VVT-i controller?

i got banned from scionlife
i can't see the thread

Originally posted by mach5@May 14 2005, 05:22 PM
i got banned from scionlife

i can't see the thread

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How did you do that - Marty and me tried - they didn't ban us

the gts has VVTL-i...vvti-i with lift. it has a secondary lobe on the camshaft that it switches over to at a ceratin rpm, similar to vtec. VVT-i alone is variable timing, it simply advances or retards the intake cam (and soon exhaust cam with toyotas new Dual VVT-i ). This movement of the intake cam is based on rpm and load andis constantly moving, it doesnt "switch over like VTEC and a controller like the one being discussed would show no benefit.

Originally posted by zoltiz+May 14 2005, 05:01 PM-->QUOTE (zoltiz @ May 14 2005, 05:01 PM)

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@May 14 2005, 05:22 PM
i got banned from scionlife 

i can't see the thread

Click to expand...

How did you do that - Marty and me tried - they didn't ban us

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i'm just that good
tell a girl that i will straighten her out with my pipe in her ass
tell someone to go end themselves
call the whole site a joke
etc etc

it all added up to a good ole bannin

I read through the English documentation on the install and tuning. It gives you control over VVTi and basically fools the computer into thinking you have more or less air than you actually do, it's not really an enrichment scheme per se, it's a work around that is common to most piggyback fuel controllers that don't directly control the injectors (S-AFC, etc.)

Personally, I wouldn't waste my money on this. I'd spend the money necessary to put in an F-Con V to get direct control over the engine and have the self-tuning features the F-Con has. One of the biggest problems with tuning Toyota engine control with piggybacks is TCCS's ability to modify the fuel maps based on data provided by the O2 sensor. Since the 2AZ has a wideband, I'm sure this is even more challenging.

Here's what happens: you adjust for a richer mixture, the wideband detects a rich condition, and adjusts the fuel maps to bring it back to what it was told is normal at the factory. Your rich adjustment just went away, so you go back to the piggyback and dial in more rich. TCCS sees it again; and again, adjusts it back to what it wants. This continues until you exceed the 20% built into the ECM, and your piggyback is attempting to make adjustments outside the ECM's ability to change. Game over. Engine is in poor tune, and you have to reset everything to zero and start all over again. LOTS of Supra tuners learned this the hard way.

Tuning Toyco engine management with piggybacks is very challenging with only rpm and airflow inputs. You need to know a LOT more about what is going on to fool the ECM and have it stick. That's part of why most serious aftermarket tuners ditch the OEM ECM and go for AEM, MoTeC, Autronic, Haltech, or some other aftermarket device. It's just too difficult to tweak the OEM setup with piggybacks.

This doesn't mean it's impossible to do, it's just harder. HOWEVER, the tC ECM does have the ability to be modified using an external device. I don't know the details of this, nor do I have the $8k to buy the tools to do this, but I suspect this is how Scionspeed is modifying the ECM to work with their turbokits. I could be wrong, but my understanding is they don't depend on piggybacks. FWIW, the GReddy eManage is also a piggyback with highly advanced capabilities, the F-Con V can also be a piggyback or a standalone. Both of them are far beyond the ability of this device, and offer a MUCH more comprehensive solution to the tuning problems brought on by aftermarket FI.

Here's the link to their documentation.

why do i always enjoy reading Lance's and ZEROmotorsports's posts. This is why i love being a member of this forum.