VVT opinions & help please!!!!
11-04-2012, 10:24 PM
#1
Staging Lane
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VVT opinions & help please!!!! Ok... Ill try to keep this short. I have a 67 olds convertible with a 2009 LY6/4L85e/9 inch 3:70. The motor has the Mast VVT HO cam & springs, Camaro LS 3 intake & injectors, long tube headers 3" exhaust.
After MUCH headaches getting it tuned and running im getting close but need advise. The only local tuner knows LS motors but has never messed with a VVT setup. He was not able to get the VVT running right and feels it doesn't do much anyway so he has it turned off. Don't get me wrong the car runs good and pulls pretty hard from a rolling start.... But to me it doesn't feel like a 480-500 hp car. According to MAST Tech guys, Vengeance racing and other posts my build should be right on 500 or so. I have had low 11 sec cars in the past and this ones just not there. I know it's a 3500 lb car and I also think I need a converter because the donor converter I feel is just too tight. Its a dog off the line, cant even spin the tires. Although very fast by most standards, I'm not super happy with the performance.
So my big question is "do I change my build, delete the VVT and change cams so that I fit my local tuners expertise" and then he can really dial in my car OR do I use a VVT experienced tuner that is 300++ miles away and leave my build alone???
I am planning a power adder after new year (procharger or twins... Not sure yet)
If that makes a difference. Also would love opinions on what converter to use.
Please give me advise based on actual experience if possible as this crap is expensive!!!! Not sure how to attach my build but you can probably find it if you search my name or 67 CUT-LS.
Thanks for any & all help!!!!
After MUCH headaches getting it tuned and running im getting close but need advise. The only local tuner knows LS motors but has never messed with a VVT setup. He was not able to get the VVT running right and feels it doesn't do much anyway so he has it turned off. Don't get me wrong the car runs good and pulls pretty hard from a rolling start.... But to me it doesn't feel like a 480-500 hp car. According to MAST Tech guys, Vengeance racing and other posts my build should be right on 500 or so. I have had low 11 sec cars in the past and this ones just not there. I know it's a 3500 lb car and I also think I need a converter because the donor converter I feel is just too tight. Its a dog off the line, cant even spin the tires. Although very fast by most standards, I'm not super happy with the performance.
So my big question is "do I change my build, delete the VVT and change cams so that I fit my local tuners expertise" and then he can really dial in my car OR do I use a VVT experienced tuner that is 300++ miles away and leave my build alone???
I am planning a power adder after new year (procharger or twins... Not sure yet)
If that makes a difference. Also would love opinions on what converter to use.
Please give me advise based on actual experience if possible as this crap is expensive!!!! Not sure how to attach my build but you can probably find it if you search my name or 67 CUT-LS.
Thanks for any & all help!!!!
11-05-2012, 10:58 AM
#2
You are definitely leaving power on the table if the cam phasing is "turned off" because that cam is is probably ground with a lot of advance to take advantage of the retard range added by VVT.
I would call Mast and ask them for a screenshot of their cam phasing table they tuned their HO LY6 crate motor with. I know they use a different ECM, but phasing vs. RPM can be transferred easily enough. Ask if the phasing is in cam or crank degrees; the factory ECM uses cam degrees (crank is twice cam). Take that table to the tuner. Have them replicate the Mast phasing by changing it incrementally from zero. They can dial in the rest of the tune as they go. My understanding from reading is that you will need to make changes to the fuel & spark tables as you add cam retard. You might be able to get that info from Mast as well, but it will take some translating to get it into the stock ECM.
I would call Mast and ask them for a screenshot of their cam phasing table they tuned their HO LY6 crate motor with. I know they use a different ECM, but phasing vs. RPM can be transferred easily enough. Ask if the phasing is in cam or crank degrees; the factory ECM uses cam degrees (crank is twice cam). Take that table to the tuner. Have them replicate the Mast phasing by changing it incrementally from zero. They can dial in the rest of the tune as they go. My understanding from reading is that you will need to make changes to the fuel & spark tables as you add cam retard. You might be able to get that info from Mast as well, but it will take some translating to get it into the stock ECM.
11-05-2012, 09:13 PM
#3
Staging Lane
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Thanks for the feedback... I will call call mast as well. I don't know much about the tuning software but he did tell me the VVT was turned off in the software when doing the tune. I think he said it wasn't even working because the ECM wasn't getting an oil pressure reading due to the fact that I changed sensors to run my auto meter gauges. Without that reading, the ECM won't use the VVT anyway, so just turn it off.
