PI : DI Ratio Discussion

[thambu19]

Originally Posted by KoolBRZ

Because it can't be that warm where you live. I've visited Michigan, in the summer. Of course PFI/DI will be perfected by the time you get back. Then you'll show me where I went wrong and I'll have to start all over again. You should see my AVCS tables. Works of art but probably wrong in any number of places. I'll post them in the other AVCS threads. I have to swallow my pride if I want to learn how to tune better. I think it's safe to say that you are a master and I'm not.

Hey budd I will take a look. Always remember that cams and spark have to go together. Any cam change will need a change in spark timing. I am no expert by any means. I do engine development and calibration as a profession so I can see why certain calibrations are a certain way due to emissions or nvh etc.

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[KoolBRZ]

Yes, but there is a big difference between wanting something somehow better, and not knowing how or why, and knowing why, visualizing what should be, and finding out how. BTW, I think we need another map for cold while using your map for warm/hot.

[ztan]

Originally Posted by KoolBRZ

I loaded a tune with your suggested revisions first, and didn't even load any of mine to compare. It was so much better! @!#*&% you! I made 4 other tunes to try out, and now they are all worthless! Blast you and your intelligent mind! Now I'm going to have to rethink these principles you based your revisions on so I can find how far the limits are so I can push it to the limit.

I concur with @KoolBRZ that the PI DI map posted by @thambu19 works extremely well and runs really smoothly.
http://www.ft86club.com/forums/showp...&postcount=112

[thambu19]

Originally Posted by ztan

I concur with @KoolBRZ that the PI DI map posted by @thambu19 works extremely well and runs really smoothly.
http://www.ft86club.com/forums/showp...&postcount=112

Hey I totally made those up in my head so you guys might want to make some tweaks here and there. Did you add some spark where we are running di now where it was pfi before. It is important to do that.

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[solidONE]

Fantastic! lol

Edit: Thanks Happy Turkey day!

[KoolBRZ]

Originally Posted by thambu19

Hey I totally made those up in my head so you guys might want to make some tweaks here and there. Did you add some spark where we are running di now where it was pfi before. It is important to do that.

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There wasn't a single change that didn't make it worse. Next I'll try adding some timing in the DI areas.

[ztan]

Originally Posted by thambu19

Hey I totally made those up in my head so you guys might want to make some tweaks here and there. Did you add some spark where we are running di now where it was pfi before. It is important to do that.

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Have been running some high intake AVCS values (45) but was getting knock at cruising speeds (2800-3000 rpm, at 0.9-1.5 g/rev) even full DI with IAM dropping.
I've just re-reduced the AVCS intake cam to 40 which has settled the knock signal and about to add in ignition.
I'm not sure if it was true knock or just intake AVCS noise too close to the cam advance limits, but the engine is behaving much better with a bit less cam, more PI lower down, full DI up top.

[thambu19]

Too much intake advance means intake is opening when piston is travelling up in exhaust stroke. This can send exh gas up intake runner and re breathe increasing residuals and knock. So there is always a fine balance.

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[thambu19]

This is more so at lower speeds

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[freerunner]

Originally Posted by thambu19

When you get a chance can you try something like this? At WOT I have gone 100% DI. This means you need to a degree or so more spark there to use the full potential. If you do not then it will feel sluggish compared to stock calibration.

Flashed your PI/DI map yesterday. Added 3 degrees ignition advance at
load > 0.90 up until 3,8k rpm or so. And there's still headroom for more spark left.

Feels better than before. Seems worth to play around with these tables.

[thambu19]

Originally Posted by freerunner

Flashed your PI/DI map yesterday. Added 3 degrees ignition advance at
load > 0.90 up until 3,8k rpm or so. And there's still headroom for more spark left.

Feels better than before. Seems worth to play around with these tables.

Be careful adding too much spark at engine speed making peak torque. Up to 3800rpm should be okay. Some engines I have worked on goes straight to pre-ignition. Don't want thatone

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[arghx7]

I'm not too active on this forum lately but I did get caught up with this thread, as these things tend to die and suddenly get revived.

The AVCS intake side has the negative values @thambu19 and others were talking about because it is a mid lockpin AVCS. That means the intake side can retard, not just advance. The retard is a fuel economy thing. It's the same type of AVCS that's on the FA20DIT. In fact, it's the BorgWarner phaser technology that Ford uses on the 5.0 Mustangs. On those FA20DIT engines when you delete the tumble generator valves you need to advance the AVCS or it runs like crap without all that tumble motion in the combustion chamber.



more details (mostly relevant to FA20DIT) here http://forums.nasioc.com/forums/show....php?t=2687550

[solidONE]

Originally Posted by thambu19

When you get a chance can you try something like this? At WOT I have gone 100% DI. This means you need to a degree or so more spark there to use the full potential. If you do not then it will feel sluggish compared to stock calibration.

Any one else notice the fuel trims go crazy after loading these tables? How are you guys dealing with it?

[thambu19]

Originally Posted by solidONE

Any one else notice the fuel trims go crazy after loading these tables? How are you guys dealing with it?

Could it be because now engine is scavenging with pure air instead of air fuel mix

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