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I supported Toymods
Location:
Ademelaide, SA
Registered:
July 2003
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20v vvti actuator
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Tue, 11 October 2005 02:00
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is it necessary to run vvti with aftermarket ecu and a t28 turbo on a blacktop 20v?
the reason i ask is, my new engine has a broken vvti actuator.
would it be beneficial at all to blank off the hole in the side of the head, or maybe even set the actuator so the vvti is on all the time?
cheers
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: 20v vvti actuator
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Tue, 11 October 2005 02:03
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It's not necessary to run it. On most engines, it's beneficial if it's working, especially if you have control of the change over point.
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: 20v vvti actuator
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Tue, 11 October 2005 02:03
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Oh, and it's only vvt 
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Registered:
July 2005
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Re: 20v vvti actuator
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Tue, 11 October 2005 02:54
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loose a bit of torque, but then again you got a turbo
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Location:
SA
Registered:
August 2005
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Re: 20v vvti actuator
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Tue, 11 October 2005 07:23
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it's an electronic controlled solenoid, as far as i'm aware, so even microleb's can switch it on and off...
what i want to know is, can i have it on permanently, and will it affect the way it runs?
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I supported Toymods
Location:
Ademelaide, SA
Registered:
July 2003
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Re: 20v vvti actuator
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Tue, 11 October 2005 09:33
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sorry Jon 
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Location:
Tasmania
Registered:
May 2002
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Re: 20v vvti actuator
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Tue, 11 October 2005 11:18
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I can hardly believe people are still wreseling with the basics of this.
As far as I know, the actuator in the silvertop and blacktop are the same. On the Silvertop is it called VVT, and the cumputer only uses one thing (to decide) to switch the solenoid on or off. I think on the Blacktop its called VVTi, because the computer uses more than one thing to decide when to switch it.
Wether your aftermarket computer controlled system is VVT or VVTi depends on how inteligent you think you have made it, and its up to you to decide. What sticker would you rather?
Wether its working or not, valve timing is still important. Use a degree wheel and dial gauge and sus it out!!!!
As for turbo, I can't think of any factory turbo system that uses VVT of any type. (My knowledge is limited to popular Toyota models). Maybe late model 2JZ-GTE uses VVTi? I'm not sure. Either way its not really needed. But if its fixed, be sure to know what the valve timing is!!!
Also beware. If the VVT controler is not connected or not working, the intake sprocket will not be locked to the cam when the engine is off and can still turn either way, so be aware of this if you are dialing in the cams with the VVT system still in there. For a serious motor not using VVT, you would get a new sprocket or cam or whatever and make sure the sprocket is properly locked to the cam.
But thats just my opinion, dont take as fact...
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Location:
Toowoomba
Registered:
May 2002
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Re: 20v vvti actuator
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Tue, 11 October 2005 12:06
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Jonny is almost correct. If you don't have the VVT / VVTi actuator working how will you maintain oil pressure to keep the cam sprocket fully advanced or retarded to the position where you have set the cams up. You would be better to replacae the sprocket with a standard one except that they don't fit onto a VVTi camshaft.
Both the 1JZGTE and 2JZGTE (both turbo'd) have VVTi versions - only on the inlet camshaft. I have a '98 model 1JZGTE VVTi in my Lexus IS200. When you dismantle the VVTi cam gear it is activated by maintaining oil pressure on both sides of the piston.
The control of the actuator is a PWM (pulse width modulated)signal - not an on / off signal hence most computers can't control it. Motec and Autronic are the most likely units to control it.
You can run without the VVTi with little difference in overall power - you just looose a lot of the VVTi advantage of much better torque at lower revs. It will feel different to drive.
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Location:
sydney
Registered:
March 2003
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Location:
Brisbane / Gold Coast
Registered:
May 2002
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Re: 20v vvti actuator
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Tue, 11 October 2005 13:02
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Guys.
20v's of any colour top have plain old VVT.
The cam is advanced with oil pressure that the VVT solenoid lets in, and retards when the VVT solenoid turns off.
That's as complex as it gets.
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Registered:
October 2005
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Re: 20v vvti actuator
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Tue, 11 October 2005 13:25
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You could dodge something that'd do the job with a tacho that supports a shift light. Rig the shift light to a relay and then to the solenoid.
There's possibly a moderately simple way to emulate the i part of vvti.
Find some form of vacume operated switch, rig it to switch at about 8" of vacuume (same as the gze supercharger is) and put it in sequence so that it has to be above 8" of vacuum AND above 5500 rpm.
Ofcourse, a properly tuned computer with an auxilery switch would be the best idea.
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Location:
Tasmania
Registered:
May 2002
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Re: 20v vvti actuator
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Tue, 11 October 2005 13:27
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... same with the new Camry and Corolla (1AZ-FE, 1ZZ-FE).
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: 20v vvti actuator
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Tue, 11 October 2005 23:52
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| Jonny2TG wrote on Tue, 11 October 2005 21:27 |
... same with the new Camry and Corolla (1AZ-FE, 1ZZ-FE).
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They both use vvti, not plain vvt. As deesonet described, vvti isn't just simple on/off, it uses a PWM controlled solenoid to advanced and retard the timing between two points.
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