Pro's and cons of VVTI?

[LOGIE]

As some of you may have read elsewhere im currently doing my own NA-TT. Ive found a seller offering a 2JZ-GTE engine from a 2000X/Y reg supra so its a VVTI which ive never really looked into, Ive read that these have better torque at bottom end but thats all i know difference wise from the pre-vvti. Could someone tell me any pro's and cons to running a VVTI engine?

 

Thanks all

[ripped_fear]

IIRC VVTI can cause problems when going single, i only know of a few vvti motors that have single turbo's one of which the tuner had ditched the VVTI.

[tkddav3]

ask ibrar? his monster build is vvti

Edited April 29, 2012 by tkddav3 (see edit history)

[James]

ask jurgen? his monster build is vvti

 

You mean Ibrar.

[ashbuster]

http://www.mkivsupra.net/vbb/showthread.php?33302-VVTi-A-discussion

you probably seen this link tho

 

i dont like the idea of this

 

Trac. The VVTi TRAC is too over-sensitive. Pulling the fuse will put the car into "snow" mode.

 

and MAF. The VVTi uses MAF, The MAF is far more accurate than a speed density system. The downside is that the MAF will eventually become a restriction if big power is required.

 

be easier if i pasted this lol

 

 

PRO's

 

ECU. The VVTi has 2 x 16 bit whilst the stock JDM is 2 x 8 bit. The ecu is obviously much faster. It is based upon the later Lexus units and is very powerful.

 

Fly-By-Wire. In conjunction with the ECU the FBY system will close the throttle if it senses detonation, high coolant temps, etc

 

The VVTi system. Adjusts the intake cam timing. This gives significantly more low end torque, and helps the larger turbo'd car spool earlier.

 

Rev Limit. The rev limit on a stock VVTi is 7200 rpm whilst the Stock JDM is 6800 rpm.

 

Neutral

MAF. The VVTi uses MAF, The MAF is far more accurate than a speed density system. The downside is that the MAF will eventually become a restriction if big power is required.

 

Inlet. The VVTi uses a smaller inlet manifold. This will improve torque, but may become a retriction on really big power cars ( 650+ bhp)

 

 

Cons

 

Wasted Spark ignition. This IMO is a step backwards to coil on plug.

 

Trac. The VVTi TRAC is too over-sensitive. Pulling the fuse will put the car into "snow" mode.

 

Engine Mounts. This applies to all Facelift cars. TMC changed the engine mounts for some strange reason. These are prone to failure and are not as "beefy" as those on earlier cars.

Edited April 29, 2012 by ashbuster (see edit history)

[LOGIE]

http://www.mkivsupra.net/vbb/showthread.php?33302-VVTi-A-discussion

you probably seen this link tho

 

i dont like the idea of this

 

Trac. The VVTi TRAC is too over-sensitive. Pulling the fuse will put the car into "snow" mode.

 

and MAF. The VVTi uses MAF, The MAF is far more accurate than a speed density system. The downside is that the MAF will eventually become a restriction if big power is required.

 

be easier if i pasted this lol

 

 

PRO's

 

ECU. The VVTi has 2 x 16 bit whilst the stock JDM is 2 x 8 bit. The ecu is obviously much faster. It is based upon the later Lexus units and is very powerful.

 

Fly-By-Wire. In conjunction with the ECU the FBY system will close the throttle if it senses detonation, high coolant temps, etc

 

The VVTi system. Adjusts the intake cam timing. This gives significantly more low end torque, and helps the larger turbo'd car spool earlier.

 

Rev Limit. The rev limit on a stock VVTi is 7200 rpm whilst the Stock JDM is 6800 rpm.

 

Neutral

MAF. The VVTi uses MAF, The MAF is far more accurate than a speed density system. The downside is that the MAF will eventually become a restriction if big power is required.

 

Inlet. The VVTi uses a smaller inlet manifold. This will improve torque, but may become a retriction on really big power cars ( 650+ bhp)

 

 

Cons

 

Wasted Spark ignition. This IMO is a step backwards to coil on plug.

 

Trac. The VVTi TRAC is too over-sensitive. Pulling the fuse will put the car into "snow" mode.

 

Engine Mounts. This applies to all Facelift cars. TMC changed the engine mounts for some strange reason. These are prone to failure and are not as "beefy" as those on earlier cars.

 

Cheers Ash i had seen a similar thread before but not as well written as this. VVTI might be an option for me then with a good RLTC fitted and use either SRD or old skool engine mounts

Edited April 29, 2012 by LOGIE (see edit history)

[LOGIE]

Ive also come across a few Aristo engines but i hear they are a pain to fit ie a lot of parts needing swapped..

[letmeshowyou]

Hodge's build started with an Aristo engine IIRC, have a read through his thread

[tkddav3]

You mean Ibrar.

 

aha that more like it. brains not functioning very well today !

[LOGIE]

Hodge's build started with an Aristo engine IIRC, have a read through his thread

 

yeah i read all his build thread amazing stuff however ididnt learn much on the "difficulties of fitting an aristo lump," apart from the sump all his other parts ie throttlebody etc is all aftermarket. I was wondering just what stock parts would need swapped.

[johnny g]

VVT-i makes the car smoother, when mapped with appropriate ECU's. Ryan commented on how smooth mine was, even with 272's.

 

For stock, it's great. BPU brings it alive. MAF is no real issue at BPU. Going single or standalone would mean going MAP anyways, and most ECU's use an aftermarket MAP sensor.

 

The biggest issue, I see, is the intake cam choice. You can have HKS 264, Titan 264 & 272, Tomei 264 and BC 264 & 272. I'd not choose BC after the results of my last setup.

[LOGIE]

VVT-i makes the car smoother, when mapped with appropriate ECU's. Ryan commented on how smooth mine was, even with 272's.

 

For stock, it's great. BPU brings it alive. MAF is no real issue at BPU. Going single or standalone would mean going MAP anyways, and most ECU's use an aftermarket MAP sensor.

 

The biggest issue, I see, is the intake cam choice. You can have HKS 264, Titan 264 & 272, Tomei 264 and BC 264 & 272. I'd not choose BC after the results of my last setup.

 

Thanks Johnny, good info there.

[muzzytt]

there is a kit available that does away with the ecu controlled throttle its expensive but worth it if going single.

 

http://www.supraforums.com.au/forum/a80-mkiv-discussion/83895-vvt-i-throttle-control-override-kit.html