Speed Density and Throttle Possition
 

The basic operation of any aftermarket fuel system is to base a fuel and ignitino curve off of MAP, TPS, water coolant, and intake temp. Of corse there are other things but this is the main stuff.

Out of those four it really comes down to MAP and TPS since temps are basically constants compaired to rapid changes of map and tps. So a Speed Density system primarily works from MAP and TPS readings.

Now when a microtech distributor tells me I can use the stock TPS in my S4 tII, it makes me wonder. The stock TPS only measures the first 20% of throttle travel. So I emailed the distributor back and he said thats fine, microtech only needs tps for idle.

So then that means the microtech works MAINLY from MAP pressures and temperatures rather than tps. Well, how does the ECU see the difference between:

1/2 throttle at 10 psi of boost and
full throttle at 10 psi of boost

Same boost, different throttle points, and obviously more airflow and power from the engine, requireing changes in fuel.

Basically I am just asking if the Microtech can trim fuel with throttle position.

The stock tII ecu can get away with the crappy tps due to the AFM.

10psi of boost at half throttle and 10psi of boost at full throttle is still 10psi boost, tuning on throttle position while in boost is a quick way to blow your engine, with a turbo you can get the same boost at different throttle positions,

the microtech can use TPS while the engine is in vacume then it will swap to map when it comes in boost, if you want to use this feature you will have to change the TPS for one that will read correctly to 99%, i would reccomend using this if you have a big port that has low vacume at idle.

so what you are saying is that the microtech will shoot the same amount of fuel at 1/2 throttle, 10psi, as it would at full throttle, 10 psi??


Im not talking about using tps alone, Im talking about tps trim on top of map readings. Does the microtech have the ability to tune to partial throttle possitions under full boost???

yes, 10psi is 10psi,

you will not get full boost under partial throttle,

it only uses map when it boost, not a mix of TPS

He is asking whether or not the Microtech has a TPS-based acceleration enrichment function, deceleration enleanment function, or other transients. ;)

Maybe this link will help answer that question:
http://www.chiptorque.com.au/105701.php

Good info Evil.

ah ok,

yes you can set the pump1 and pump 2 to work off TPS and will add extra fuel when the throttle is pressed, there are no other functions to add fuel through the TPS

You have 10psi at 3500RPM
You have 10psi at 8000RPM

you use the RPM WOT to add percentage of extra fuel required at 8000RPM @10PSI

The RPM WOT values can be adjusted to compensate.

Matrix mode is the way to use these new Laptop versions as you can graph a fuel map at rpm independant of the load map.

Dont get to technical cause I'm learning matrix now myself.

in Maxrix mode RpmWOT dosent do anything, it is only used in normal mode,

For those that dont know Matrix mode is the new LT and normal mode is the older MT series

Dale

yes i should of clarified that i was telling you guys how to make adjustments while in map mode. Which is how you are expecting or using them currently.

It sounded like i was telling you how to do it in Matrix.
My bad.

On my quest to make my car fast (but trying to not be too expencive) I stumbled on this thread.

I don't think anyone has made this point, but from my understanding, 10psi at half throttle and 10psi at full would be the same amount of air flowing into the engine.

If you think about it, the part that is pressurized to 10 psi is after the throttle plates. There is 10 psi on the LIM, and part of the UIM (there would be more pressure on the intake side of the throttle plates, since you are restricting the flow). The engine is still gulping the same amount of air at both times, and it doesn't know that the throttle is open or closed, it just knows its being blown by 10psi. So as long as you are set for 10psi with your sensor, you should be fine.

Its kind of like, flooring it at 1500 rpm. You get maybe 1, or 2 psi, right? But if you go at half throttle, you're still at 1 or 2 psi. Its different, but quite similar... the same amount of air is going in, because our engines really suck at 1500 rpm, especially if you have bigger porting.

Thats how I see it anyway, if someone can correct me if I'm wrong, well... good :D

No, the volumetric efficiency of the engine changes with load and rpm, as does the thermal efficiency of the turbocharger.

I'm saying in the same rpm and same load conditions, and just focusing on where the throttle is. Sorry.

In that case it comes down to the acceleration enrichment or deceleration enleanment issue.

the what? can you explain that in a little easier terms? I've only been through a basic physics course, but I think I pick up on this stuff a little better than a lot of people.

Throttle response is improved by adding fuel on acceleration, and taking away fuel on deceleration. It's just a simple way to make up for the lag in the ECU collecting and responding to data input. The TPS is usually the sensor for fuel enrichment.

Here is a bunch of physics stuff that you may like:
http://www.diy-efi.org/efi332/equations/algorith.htm

Thanks, I took a look... not too bad, hard to look at after 5 or 6 hours of classes.

With the stock S4 TPS... half throttle is 100% on the sensor. Thats what I was thinking of, not a good TPS :)

So to answer the original question, as boost is only the ammount of air being supplied that an engine is unable to consume at a given time, the air flow is the same regardless of where the tps is. Microtech can be mapped in either tps or psi or a combination of each. It also has air temp for thermal efficiency and a dual cycle pump enrichment that can be corrected for sensitivity, ammount, extra injector pulses added, duration, rpm, temperature etc, it also can adjust for deceleration by a decel cut or purely by going to the load site that would traditionally not be seen under normal load. After using the system extensively on ported rotaries or large camshaft overlapped piston engines, this system works exceptionally well and I would gladly compete with it against any of the others. The new systems that are to be released shortly will also allow tps over load with user defineable points which will be another useful tool for these type of applications.
Hope that has helped.
Regards-Anthony Rodrigues

New system???? What where when and how can I get it?

They have been prototyped and finished and now just awaiting new components. I will keep you informed.
Regards-Anthony Rodrigues