sawood12

Few! Just used the search and read a whole load of threads on the subject, none of which answered my question! I'm just trying to establish is the SciVision system works like a true MAF under all conditions or are there some conditions where it reverts to effectively being an AFM? If the barn door of the AFM is fully open at say 4krpm under heavy accellaration (not under WOT) then the voltage signal from the AFM will be 5V. How does the SciVision system get around that to continue feeding the correct air flow data to the ECU?

Transaxle

What is a "true MAF" compared to to an AFM ?

Finally both send a voltage signal to the DME representing an actual airflow. How the DME works with this signal depends on its programming - not on the source of the signal.

Pauerman

What is the flow limitation of the HMF5 sensor? How large of a turbo will this sensor accomdate?

I'm glad you and Russell are working together on this. I'm sure the US 951 crowd is going to benefit from this partnership.

rberry951

In regard to the AFM, as Tom said, it makes absolutely no difference if the AFM/MAF signal reads voltage wise, in WOT mode the ECU is fueling based on the RPM of the WOT maps. As with ANY metering device, AFM/MAF/MAP, the chip has to be configured to the turbo and overall flow of the engine, it's power band characteristics (which is mainly dictated by the turbo) and fuel injector size.

But if all we ever used is the WOT there would be no need for anything to meter air. The fact is we spend most of the time driving in the part throttle maps, this is where a proper metering system comes into play. The computer is designed to use the signal range of the AFM, the Scivision properly mimics that signaling, so most AFM chips will work well with it. I will also optimize a set of chips based on the variation I see between the characteristics of air flow between the AFM/Scivision. Just as I customize chips for other applications.

Regards,
Russell

Keithr726

Yes but we are from CA which has a visual inspection and if they see anything other than stock you won't pass. Even if it improves the car.

danny951

Correct me if I'm wrong Russell, cause I am in no way an expert, but is this type of solution more limiting than newer cars that were designed with MAF setups from the start? -- being bound by the limitation of the AFM chips?

If that is the case, can your 951MAX chips that you sell be setup along with this MAF to go beyond this limitation of the AFM chips?


P.S. I resent my email after filling out that web form you posted.

Jeff N.

Keith? Do you think they'd find the MAF kit connected to a stock air box? I doubt it. Maybe if you had a full cone filter and rerouted intake they might... My SciVision kit is pretty much invisible.

My buddy has a modded BMW 535 that he converted from a bosch AFM to a MAP system and the cali emissions police didn't find that. That was much more obvious too - the whole flippin' AFM is gone from the top center of the motor. On the Bimmer, the AFM is mounted like a trophy on the top of the engine. With the P-car, there's the benefit of a ton of plumbing to hide your changes...

Jeff

sawood12

The way I see it this kit differs from the other MAF kits on the market because it basically replaces the AFM and mimicks it as far as the ECU is concerned. Now while this seems a good idea from an installation and set up perspective but since the AFM is a very crude and rudimentary device at the best of times it must limit the effectiveness of the system as it is disabled by the inadequacies that the AFM suffers. One of the main problems as far as I can see is that under heavy accellaration NOT UNDER WOT it is possible for the AFM barn door to be fully open (at above 4k rpm I believe) thereby providing the maximum 5v input into the ECU. Now whilst the MAF might well be capable of continuing to measure the airflow beyond this region the ECU cannot take advantage of this because it's input voltage is maxed out at 5v and is reading purely from the DME map against engine RPM. I see this as a severe limitation to the system and am trying to understand if the SciVision system reverts to the same behaviour as the AFM under these conditions or is there some clever way it gets around it and continues to measure air beyond this region.

rberry951

Well now you are speaking of conditions where there are modifications to the car that will actually result in more air flow than the AFM could handle. Hence the main reason for going to a metering device that is larger, to remove the physical restriction. So how then does your XYZ MAF system talk to the ECU. One of two ways, either there is a piggyback that scales the voltage to something the ECU can understand, or you have chips that have a transfer function that understands the scale of the MAF directly. Both doing the same thing in different ways. If you have a bigger turbo, the chips have to be mapped for that difference. The metering device is just that, a measurement of air flow. Regardless of what device you use, the ECU is still reading that scale only one way, and how it behaves based on that scale is back to the programming of the chips.

I see where you are going with this argument, but I do not want you to think that the 0-5V scale (actually the AFM never reaches 5V) is the absolute correlation to air flow. The chips can be made to interpret different voltages as different amounts of air volume. That's the key right there, volume. The bottom line is the voltage scale is NOT the limiting factor of any tuning system, only physical restrictions in flow is.

Regards,
Russell

Jeff N.

Does this imply that you expect to improve your current chips already setup for the SciVision MAF?

As current user of this setup, I'd be interested in keeping up with any changes you might make..

Jeff

sawood12

Thanks Russell, that explains it.

billthe3

Will the MAF come with the adapter plate and connector to hook it up to the air box, as shown in the picture you posted on the first page?

marcoturbo

The updated "emulator box" built with the harness looks better than the former grey box I've got on my car. It really looks OEM !

Russell, will you sell J-boot adapters to fit larger turbos than K26s ?

(I do want to keep the stock airbox with its paper filter and don't want a K&N filter behind the headlights, which isn't stealth...)

Duke

If the DME only looks at rpm vs chip map values at WOT, how could any piggyback work?

Transaxle

One way to fool the DME at WOT would be to hook into the NTC2 line.