I have a huge project coming up. I would post pictures when I get the stuff, BUT, with the ScionLife curse murking around, I most likely won't. It's going to suck, because I like to show people my stuff. But, this is huge. Only 2 people know about it. So, I will be asking A LOT of questions to learn.

So, what is DBW exactly?
Why do we want it out?
What is VVT-i?
How would controlling it help us?

I know these may sound newbish questions, but I need to learn everything about our motor to do this project. I looked for a Helms or Chilton guide for our car, but couldn't find any. HOWEVER, should I just pick one up for a Camry since we basically have the same engine?

 

dbw is just that, electronically controlled throttle system. Our throttle is controlled by a potentiometer with a computer to smooth out the throttle inputs. The only reason i could think of to get rid of it is for a ITB system or switching out the throttle body.

VVT-i is toyotas variable valve timing system which, on our cars, is hydraulically controlled, and changes the intake valve timing.

 

So, what is DBW exactly? Drive By Wire and ^^explained it pretty good
Why do we want it out? Most likely ur gonna wanna keep it...not a bad thing
What is VVT-i? Variable Valve Timing and i forgot what the "i" is
How would controlling it help us? You can squeeze a little more hp (and i do mean a little) if it's tuned properly...possibly with the Greddy V-Manage

 

i = with Intelligence

 

You want DBW out because the computer is controlling throttle, instead of throttle...sort of. Not like older cable systems where the pedel directly controlled how much throttle your giving.
The real reason is there tends to be the slightest lag between pedel push and throttle response...once you start introducing other electronics (piggy back systems) it COULD get worse.

vvt-i is like vtec on a honda, except vtec comes on at a set RPM where vvt-i comes on at some combination of RPM, speed and throttle position, so it's hard to determine when to compensate for it



let's see, your asking about ditching DBW and controlling vvt-i :poonder: I see at LEAST a standalone (AEM EMS) in your future and probably an intake manifold for starters?

 

by the way...i just looked up both DBW and vvt-i on wikipedia after I posted and the explenations there seem pretty good.

 

The reason we don't want DBW is that no stand alone can actually control it. Right now stand alones need the stock ECU still to control the DBW (which really doesn't make it a stand alone) but if you switch to cable then you can have a true stand alone replacement ECU (but it would not be easy because of all the different uses the DBW is used for).

Honestly I believe there is no real lag time with the DBW. My boost gauge changes instantly with the gas pedal but the actual change in RPM is slow. This is due to all the mass the engine has to move to change RPM (balance shafts, flywheel, etc). Our engines are not race engines, they are from a Camry and therefore response was not a major issue when they were being developed.

VVT-I is Toyota's version of variable cam timing. This is a continuous change that the ECU probably has it's own map for (it's not an on/off switch). Controlling it could allow more power and in the case of a turbo car, it could decrease spool up time if tuned correctly.

 

Getting rid of the DBW in itself is easy...and the conversion doesn't take as much work as it might sound.

The problem is, you still need the factory ecu for allot of other things to work. Then you must "fool" the ECU into thinking the dbw is still there. Otherwise you have to ditch the factory ECU all together, but then you are going to re-wire most of the car and put analog guages in your dash. Cool but allot of tedious work.

Glad to see someone else building a big project, we need more of these.

Regards-

Todd

 

VVT-I is Variable Valve Timing with Intelegence.

How VVT-I works is in a nut shell when you reach a certin oil pressure your cam adjuster re-tentions the Chain that drives your cam shafts. This causes your Valves to stay open longer allowing more air to enter your head creating more power. A reason it's not as tunable as Vtec is because VVT-I is on the intake side only. Thus making it hard to move all the extra air that you just let in out. Vtec is Exhaust and intake but unlike VVT-I it switches to a whole new lobe in the cam shaft. so while the theory is the same with vtec and vvt-i they're not that much alike at all.

 

happy birthday, syldrin!

 

hey thanks.