Top 5 Gtr Times-what Ecu Are Bieng Used

[Sydneykid]

Another view on the MAF v MAP debate, from Ben Strader - one of the better Autronic tuners in the U.S. and founder of www.efi101.com

Regards

Andrew

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The Autronic unit differs slightly in the way it calculates fuel and ignition from the stock unit and most other aftermarket systems in that it uses "speed/density" to calibrate with.

Basically it uses a "map sensor" to indicate the pressure inside the manifold {negative or positive} and then references that value against the engine speed.

Then, using a complex mathematical sequence based on the

PV=NrT theory it calculates the actual amount of air in the engine for one cycle.........multiplies that time RPM {number of cycles} and then looks that value up in a "Base Fuel Table" which the user can modify to add or subtract fuel to obtain a desired A/F ratio.

The factory and some aftermarket systems use a MASS FLOW system which directly measures the air entering the engine {corrected for temperature} and then uses the same style of tables to look up user entered values. This sytems works well, but does have some drawbacks.

First, beacuse all of the air going into the engine must be actually measured, it must pass through a calibrated orifice called the Mass Air Flow Sensor. This sensor poses a restriction to airflow and can be a horsepower robber at elevated power levels.

Second, any air leaks after the sensor, but before the throttle body will cause a lean condition because there is no means of measuring that "sneaky" air.

The Speed/Density method only cares about the air inside the manifold at any given time and is therefore a bit more flexible.

Plus, you can eliminate the stock mass air meter to gain additional power, or leave it in place to maintain the stock appearance.

Plus the Autronic comes with the Auto-tune option and Anti-Lag functions plus unlimited options for data logging as STANDARD options........all inculded in the price.

Again I think the UTEC is a great system and I have NO complaints about it. The Autronic is just another good option for everyone.

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Hi Andrew, what Ben says is absolutely correct. But think about what he actually says........."it uses a "map sensor" to indicate the pressure inside the manifold". We are talking about turbo charged cars here with wastegates and boost controllers that very accurately control "the pressure inside the manifold". I don't know about your engine and boost controller, but mine has the same boost level from 4,000 rpm to 7,500 rpm. So the MAP sensor is basically useless, it means the formula has a constant "P" and that is one of the vital inputs in the Ideal Gas Law formula.

Next think about..........."the air..... must pass through a calibrated orifice called the Mass Air Flow Sensor. This sensor poses a restriction to airflow"......this only applies if you have chosen an AFM that is too small for your power level target. I don't see how that is any different to me saying MAP sensor based ECU are no good because I choose to have too small an air filter. It is irrelevant in choosing an ECU.

Lastly ....... "any air leaks after the sensor, but before the throttle body will cause a lean condition because there is no means of measuring that "sneaky" air". Obviously Ben wrote this for N/A engines not turbo charged engines, as any air leaks after the turbo would cause a rich condition.

cheers

Edited September 18, 2005 by Sydneykid

[BBGTR]

Yep, all very true on both sides.

I guess my questions is: Why do 90% of the race engines I see use a MAP based system rather than MAF?

I think ARC rally cars are the only race engines I've seen that use MAF and that's only because of the production based regs.

Some good discussion starting to happen here.

Regards

Andrew

[exXU1]

Excellent gentlemen, more discussion please as this is all good stuff.

Yep, all very true on both sides.

I guess my questions is: Why do 90% of the race engines I see use a MAP based system rather than MAF?

I think ARC rally cars are the only race engines I've seen that use MAF and that's only because of the production based regs.

Some good discussion starting to happen here.

Regards

Andrew

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[Sydneykid]

Yep, all very true on both sides.

I guess my questions is: Why do 90% of the race engines I see use a MAP based system rather than MAF?

I think ARC rally cars are the only race engines I've seen that use MAF and that's only because of the production based regs.

Some good discussion starting to happen here.

Regards

Andrew

<{POST_SNAPBACK}>

Hi Andrew, we use MAP based ECU's on N/A race engines (eg; V8SuperCars) otherwise I would have to run 8 X AFM's. On the SuperTourers I would have to run 4 X AFM's, one for each throttle body. Every little tiny bit of restriction is avoided at all costs, so we have gigantic air inlets with huge filters.

On a turbo charged engine there is one air inlet (for each turbo) so it is not so much of an issue. Plus tiny restrictions on the inlet to the compressor mean nothing, the turbo has more than enough airflow to make the power target within its efficiency island.

On a 100% race engine I really don't give a rats about cold start and run, hot start, air con / power steer / electrical load compensation etc. All the stuff that makes an AFM driven ecu superior on a road car is pretty much irrelevant on a race car.

Plus AFM voltage ramp tables are hard to program from scratch with altitude / humidity / temperature compensation. This is not a problem when using a Power FC, Apexi have done it all for us.

This is not a simple, one is ALWAYS better than the other. Horses for courses as they say.

cheers

[nitemare5]

I love you Sydneykid.

[djhatton]

I love you Sydneykid.

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lol

[Rj34GTT]

What HP ATTW < what performance and times?

I am anticipating with my build + or -  800 .

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My reading i got last dyno run was 247hp. i was using a Pod filter at the time and the bracket did not sit on properly.i have changed it back to my panel now though so power might be a little higher..