As I said. VVT-i (Variable Valve Timing with intelligence) is worth the disadvantages of ceramic turbos, smaller injectors, and the evil maf. Once built up it is pure advantage and surpasses the other engines.

 

Interesting theory. Do you have any data to back that up? Perhaps some dyno runs to show a built up vvti making superior numbers compared to a non vvti example?

I keep hearing about how vvt-i is superior and perhaps it is, but I have never actually seen any superior dyno numbers from one compared to a non vvt-i.

It seems to me like the engine is more refined than the non vvt-i, and that when at or near stock levels it will make a little bit more power under the curve, and probably get slightly better fuel economy.

Once it is "built up" as you say, I would like to see the numbers that prove it is worth the trouble to swap over a non vvt-i variant.

 

http://www.youtube.com/watch?v=iKo28HMLhK0

What is this trouble to swap over you speak of?

 

Mostly just cost. Also, sourcing parts and then of course the tuning. Nice video, but I know how it works. Like I said, some proof of any measurable, practical advantage would be nice. Just knowing there are more moving parts and complexity don't make it worth swapping to.

 

http://alflash.com.ua/vvt.htm

With the exception of the valve cover, water pump neck & MAF sensor all the 2JZ-GTE VVT-i parts are available from either the USDM 2JZ-GTE or the USDM 2JZ-GE VVT-i.

 

Ok, so its clear that I am not going to see actual measurable results here. Thanks for the documentation related to theory and operation specifics though.

 

It is not theory. VVT-i engines do not have EGR systems because the operation truly works as stated.

http://www.3sgte.com/1JZGTE.htm

 

I have also read that tuning the VVTi can add another variable when shooting for high numbers. The non-vvti head and platform is overall easier to work with when tuning via ems, but I do not have first hand experience with this.

After reading so many horror storys of used JDM engine purchases I'm starting to lean towards the possibility of buying a brand new shortblock from toyota for 2134.00 plus shipping. Realizing that the JDM motor is probably tired and probably needs to be refreshed anyway, going to a brand new shortblock from the getgo might save me some time and money in the end.

I read through turbo's vvti build and he eventually had an oil pump failure which made him completely rebuild the short block .

Of course I'll be replacing all the maintenance items either way I go like waterpump, timing belt, gasket overhaul kit etc etc.

I've also decided that going to a single turbo setup from the start also might save some install headache as the stock twins are apparently ridiculous to work on when in the engine bay. A nice treadstone cast manifold for 300 bucks, and insert billet waterless turbo and I think I'll be better off.

 

I have heard that vvti is undesireable above stock boost levels cause there is a chance of the vvti cam moving under boost if oil pressure fluctuates or soomething like that, I dont remember exactly but I know something really bad results from that, which is why its usually disabled, even if you know how to tune for it.