Hi all, total newber here. I just purchased a sweet black 09 SS/TC a few weeks prior.

I noticed that whenever I'm fiddling with my little gran turismo fisher price gauge and watching boost pressure, it doesn't hit 15 unless my tires are filled properly. If, for example the cold weather throws my TPMS sensor light, she steals my psi!!

Im right, right? What parameters does the ECU consider when deciding how to operate the wastegate? My buddy tells me NO WAY, and that the car is most probably taking things like ambient air temps, IAT's (whats that??) coolant temp and knock history into account. But im saying I have first hand experience here.

HALP!

 

dude the TC balt has TQ on demand.. meaning it only pushes the PSI needed to keep the car at 260 TQ...

 

Put more air in your tires.

It is doing it because you don't have enough air in your tires to safely run that fast.

 

On demand torque..?

So you're saying that the ECU sees throttle position as a "requested torque" parameter? Or are you saying the car will adjust wastegate duty cycle to find a specific caluculated load within its abilities taking air temp and barametric pressure into account?

And I know right... i filled my tires and bam, 15psi!!!! So who's right?

 

There is a desired air load table along with a torque management table

The car is programmed to make 260 ft lbs stock no matter what

If it makes more...you will boost less to make less tq

In the winter on a stock tune I boost 10 lbs.

 

well maybe the car thought you had a flat.. so it would limit boost.. but IDK.. the TC balt has even more OBDIII crap on it then the 07 SS/SC.. and OBDIII is JUNK!!!!!

 

Ok, I understand now I think. What I don't understand is how the "car" as you say (more the ECU/ECM) determines a boost pressure suitable to make 260 tq. For example if we can calculate load which is simply MAF measured g/s x crank revolution (either 360 or 720 depending on how fancy chevy engineers are) then we can "estimate" torque. But the loading conditions like air temp and humidity play a HUGE part of finding true true max torque.

And btw fellas, max torque hits as a peak on a continuous curve through your power band... so WHY exactly am I boosting 10psi from onset to redline???

If I were to fill my tires to say, 45psi would I offset the 10psi and maybe hit 15 again??

 

There is no such thing as OBDIII

Are you on drugs? Seriously?

 

I answered the OP's question

It bases it off of EVERYTHING.

Want more boost? Tune it...don't over inflate your tires and die.

 

Troll?

 

I lol'd, Try again n00b

 

turbo cars iat(intake air temp) are low that nots a problem

the comp is limiting your boost because it does not have to work as hard to hit 260hp

you arent knocking with a stock car unless your using 0 octane fuel lol... but 91 or better in it and you will be fine

keep tires at 32 psi range

 

My head hurts trying to read some of these ******* posts.

 

possible troll is possible

 

What is a troll exactly?? Was it the halp or the 45psi comment??

In all seriousness I want to run a winter wheel/tire combo and I do NOT want to mess with moving the sensors over. Will having NO sensors (and surely tripping the system warning) effect anything?

Thread CN: Does to ECU use TPMS info to modify requested torque, or does the TPMS work as an independant system that does nothing more than flash a light at me?

 

Unless your car is flashing reduced engine power on the display there are no problems. It maybe running less boost because it is colder outside, but your TPMS has no influence on your boost pressure or engine power whatsoever.

 

if u lower your tire pressure, it does limit boost for "safety precautions" to ab 5psi

i found this out on the track sunday

 

How low do you have to go for it to do that?

 

that's weird, i've got a TPM warning atm from how cold it dropped and i haven't filled the tires back to 33psi, they are nearing 25psi atm but i haven't notice any reduced boost.......other than because it's cold

 

I drop my front tire pressure at the track and there is no boost change whatsoever

 

Well on my 2008 Sky Redline I run my tires at around 24psi when I drag race. never has affected the power. If it is colder outside the boost wont go as high because it doesnt have to to keep the power at around 260. I could see it going into low boost mode if the tires were really low but how low do yo uneed to go to race?

 

well since already the majority of the post on the thread CLEARLY STATE that low tire pressure cannot cause low boost........unless the senor is completely faulty which so far nobody here has had happen to them........... i still think this guy is a troll

 

i'm just lettin' ya know what happens in my balt perhaps mine is the only one in the world that does it, idk...

 

I think the display is hording your boost like a squirrel hiding nuts....when you need it you will find it.

 

did you check your fuses????