PC-PRO how it works...

[mx5jmcb]

Another ....PC-Pro how it works? thread


Seems the more i read about PC-PRO in this section, the more mixed up i am about how it works. I've read Tom's instructions but i found it hard to understand how each setting works independently of the other. For the basics, here's how i see things:

Green

Rate of gain 0-2800rpm

Yellow

Rate of gain 2800-5000rpm

Red

Rate of gain 5000-7000rpm

I'm assuming these settings "rate of gains" are all load based and adding gain (+) will increase the slope of the fuel curve adding more fuel per unit of load and therefore adding more fuel on the whole range in the process. Removing (-) gain will do the opposite.

Yellow-blue & red-blue

Here's where it gets tricky, i still don't understand what these do vs. the rpm based rate of gain settings. How does one affect the other?

The instructions from the normal non pc-pro powercard (the pc-pro instructions arent on the website) describes the yellow blue, red-blue settings as the transition point setting. Basically decreasing (-) the transition point seems to make the system more responsive to light amounts of load whereas adding the transition (+) seems to make the injection system responsive to higher amounts of load.

Taking this into account, the amount of fuel provided by the extra injector would be fixed (since we do not use the rate of gain settings) but we would have control over the transition points hence what load we want it to start injecting at.

I honestly do not know if this is right, but it seems to be more logic to me even though there are still some parts i dont get. What do you guys think, does this make sense?

[FormerDatsun510Man]

Here is what I understand:

1) Yellow-Blue: This is the main fuel adjustment. This is basically the rate of gain of fuel that the PC Pro adds as a function of boost psi. However, the PC Pro is a little more advanced than the prior Powercard in that it has another input parameter (which I believe comes from the MAF) that determines the load. The net result is that the fuel that the PC Pro adds gets adjusted by both the boost psi and the load. Simply put, the Yellow-Blue is just adjusting how much fuel the PC Pro adds based on the boost psi input parameter. The higher the value, the more fuel per psi of boost that will be added.

2) Red-Blue: This adjusts how the PC Pro adjusts the fuel based on the Load input parameter. The higher the value, the more quickly the PC Pro will trim off fuel with decreasing load. In other words, at a given boost psi, based on the Yellow-Blue adjustment, the PC Pro will add a certain amount of fuel. However, perhaps at that same boost the airflow rate may be different, which would result from the load being different. For example, going uphill vs. downhill at the same boost psi would result in a different airflow rate, due to a different load. Likewise, if you were in 2nd gear rather than 4th gear the load would be different. If the Red-Blue setting is higher, this means that the PC Pro will make a larger adjustment per change in load. The way you adjust this setting is once you have established a good solid a/f ratio in say 4th gear, try it again in 3rd and 2nd gears and see if the a/f ratio changes. If it goes too lean in these lower gears, it means the PC Pro is taking out too much fuel with decreasing load. This means that you need to reduce the Red-Blue setting. Likewise, if the a/f ratio gets richer in the lower gears, raise the Red-Blue setting. It seems to work pretty well when the Red-Blue is set to the same value as the Yellow-Blue.

3) Green, Yellow and Red: This adjusts how much additional fuel the PC Pro will add in each of the corresponding rpm zones. It activates with boost like an on/off switch, that is, it doesn't change the amount of additional fuel to add with boost. Think of this adjustment as a final fuel trim once you have the Yellow-Blue and Red-Blue at the best values.

Bill

[Tom @ Fast Forward]

The Green, Yellow and Red simply add fuel in the three zones (now changed to 1500-3000, 3000-5000 and 5000-7500 RPM respectively). The fuel they add is in addition to the Yel/Blu and Red/Blu fuel.

For example, if the A/F looks pretty good but you want to add a little fuel from 3000-5000, simply add a couple Yellow lights.

[mx3jmcb]

Here is what I understand:

1) Yellow-Blue: This is the main fuel adjustment. This is basically the rate of gain of fuel that the PC Pro adds as a function of boost psi. However, the PC Pro is a little more advanced than the prior Powercard in that it has another input parameter (which I believe comes from the MAF) that determines the load. The net result is that the fuel that the PC Pro adds gets adjusted by both the boost psi and the load. Simply put, the Yellow-Blue is just adjusting how much fuel the PC Pro adds based on the boost psi input parameter. The higher the value, the more fuel per psi of boost that will be added.

2) Red-Blue: This adjusts how the PC Pro adjusts the fuel based on the Load input parameter. The higher the value, the more quickly the PC Pro will trim off fuel with decreasing load. In other words, at a given boost psi, based on the Yellow-Blue adjustment, the PC Pro will add a certain amount of fuel. However, perhaps at that same boost the airflow rate may be different, which would result from the load being different. For example, going uphill vs. downhill at the same boost psi would result in a different airflow rate, due to a different load. Likewise, if you were in 2nd gear rather than 4th gear the load would be different. If the Red-Blue setting is higher, this means that the PC Pro will make a larger adjustment per change in load. The way you adjust this setting is once you have established a good solid a/f ratio in say 4th gear, try it again in 3rd and 2nd gears and see if the a/f ratio changes. If it goes too lean in these lower gears, it means the PC Pro is taking out too much fuel with decreasing load. This means that you need to reduce the Red-Blue setting. Likewise, if the a/f ratio gets richer in the lower gears, raise the Red-Blue setting. It seems to work pretty well when the Red-Blue is set to the same value as the Yellow-Blue.

3) Green, Yellow and Red: This adjusts how much additional fuel the PC Pro will add in each of the corresponding rpm zones. It activates with boost like an on/off switch, that is, it doesn't change the amount of additional fuel to add with boost. Think of this adjustment as a final fuel trim once you have the Yellow-Blue and Red-Blue at the best values.

Bill


Thanks Bill that somewhat clears things up...where did you gather that info?

[FormerDatsun510Man]

Many phone calls with Tom :), testing of my own and importantly there was a prior post where Tom shared some graphs from the programming software for the PC Pro. This cleared up the yellow-blue and red-blue functionality for me when I saw those graphs.

Bill

[Tom @ Fast Forward]

I wouldn't say we have a lot of phone calls. Just that 3-4 hours at a time makes it seem like a lot. ;)


Many phone calls with Tom :), testing of my own and importantly there was a prior post where Tom shared some graphs from the programming software for the PC Pro. This cleared up the yellow-blue and red-blue functionality for me when I saw those graphs.

Bill

[tann3r]

This is very good info. from my testing after Tom posted the graphs, I got similar results to what Bill posted. I'll have to mess with the red/blue setting more, i like the way you put it into word Bill.

And i'll second the recommendation to get it close w/ the yellow/blue then fine tune w/ the green/yellow/red.

Thanks yall!

[mx5jmcb]

I think Bill's description on how the pc-pro works should be stick"ied".

[Tom @ Fast Forward]

This thread is now stuck. :)