Printable View
Hey guys, I have a buddy that got his hands on a 2017 Tahoe police package...Its all factory, no bolt ons yet, According to him its slow and not much pep... being that its a ?17 theres not much out there in the repository for a quick plug and play either. Is there anything I can do with the tune on a stock 5.3 to get a little more out of it off the line???
I wouldn't trust anything from the repository anyway, that's not really what it should be used for in the first place.
There are things you can do but you need to understand this torque based computer to really get something from it. Minor things like power enrichment settings, changes to the timing curve may help. Transmission tuning can go a long way too. Adding in a alcohol sensor to run E85 fuels is a good way to get a little power bump.
Being a police package I'd be curious what rear end gears it comes with. If it's like 3.23's, those are hurting things a lot. It needs different gears to really help, like 3.73's or 4.10's with that 6 speed auto.
Thanks for the reply! He has plans to do a cam swap and possibly rear gears... Just trying to help him out in the mean time. Havent even had a chance to look at it in person. And I dont know the first thing about tuning these 5th gen engines. Was hoping there were a few small adjustments we could make in the meantime...
Stock file from PPV Tahoe we just put a whipple on. Looks like 3.08 gears.
Attachment 92466
The most notable change you can make will be the cam timing. Easiest thing to do is zero out all three tables. You can add two degrees cam timing on the other end starting at 5000 and step up to 6 degrees at 7000. interpolate between 5000 and 7000. Thats a good starting point for any vvt engine. The factory retards the camshafts for "egr" effect, and it hurts power by robbing compression. You will notice the exhaust tables are already zeroed out because its not used. You will have to adjust the intake vvt side. Make sure to get all three tables. Drop power enrich enable to 60 percent so it comes in a little quicker. PE rate set at 1.1.
Just wondering why advance cam timing at upper end and not at the lower rpm range. I thought advancing it in the lower rpm range and retarding as it comes up and fully retarded by 5k would give the most torque and rpm range. Enlighten me, I know it's only a single cam and maybe it's just the way they are ground and in the real world the way you described may be the best ?Quote:
Originally Posted by Mbrowning
You are correct. The numbers refer to retard, not advance....and 0 refers to the cam's parked position with in most cases is about 8-8.5 degrees advanced. It takes a few moments to get your head around it.
Search VVT on here and you can read what several of us have already written about it.