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Re: MAF Tuning For Larger Cam - Roller 304 Engine

Posted: Sun Feb 01, 2015 9:13 pm
by Monarols71
Thanks Jayme. I mean attach a picture at the end of the post, not the start.
Picture of requested chart, but still trying to work out how to attach whole log .xdl. :oops: :oops:
HQ355 - The lift of the new cam is almost the same as the Comp Cam roller cam, and it's in a manual series 3 VS SS ute built after April 1999, hence the (VT) roller cam engine.
Knock.PNG
Knock.PNG (69.32 KiB) Viewed 4336 times

Re: MAF Tuning For Larger Cam - Roller 304 Engine

Posted: Sun Feb 01, 2015 9:37 pm
by Jayme
ahhh... after you have uploaded it. put your cursor where you want the attachment, then click the 'place inline' button next to the attachment down the bottom in the posted attachments section. (I have edited your post to show you what I mean)

as for uploading the xdl - if you go into acquisition - load log file in tunerpro, that shoudl show you where the log file is stored... you can copy the address out of the adress bar and open the forum then open the file upload box and paste it into the address bar of the browse window to go to that location, then select the xdl file to upload.


just looking at the part of the log you posted, looks like you are right, there is some knock happening down at low rpm, you can try removing some timing from there to stop it. in the log, you should see an item called, "milligrams per second per cylinder" that is the horizonal axis of the spark advance table. you can use that to match up to the RPM and MGC of the advance table to find the exact cells you need to lower.

Re: MAF Tuning For Larger Cam - Roller 304 Engine

Posted: Sun Feb 01, 2015 9:39 pm
by Monarols71
:roll:
VS 3 A6 Engine and trans TP5 v104.adx

Re: MAF Tuning For Larger Cam - Roller 304 Engine

Posted: Sun Feb 01, 2015 9:41 pm
by Monarols71
Thank you

Re: MAF Tuning For Larger Cam - Roller 304 Engine

Posted: Sun Feb 01, 2015 9:52 pm
by Jayme
There is still the possibility that it is false knock and the noise you and the knock sensor are hearing is just a noisy valve train. Ive found big cams have a tendency to trigger false knock. If you lower the timing heaps and the knock doesnt go away then it is most likely false knock and you need to be adding ignore knock counts at that rpm

Re: MAF Tuning For Larger Cam - Roller 304 Engine

Posted: Sun Feb 01, 2015 10:10 pm
by vlad01
Jayme wrote:There is still the possibility that it is false knock and the noise you and the knock sensor are hearing is just a noisy valve train. Ive found big cams have a tendency to trigger false knock. If you lower the timing heaps and the knock doesnt go away then it is most likely false knock and you need to be adding ignore knock counts at that rpm
just like my engine and it was all stock other than a rollmaster timing set. I couldn't hear any noise other than the exhaust rattling against the floor pan at hard take off. Not sure what it was picking up as it most certainly not knock. impossible at 9ยบ timing at full noise :lol: < that was my test to see if it was real or not.

Re: MAF Tuning For Larger Cam - Roller 304 Engine

Posted: Mon Feb 02, 2015 4:50 pm
by Monarols71
I've been having a play with various bins and stuff since I got home from work, and it seems most of the tunes don't start taking spark out until 350 mgc or more. Is the lowoctain spark table the one the ecu looks at when it detects knock and retards the spark, and then switches back to the main table when the knock stops?? And then there's half a dozen more "variables" charts that I don't fully understand yet, but it's a work in progress.
The cam is by no means "big", and being a flat tappet, it is not as aggressive in the valve opening and closing as a roller cam, but it's all down to the extra 10 degrees duration.
Has any one tuned a VT 304 with a Crow 4761 or a Crane 284 or 286. Anything around that mark would be a huge starting point.
The more I fiddle (with some very helpful guidance from you people) the more some of it makes sense. Cheers

Re: MAF Tuning For Larger Cam - Roller 304 Engine

Posted: Mon Feb 02, 2015 5:34 pm
by VL400
The low and high octane maps are blended between each other. The more knock that happens the more the low octane table is used, it slowly returns back to the high octane if there has been no knock. Some more info here .. http://pcmhacking.net/forums/viewtopic. ... ane#p36111

Re: MAF Tuning For Larger Cam - Roller 304 Engine

Posted: Mon Feb 02, 2015 8:16 pm
by Monarols71
Thanks VL400. Where I get confused is trying to differentiate between MAP and MAF tables. The tables of that link look nothing like what we have.
MAF Spark Tables.PNG
MAF Spark Tables.PNG (126.96 KiB) Viewed 4276 times

Re: MAF Tuning For Larger Cam - Roller 304 Engine

Posted: Mon Feb 02, 2015 10:52 pm
by VL400
The link explains the blending of the high and low tables as you were asking how the tables are used, its got nothing to do with the tables in your latest picture. Most XDFs probably do not have the adaptive spark defined, but just keep it in mind as to what is happening behind the scenes when your logging.