Timing on bigger cams
08-03-2006, 05:46 PM
#21
My idle airflow is w/ in .1 across the temp range. My IAC is never above 50. I have not done any playing with the throttle cracker or follower tables. I will check that out. I reduced my over and under spark values so that they dont swing so much also.
08-04-2006, 09:42 AM
#22
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I would suggest going to the .BIN repository sticky at the top of this forum and downloading some of the files there with similar duration camshafts and then comparing their IAC and timing tables with your own. It may point you in the right direction. I have found this to be quite the valuable resource and learning tool. You would be surpised at what you can learn by picking through the tunes of others. Some have paid some very talented people to tune their cars and the information stored in some of the tables within their .BIN files would otherwise cost you a good bit to duplicate using a professional tuner. Hope this helps. 
Jim C.
Jim C.
08-06-2006, 11:16 AM
#23
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Originally Posted by 98Z28CobraKiller
My idle airflow is w/ in .1 across the temp range. My IAC is never above 50. I have not done any playing with the throttle cracker or follower tables. I will check that out. I reduced my over and under spark values so that they dont swing so much also.
Filtered RPM Airflow Correction
Learned Airflow Correction
and
Direct Airflow Correction
The hunting idle my friends A4 was experiencing went away after that. Hopefully you can find the corresponding tables in HPT. They were under the Engine/Idle/Learning folder in my software.
08-06-2006, 02:48 PM
#24
Originally Posted by SSpdDmon
Sounds like you could close the TB set screw a hair. I try to shoot for 60 counts at warm idle. The throttle cracker is where most problems lie. You'll have to play with that one. As for the follower, I usually just lop off 50% and call it quits. However, I wouldn't mess with the spark modifiers too much. On the 232/234 car I just tuned, I left the idle spark adjusters stock. I took about 25% out of the 3 IAC tables and it drives almost likes stock now. Those tables in EFI Live are called:
Filtered RPM Airflow Correction
Learned Airflow Correction
and
Direct Airflow Correction
The hunting idle my friends A4 was experiencing went away after that. Hopefully you can find the corresponding tables in HPT. They were under the Engine/Idle/Learning folder in my software.
Filtered RPM Airflow Correction
Learned Airflow Correction
and
Direct Airflow Correction
The hunting idle my friends A4 was experiencing went away after that. Hopefully you can find the corresponding tables in HPT. They were under the Engine/Idle/Learning folder in my software.
If I close my set screw any more my counts will go to zero. My counts never exceed 50 and are closer to 20-30 after it warms up. I will look for the tables that you mentioned. I have my timing up to 41 in the problem area and have made it a touch rich in those areas as well which seems to have helped but I want the bucking gone. I took like 20% out of the cracker table which I am not sure if that did anything at all.
08-07-2006, 07:25 AM
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Closing the set screw and throttle body will allow less air through which means the IAC needs to open more which increases IAC counts. I was just saying if you get too close to 0 IAC counts, the motor might get too much air at some point and not have a way to close off the incoming air anymore (since the IAC is completely closed at 0).
08-07-2006, 08:13 AM
#26
Originally Posted by SSpdDmon
Closing the set screw and throttle body will allow less air through which means the IAC needs to open more which increases IAC counts. I was just saying if you get too close to 0 IAC counts, the motor might get too much air at some point and not have a way to close off the incoming air anymore (since the IAC is completely closed at 0).
08-07-2006, 12:46 PM
#27
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in my 408 setup with a 250/254/615/619 110 LSA i am running 43 degrees of advance down low. driveability is MUCH better now that we advanced it (5 degrees more than previus surgy tune) i have not had any problems whatsoever and it has gotten rid of surging pretty much all the way. 
08-07-2006, 04:48 PM
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Originally Posted by 98Z28CobraKiller
I have it uo to 41 degrees in the problem area and is better but I was affraid to give it anymore. Maybe I will just go for it
hehe we took it up to 45 degrees for ***** and giggles... no knock but iddn tsee any better response so we took it back down
08-08-2006, 03:29 PM
#30
I went looking around at some others tunes on Horists sight to see what the timing table should look like. There were some ugly ones and some nice ones (in the 3D view). I went with a pretty one. I hope that it works good. I guess I have to try it and see.
08-08-2006, 03:42 PM
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Originally Posted by 98Z28CobraKiller
I went looking around at some others tunes on Horists sight to see what the timing table should look like. There were some ugly ones and some nice ones (in the 3D view). I went with a pretty one. I hope that it works good. I guess I have to try it and see.
Jim C.
08-09-2006, 07:54 PM
#33
Originally Posted by GuitsBoy
I really havnt found any good cam files on horist's site. Ive found more useful info here than by looking at everyone else's first attempt at a tune.
08-09-2006, 08:16 PM
#34
Originally Posted by 98Z28CobraKiller
LOL. I think that you have to be able to look at a few and see what the "shapes" look like. Some are down right brutal but I found one that looked good. I made the changes to my timing table to give it a more proper shape, bumped the timing up in the problem cells and I still have bucking. I am going to pull the plugs tomorrow and check to make sure that all is good. I don't have any misfires reported (I hope that the knock sensors are not required for misfires). I still think that the problem is similar to running a carb that is too large at lower RPM's and therefore fueling related. I changed my timing table some more and gave it even more timing in the problem area while lowering some other areas that I felt looked too high.
for bucking .... try adding soem fuel..its almost always a lean condition when its bucking..timing is most likely not yoru solution...
08-09-2006, 08:53 PM
#35
Originally Posted by soundengineer
for bucking .... try adding soem fuel..its almost always a lean condition when its bucking..timing is most likely not yoru solution...
08-09-2006, 09:03 PM
#36
The thing that really bugs me is that nothing that I am scanning is jumping around. You really can't see any values jumping around. The only thing that jumps is the vaccuum. Here are a couple of my scans.
http://www.hptuners.com/forum/showth...0336#post50336
http://www.hptuners.com/forum/showth...0336#post50336
08-09-2006, 09:10 PM
#37
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The remainder of what you're trying to fix might just be the natural characteristics of the cam. Those stories of the perfect, big cam'd tune is starting to sound like a myth to me. I honestly believe you can reduce the affects of a post-cam install on the stock tune. But to completely eliminate issues on a cam designed to perform in a 2,000-7,000 rpm range....I wouldn't be surprised if there is no 'perfect' answer.
08-10-2006, 07:55 PM
#38
My cam isn't even "that big" for a 402 from everything that I have read. I still think that my problem might live in the inj offset table. Unfortunately, I cant seem to find anything on that that shows any sort of conclusive formula that you can use for proper setup of the inj offest table. I do now that the stock table for 28lb'rs that I am using cannot be the same as what it should be for a complete stroker swapout with 60# injectors.
08-10-2006, 08:03 PM
#39
There's this spreadsheet. Its supposedly for SVO injectors. Im trying it on my 30# SVOs. The numbers are very skewed. it goes from .300 to .700 in some sections. Totally have to rework the VE table and then the MAF table to get it to work without being absurdly rich. I have no idea if its worth while yet as im only about 3 VE revisions into it now. Still a far way off from a polished VE table. If youre bent on trying something a little different, it may be worth a shot.
08-11-2006, 08:59 AM
#40
Originally Posted by GuitsBoy
There's this spreadsheet. Its supposedly for SVO injectors. Im trying it on my 30# SVOs. The numbers are very skewed. it goes from .300 to .700 in some sections. Totally have to rework the VE table and then the MAF table to get it to work without being absurdly rich. I have no idea if its worth while yet as im only about 3 VE revisions into it now. Still a far way off from a polished VE table. If youre bent on trying something a little different, it may be worth a shot.
I had this thought this morning when I woke up.
I was thinking that perhaps the reason that I can't seem to get it dialed in perfect is that I am only getting the WB02 readings from one bank. I have true duals that are not crossed over in anyway. 2 independent exhaust pipes. Is it possible that bank 2 (passenger side) is leaner or richer than bank 1 and therefore I am not tunning an average of the 2 sides?