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Thread: LNF Cam Tables

  1. #1
    Advanced Tuner
    Join Date
    Sep 2007
    Posts
    471

    LNF Cam Tables

    Let me start with a precautionary:
    First off, USE AT YOUR OWN RISK. Now to begin, please read this entire post and more posts before trying. The higher the rpm the faster the cams are moving so do not try and make drastic adjustments to these tables. Look at the stock adjustments from one cell to the next to get an idea of what was considered factory safe.

    Moving on:

    Idle: Ensuring ALL tables have the cams parked at idle will ensure a lot smoother idle. I shouldn't have to beat this to a dead horse. This has been put out before.

    Cruising: Hopefully if you've read other reads you'll see that more overlap is better for mpg. This is where things will get different depending on your setup. I currently am running the Hahn s20g. It is a later spooling turbo which I feel is ideal. I currently run almost full factory overlap and did not have to sacrifice it much allowing me to keep my mpg relatively the same in that area. For stock turbo or turbos like the ZFR that spool at a lower rpm range you will start to sacrifice more. I will explain more throughout this post.

    Spool up: It is possible to affect spool up with the cam tables. Even with my turbo spooling later I tried speeding up my spool up and actually hindered what I had. Instead I opted for performance and my spool up stayed the same.

    Performance: To help increase performance in the HIGHER RPM RANGE, you would retard the cams. I did most of my changes to the exhaust side but do not let that fool you, my intake tables is far from stock. Most values have changed. I would be less worried about performance in the lower rpm range due to not actually being there except for first gear when drag racing. I feel most performance should be focused on 3000 rpm or higher. Mine is closer to 4000rpm focused due to the turbo. This should help you focus on performance and mpg.

    Fuel Tables: Hom Tables should be adjusted. This is where my testing is still going on. I have drawn out rpm diagrams from 4000-6000 comparing stock opening and closing of exhaust and intake on a 720deg arc while mapping out fuel injection starting deg. I then took my logs and took my Fuel MS and calculated Injection Spray Time (in degrees) to find out when the injector should stop spraying. I then mapped out my spark for each of those rpm ranges. CAUTION: When dealing with PID tables, and causing ramp up to be quick it will cause fuel to max at the top of the oscillation window. With that you will notice that as you get higher in rpm your Injector MS will actually start to drop even though you are commanding the same fuel and are using the same boost. I am finding out currently when the best time to start the injection is and how it will affect my Injector MS. The goal is to lower it for my setup. This is where setup will take priority. I currently drop some fuel pressure due to running 27psi on e47 with 24deg timing. The goal is to drop the MS down so to not require so much fuel pressure, while maximizing injector spray time to allow proper fuel atomization prior to spark allowing the car to run optimum. Obviously it would be easier to just add fuel either through the 5th injector setup or the larger lobed cam. With that you would still want to map it out and have the system operating perfect and have the extra fuel.

    JUDGING PERFORMANCE!!!:
    I have not read all of the cam posts but one thing I noticed that I would like to clear up is you do not want to judge your cam tables strictly on VE or MAF airflow. If you make proper cam table adjustments YOU WILL see a drop in boost pressure due to better flow. I dropped boost from better flow and my elapsed time from one point to another (most people use 60mph - 100mph, I use a different method) dropped a significant amount. I was then able to raise boost more and see even more results which is when I ran into fuel pressure issues. In fact if I remember correctly my VE and MAF numbers both dropped with the better flow but this could be associated with the lower boost level from the better flow. Judging your 60mph - 100mph or whatever your method is, is definitely ideal. If you use a dyno, I would still log and base it off of the same 60mph - 100mph time frame or whatever speeds you use for you setup. 60mph - 100mph is not ideal for me since I spool later. Just ensure that when you are testing that you always keep variables the same. Dyno is ideal because you can test numerous times in a row and are not affected by outside conditions, weather, etc. Also ensure you start at the exact same speed every time. I also like to let my cars rpm drop by keeping the clutch in a little extra to make sure that I am starting in the same manner every time.

    This post was not designed to be the end all do this to your car or try these tables. These tables SHOULD be different for everybody to some extent. Most differences will be seen with larger upgrades that shift the power band around.

    There are some good reads on max retard and max advance for both cams, and a lot of other good info that you should understand first. If I get the time later I will look them up and add links to some of those good posts or if someone already has them available please add them. As with anything do not be afraid to make a good sized change. Just do your math, recheck your math, recheck it again, and then check it again (all at different times of the day). Make sure that the changes you make are smoothed by hand and you do not have huge jumps from one cell to the next in any direction. You could very well get away with changes to these tables without checking anything and your car could run fine but not optimum.

    I sometimes ramble on so I apologize. With that I may have misspoke on something so if I did please let me know and I will edit my post to update with correct information.

  2. #2
    Advanced Tuner
    Join Date
    Sep 2007
    Posts
    471
    I hope by now with all of these new posts recently explaining stuff that is not talked about as much that people will understand how much these tables interact with each other. You should not blindly change on table that this forum says is safe to change in the same manner that they changed it. You should continue to question everything and test it in your own manner. I will say that some of what I have seen on here I have changed differently or approached differently then what the norm is and have seen some great results. You should always be comparing examples of peoples tunes and logs posted vs stock vs gm flash tune vs any tune you created to see how people decided to go about things and to see what effects things have on one another.