Self Tuning With SCT Pro Racer

[01yellercobra]

Anything I need to watch out for? My car has all its systems. AC, abs, cruise, tc, ect.

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The MS3 has its own traction control. It requires a speed sensor and I'm currently working on figuring out the set up. I haven't used traction control in forever so I don't really miss it. Everything else works as it should.

The only issue I've had is the speedo bounces above 65mph. This is an issue across all of them. Last I talked to them they were close to a fix. But it's been about a month so hopefully thats not an issue. But I've put some miles on my car without a hiccup otherwise.

And this is the gauge I was referring to:
Perfect Tuning Universal Gauge

IMO you'll want to switch to widebands that can run off CAN Bus. I have Zeitronix ZT-3's. But the 14point7 Spartans are really popular too.

 

[03cobra#2]

Thoes are small issues. I would be just fine with no tc. To get wideband to read on both banks can I just switch the front narrowbands to widebands and the Ms3 takes care of the rest?

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[01yellercobra]

Thoes are small issues. I would be just fine with no tc. To get wideband to read on both banks can I just switch the front narrowbands to widebands and the Ms3 takes care of the rest?

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Basically. I removed the narrowbands and put the wideband sensors in those spots. Then you hook the widebands up to the MS3 and tell it these are two widebands. You also tell it which cylinders are connected to which wideband. It's pretty cool really.

 

[03cobra#2]

So does this negate the need for a wideband controller?

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[01yellercobra]

So does this negate the need for a wideband controller?

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No. You still need the controller itself. The MS3 reads the output from the controller. That's why I suggested the kind that can use a CAN Bus communication. Easier to set up and won't tie up multiple analog inputs.

 

[03cobra#2]

I have the money cued up and ready to go if I decide to go with the MS3 PNP. For now I'll stick with the SCT PRP and see where it takes me. I would like to get my car dialed in with SCT first before moving to the MS3 ideally.

I'm trying to wrap my head around load. In the software I set the WOT aircharge to 1.9 and disabled the failed maf table until I get my maf curve dialed in. While going through one of my datalogs I noticed when I stepped on the go pedal and got into a bit of boost that the load was pretty quick to peg at 2.0, even only at part throttle. Is this normal & ok? Still waiting to get my car on the dyno so I can dial in higher up on the maf curve.

Edit: from what I just found out that load is what it is and the fact that it pegs at 2.0 pretty easily is normal. So at least that's something off the worry list.

When I get on the dyno I have 2 concerns. Pegging the MAF and running out of injectors. I think I understand how & what I need to scale if I hit the 63.9lb limit on the maf (scale the maf table, injector slopes, and displacement). If I end up running out of injectors I guess I can raise base fuel pressure to 50psi and scale the injectors...or just upgrade to larger injectors.

 

[01yellercobra]

That's not a bad idea. I used SCT for 12ish years. I know it's "old school", but I'm comfortable with it. I had my tune about 80% there, but the MS3 has everything I've been wanting in a ln ECU. I have plans for the car and I think I'm better off with the MS3.

As for load, that used to be debated a lot. I've always tuned to set everything up and load will be what it will be. But then on those set ups I usually had a little head room. Other scale everything to bring the load down so that there is at least one extra row in the timing table. The perk of that is you can set that row a little lower in case you're out on a cold night and make a little more power.

However, I don't think that's as necessary on an E85 set up. Maybe more of a pump gas thing.

 

[HuntFishCobra]

I have the money cued up and ready to go if I decide to go with the MS3 PNP. For now I'll stick with the SCT PRP and see where it takes me. I would like to get my car dialed in with SCT first before moving to the MS3 ideally.

I'm trying to wrap my head around load. In the software I set the WOT aircharge to 1.9 and disabled the failed maf table until I get my maf curve dialed in. While going through one of my datalogs I noticed when I stepped on the go pedal and got into a bit of boost that the load was pretty quick to peg at 2.0, even only at part throttle. Is this normal & ok? Still waiting to get my car on the dyno so I can dial in higher up on the maf curve.

Edit: from what I just found out that load is what it is and the fact that it pegs at 2.0 pretty easily is normal. So at least that's something off the worry list.

When I get on the dyno I have 2 concerns. Pegging the MAF and running out of injectors. I think I understand how & what I need to scale if I hit the 63.9lb limit on the maf (scale the maf table, injector slopes, and displacement). If I end up running out of injectors I guess I can raise base fuel pressure to 50psi and scale the injectors...or just upgrade to larger injectors.

What did you read to nail down the concept of load? I haven’t really found enough to be fully comfortable with it yet.

 

[03cobra#2]

What did you read to nail down the concept of load? I haven’t really found enough to be fully comfortable with it yet.

I reached out to Don Lasota with whom I bought my prp from and provided me the base tune. Asked him specifically about my load being pegged and he said that is to be expected with a combo like mine. And goes on to say that as long as your maf function, injector values, and you are hitting your target af your ok.

I've been reading everything I can about load and if you need to scale it or not. In the end I'll trust what Don is telling me.

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[HuntFishCobra]

Ok great maybe that’s why I haven’t found much. Guess it’s just something that is a reference rather than a tuneable parameter. Thanks!

 

[01yellercobra]

Ok great maybe that’s why I haven’t found much. Guess it’s just something that is a reference rather than a tuneable parameter. Thanks!

It's something that's inferred from a few other areas. I don't remember all of them, but things like displacement and manifold volume play a part in the equation. That's why scaling those things changes the load. The other stuff (injector slopes, breakpoints, MAF curve) are scaled to keep everything in line.

 

[HuntFishCobra]

It's something that's inferred from a few other areas. I don't remember all of them, but things like displacement and manifold volume play a part in the equation. That's why scaling those things changes the load. The other stuff (injector slopes, breakpoints, MAF curve) are scaled to keep everything in line.

Boom perfect. Thanks for translating a dozen google searches lol

 

[03cobra#2]

Sat down and reread dons book again last night.

So it looks like when you hit 2.0 load what ever fuel and timing you have in the top rows in your tables is what the car will use.

I had concerns about what to do if my maf pegs, and if I run out of injectors (FIC1000's). Looks like it's pretty straight forward to scale the maf and injector slopes / breakpoint, and raising base fuel pressure to 50 psi and scaling lnjector slopes slightly to get more out of the injectors if I hit say 90% duty cycle.

Im sure if I have to do that I'll need to tweak drivability.

Thoes were 2 things that came more into focus for me.

I also have been reading up everything I can about the spark tables, spark modifiers, ect iif I need to tweak that for best drivability and safe power at wot. I will reread that section in Dons book a couple more times.

Obviously there will be a lot of tial and error but I am starting to understand a bit more and more about all these values is SCT and how to work around potential road blocks.

At my work we have a awd mustang dyno that is not being used. Literally has junk on it just sitting there not being used. I've been patiently waiting or 2 weeks now for my service department to clean it off so I can get my car on it and finish my tune. Hopefully that happens this week.

I know my maf curve is going to need a lot of work at the mid and upper values as I haven't touched that yet.

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[JAJ]

I've been where you are and tuning can be a bit baffling, not because of the concepts but because of the language. For instance "load". Load is actually simple, but nobody explains it. It works like this. The Misc -> Scalar -> Engine Displacement value is the weight in pounds of the air in the swept volume of one cylinder when the engine is stopped. The more the displacement, the larger this number gets. Load is just the ratio of the weight of air that actually gets into each cylinder when the engine is running divided by this static value when it's stopped. Simple, actually.

If you have a NA engine, then load usually tops out around 1, although a clever intake manifold that uses tuned pipes can get it above one, maybe as much as 1.2. With a blower, you can get any load you want, at least until something breaks.

You can calculate load by first taking MAF in pounds per minute and dividing it by RPM to get the air intake per revolution. Then divide that result by 4 because the air from every revolution is split between 4 cylinders. That'll tell you how much air is getting into each cylinder. To calculate load, divide that by the number in Misc -> Scalar -> Engine Displacement.

Thing is, this only works if you have an accurate MAF curve - accurate in the sense that if it says 50 pounds per minute, it's actually 50 pounds per minute. When you tune AFR by changing the MAF curve, that calibration goes out the window, and it's hard to know what "load" actually means.

 

[cj428mach]

It's something that's inferred from a few other areas. I don't remember all of them, but things like displacement and manifold volume play a part in the equation. That's why scaling those things changes the load. The other stuff (injector slopes, breakpoints, MAF curve) are scaled to keep everything in line.

Manifold volume doesn't change load.

 

[01yellercobra]

Manifold volume doesn't change load.

It affects something. And needs to be scaled correctly. But to be honest I haven't messed with it since my blow through days when i had to take into account all the pipe. Don't miss that.

Maybe it was LWFM table. Like I said, it's been a bit.

 

[cj428mach]

Load is air flow/displacement. So the only thing that changes load in the tune is changing maf or changing displacement.

 

[JAJ]

It affects something. And needs to be scaled correctly. But to be honest I haven't messed with it since my blow through days when i had to take into account all the pipe. Don't miss that.

Maybe it was LWFM table. Like I said, it's been a bit.

The ECU uses manifold volume to calculate how long it waits to increase or decrease fuel injector timing after the throttle position changes. If you're idling with the throttle almost closed, and then you open the throttle, it takes a while for the manifold to fill up with air (it's only milliseconds, but it's not instantaneous), and the manifold volume number tells the ECU how long it needs to wait before increasing fuel flow. If the volume setting is set too high, the fuel delivery change that follows a throttle movement will happen too late and you'll have a lean surge. If the volume is too small, it'll happen too fast and you'll have a moment of richness. The difference is milliseconds, but it affects driveability at low throttle openings (like city driving). It doesn't matter as much at higher throttle openings because once the bypass valve closes, everything changes.

 

[03cobra#2]

The ECU uses manifold volume to calculate how long it waits to increase or decrease fuel injector timing after the throttle position changes. If you're idling with the throttle almost closed, and then you open the throttle, it takes a while for the manifold to fill up with air (it's only milliseconds, but it's not instantaneous), and the manifold volume number tells the ECU how long it needs to wait before increasing fuel flow. If the volume setting is set too high, the fuel delivery change that follows a throttle movement will happen too late and you'll have a lean surge. If the volume is too small, it'll happen too fast and you'll have a moment of richness. The difference is milliseconds, but it affects driveability at low throttle openings (like city driving). It doesn't matter as much at higher throttle openings because once the bypass valve closes, everything changes.

That is great info! So if I'm having lean or rich tip in problems I can adjust manifold volume to fine tune part throttle drivability? Will small adjustments affect anything else?

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[JAJ]

That is great info! So if I'm having lean or rich tip in problems I can adjust manifold volume to fine tune part throttle drivability? Will small adjustments affect anything else?

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It might help, but if the problem is somewhere else, it won't compensate. An NA manifold is usually around 7 liters and a blower can be 18 or more depending on the size. The volume is the manifold, intake runners and ports and any attached volumes like the rotor housing (deducting the volume used up by the rotors themselves). This is all the places air gets to fill up while the bypass is closed. As for other things it interacts with, transient fueling is one, and that's a very complex area.