Injection timing help

[kennyspec]

Hey guys I was wondering if I could get some help with tuning injection timing. Car is a 2010 Camaro manual LS3 with a texas speed 229/236 cam. Long tubes and a K&N CAI.

specs of the cam are
intake duration at .004 282
exh duration at .004 289
LSA 112
Centerline 110

I have entered the specs into the calculator Ghuggins posted here and this is my results.

http://wallaceracing.com/cam-deg-calc.php

IVO is 31.0 ? BTDC ( - indicates ATDC)
IVC is 71.0 ? ABDC
EVO is 78.5 ? BBDC
EVC is 30.5 ? ATDC ( - indicates BTDC)
Overlap is 61.5 ?

I have also entered the values into this spreadsheet that I seen Ghuggins posted again (in the knock retard hell thread)

I would just like to confirm that I am using the correct inj information to get my actual pulse width. Should I be using the pulse with at 2500rpm of the 3rd gear wot pull or from max rpm at wot?? also where do the values for the boundary (deg), normal ECT (deg) and normal rpm come from?

Any help pointing me in the right direction would be much appreciated.

attached should be the current tune, a 3rd gear pull and the injector spreadsheet.

[GHuggins]

If nobody post anything, I'll try to post up something tonight showing what to use for the pulse widths... Short answer look at your module voltage during the pull - go to that module voltage and as long as your running roughly 60psi fuel pressure - use the 400kpa column from your tune - add that to what your seeing in your log... You can take somewhat of an average of corresponding cells too... This better hits your target...

Did those do any good on the dyno?

[kennyspec]

I assume the table you are talking about is the offset vs press vs IGNV?

Car has not seen the dyno yet. I will have to do a pull logging battery voltage. The log attached is just one I had saved from before to use as an example. As for the cam they seem to make about 450-470whp on the dyno depending on the tune and other mods. It isn't a crazy cam by any means but the car is my daily driver that my wife also has to drive through traffic. the car feels a lot faster with the cam so I assume its making decent power.

[GHuggins]

I also forgot you need to add the regular offset into the equation when doing your figures...

Attached is something for you to try... Should better suite your cam...

Adjust your ECT table by allowing your engine to get to where it just starts to move the temperature gauge then perform a quick throttle snap - if it's perky, then it should be about right - if not add or subtract until it is...

[GHuggins]

If you want to focus more on fuel economy - add around 15 to your ect table - should put soi more around 360 to 365 degrees...

[kennyspec]

Thanks so much for putting the time into this for me. I am headed to the lake for the weekend but am sure to give it a try once I get back.

am I correct in reading that the normal rpm table should be all zeroed out as that is how it is in the spreadsheet you provided?

once again thanks!

[GHuggins]

Yes - all 0's... The boundary table breaks the rpm points down good enough IMO, so I always just 0 it out...

[kennyspec]

I finally have time to look at this again and I really do appreciate all the help. I just have a couple questions so that I can better understand all of this. I have read through numerous threads and they all seem to have conflicting info lol.

My understanding is that EOIT is the boundary table - normal ECT - normal RPM. So for example in my stock tune the EOIT for lets say 3072rpm would be (boundary)520- (normal ECT) 110 - (normal rpm)62.2 = 347.8 degrees.

If I use the same example for the numbers Ghuggins posted I would come up with a EOIT of 562-110-0=462

if I am understanding correctly the eoit has been retarded by about 110 degrees? seems like a lot. I am not trying to doubt your numbers I just would like a better understanding of what is being changed.

[JBZ]

You are correct, you will retard it quite a bit. What boundary rpm is the example(562-110-0) from ? And if it makes you feel better i retarted my boundary at 6k rpm to 595 (i think) with a stock cam. and it works great. Thought about trying to take just a hair more out at higher rpm. You can also take some out of your ect table but be sure not to take to much out, from my understnding this is where the makeup pulse width takes place.

[kennyspec]

sorry it should of been 572-110-0. that example is from post #4 where Ghuggins provided a spreadsheet also from the 3072rpm with the new numbers.

so lets say you have a final boundary number of 462 throughout the entire rpm range (just for example) does this mean that the EOI will be at 462 degrees of 720 and the SOI would vary with the length of the injector pulsewidth?

[JBZ]

sorry it should of been 572-110-0. that example is from post #4 where Ghuggins provided a spreadsheet also from the 3072rpm with the new numbers.

so lets say you have a final boundary number of 462 throughout the entire rpm range (just for example) does this mean that the EOI will be at 462 degrees of 720 and the SOI would vary with the length of the injector pulsewidth?

Yes to my understand that is correct.

[Paz]

Wondering if someone can give me some guidance in EOIT (posted here as didn't want to start another thread) , I've been reading for the last two days trying to make sense of this and it still isn't sinking in.

Main issue i have is the cam specs i have are @ 0.050", for the life of me i cannot work out how to swap that over to 0.004" as per suggested in the Knock Retard Hell Thread by GHuggins.

Stock cam @ 0.050" (L77 motor) was approx- 200/208 116.5lsa which = -29 (no overlap)
Fitted cam @ 0.050" is now- 233/238 115lsa= 5.5 overlap

I've got a fair amount of difference.

At idle (900rpm) i currently have an approx injector PW of 1.1 to 1.3ms as read from my scanner(upgraded bigger injectors).

So to work out injector firing degrees in rotation= 0.006 x 1.1(IPW) x 900(RPM)= approx 6 deg?

I'm thinking i should be subtracting about 19 to 25deg from my boundary table, zero Normal RPM as per GH suggests, Normal ECT has me stumped?

Pic is my stock settings at the moment, the 4x 964 figures i have not seen on any other compare file yet?

[JBZ]

You really need to get your advertised duration and then follow what Greg has posted here.
http://www.hptuners.com/forum/showth...for-help/page2
This thread has a ton of good advice if tou havent read through it already i would suggest reading from page 2 until the end. You will need to go to wallace cals to get your advertised duration events and how they line up compared to crank rotation. There really is no way that i know of or have read to find your advertised duration from .050 specs.

[Paz]

You really need to get your advertised duration and then follow what Greg has posted here.
http://www.hptuners.com/forum/showth...for-help/page2
This thread has a ton of good advice if tou havent read through it already i would suggest reading from page 2 until the end. You will need to go to wallace cals to get your advertised duration events and how they line up compared to crank rotation. There really is no way that i know of or have read to find your advertised duration from .050 specs.

Mate i have read that thread a dozen or more times in the past week, actually it is most likely due to that thread that i know i def have to do something with my EOIT.

I've got my cam specs and the card that it came with, just here in Aus we do not use 0.004", it's either 0.050" or 0.012".

Guess i'll try the supplier and see if they can supply 0.004" specs.

[JBZ]

Mate i have read that thread a dozen or more times in the past week, actually it is most likely due to that thread that i know i def have to do something with my EOIT.

I've got my cam specs and the card that it came with, just here in Aus we do not use 0.004", it's either 0.050" or 0.012".

Guess i'll try the supplier and see if they can supply 0.004" specs.

The .012 should work alot better than .050. For now you might try and use those and see what it gets you. It would be a very minimal amount of difference in crank degrees (i would guess less the 5) from .012 to .006/.004.

Sorry didnt relize you read tht thread already, i probably read it 50 times lol

Edit: also to answer one of your questions for your post 12, i believe that the ect table is there for makup pulse width so needs to be a large enough to allow a complete makeup pulse width. Like yours mine 110 degrees at operating temperature but i believe that with my injectors makeup pulse width will never be longer than 30* of rotation so i would think it would be safe to drop that number if you cant seem to get your eoit far enough back. Others my be able to chime in better and correct me if im wrong.

[GHuggins]

When you figure up the injector pulse widths - what's reported in the scanner isn't the final - at least from what I was always told or taught - you have to add in min pulse width and your adder tables straight out of your tune to get the final pulse width... Also if your going by my thread on this - you wouldn't just add in or subtract a set amount - that is the easiest way to do it, but your losing some benefit compared to doing it the way I do it... Since you've added overlap - usually - your better off to retard the injection timing - you do this by "adding" to the boundary - not subtracting...

Add to boundary = retarding injection timing
Add to ECT table = advancing injection timing
Add to RPM = advancing injection timing

I only use valve timing for making sure I'm not hitting a limit anywhere now... I target peak port velocity and bdc of the pistons stroke - I no longer go higher than 630 unless it's one heck of a cam. I also focus around duty cycle of the injectors more so now than before... You have to take into account whether or not your FI too... There should have been some pics for representation of the boundary tables in that thread to give you an idea on the route to go with it...

[schpenxel]

Correct on PW. On gen 4's it reports the "base" PW, before short pules adder and offset. For gen 3's it reports the total PW. So, for gen 4's you have to add it in manually when doing stuff like this.

[Paz]

Thanyou for the replies gents, very much appreciated.

JBZ, i'll use the 0.012" and give it a whirl and don't be sorry, it's guys such as yourself (not to mention Ghuggins and Carson) that gives us total newbies the time of day to actually guide us!

[JBZ]

Thanyou for the replies gents, very much appreciated.

JBZ, i'll use the 0.012" and give it a whirl and don't be sorry, it's guys such as yourself (not to mention Ghuggins and Carson) that gives us total newbies the time of day to actually guide us!

Im a noob also and greg, carson, barum and a few others have been pivotal in my learning process and understanding. I think there is no better forum out there for getting reliable info and good communication to get through the tuning process.