More EOIT questions

[Widebody06]

I started playing with DStecks EOIT calculator and have a few questions.

My first area of confusion is the RPM table goes up to 4K and we are inputting delivered pulse length...obviously at idle the pulse is stable as we are not using throttle. But above idle we are...and for example in my case PE comes in at 1200 RPM(yet another topic but that seems way too early) and of course it takes throttle to rev it up. So what do we use? No load data? Disable PE etc?

Also I'm doing this for no tears idle AND mileage at and below cruise...seems to me once the motor is on the cam, even at low loads you would not gain anything as 'short circuiting" to the exhaust would not be significant.

A big thanks to DSteck, my first attempt produced noticeable results despite doing a few stupid things which I've now corrected - had two guys express disbelief at the improvement in idle, its really coming together with HPT.

[Kyne]

It only needs to be done at idle, if you make global changes according to what idle is in the ECT table it will fix everything.

[DSteck]

A big thanks to DSteck, my first attempt produced noticeable results despite doing a few stupid things which I've now corrected - had two guys express disbelief at the improvement in idle, its really coming together with HPT.

Made my day. Glad you're getting good use of it.

I typically only use it for idle.

[Widebody06]

SIMPLE answer but I'm not understanding...newbie who doesnt know about global changes...I did find changing Ect values in the spreadsheet allowed me to extend changes (white cells) to lower temps. ARE you saying changes from spreadsheet should be made into other ECT tables?

It only needs to be done at idle, if you make global changes according to what idle is in the ECT table it will fix everything.

[Widebody06]

DSteck says not to mess with 'the colder section'...wondering what temp might be a good place to stop adjustments...its not like I can experiment when its 70* and I don't have the slightest idea why GM "did it for a good reason" so its one of those counter intuitive deals for me

[Kyne]

Before Dsteck posted his calculator I always just kept adding 10* to the entire ECT table until low speed bucking would go away. I still do that unless I have a cam card with .006 valve events to use his calculator. The timing is retarded stock at low temps so that it injects on the back of the valve to atomize better. I add to the entire table because the valve opens later anyways and will most likely need it in the cold sections as well. That's my reasoning. And usually if you wonder why GM did it a certain way the answer is usually "emissions".

[Widebody06]

Hey, thanks for your work on this, seen many of your posts. So when I change the 155's to 110s the white cell area gets bigger...would have thought I'd get red by being too less retarded..Boundary - ECT - RPM. Guess I'm thinking in the wrong direction so to speak....but larger values for low temps...so confusing for something so basic

But what I really dont get is: if you make global changes according to what idle is in the ECT table it will fix everything.

[MikeOD]

Before Dsteck posted his calculator I always just kept adding 10* to the entire ECT table until low speed bucking would go away. I still do that unless I have a cam card with .006 valve events to use his calculator. The timing is retarded stock at low temps so that it injects on the back of the valve to atomize better. I add to the entire table because the valve opens later anyways and will most likely need it in the cold sections as well. That's my reasoning. And usually if you wonder why GM did it a certain way the answer is usually "emissions".

Stock my ECT table had 110 in it for operating temps. Now I have 90 in it to clean up the smell...are you saying you'd have a higher number instead to clear up bucking/surging? I constantly battle with this in my stupid car.

[Kyne]

Yeah, I will post my table from my car when I get home. I can idle in 6th 800rpms 35mph no bucking with it. I use mine as a starter and add 10* until bucking stops.

[MikeOD]

What are your cam specs?...is it smooth around 1400-1600 rpm at extremely light throttle too?

[Widebody06]

My stick is just under .600 lift 300* advertized 24* overlap at 050 69 at 006 112 sep and it will smoothly pull up hills at 1200, no buck at any rpm, all codes enabled, all 4 narrow bands working and such, never get CELs now. Still not even tweaked out all the way. Just sayin' its not hard to get stock manners with a decent size stick and full boltons.
Oh and I'm mostly leaving ECT alone and tweaking RPM...that allows me to reduce ECT in the 155+ cells to increase the range of white cells in the calc sheet. Thats probably not necessary but I'm hoping that means it will run cleaner before it warms up any.

[MikeOD]

My stick is just under .600 lift 300* advertized 24* overlap at 050 69 at 006 112 sep and it will smoothly pull up hills at 1200, no buck at any rpm, all codes enabled, all 4 narrow bands working and such, never get CELs now. Still not even tweaked out all the way. Just sayin' its not hard to get stock manners with a decent size stick and full boltons.

Mine is smooth when there's any load on it...it's when I'm trying to hold constant speed on flat ground, and not moving that fast...can't have the tach in the 1400-1600 rpm range. 1200 is fine. Have to pick a different gear, and it's very annoying.

[Kyne]

This is mine for my car, 228/236 cam.


And for a buddies head cam Z06, i think like 236/24X .660 lift cam


both have no bucking and neither used the calculator only because I did mine a few years ago and I couldn't get .006 valve event figures from the guy who cut the cam on the Z. If you are tuning the MAF doing WOT and not steady state that's why you need the load, sounds like a fueling issue. literally both of these will idle in 6th gear foot off the gas. Hope that helps, and you probably don't need as much retard in the lower ECT but Ive been doing it that way for two years with no known ill effects. Though I let mine warm up for the springs anyways before I drive.

[Widebody06]

I've been doing my adjustments with Dave's spreadsheet and making the changes to RPM mostly and as stated above reduce a couple ECT cells to extend the range vertically
You have more experiance so I lean towards thinking I"m doing it wrong but on the other hand, its working wonders

click to view

EOITcalc.jpg

[Kyne]

No you are doing it right, more than one way to skin a cat.

[DSteck]

Just to be clear, raising the ECT numbers ends injection earlier.

[Kyne]

That's what I thought too when I first started playing with it on my car a few years ago. Went down to like 60 at operating temp and couldn't get it to stop bucking. Tried it higher and it all went away and that's how I've done it ever since. I have videos of my car driving and can get some of other cars. I've done as big as a MS4 cam and a giant EDC cam 24x/25x that way and it ran so much smoother with higher numbers. I can drive any speed down to 35mph in mine at any load no bucking. Mine isn't the biggest cam but it has worked on all of them.

[DSteck]

I'm not saying it doesn't work. I'm just making sure people understand what raising or lowering values will do. There's a reason there is a RPM modifier.

[Kyne]

Hmm why would it work then? What would advancing the inj timing actually do to get rid of the bucking and fuel smell?

[DSteck]

All I have are guesses. I can't say why the smell would improve.