VVT Tuning.....
Dec 3, 2011 | 09:30 AM
#31
Do you have access to any engine simulation software? If you do, plug in a given cam, then advance it 4-8* from striaght up and note the power, then retard it 4-8* and note the power....There will be a decent difference...that is exactly what the VVT system could be used to do. While I don't put a ton of weight in exactly what sim software says, it gives you an idea of what the outcome would actually be.
I am actually very surprised that more vendors haven't done dynos with different VVT tables on their cam, and shown the differences.
I am actually very surprised that more vendors haven't done dynos with different VVT tables on their cam, and shown the differences.
I understand what you are talking about and 100% agree with that. I worked at 2 high performance machine shops for about 5 years. 4 to 8° is not a 60° swing.
Dec 3, 2011 | 10:19 AM
#32
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There is some very good info in the last few pages (post 125+)of this thread by "J-Rod" and "cam".
VVT Cams - LS1TECH
Dec 3, 2011 | 01:25 PM
#33
I agree, If you take 2 motors with the same cam specs, one with VVT (and proper advance/retard tables setup) I don't see how it can't make quite a bit more low end, and a little more top end?
Dec 3, 2011 | 04:09 PM
#35
Moderate advance and retard for powerband tweaking, and big swing to produce a "late intake valve closing" cycle to reduce pumping losses.
Dec 3, 2011 | 07:21 PM
#36
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I did some dyno tuning with a stock cam and found changing the table settings to be worthless as performance modification. I'm not saying someone else could find something but I didn't.
I did find that I could run a little larger aftermarket VVT cam and maintain low rpm drive-ability (Speculatively) vs. what I THOUGHT a same sized non VVT cam would idle and drive like. After trying a few VVT cams and opt'ed to remove the VVT and go with a standard cam. My opinion was that the VVT wasn't working well with my Higher spring pressure valve springs which defeated the whole purpose of VVT. As my logs showed that the actual cam angle wasn't following my table values with the larger cams.
Someone may find some magic power available through VVT but currently I don't think its worth hunting for it.
I did find that I could run a little larger aftermarket VVT cam and maintain low rpm drive-ability (Speculatively) vs. what I THOUGHT a same sized non VVT cam would idle and drive like. After trying a few VVT cams and opt'ed to remove the VVT and go with a standard cam. My opinion was that the VVT wasn't working well with my Higher spring pressure valve springs which defeated the whole purpose of VVT. As my logs showed that the actual cam angle wasn't following my table values with the larger cams.
Someone may find some magic power available through VVT but currently I don't think its worth hunting for it.
Last edited by MNC5; Dec 3, 2011 at 07:29 PM.
Dec 3, 2011 | 07:27 PM
#37
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So you're retarding the cam an extra degree above 5500? I have yet to mess with the upper end of the VVT table, but have decreased the amount of retard in the midrange by about half, and so far don't have any issues. You should be able to pick up some midrange tq gains by doing this. I also tamed down the corresponding VVT spark tables a bit, due to the now higher cylinder pressure.
Dec 4, 2011 | 08:39 PM
#38
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I did some dyno tuning with a stock cam and found changing the table settings to be worthless as performance modification. I'm not saying someone else could find something but I didn't.
I did find that I could run a little larger aftermarket VVT cam and maintain low rpm drive-ability (Speculatively) vs. what I THOUGHT a same sized non VVT cam would idle and drive like. After trying a few VVT cams and opt'ed to remove the VVT and go with a standard cam. My opinion was that the VVT wasn't working well with my Higher spring pressure valve springs which defeated the whole purpose of VVT. As my logs showed that the actual cam angle wasn't following my table values with the larger cams.
Someone may find some magic power available through VVT but currently I don't think its worth hunting for it.
I did find that I could run a little larger aftermarket VVT cam and maintain low rpm drive-ability (Speculatively) vs. what I THOUGHT a same sized non VVT cam would idle and drive like. After trying a few VVT cams and opt'ed to remove the VVT and go with a standard cam. My opinion was that the VVT wasn't working well with my Higher spring pressure valve springs which defeated the whole purpose of VVT. As my logs showed that the actual cam angle wasn't following my table values with the larger cams.
Someone may find some magic power available through VVT but currently I don't think its worth hunting for it.
What springs are you running?
Mar 12, 2015 | 11:39 PM
#40
I know this is old but what tables on a hptuner file are to modified if i buy a vvt cam?
I did't pay attention at the beginning since i always delete it on my trucks, but know that the 14's all are vvt i would like to start looking at this tables and see how they work.
I did't pay attention at the beginning since i always delete it on my trucks, but know that the 14's all are vvt i would like to start looking at this tables and see how they work.