So I had some GSC S2 cams installed and noticed that when the car is cold, the car studders when trying to go over 2k rpms. Is this normal of cars with cams or is something wrong with either the install or tune? The car doesn't throw any lights and the AFRs seem to be within tolerance but the car is definitely not happy. When the car is warmed up, it runs perfectly fine and made 380whp on a mustang. I have no idea what's going on and my tuner says there is nothing he can do to improve it.

 

You need a new tuner; seriously.

 

Beacause of the shudder or the power? 380 on their mustang is the same as 463 at RRE.

 

Who is the tuner? PM me if you feel better about that, but yes, Kracka is correct, find a new tuner because you should not have that issue.

 

I got off the phone with two different tuners and both said it's normal when you have big cams, big injectors and the car is cold cold.

 

It would help if you described the exact scenario. This doesn't happen in first gear, right? Probably not second gear, either. I'm guessing, this happens when you're, say, in 4th and trying to accelerate from 2000rpm where the car is under load and there's virtually no torque due to the higher lift cams and a lack of boost.

 

This very well could be; however, if his driving style were to get that driving shudder that you are describing, it would also happen when the car is warm, no?

 

IME, not necessarily. Once the car is up to temp, the effect isn't as apparent. Perhaps someone more technically savvy than myself can explain why.

 

I have the same cams with 1200's and dont have any issues. I start the car and let it run for a minute or two and they start driving.

 

My guess is they made the cold and warm MIVEC maps identical. Especially with those cams, you need to be nice to the engine when cold.

 

First and second gear only when the car is first started.
This may be the problem but I don't let the car sit for a minute or two. I start it and head off.
this could be. I only have problems when it is the first time starting the car for the day. If I let the car sit for several hours and become cold again, I don't have the problem.

 

^^^ Talk to your tuner as suggested earlier, or wait a minute or tow 'till the car warms up a tiny bit. If that solves the issue, there is no real issue. I haven't seen the X owner's manual, but the one for the IX suggests a minimal warm-up. It's a turbo car and a cold time of the year. It's not a bad idea wait wait a minute or two, regardless, when staring the car after it sat overnight. I drive my family cars right after firing up. They're not turbocharged and they're not equipped high-performance drivetrains manufactured and setup for a given level of tolerance. This being said, talk to your tuner and see what he can do for you. Good luck.

 

Yea I suppose I'll have to let it warm up haha.

 

This happens only if the car has not been warmed up on cool or cold day.

P.S. I let it idle for a few minutes but 4-5 minutes is minimum in below 32F weather in my experience otherwise the car feels stiff

 

Jeez, let it warm up for at least a minute and our cars warm up the fastest out of all the cars I've driven, the heat from the turbo helps warm up the coolant also but still I think its very quick. I see women do it all the time, they start it up and before it even has time to build up oil pressure the car is in gear and they started to drive off, seriously makes me cringe everytime. You wouldnt wanna go for a run when you just got out of bed would you? haha