vvt-i and reground/aftermarket cams

[WDoherty]

So, with most engines today having variable valve timing, are people going to be able to fit aftermarket cams? I know they have had them for v-tech's for years, but i'm not sure if those v-tech only have variable lift or continuous timing as well, plus they had tuners to specifically design the cam for the car. For example, the vvt-i 1uz. Having the exhuast cam reground shouldn't be a problem since it had fixed timing. What about the intake, can you give performance grind to that and have it designed to work in tandem with the oem vvt-i? I saw on clublexus that someone wanted to add cams to an sc400, but i was just thinking about how the low-end torque around sucks and decent cams would make it even worse. But the vvt-i motor makes a alot more torque, at much lower rpm (doesn't it make like 90% of the peak in the 2k range, while the early 1uz is in the 4k range?) So if one could find a 98+ sc400, regrind the cams, maybe some head porting, headers, s-afc for tune, and hope the vvt-i could control an aftermarket grind, you could make 400+hp n/a, have small block low-end torque and not spend alot of money. So where does the world stand at this point with vvt-i tuning and are aftermarket profiles out of the question with oem control?

 

[WDoherty]

come on, i thought i saw someone around here mention there were vvt-i regrind profiles available.

 

[Zuffen]

A reground cam doesn't need a profile or blank.

You use your own cams and grind them to the spec you want.

This will usually include hard welding the faces to get enough lift.

On a VVTi engine with shim under bucket you may get away with reducing the base circle and hence avoid welding.

 

[Edwin_S]

On a VVTi engine with shim under bucket you may get away with reducing the base circle and hence avoid welding.

Yeah, we did this on a 2JZ VVTi. Just reduce the base circle and convert to shim under bucket.

You also could have a set of cams custom made.

 

[WDoherty]

and the ecu reacts ok with as far as cam timing with the altered camshaft?

 

[Zuffen]

Now you're talking a whole different ball game.

I doubt anyone has the definitive answer and I know I certainly don't.

I doubt the average hotrodder can program an engine with VVT1 to work properly.

 

[Edwin_S]

We in Holland allready did a 1JZ with VVTi, used a AEM "race" version, and the VVTi works!
It will take a dyno with stready state to tune it to the max, but we don't have a good dyno here yet.

 

[cribbj]

Edwin, very interested in hearing more about the 1JZ VVTi with the AEM setup. Several of us are running AEM's on our 2JZ's in Supras and are planning to use them on our 1UZ conversions, with & without VVTi.

Did you get some assistance from the AEM engineers, as in a sample VVTi mapping? Was Arnout involved in this setup? Do tell more.....

John

 

[Edwin_S]

Arnout is my boss. We have had quite some mail traffic between Arnout and Mitch. The biggest problem was that the 1JZ VVTi engine uses a different crank timing pattern. And the EMS was unable to Sync. We had to change a resistor in the EMS itself to get it to Sync.

Mitch was kind enough to give us a testmap of their own. They where busy testing a lexus with a 2JZ-GE VVTi. So we got that, but had to change just about everything in the calibration

 

[Lextreme II]

Actually we can try the VVTi if you send them to me.....

 

[JBrady]

It may be hard to find an extra set of 1uzfe or 3uzfe cams. Also, the VVTi may prove problematic if you try to get far from the base cam timing. Another possibility would be a set of 2uzfe cams. I believe these came in both VVTi and non-VVTi variations. They have their gears on the ends and probably bolt into the 1 and 3 heads. You could convert to non-VVTi and regrind/weld grind to produce some fairly stout cams. Just a thought.

 

[StiCk3]

i was under the impression that Autronic SM4 already offers this. does it actually give you control of the VVT-i or does it just maintain it??

 

[gte]

I have ordered a set of 2uzfe vvti cams from Eric, so they do make them