from what ive heard, the car is tuned like this for emissions. however, i really dont appreciate the added synchro wear it causes in addition to clutch wear. If i wanted, i could wait 3 seconds for the rpms to drop going from 1st to second, but that is just ridiculous. i dont like to wait so ill get the synchros working and spin the clutch a little when going into second. to design a car with emissions priorities over longevity seems kind of retarded to me. i know a lighter flywheel will also help, but i have a feeling the tuning of the ecu is the major player here.

so what if i go to a gm dealer and tell them that the rpms hanging like this is bad for the clutch and trans. do you think they will tune it out for me without voiding my warranty? i would be willing to pay them for it of course. i know they do the stage tuning, so this should really be a piece of cake IMO. my car is completely stock.

 

clean your throttle plate and the slow dropping rpms wont hurt a thing

 

Turn on your AC. Seriously, it puts a load on the engine and causes the RPMs to drop MUCH faster.

 

 

Drive with the a/c on. You can't "tune it out" unless you remove the supercharger, since the rotating mass of the blower is generally what's causing the delay in the first place.

 

sounds like you might have a vacuum leak....

 

does anyone know if the throttle plate is being fully released at high rpm with no throttle? because its drive by wire, the ecu could leave it slightly more open until the rpms drop to idle. this would explain it more than anything if thats the case. my corvette has at least twice the amount of rotating mass than the cobalt even with the addition of the supercharger, and its rpms drop much faster. so im not buying the inertia of the sc being the main issue. i definitely have no vacuum leaks, and i dont want to be driving around with the ac on all the time. ill try cleaning the tb tonight and let u guys know how it turns out.

 

i found this thread that confirms the throttle body is staying open. sadly, noone seems to have figured out a solution...

https://www.cobaltss.net/forums/2-0l...13/index4.html

 

whats the vacuum gauge reading at idle??

 

19 in hg at idle running 12.5psi wot. no leaks.

 

if your talking about having the clutch in coming to a stop then drops down to normal idle it does that to aid in reaccelration from not coming to a complete stop its just the way it is so i would suggest you just learn to live with it like we all have

 

There is no "fix" for it. HPT doesn't have the emissions tables that cause the slow throttle release acessible, so you can't tune it out. Just learn to deal with it, it will always be there. Lighter flywheel doesn't change anything, it's the car holding the throttle open to maintain rpms and keep air flowing though the engine so you don't get unburnt fuel out of the exhaust.

 

I don't see what the issue is, I find it helpful in pittsburgh tunnel traffic, it keeps the engine rpm up so the engine doesn't have to force the clutch to slip up to transmission speed, in moving stop and go traffic

 

well that blows. guess ill deal with it.

 

if you raise the etc scalar in hptuners it should fix your problem easily.

 

etc scalar defines the cross sectional area for the airflow through the tb right? how does changing this value affect the speed at which the throttle plate closes? sounds like it would take a lot of effort. all of the fuel tables would need to be remapped.

 

in for answers

 

no the fuel maps dont need remapped when changing the scaler the scaler controls how fast or slow the the throttle plate moves

 

wow thanks man. every post i have read says there is no access to directly control the speed of the throttle plate. although most of them were from 2-3 years back. i knew someone would eventually be able to figure it out.

However, everything else left alone, would this cause lean spikes when the throttle is punched, and rich spikes on immediate decel?

has anyone done this??

 

sounds like you need tuned you can use the scaler like when you put ona ls4 to slow the throttle plate down

 

If you did that, and cut the value down low enough to eliminate the hanging rpms when the engine is freewheeling down, you'd also have issues with the ETC during IAC functions, might end up with surging or possibly stalling.

If your car is hanging that badly that you are considering a retune to fix it, id suggest check for vacuum leaks. Normal operation just isn't that bad to worry about.

 

its not like its a problem with the car or anything, just an annoyance. all lsj's do it. i just dont like it. ive seen a lot of other compact cars do the same thing, and its annoying.