Curious! Why do so many take VTC out after Tune?

[frack]

I put my vtc in after first tune and stock motor. I have a Vmax ported throttle body, SS3 VVT cam and tune from GPI now and I still have not taken mine out. Even with all my mods I still love to have this thing on. Car feels much more sluggish when taking off when this is dialed down to 0. However, my stall converter is 3800 stall that feels more like a 4000 to 4200 stall. So if I am not punching the pedal or using the paddle shifter you would understand the feeling. With that said, I do not generally dial past 3. Only if I am at a light. If it is dialed past 3, it can get a bit temperamental. So just really curious why everyone says they are selling theirs because now they have a tune. In my case a tune did little to nothing for throttle response. The ported throttle body was done after VTC, so the VMAX felt like a total waste of money.

[Olddudesrule]

Left mine on, saw no reason to remove it. I keep it on SP7 nearly all the time. Still love the response. I also ported my TB after installing the VTC. Noticed a difference, but mainly on initial tip in of the throttle. Got rid of a good amount of the slight hesitation that was there, so along with the VTC's improvement of the throttle response in general, it was a good match IMO.

[mydreamcar]

Same here left mine in, as it was very jumpy after my tune and gear install. So for normal driving, stop and go it's on zero, track and aggressive driving I turn it up. Besides it was such a pita to get to it with my bad back I wasn't going to mess with it again

[shibbs]

A good tuner will adjust your throttle map any way you like.

[Rhino79]

The throttle maps on the e38 ecm will force reduced engine power and could brick the ecm if moved more than a couple percent.

[InFiD3ViL]

I got my VTC after my tune. Made things much nicer and never had an issue at SP8 at all times.

[Ace0751]

With a tune, the vtc will mess with the numbers in the tune giving it more response than it was setup for. This will result in reduced engine power and a check engine light afterwards. At first the tune will coexist with the vtc but eventually something will fault and will reduce your engines power. Had mine installed for a few months after the tune and eventually took it off, didn't feel a difference after removing the vtc. Plus a custom tune will map the throttle response to your liking with the right tuner.

[CamaroFred]

You do know these fly by wire cars will learn your driving preference and adapt?
For instance you drive a lot in downtown Chicago it will figure out you don't need 100% opening every time you start to move and will slow the throttle opening to adjust, making it easier to flow with traffic.
Start to drive in the suburbs where traffic and speed limits are faster it can take some time but it will adjust to that.
Move out to Wyoming were every one wacks it to 100 ASAP and it will adjust to that.
All the VTC does is fool the computer to think you are driving in Wyoming even though you are in downtown Chicago. Which can actually make the vehicle more difficult to control.
Wide Open Throttle is still always WOT in case of emergency. Like a school bus is going to whack you in the door if you don't move.

[frack]

SP8!! Wow! I dialed up to 8 today sitting at a stop light early in the morning on the way to work and could hardly touch the pedal when I dumped it down. Felt like I was just learning how to drive a manual for the first time. Should of went that route instead of an auto. Every fraction of movement on the pedal was making car bounce up down the rpm range. However, the car was literally just getting warm. I have noticed these throttle bodies are a bit touchy when cold. Glad no one was around to see that shit. So far the VTC is at its best when on a road course. Getting in and out of corners quickly.

[Bo White]

Yeah Ive seen alot of people put them up for sale once they get a tune and/or ported TB. An aggressive idle tune or port will throw a code alot of times if one is left on 50% of the time.

[InFiD3ViL]

Originally Posted by frack

SP8!! Wow! I dialed up to 8 today sitting at a stop light early in the morning on the way to work and could hardly touch the pedal when I dumped it down. Felt like I was just learning how to drive a manual for the first time. Should of went that route instead of an auto. Every fraction of movement on the pedal was making car bounce up down the rpm range. However, the car was literally just getting warm. I have noticed these throttle bodies are a bit touchy when cold. Glad no one was around to see that shit. So far the VTC is at its best when on a road course. Getting in and out of corners quickly.

I know exactly what you are talking about in regards to the bouncing or rocking. That is the exact wording I used when trying to explain it to my son when I let him drive it. I told him that if you are not careful, it will look like you are just learning how to drive a manual. He wasn't and it did.

It took a little time to get used to of course. If anyone else tries to just jump in my car and drive off, it can be very intimidating...or scary. When I got my stripes done, the shop owner was amazed. He told me when he just tapped the gas peddle that the car felt like it was going to take off on him. That was my own fault, as I usually dial it down if I am having work done on it at a shop.

But overall I really like the thing. If it ever gives me trouble I will uninstall it, simple as that. I am usually not into any mods that 'fool' the ECU with false or skewed readings, but the VTC has performed exactly like I wanted and even more than expected. I certainly can understand that it is not for everyone though.

Eventually I plan to go with a Bo White Stage II PTB. Once I do that, I will probably remove the VTC.

[christianchevell]

A potentiometer adjusts the resistance to delayed pedal response that is built into the pedal in Drive By Wire that can be useful to those who want to " burn rubber with what the factory gave them", even though they may be dealing with Torque management also and lack of low end grunt. Making the pedal more instantly responsive also allows the car to put the sudden jolt to the wheels compared with the car deliberately not wanting to burn rubber with all its systems and sticky tires stopping even with traction control off the wheel spin as its not sudden being delayed with time for torque management to kick in there also ....LOL

The reason for not having one..well when you get higher in power you have to avoid burning rubber with a good tune;( and the torque to burn rubber with all the nannies on I have, and I have to avoid even the possibilities of accidental rolling burnout. I get fishy a little if I hit it hard..a lot but counter of course its about engine torque down initial launch or rolling torque down from high rev shift. And I have suspension mods to counter for better control and to avoid wheel hop.

That and well lots of guys have had CEL problems and other related problems while some swear by them..they just try to adjust the magnetic resistor to remove the delay made to make the car safer in general motors terms....

[Pace]

I am tuned and keep mine on 4. I wouldn't want it tuned that way though. If I need service or wife drives I like being able to adjust on the fly back to zero.

[Olddudesrule]

Originally Posted by Ace0751

With a tune, the vtc will mess with the numbers in the tune giving it more response than it was setup for. This will result in reduced engine power and a check engine light afterwards. At first the tune will coexist with the vtc but eventually something will fault and will reduce your engines power. Had mine installed for a few months after the tune and eventually took it off, didn't feel a difference after removing the vtc. Plus a custom tune will map the throttle response to your liking with the right tuner.

The use of the word "will" is misleading. In your case, and obviously in some others it has created or assisted in creating issues. I've had mine on for over 1 1/2 years, and it's coexisted nicely with the ECM. These cars have modern electronics, and as we have all read, will throw codes for many, many reasons. Finding the causal factor is sometimes hard to do. Couple this with the "shading" forums give certain issues, like the LS7 valve stem issues with some C7 Z06's, and you'd think that the majority are having these issues, or the most definitely "will"......

Look, I like the changes I got with the VTC, some don't.....live and let live, we rarely live in a world of absolutes.