Printable View
I have an issue where my Cruze will reduce the throttle when trying to accelerate. Sometimes it will cut back to about 25% but isn't always as drastic. I could see if it was spinning the tires but it isn't. It will do this ]even on the expressway. The knock retard when it does this is typically only a couple of degrees max when this takes place. It also shouldn't be trying to reduce torque because those values have been increased. I am at a loss why this is taking place.
So, it coud be a few things. First, please post a log and the tune you made that log with. The throttle is used to control more than just knock and stuff. The way I think about it, is that "torque" is controlled by the amount of air coming in, aka your TB. It's just a way someone explained it to me, and it started to make sense. So, in a given condition, for instance WOT, if you want your throttle blade to stay open, your driver demand (commanded pedal torque or whatever) needs to be higher that your max engine torque in that same condition.
Lets say at 5000 RPM, you have your max engine torque set to 200 lb/ft. Your driver demand table at that same RPM, at 100% pedal, to 180 lb/ft. You throttle blade will only open up as far as it needs to in order to make that power. Since it's lower than your max tq, it only needs to open 90%, because that is all you are asking it to make. If you set the dd from 180 lb/ft instead, it will keep going as high as the max torque will let it, keeping your throttle blade open. Granted, there are a lot of other variables, but that is the general idea. If you are increasing torque values, how and where are you increasing them?
Regardless without a tune and log file it's impossible to tell. So please post those and I am sure someone, if not me, will take a peek. As for the KR, even just a degree or two will cause it to take measures to reduce torque, with one of the safer/easier ways is to simply close the throttle blade, and let the rest of the system follow suit (less air coming in, spark stops being so aggressive, etc, just like you let your foot off the pedal. I mean, I am up so if you see this post the tune and log and I will check it out.
I think I figured out what was going on after reading a different thread that was talking about the same thing. I didn't see it before posting this one. I am going to make a couple changes that were suggested there and make changes to the dd which were not done. It was still stock values.
Post your tune up. Sounds like you're heading in the right direction, when you tune these you have to up driver demand. Also make sure you're not hitting one of the TQ limits.
Ok I got it sorted. Either something was corrupt in the tune or I had something messed up. I went back to my stock tune and started over. All seems good now. When the check valve in the intake failed and was bypassed with a fix to an external one the intake was ported. After that I wouldn't get to 10psi of boost. Now I get 15 but I'm pretty sure now I am getting close to the limits of stock turbo. I think it's time for the ZZ Performance Big Wheel turbo for it.
Glad to hear it!
FWIW, you can go up to 22-24psi on the stock turbo, but it's not efficient up there and service life is severely diminished. I've been running ~20-21psi on my Sonic for over a year now. Make sure to focus on overall airflow, not the boost psi.
Well in my current tune I now peak out at about 18 psi. I don't think I would see 21 with the ported intake. These intakes unported have very restrictive runners. Stock tune with the ported intake it only gets to 9 psi. I really cant push it any harder right now than I am either because it is basically out of injector. The duty cycles are getting into the 90s by 6k rpm. It has to be right about 200hp on premium fuel right now. It's time for an injector upgrade and quite possibly a flex fuel kit so I can run E85.
I'm running 25 psi on a ported intake and stock turbo + other stuff.
I'm curious how you did that with the stock turbo without seriously overspeeding and overheating it. You must have changed injectors to run that much boost unless your airflow is low for some reason. Like I was saying I'm out of injector and only peaking at 17.5 to 18 psi. I would find it hard to believe if you still have stock injectors that isn't going lean up top.
It has 60lb injectors. The turbo is fine, and when it isn't I will install the big wheel, if not before. I've been running it very hard for a long time. Made some people very mad, too ;)Quote:
Originally Posted by jmardlin
I would also ditch the aftermarket boost check valve and just install an OEM intake and monitor the flapper. I used the popular fix on cruze talk and while it works it doesn't work well. The OEM system is so much better, even if it has a limited life.
I still cant get more than 18psi of boost.
Jeff which one of the pcv kits did you have ? I have the version one with the big ol brass valve. What mods do you have?