Any experience with VVT tuning for BTR V225

[DongBilzerian]

Right off the bat I'm the driver of this car, while I did have some experiencing with tuning my boosted VQ prior via Ecutek, I have not even remotely tried diving into this car. So the problem I have here is I've moved to a '14 C7 LT1 and put a BTR V225 in it. I gave the tuner the VVT tables from BTR and they said they noticed no difference in power using the tables provided by BTR vs setting it to 0 throughout all gears. That's six and a half dozen to me, however now the car has a light surge if you're sensitive to it at partial/light throttle when cruising under 2300 RPM. I found someone else with this issue on a different forum whose tuner said it was due to the VVT, after trying to fix it three times, they went to a lockout instead of a limiter. I'm running out of money here trying to iron out the remaining issues on this car, does anyone else have any experience with similar issues on this setup and either have a recommendation on a tuner in SEPA or any information I can discuss with the tuner to remedy this situation?

[Alvin]

The VVT surge that you're likely reading about is at lower RPM where the factory cam advances by some huge number like in the 20's. +/- 4 degrees cam advance is barely going to make a difference.

The issue is likely in the tune somewhere. Without seeing it.. it would be hard to know what it is.

[1scls1z]

Right off the bat I'm the driver of this car, while I did have some experiencing with tuning my boosted VQ prior via Ecutek, I have not even remotely tried diving into this car. So the problem I have here is I've moved to a '14 C7 LT1 and put a BTR V225 in it. I gave the tuner the VVT tables from BTR and they said they noticed no difference in power using the tables provided by BTR vs setting it to 0 throughout all gears. That's six and a half dozen to me, however now the car has a light surge if you're sensitive to it at partial/light throttle when cruising under 2300 RPM. I found someone else with this issue on a different forum whose tuner said it was due to the VVT, after trying to fix it three times, they went to a lockout instead of a limiter. I'm running out of money here trying to iron out the remaining issues on this car, does anyone else have any experience with similar issues on this setup and either have a recommendation on a tuner in SEPA or any information I can discuss with the tuner to remedy this situation?

I think VVT and VTT is being confused here. More than likely the Torque Model is off. Timing is probably swinging down into the negative range making it surge. Log idle timing and torque and see where it is at. Ideally you want it in the teens. You will need to pull torque in the idle areas of the torque model for the -10,0,10 degree maps to get the timing up. I do all the of the VTT maps...air mass, map, e85 airmass, e85 map. I set E85 a little higher than gasoline.

[edcmat-l1]

I think VVT and VTT is being confused here. More than likely the Torque Model is off. Timing is probably swinging down into the negative range making it surge. Log idle timing and torque and see where it is at. Ideally you want it in the teens. You will need to pull torque in the idle areas of the torque model for the -10,0,10 degree maps to get the timing up. I do all the of the VTT maps...air mass, map, e85 airmass, e85 map. I set E85 a little higher than gasoline.

I agree with this. Most likely in the virtual torque. Seen it many times.

[GHuggins]

Without seeing a log or tune we're all just guessing at what's going on, but something I often see is throttle surge. Throttle surge can be caused by cam timing moving around which is what you're referring to reading about. Usually something is damaged on cam install to cause this and what happens is the cam will rock causing the referenced torque model to change.

Throttle surge can also be caused by other things though. Since I do a lot of trucks I see it due to background throttle control settings. You can alter the torque models to help it but that can cause other problems on it's own and if it's doing it with a stock torque model then you're going to have a lot of work ironing it out.

personally I prefer to run variable cam timing in everything possible. Is it time consuming to dial in - hell yes, but it's worth it. All you have to do, as long as the VE has been dialed in, is look at the VE table with changing cam timing to see if it's adding airflow or not. They nearly always do when retarded some, plus you can gain some decent mpg's with retarded cam timing in the lower loads.

Make sure your VE is dialed in. You can use these channels to post a log with. To load them - download - right click - show in folder - copy - open the scanner - open recent channel config - open recent config - paste here and click on.

[Alvin]

I almost guarantee that the tuner didn't touch VVE and therefore virtual torque is jacked up. Post the file and we will see.