Cam Tables and Injection Tables

Let's see if I can break this down enough.

I posted the first picture a while back, which shows the cam angle relations for intake and exhaust, while also showing Start of Injection. The parts I wanted to add were the tables involved. Too many times people will change tables, but no one will change the column and row values. My suggestion that I have used in the past is to change the values of the Injection Table to follow suite with the Cam Tables. I would even go as far as changing the values in the cam table to make it a smoother transition. I would post a pic of better cam column and row numbers but since wiped out my hard drive I have to download all of my tunes still. I showed a basic example in the second picture of how to closer work the two tables. ***CAUTION*** Not all tables will allow control of the vehicle if you change the column and row values. I have personally had issues with changed values on some of the tables. I do not have a list of which ones can be changed and which can not, and I do not have a list of acceptable parameters for each table. My best recommendation on that is to try it out and don't get crazy. I have had no issues with changing the Injection Table values, but I would still exercise caution and pay attention to what it is you are doing.

From there, I would hand smooth the tables.

Ok I lied. I uploaded an example of how to properly smooth out a table (In My Opinion). Not all tables need to be this smooth, but I would highly recommend smoothing them out to this extent with the exception of the OP Spark Tables. If the OP Spark Table's are done correctly, they SHOULD NOT be smoothed like this.

I know this doesn't offer much information on what changes to make, but this will get you started.

If you look at the tables, everything is based on a 360deg mid point. If Exhaust read 0, it would start at 360deg like I show in the pic. If it read negative 6, it would end at 366deg. If it read positive 10, it would end at 350deg. The opposite will hold true for the intake tables. If it reads negative 6, it would start at 354deg. If it read positive 20, it would start at 380deg. All of this holds true with how I drew it out. If you look at the info on the picture, and what I have typed up here it should make more sense.

***Caution*** I have not worked these tables in a long while so if I messed up my order on anything, and someone notices it, please let me know so I can edit this post. I do not want to give out misinformation so please use caution when adjusting these tables.

If you look at the fuel picture, you will notice how some simple adjustments with numbers will adjust how long the fuel will spray. Before anyone tries to question this, I spent a lot of time logging and adjusting and comparing to come up with that drawing. I promise it was drawn accurate.

If anyone has any questions feel free to ask.

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Hey Mike, thanks for posting this.

I'm just getting started on adjustments to the cam tables and knowing I have to adjust my injection tables also is very helpful.

I see you've adjusted a few cells on the intake and exhaust cam tables significantly around 3000prm and 50% load, is this for fuel economy or for power generation? Just looking for a general direction to head for fuel economy (long trip coming up in about a month, I'll be able to test fuel consumption during the week as I drive about 50 miles a day mostly highway).
Thanks Eric.

This is definitely not for fuel saving. This is actually a mock up from Bills tables, just smoothed over differently. I haven't had time to test any further then he did, and he saw good gains from it, so I rolled with a similar approach. Because of my family situation, I have not had time to tune anymore, so testing is out of the question on my end.

No worries on not having time for testing, I'm not looking for spoon fed answers, just wanted to know if that was the direction to head for fuel saving on the LNF as a starting point. I'll start making some adjustments and post what I discover, and now I need to go dig up Bills thread (read it awhile ago, I'm assuming the race cam thread is what you're referencing too).

Yes that thread is the one. If you want to save fuel, do not use this design.

Quote:

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Originally Posted by MikeM173

If you look at the tables, everything is based on a 360deg mid point. If Exhaust read 0, it would start at 360deg like I show in the pic. If it read negative 6, it would end at 366deg. If it read positive 10, it would end at 350deg.

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im a little confused here. if it reads 0, wouldnt the exhaust valve be closed at 360?

By start I do not mean open. If you look at the pic, if the value was 0, it would close at 360.

so, if im understanding this right (which im probably not lol) based on the stock intake cam table and injection table, the injector starts to fire 20 degrees before the intake cam starts to open? see highlighted cells (50 load, 3k rpm).

Attachment 66290

No, it would fire 20deg after the intake has started to open. Everything is based at the 360 marker. -40 Intake would be 320deg, and the injection isn't firing until 300deg. The numbers are going down during the cycle.

0* is compression/power cycle
360* is overlap/scavenge cycle
720* is compression/power cycle again

Ok, thanks. that makes sense, yet i am once again confused. with the stock LHU cams, to get the most overlap possible, i'd want the intake table at 10 (because 10 is actually 0), and the exhaust at 44 (because the exhaust cam is at 0 when it's at 6) correct? the intake would then start to open at 360 (and close at 156.4, it has a 203.4 duration) and the exhaust would (open at 504 with a 194 duration) close at 310 giving 50 degrees worth of overlap... but yet the thread i linked below says id get more overlap by making the intake cam more in the negative on page 6.

http://www.hptuners.com/forum/showth...justment/page6

thanks for the help guys. i've also been reading CSSOB's thread about the cam timing but it's bit different with him using the peak of the lobe to plot out when it opens, closes, overlap... on non vvt cams.

http://www.hptuners.com/forum/showth...jection+window

think of it like this....
the min and max values in cam adjustment for gm ecotec are as follows:
intake min: retarded (max separation)
intake max: advanced (max overlap)
exhaust min: advanced (max separation)
exhaust max: retarded (max overlap)

the exhaust event happens first which is why retarding exhaust causes overlap. retarding exhaust pushed the cycle towards the intake cycle causing overlap.
same goes for intake but in reverse. advancing the intake forces it closer to the exhaust because it occurs second which in turn also increases overlap.
camshaft information is always read in exhaust first. once you wrap your head around that, cam cards, degree kits and programming become much easier to understand.

At the risk of being laughed at for bringing up a long dead post, and as my first post at that.

I've been studying the posts on Cam Timing for the LNF, and I can't wrap my head around what this one is trying to say (been studying this for hours). In the first post it says intake -6 is intake opening at 354^. In the last post it's -40 is 400^. I think the direction is correct in the last based upon other threads, and if true I think I'm understanding correctly. Can anyone confirm which is correct?

I deleted the last post as I didn?t double check that work before posting. My first post is confusing since you can?t have +20 on intake. +10 is max (parked if I recall correctly). That would move the intake arc to 370deg. +40 exhaust would move the arc to 320deg. -6 exhaust is 366deg.

So -6 exhaust with -40 intake would be no overlap. Exhaust arc stops at 366 and intake arc starts at 320 if you read that drawing left to right.

+40 exhaust would be 320deg and +10 intake would be 370deg, so max overlap.

This is all off of memory, so if I?m wrong I apologize. I haven?t touched these tables in about 4-5 years. I?ll double check this when I have time and post back with corrections. The drawing I did was not in reference to any tables, it was simply an example of how the fueling was affected and what to do to correct.

Thanks for responding. So within the LNF tables positive values on exhaust and intake move the valve events closer together or toward the middle of your drawing and negative values move them apart or towards the end of your drawing?

As much as I hate bumps, I'm bumping this thread again. I have spent a lot of hours reading the LNF cam threads and "think" I have a handle on this but if so, the last post by MikeM173 has the +/- values incorrect. Building on COB's post in bold below is what I have been putting together.

Quote:

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Originally Posted by cobaltssoverbooster

think of it like this....
the min and max values in cam adjustment for gm ecotec are as follows:
intake min: retarded (max separation) -40 degrees table value = intake valve opening at 320 degrees degrees crank
intake max: advanced (max overlap) +10 degrees table value (parked) = intake valve opening opening at 370 degrees crank
exhaust min: advanced (max separation) -6 degrees table value (parked) = exhaust valve closing at 366 degrees degrees crank
exhaust max: retarded (max overlap) +44 degrees table value = exhaust valve closing at 316 degrees degrees crank

the exhaust event happens first which is why retarding exhaust causes overlap. retarding exhaust pushed the cycle towards the intake cycle causing overlap.
same goes for intake but in reverse. advancing the intake forces it closer to the exhaust because it occurs second which in turn also increases overlap.
camshaft information is always read in exhaust first. once you wrap your head around that, cam cards, degree kits and programming become much easier to understand.

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EX -6 & Intake +10 is 4 degrees of valve overlap (cam adjustments parked)
EX 0 & Intake 0 is 0 degrees separation (exhaust closing and intake opening at 360 degrees crank)
EX +44 & Intake +10 is maximum overlap available at 54 degrees of valve overlap
EX -6 & Intake -40 is maximum separation available at 46 degrees of separation

I'm not even sure why I'm worrying about this since this is way beyond were I am tuning, but once I started down this hole, I can't stop.

If you want to via phone, just PM me your number and we can go over it. It?ll probably be way easier doing that than going back and forth on this with a lot of context left out.

PM with phone # sent.

After a discussion with MikeM173, I think I've finally got a handle on this. I've corrected the info in post 16 and the info in post 15 is correct as far as which direction positive and negative table values move things.