Self Tuning With SCT Pro Racer

[03cobra#2]

Are you using the ability to move tables out of PRP into Excel? It's really handy. You can pull two versions of a table out of PRP, compare them or manipulate them in Excel, and copy a revised version back to PRP. It's really handy.

What I'm thinking is maybe compare the table you just made with the stock table, but reverse the changes. If the stock table value is 1.0 and your new table is 1.2, then try running 0.8 instead. It could be you made the right changes but in the wrong direction. BTDT.

Thank you for the excel tip. The table I'm coming up with is drastically different from stock.

When I start the car and pull the maf the car does stay running and I can gently Rev the engine. If I Rev it to quickly it bogs. So I now the table is at least in the ballpark but needs work. If I log the values from livelink and plug them into the failed maf table the car don't run well when I pull the maf plug. So something is not adding up. I did more driving and logging today ho hopefully I can get all the values filled and I suppose I'll mess with the table until I can get good results with the maf plug pulled.

It's like tuning the car all over again.

Sent from my Pixel 2 XL using Tapatalk

 

[wkornf]

Ford Tuning: Load with failed MAF table(s) « Moates Support


Good info here too. specifically a caveat about turbo cars. looks like you can't ever get it totally right since your load is heavily based on boost and not just rpm.

lwfm is Just a bad way of tuning so you gotta do what you can.

I believe holley and megasquirt have logic to handle Accel enrichment that doesn't involve guessing your load.

Sent from my LM-G710VM using Tapatalk

 

[03cobra#2]

Got a chance to do some driving today and datalog. It looks like it may actually be a lean tip in problem. I'm gonna take sometime and really dissect my log.

On a seperate note I did a wot pull up to 6400rpm and everything looks pretty good. I think my timing may be a little low for E85. I peaked at 19*. I'm gonna do a bit of research and see what I should be safely topping out at.

Edit: after looking at my spark tabled timing is 21* max at 6500 so I'll leave it there.

Looking at my logs further there is definetly a lean spike up to like 1.25 or so during tip-in with a increase of TP of like 15 counts or so. I still get rich tip in during certain situations.

Next step is to go out and log my tip-ins over and over lol. If it is in fact a lean tip in I am feeling that is good news because I can go back to my transient fuel tables and try everything the other way.

 

[Wings65288]

How's the car feeling on those pulls?? Are you at 25#'s now?

 

[03cobra#2]

Car felt great on thoes pulls. Especially 4000 rpm and up. Generally speaking it drives so good I'm shocked at what I have accomplished. Car sees 25-26lbs of boost.

Still dealing with this tip in problem. Looking closely at my logs it shows it going lean (very brief spike) I've played with the failed maf table, tried disabling anticipation logic, and also tried making big changes to the transient fueling tables and nothing. It is most noticeable in 1st & second gear at 1000-2000 rpms. Im going to send a log to the guy that tuned my car on the dyno and have him look at it.

Sent from my Pixel 2 XL using Tapatalk

 

[Wings65288]

This is awesome lol. You've come a long way man. You might have a niche

 

[03cobra#2]

This is awesome lol. You've come a long way man. You might have a niche

I definetly know these cars much better that's for sure.

So I was looking at data logs of my lean tip in issue and it's perplexing because all the numbers look OK in live link, and any changes I made to fuel transition tables seem to have no effect. I wonder if it's the boost bypass opening up? Is there a way I can test this theory?

Sent from my Pixel 2 XL using Tapatalk

 

[JAJ]

It's not the bypass. It opens when there's vacuum in the intake after the blower - it only closes when the pressure back there is more than atmospheric (as you go into boost territory). There wouldn't normally be boost at tip-in.

I'm not sure how that vintage of ECU handles tip-in, but one of the parameters I have in the files I'm licensed (2014 ECU) for is tip-in spark. The ECU can change spark instantaneously - it doesn't have to wait for air to move around - and it could be that your hesitation (that's the problem, right?) could be addressed with a tip-in spark adjustment. I'm not sure where you'd look in your system though, so this could be totally wrong.

 

[01yellercobra]

There should be some sort of tip-in spark retard table. I remember zeroing mine out and it helped with getting things moving.

 

[03cobra#2]

Thank you for the tips. I'll look in prp tonight and see what might be available.

Sent from my Pixel 2 XL using Tapatalk

 

[03cobra#2]

It's not the bypass. It opens when there's vacuum in the intake after the blower - it only closes when the pressure back there is more than atmospheric (as you go into boost territory). There wouldn't normally be boost at tip-in.

I'm not sure how that vintage of ECU handles tip-in, but one of the parameters I have in the files I'm licensed (2014 ECU) for is tip-in spark. The ECU can change spark instantaneously - it doesn't have to wait for air to move around - and it could be that your hesitation (that's the problem, right?) could be addressed with a tip-in spark adjustment. I'm not sure where you'd look in your system though, so this could be totally wrong.

I do have a section under spark for tip-in spark. Ill look at my logs and see if I can see the spark change at all. If it's a lean spike would that indicate it could possibly be too much spark?

Edit: also my problem is very light pedal movement during easy acceleration from say a stop light.

 

[JAJ]

Hmmm... I wouldn't have considered a bit of surge under light throttle to be a tip-in problem. Tip-in problems happen as you engage the clutch and the engine gags or gasps for a moment. What you're talking about sounds more like a plain ordinary lean surge, or that's where I'd be looking for a solution. Use logging to map the bottom of the MAF curve to the AFR - all it might take is a tweak down low on the MAF curve.

 

[03cobra#2]

Hmmm... I wouldn't have considered a bit of surge under light throttle to be a tip-in problem. Tip-in problems happen as you engage the clutch and the engine gags or gasps for a moment. What you're talking about sounds more like a plain ordinary lean surge, or that's where I'd be looking for a solution. Use logging to map the bottom of the MAF curve to the AFR - all it might take is a tweak down low on the MAF curve.

You have to press the pedal just right to get it to do it. If you are really easy on the gas pedal everything is good. If you press the pedal fairly firm for a somewhat brisk acceleration it's fine. If you do a medium / normal pedal press to accelerate you get the lean spike / buck. It will happen once then continue acceleration like normal. So lean spike / buck, then righ to 1.0 lambda like normal.

I'm leaning towards something that is happening at a particular threshold during tip in. I suppose if spark is increased for that split second during tip in that could cause a lean spike. More testing to come.

Sent from my Pixel 2 XL using Tapatalk

 

[JAJ]

You have to press the pedal just right to get it to do it. If you are really easy on the gas pedal everything is good. If you press the pedal fairly firm for a somewhat brisk acceleration it's fine. If you do a medium / normal pedal press to accelerate you get the lean spike / buck. It will happen once then continue acceleration like normal. So lean spike / buck, then righ to 1.0 lambda like normal.

I'm leaning towards something that is happening at a particular threshold during tip in. I suppose if spark is increased for that split second during tip in that could cause a lean spike. More testing to come.

Sent from my Pixel 2 XL using Tapatalk

Ok I understand it now, but I really don't think that's a tip-in problem. I think it's light throttle acceleration. Tip in is pretty much over once the clutch is engaged - after that you're running on the closed loop map. I had a problem like this on my 2011 GT with a TVS on it and it was really difficult to find and fix. In my case, the throttle plate would swing through a few degrees, which was the actual cause of the surging. For some reason, that might come back to me if I think about it for a while, the ECU couldn't figure out where to put the throttle plate. It might be worth logging the throttle angle as you go through this zone.

 

[03cobra#2]

Ok I understand it now, but I really don't think that's a tip-in problem. I think it's light throttle acceleration. Tip in is pretty much over once the clutch is engaged - after that you're running on the closed loop map. I had a problem like this on my 2011 GT with a TVS on it and it was really difficult to find and fix. In my case, the throttle plate would swing through a few degrees, which was the actual cause of the surging. For some reason, that might come back to me if I think about it for a while, the ECU couldn't figure out where to put the throttle plate. It might be worth logging the throttle angle as you go through this zone.

So I just took the car for a spin. The buck / surge / lean spike happens as your letting the clutch out AND also does it if the clutch is fully disengaged and you accellerate.

Funny thing is I can pretty much reproduce the problem anytime I want. I did notice that when the problem happens the boost / vac gauge was either very close to 0 or transitioning from vac to boost.

I have a feeling when the transition is just right from vac to boost the bypass is snapping shut causing the problem. I could totally off base here.

I have been logging absolute tb and I can see what the tb is doing during all of this. Also my logs show that the spark is pretty steady during the problem and is not doing anything crazy.

I wonder if I can find a way to keep the boost bypass open, go for a quick spin and see if the problem goes away.



Sent from my Pixel 2 XL using Tapatalk

 

[JAJ]

So I just took the car for a spin. The buck / surge / lean spike happens as your letting the clutch out AND also does it if the clutch is fully disengaged and you accellerate.

Funny thing is I can pretty much reproduce the problem anytime I want. I did notice that when the problem happens the boost / vac gauge was either very close to 0 or transitioning from vac to boost.

I have a feeling when the transition is just right from vac to boost the bypass is snapping shut causing the problem. I could totally off base here.

I have been logging absolute tb and I can see what the tb is doing during all of this. Also my logs show that the spark is pretty steady during the problem and is not doing anything crazy.

I wonder if I can find a way to keep the boost bypass open, go for a quick spin and see if the problem goes away.



Sent from my Pixel 2 XL using Tapatalk

Keeping bypass open is dead easy - unplug the vacuum line, plug it with a screw and go for a drive. You'll learn a lot from the datalogs.

 

[03 Cobra DSG]

I have a 3.4 with crower stage 3 sc cams, my tuner made sure i had the lighter bypass valve before he tuned it. He said i would get a surge upon light throttle because of the big cams. Kinda sounds like what your explaining.

Sent from my SM-G950F using the svtperformance.com mobile app

 

[03cobra#2]

I have a 3.4 with crower stage 3 sc cams, my tuner made sure i had the lighter bypass valve before he tuned it. He said i would get a surge upon light throttle because of the big cams. Kinda sounds like what your explaining.

Sent from my SM-G950F using the svtperformance.com mobile app

Was he saying that you would get a surge WITH the lighter bypass? Or you would get the surge without?

When I start the car at idle the bypass locks open no problem.

Sent from my Pixel 2 XL using Tapatalk

 

[03cobra#2]

Keeping bypass open is dead easy - unplug the vacuum line, plug it with a screw and go for a drive. You'll learn a lot from the datalogs.

The new gen whipples have a pre installed vac line on the bypass. There is no vac line that I needed to attach to it. Only bad part about that new design.

I degreed my cams with a 116 lsa so my vac at idle is pretty good.

I may try a very light spring on the actuator arm to help it pull closed. If I get the right spring and my thinking is correct the bypass will start to close a bit earlier (before getting into boost) and not causing surge / lean condition. Similar to running a bypass with a heavier spring. I should be able to sneak a spring on the arm and attach the other end somewhere to give it some tension.

I could be barking up the wrong tree but it won't hurt to try.

Sent from my Pixel 2 XL using Tapatalk

 

[01yellercobra]

Keeping bypass open is dead easy - unplug the vacuum line, plug it with a screw and go for a drive. You'll learn a lot from the datalogs.

Without a vacuum source the bypass won't open. He'll need to lock it open somehow.

Was he saying that you would get a surge WITH the lighter bypass? Or you would get the surge without?

When I start the car at idle the bypass locks open no problem.

Sent from my Pixel 2 XL using Tapatalk

Malcolm went through something like this. You need the lighter bypass spring so you don't get surge. Although I don't remember if he was able to totally get rid of the surge. It had to do with the sudden rush of air.