuum. If you addressed the transfer function for the MAP's 'scale', you still have to address the MAP's behavior, in that it is differet from an AFM or a MAF. Those issues I believe are better addressed in an external manner to tame its behavior. I don't have any circuitry in hand to perform such a task, but I can certainly envision it, and I think you'll be seeing such devices on the market at some point.

A lot of people have told me a lot of ideas about addressing metering issues, and they vary in concept. I would like to re-write all the code to deal with purely load based maps and do away with the WOT maps all together. Other's would like to go with a purely RPM WOT type map and do away with load maps all together. There are many approaches to address the same issues. Which is best can only be proven over time.

Regards,
Russell

bleucamaro

Russell, I really like your approach, and a true speed density is the best way to tune (IMO). I suppose I am a bit naive when it comes to the Motronic computer, and was under the impression that all you are buying in a 'chip' is modified fuel and timing tables, and the algorythm to derive the "answer cells" remained the same. I understand that piggybacks 'cheat' the inputs to the DME to elicit the desired answer cell, but it is often easier to describe as changing fuel and timing.

When changing the transform function, does the function change dynamically, depending on the inputs, or does in need to be derived on a dyno. The reason I ask is this could be huge for future modifications. Personally, I have a water injection setup planned, and then more boost. Would the Maxtronic setup be a better bet?

Don't worry about sounding like a salesman, because you don't, and you actually bring some knowledge to the table.

rberry951

I agree that the concept of MAP is the way to go, but needs to be perfected for the application. But as I stated, I think it is very doable.

A lot of tuners do only address basic fuel/timing maps. And you can do a lot with that. But you cannot take a device like a MAF/MAP and compensate for it in the basic maps, there's just no way to tune that way consistently. And in most cases, you fall outside of range, run out of room in those cells.

Advanced tuners have the ability to dissassemble the code, and make it do what we need it to do within the boundaries of the circuitry available, inputs, etc. The AFM transfer function is a hard coded set of routines and values that act upon the numbers fed to it via the A->D converter on the board. There are many variables to tweak, and other variables outside the function proper like the AFM min/max values and the factors used in the flow/load calculations. So in using all the available resources in the code, we can make it work with just about anything. It just takes time to develop, and as many times as I have stated "it's just math", it is a bit more involved, as devices don't always abide by the rules of basic math. Again, the computer is digital, the engine is not. Theory works great until you turn the key.

The Maxtronic is a simple device, but is the path to tuning. The typical user won't have the ability in MaxTune to manipulate the transfer function proper, but the tuners who use it will have access to everything, even a built in hex editor to change raw values anywhere in the chip image. This will make their lives easier. And I'm designing everything with openness in mind so as to not lock anyone into using mine, or anyone else's chips software exclusively. This tuning ability spans many types of cars and computers.

Now the warning. If I write in protection against the basic maps to the point you can't hurt anything, then you won't be able to tune much. You would be limited to very minor tweaking, and continually going back and forth between fuel/timing maps to get where you are trying to be. So I decided to protect things like not letting you copy/paste full maps during tuning, not letting the standard keyboard auto-repeat kick in when tuning so you don't get a key stuck and hear your car go POP on the dyno. But as far as limits, I'm not going to enforce them. I am going to leave it up to the community to help each other here. And this is the way it should be in my opinion. Some of you will blow up your cars, this is a fact and I expect it. Some of you will blow up other people's cars with bad advice. Another fact. But over time a knowledge base of tuning parameters will grow and it will help the overall understanding of everyone of how all of this stuff works.

Other communities, DSM, GM, Honda, you name it, have been tuning their own cars, sharing information, and generally working together to make all of their cars run better. It's high time this community had the technology to do the same thing. That is my goal.

jgporsche

AMEN to that !!!!!!!!!!!!

bleucamaro

Holleluya!!!!


and now more questions: what sort of user interface are you planning on using with the Maxtune? What I see as being nice would be two programs to run on a laptop, one a higher level one with the appearance like most piggyback/stand alone setups, and one that is lower level, more for tuners and gets into the nitty gritty. . . or even different tabs in the same software.

Wow, there is HUGE potential here.

rberry951

Well, you have your standard config screen, allowing you to pick between Maxtronic images, and which car map to use, then Pro version of same configuration screen where you can build new car maps, fuel/timing screens, then auxillary map screen standard version where you can set rev limit, and switch fuel injector size. When you switch fuel injector size, the program makes all the necessary changes in the chip image for that injector size. And fiinally the built in hex viewer, which in the pro version is also an editor. Pro version also gives you a file mode to work on chip image files directly of any type you want to build a map for.

These screenshots are a couple of weeks old, final product will differ slightly as I make better use of the available form real estate.


I made another thread for the screenshots:

https://rennlist.com/forums/924-931-944-951-968-forum/334223-maxtune-screenshots.html

jaje

My S2 is itching for a broader and stronger powerband. Hint Hint

greenshoes3

would it be able to be used on regualar "S" models, or only s2's?

promax_motorsport

www.promaxmotorsport.com or www.promax.eclipse.co.uk/maf_kit.htm

Regards,
Andrew

jgporsche

I was asking if that was what was being used.