DBW response?
Thread Starter
Joined: May 2005
Posts: 550
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From: Valdosta, georgia
DBW response? I hear some guys talking that the dbw throttle bodies aren't as responsive as cable ones. anybody have opinions on this, what if anything can you tune to make it more responsive?
Depends on the car. Some people drive a Cadillac or BMW and think all DBWs are unresponsive and horrible for performance, when in fact, these sorts of cars have a "lag" programmed into them, so when someone floors it, the car will gradually ramp up to 100% throttle, since a sudden jerk isn't desired in luxury cars. Theoretically, a DBW throttle can be just as good as a cable throttle; you press the pedal so much, the motor opens the throttle that much. I doubt a muscle (GTO, Camaro) or sports car (Corvette) is going to have any of the luxury lag programmed in, but I don't think anyone here that knows the answer to that question is allowed to give it.
I haven't heard any complaint about the GM performance cars having poor response.
I haven't heard any complaint about the GM performance cars having poor response.
the DBW on GM Vortec up to 2005 is as fast as you can move the pedal. Now I've been messing with some 2006 DBW's and there is a very noticeable delay. I can mash the throttle, and then watch the blade move to WOT with a delay. I have been looking into the tune to see if there is a way to restore the response of the 05 back DBW, nothing yet.
These were all engine swaps...not sure if they react the same in the original vehicle.
These were all engine swaps...not sure if they react the same in the original vehicle.
I'd love to hear more about this. I hate the lag of a DBW throttle body. Granted, I've only driven Cadillac and BMW with DBW so it could be a result of the "luxury lag". However, a friend with a G8 GT says it has the lag as well. Any one with a new Corvette or Camaro that can chime in?
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There are a number of tables in the GenIV ECM's that control throttle opening vs % pedal position, as well as max open rate for a given rpm or pedal position. These are in both the engine calibration and the throttle controller calibration. GM does a lot of work to slow down throttle opening to make the response seem soft and drivable, as well as help reduce emissions a little, and increase powertrain durability.
Regular tuning packages dont expose them or expose them in part with "CAUTION" attached, as if they are set incorrectly the ECM can go not just into limp mode first time you hit the gas, but may also go into permanent shutdown mode. Brick one ECM.
Which is why there are aftermarket boxes that plug in to the pedal circuit and make the throttle more snappy.
The later cars are supposed to use variable throttle rates depending on whether sports mode is selected or not (there are 3 throttle tables which can be referenced by various modes like sports or normal), but have never seen anything between the tables that will make much difference.
Regular tuning packages dont expose them or expose them in part with "CAUTION" attached, as if they are set incorrectly the ECM can go not just into limp mode first time you hit the gas, but may also go into permanent shutdown mode. Brick one ECM.
Which is why there are aftermarket boxes that plug in to the pedal circuit and make the throttle more snappy.
The later cars are supposed to use variable throttle rates depending on whether sports mode is selected or not (there are 3 throttle tables which can be referenced by various modes like sports or normal), but have never seen anything between the tables that will make much difference.
From what I understand, the lag/delay is in the software, which means a good programmer can make it anything you want.
I have an '02 ECM that is set for cable, that will have to go back to the programmer (Jeff Creech) for inclusion of the DBW code. He'll know I have a Yukon pedal and an '01 Vette TB, so I'd expect from him that there is no throttle lag.
I have an '02 ECM that is set for cable, that will have to go back to the programmer (Jeff Creech) for inclusion of the DBW code. He'll know I have a Yukon pedal and an '01 Vette TB, so I'd expect from him that there is no throttle lag.
Thread Starter
Joined: May 2005
Posts: 550
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From: Valdosta, georgia
So you can have a dbw cable ecm and use it on a dbw throttle body? and you can have a dbw ecm and use it on a dbc throttle body? with programming? Like for example if I got a wiring harness from a dbc vehicle and then I have an 05 silverado ecm. Can I upload a 05 express van tune into the silverado pcm and get a drive by cable ecm?
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I found this thread because I was searching for "GTO DBW Slow". I just got the GTO LS2 engine running in my RX7 and I notice a definite delay upon hitting the throttle. It's only very slight but I'd be much happier if it wasn't there.
The engine ticks over, and I lightly press the throttle and it seems like it's about 1/4 second behind or something, and like it builds up more slowly than the pedal movement suggests.
So what are these boxes that go in-line to the throttle body ?
The engine ticks over, and I lightly press the throttle and it seems like it's about 1/4 second behind or something, and like it builds up more slowly than the pedal movement suggests.
So what are these boxes that go in-line to the throttle body ?
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2 flavors of DBW....
I have a 2005 Corvette - LS2 & T56 CAI, LS7 manifolds, and 3" z06 exhaust....
Not very noticeable lag at all.
I also have a 2008 G8 GT - L76 and 6L80E, CAI SLP long tube headers, Corsa cat back....
There is noticeable lag, it may be the 6 speed Auto - but it seems to search for gears when you punch it at various speeds before it decides which one to use.
I have a 2005 Corvette - LS2 & T56 CAI, LS7 manifolds, and 3" z06 exhaust....
Not very noticeable lag at all.
I also have a 2008 G8 GT - L76 and 6L80E, CAI SLP long tube headers, Corsa cat back....
There is noticeable lag, it may be the 6 speed Auto - but it seems to search for gears when you punch it at various speeds before it decides which one to use.
As a former C5 owner I don't think there was much of a lag but I never cared for the feel and will avoid DBW as much as possible in the future. Yes, I know I will be in the minority.
Mine is a 2006 GTO 6spd manual, and I am hitting the throttle while parked up in neutral, and I think there's a little lag off idle.
Last edited by carl0s; Jun 20, 2010 at 04:02 PM.
I did a dbw on a swap into a 77c10 with a5.3l and the throttle response is awesome. It took a while for the owner to get used to it. The pedal was sensitive and on take offs he would make the tires cherp all the time. He called and asked if I could make it a liitle stiffer, I told him to quit crying and get used to it. He has since gotten used to it and is able to control the response and also thanks me for telling him to quit being a cry baby.
I have close to 100 hours of data-logs for DBW. I can tell you that on some Cadillac's with DBW when you go 1/4 throttle pedal the TAC is commanded to 100% 
Most LSx calibrations have over 100 different parameters. How many does HPT offer you to adjust?
I will post how many parameters later today. Maybe even over 300. I can't remember.
Depending on the operating system and the options the DBW system will work differently.
Torque Managment, RPM's per second limit, Traction Control, MPH per Second
Most LSx calibrations have over 100 different parameters. How many does HPT offer you to adjust?
I will post how many parameters later today. Maybe even over 300. I can't remember.
Depending on the operating system and the options the DBW system will work differently.
Torque Managment, RPM's per second limit, Traction Control, MPH per Second
On topic, but completly different brand... Porsche uses a similar setup, so when you pay extra for the "Sport" Button, that is part of it, better throttle response. I am notsure with the GM uses, but I really like E-throttle, it actually makes it easier to drive a manual transmission in the Porsche's.
Mark
Mark
