Turbo Project Complete. Humps And Bumps

Right, assuming your mass-air transfer function is exactly correct.

So your y-axis (load) is what, exactly? VE?
And then what do you input to fine tune the fuel? MAF xfer adjustments?
That doesn't seem very intuitive.

The following is pretty moot, but just my ramblings on the
In closed loop, I can see how far off my actual AFRs are from my desired. If I'm lean, I add VE. If I'm rich, I subtract VE. If all of the parameters I mentioned before and all the other ones in the system are exactly accurate, then the VE that gets me to my desired AFR would be the actual VE at that load-rpm.

However, I'm certain that every sensor and every parameter are not exactly accurate. Also, the "actual" AFR is really more of an average across all cylinders since I'm only on 1 Wide band O2. Therefore, the VE that gets my actual AFR to match my desired AFR is not truly the VE of my engine, it's just a ballpark approximation. For example, if my injectors flowed 10% less than what the manufacturer told me, then I would end up with VE figures 10% higher than they really are. In the big picture, it doesn't matter as long as I'm getting the desired AFR.

Even your timing will impact your actual AFR readings when in reality we know that the air-fuel inducted into the cylinder is independent from spark timing. So, if the "VE" I use to fine-tune fuel trims based on data (actual AFRs) that are so easily thrown off by a myriad of other issues, then my "VE" is a relatively meaningless number. If I got a VE of 70 (70%), I would not be worried that there's still a lot of potential in the engine. Likewise, if I got a VE of 150%, I would not believe that my engine was really moving 50% more air than its actual displacement.

Nice vids!

Couple of tips from one beginner to another (experts may chime in with better stuff):
- give the motor what it wants, not what you think it *should* want.
- Dialing in idle: Focus on warm idle first. I don't use the IAC so I let my car idle a bit higher at ~900 rpm. I aimed for and achieved 10* timing. The car seems to like AFRs in the 13.8-14.2 range.
- if your EEC has an idle delta that can adjust, use it to cradle the idle so that it advances if the idle drops too low or pull timing if the idle goes to high.
- make absolutely sure that your EEC thinks it actually is at idle. If my "TPS at idle" parameter is not higher than my actual TPS at idle, then the EEC will not use idle delta and other features.
Driveability
- for driveability err on the side of slightly rich. The car falls on its face when it goes lean. I'd rather run around a point richer than I'm aiming for and dial it back than to be running a point leaner and trying to add more in. Your car will constantly fall on its face if it's too lean, but it won't if it's too rich. Don't go to extremes, though. Though I aim for 14.5 at cruise and light loads, 12-13 AFRs aren't going to hurt anything, beyond having a bit of smoke from the exhaust. That helps keep the car from falling on its face when other cells are too lean. Then I start working it back. Go too rich for too long (like 10s or less) and you could wash down cylinder walls, I've heard. At cruising loads, I aim for mid 14 AFRs, I've gone as lean as 15 at cruise, though.
- dial in the main fuel tables before doing much with the transient tables. I thought I was having transient fuel table issues, but was surprised how much getting the main fuel tables right got rid of the need to mess with transient stuff.

After you get the warm idle working, you can start working on cold idle. Figure out how your EEC controls timing at "cold idle." There might be a coolant temperature spark adjustment table. However, for me, it's the bottom left most cell in the main spark table, even though that is not the load-rpm I'm at during cold idle. My computer considers this a useless cell and it took scrutiny of the manual to figure it out. I think mine needed somewhere around 27* at cold idle. I also had to go into the coolant-temp fuel adjustment table and richen up the mixture. I'm still working through that, though.

That's the order I tune stuff in. It might be smarter to get the WOT sorted out first, though. That might help prevent the need for adjustments. For example, I had to readjust the x and y axes to all of my tables. On a dyno, you might realize you need to adjust fuel pressure, or change a part. Or you might just find a bad part that has affected the entire tune. So, if you dial in WOT first, you might save yourself double work.

You will never get over that turbo sound!

Stevenmverrill said:

Fat thumbs hit send

1 a fox on dr's and skinny's.
Built na 351 with a 750cfm on top.
Been 10.9's

2 a cyotey swap fox on dr's and skinny's.
Been 11.6 but he may have some laughing gas this year.

Place your bets on what I'll run and what will end my day.

Stock 5.0
T35 .68 AR
Stock t5
3.73
2900lbs
Less then 10psi
315 dr's.

View: https://youtu.be/6waINuYZOkQ

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Depending on your driving skill and track experience, I will guess low 13's, maybe a high 12.

Joe

Not the best habit to get ito. Unless you're ready to follow up with a trans, I wouldn't recommend it.

Stevenmverrill said:

Any one thoughts on using 5th gear in a pass? I know it's a weak after though on the t5 hanging outside the case...
109mph is 4th gear around 6k rpm and the car is well past the power curve up there. So when I get things situated and run 115+ it will be a 5sped pass or I need to start now on 355's...

Click to expand...

5th is a define no.
Also, I think either your tach, or your math is off, or you've got clutch slip... 1:1 in 4th gear ... 109mph, 3.73's and a 26" tire is only 5300rpm... say you peak at 111mph (109 = 60' average)... still only 5400rpm. With a stock motor that's near ideal... I would guess with the hair dryer it 'should' still be making power.

You did say you are running out of fuel, so... maybe that's why it feels like it's beyond it's power band... get that figured out before using 5th or throwing gears at it.

At 109 mph trap speed I would guess mid 12's is probably the best et the car will see. That will require some low 1.6x 60 fts. With 4.10's and a 26" tire I see somewhere around 6200 rpm through the traps at 117 mph.

Joe