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Discussion Starter #1 (Edited)
As some one who has added a GTE-VVTi head to an OEM US spec TT Supra, I will give you some facts and information I have learned.

Most of the items in this post refer to the GTE platform.
  • VVTi will add low end power and torque, improve gas mileage, and spool your turbo faster
  • VVTi will in no way increase or decrease your peak HP rating.
  • There is nothing to lose and everything to gain by using VVTi.
  • VVTi is NOT hard to tune
  • VVTi is not complicated
  • It came in 97+ Supras in Japan


2JZ Block FACTS

  • ALL GTE motors have the same rod. (GTE-VVTi and GTE-non VVTi)
  • GE motors with non VVTi also have the same rods as the GTE version
  • 97+ 2JZ motors have additional motor mount locations(can be shared with other Lexus cars)


  • Blocks produced after May, 1995 have oil provisions for VVTi heads (Even US Spec) -Thanks Jeff!
    When I bought a brand new OEM Toyota shortblock it had the hole for VVTi. In this picture you can see the oil pressure adapter is removed and you can insert the VVTi oil feed.


  • GTE-VVTi blocks use a 36-2 tooth crank sprocket compared to a 12 tooth non VVTi


2JZ GTE VVTi and Non head similarities and differences


  • All parts from your GTE non VVTi head will bolt on to your GTE VVTi head (Except the VVTi cam/gear/valve cover)
  • This includes turbo manifold, intake manifold, throttle bod etc, exhaust cam gear, springs/retainers/ valve guides, shims/buckets etc.
  • GTE-VVTi uses wasted spark (This can be converted easily)
  • The factory GTE-VVTi intake manifold is slightly smaller than the non VVTi.
  • GTE VVTi- has DBW (Drive by wire)
  • GTE-VVTi has no idle control valve, because it is controlled by the DBW
  • GTE-VVTi has no EGR because it uses VVTi to adjust valve overlap
  • GTE-VVTi has only 1 Cam sensor in the rear

Performance parts
ALL exaust camshafts fit both VVTi and non VVTi
Converting a GTE to GTE VVTi
There are several ways to do this. Here is what I did
  • Removed factory GTE-VVTi exhaust manifold, intake manifold, factory cams, valves, retainers and springs.
  • Sent the head to the machine shop to check for warping, install fresh valve guides, valve job etc.
  • Installed the fresh GTE-VVTi head onto my TT motor (straight forward)
  • Put all my US parts back onto my new GTE-VVTi head. (Boost logic manifold, US spec intake manifold, throttle body, fuel rail, injectors, Ferrea valves, BC springs, retainers etc.
  • I re-used my HKS 264 exhaust cam and purchased a HKS VVTi 264 cam for the intake side
  • I had to purchase the front VVTi cam cover from a '98 Supra.
  • You will need a coolant hose from a '98 TT Supra
  • Hooked up the OEM oil feed line from the block to the head. Note that their are two Banjo bolts. The one on the bottom has a built in check valve. Make sure you install it in the correct location. My block is an OEM GTE block from a 97+ supra so it was all plug and play. If you have an older style block their are some creative methods out there to make it work. Some as simple as running an oil feed line to the head.
  • I repinned two wires from an old sequential VSV to control the VVTi solenoid.
  • You have to install the VVTi 36-2 crank sprocket (which is a good thing, it gives you more resolution)
  • You can fit all 6 of your GTE coils will fit the GTE VVTi head. Cylinder 1 you will need to trim some of the valve cover and bracket, but it does fit.
    http://i276.photobucket.com/albums/kk32/jsharkey86/A454BE38-A45A-47F5-891C-950F2588F5EA_zps1ecyyzk2.jpg
  • Re-use your original US spec harness and everything will plug back in just like the non VVTi head. With the exception of the VVTi plug we repinned using the old VSV. So no wire hacking was involved and we still maintained sequential ignition!
Since I use ProEFI, all I had to do was change the firmware for the trigger patterns and click "enable" in the software.
Re-tune the car and enjoy the better gas mileage, spool and low end power!



It's too hard to tune they said...
Theirs no parts for it they said....
You cant make as much power with VVTi they said...
All BS
My 850+whp GTE VVTi motor with OEM everything.


Cliff notes:
Bought GTE-VVTi head and installed all US parts onto it
Re-pinned a whopping 2 wires
Clicked enable on the ProEFI


Notice I used all US spec GTE non VVTi parts from my old head.
 

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Discussion Starter #2 (Edited)
This is the basics of converting. If I made a mistake with any of the oem parts or you have additional facts I should add please let me know.

I will post up my dyno showing VVTi on vs VVTi off soon.

I will also add more VVTi tuning tips as I think of them.


VVTi tuning:
  • Add some cam advance at idle to prevent the VVTi cam gear from rattling. 2degrees will suffice. I actually use 10degrees because it uses 15% less fuel and I still have a rock solid idle.
  • Ricer mod- you can play with the advance at idle and make it have a big loping dragster idle. I prefer Lexus quiet.
  • Factory can advance the cam 30degrees. Aftermarket ecu's can advance up to 60degrees. This is helpful for aftermarket cams
  • More advance is not always better. You will need to dyno tune it.
  • VVTi will eventually taper off in the upper RPM's. Mine is completely off by 5500rpm. (Every car is different)
  • You will need a load bearing dyno to tune the VVTi map
  • VVTi is not like VTEC. It is dynamic. So even at part throttle you will want some advance. It is NOT on/off. You have 60degrees of advance to play with.
 

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Good info.

In addition to the 97+ blocks having the larger port for VVTi oil feed, I have 2 95 USDM blocks that have the bigger port. One is a GTE and the other is GE, so it's possible to have a VVTi ready block even pre 97. Of course you can also run the feed from a different source if your block has the small port.
 

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Really good info. I'd like more info on the amount of degrees you can advance or retard the cam and in what increments. I've been reading you get 30 degrees in increments of 5. For example +15 +10 +5 0 -5 -10 -15
 

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Really good info. I'd like more info on the amount of degrees you can advance or retard the cam and in what increments. I've been reading you get 30 degrees in increments of 5. For example +15 +10 +5 0 -5 -10 -15
It is only possible to advance the cam. And there are no specific break points. You can do 1 degree or 12 or 13 ect...
 

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It is only possible to advance the cam. And there are no specific break points. You can do 1 degree or 12 or 13 ect...
Hey thanks! I've read your build thread a few times. Can you share how you tune the vvti solenoid with the proefi? I use the AEM infinity but I'd like some examples.
 

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Hey thanks! I've read your build thread a few times. Can you share how you tune the vvti solenoid with the proefi? I use the AEM infinity but I'd like some examples.
The VVTi oil control valve operates on an H-bridge circuit like the IAC motor. I'm no tuner but what exactly are you looking for advise with?
 

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The VVTi oil control valve operates on an H-bridge circuit like the IAC motor. I'm no tuner but what exactly are you looking for advise with?
It works on any regular low side driver, same as injectors or other actuators controlled by the EMS. Factory rate on the OCV is 3ms, but it'll work fine between that and 6ms. A flyback diode should be added if there isn't one already on the output being used.
 

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JZA80 > JZA70
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very good information, really is the most useful post
 

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thank you for such an informative post

thank god now that all those dweebs all around the world who made up those stupid myths about VVTI can now shut their regurgitating mouths up
 
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