EOIT with a smaller cam

[383]

I have the GB DVD and he explains the need to change EOIT for big cams with +overlap but what about cams with less -overlap, like my cam with -1*?
Is there still a need to adjust the EOIT with smaller cams? I tried to move it later and didn't notice any change in my wide-band at all. I did notice a drop in psi from the cam so does that mean I need to adjust EOIT?

LS2
Eforce 3.5 upper 10% od lower
1.7/8 headers no cats
223/235 .610 .620 115lsa -lingenfelter ZL1 CTSV cam-

[jarrah]

I think u should see the stock cam and compare the overlap and adjust accordingly this is my understanding since this stable is setup for stock cam and u may need to compensate for the variance

[jim2092]

I have changed EOIT on my 24* overlap cam with positive low end results. But if you have no low end problems than EOIT changes may be unnecessary.

[SultanHassanMasTuning]

depending on your overlap, you need to adjust this as larger cams are less efficient at lower engine speeds

[Widebody06]

Search is your friend- ok slap me if you must
http://www.hptuners.com/forum/showth...ereencing-what
Nice spread sheet there to figure out how much to change, should allow you to figure out if you need or want to change it. Heres a pic of the sheet: http://www.hptuners.com/forum/showth...highlight=EOIT

My question which might be answered in that thread is does the sheet work for Gen 4 engines

[383]

Found it
http://www.hptuners.com/forum/showth...ng-what/page19
Post #364

[Widebody06]

HOLY CRAP BATMAN......thought OPs statement of -1* overlap sounded low just seeing the lift figures, but its right. So I went to the Wallace Racing overlap calculator page and plugged in my cam...and the answer is 69* WHOA!!! no wonder it lopes like a big dog 291/295 112 lsa is the spec. I could be the posterboy for needing to tweak EOIT...
Apologies for any thread hijacking that results...

[MikeOD]

http://www.hptuners.com/forum/showth...l=1#post311902

[DSteck]

HOLY CRAP BATMAN......thought OPs statement of -1* overlap sounded low just seeing the lift figures, but its right. So I went to the Wallace Racing overlap calculator page and plugged in my cam...and the answer is 69* WHOA!!! no wonder it lopes like a big dog 291/295 112 lsa is the spec. I could be the posterboy for needing to tweak EOIT...
Apologies for any thread hijacking that results...

Everybody uses 0.050" events to calculate overlap. You're using 0.006" events which is why you're getting a vastly different value.

[383]

Hijack away, i got my answer

[Widebody06]

You're the expert I just followed the instructions:
"Use Advertised Duration Numbers and the Lobe Separation Angle"

I guess someone should tell Wallace Racing they're doing it wrong, but it wont be me, I'm just a newbie tuner

so 16 deg for me by the standard method, which seems fine for most purposes, but it does make me wonder how that relates to a timing event based on a closed valve rather than a valve that is open but not flowing much yet
time to check out Jim's spreadsheet to see how that works as far as duration goes

[Widebody06]

Ok so I see that as I suspected when talking cam duration specs its @ .050" and when talking EOIT specs its duration at .006" so maybe Wallace Racing should call their calculator an EOIT friendly overlap calculator

[DSteck]

Using the spread sheet, stick with 0.006".

Talking to people, use 0.050".

[383]

I can't edit the spread sheet. What am I doing wrong?

[chassis]

Enable edit.

[ingsteve]

Suggestion for e40 ls2 g5x1 114?
Do you think it worth to change the normale eoit vs rpm?

[383]

I did that..... still no go. Nothing ever works like it should for me.
It was the registration for excel it was messed up