In the 8+ years I've been working on VVTi engines, some of my customers and I have heard just about every excuse as to why VVTi would not work with high HP applications. I got responses like, "good luck!"... ... " what shop is doing it?"... ... "No one will tune it"... ... "you need expensive engine management to tune it"... ... "It will choke power in the top end"... ... " No race team is using it"... ... "wiring is difficult"... ... "no aftermarket support because it doesn't make power." Blah blah blah, blah-blah!!! Yes, I have heard it all!. So, just in case you are reading this, and YOU are one of those who have said these things, or you are one of those other shops doing R&D (Research & Duplication) sit back and learn a few things!
What is VVTi? VVT-i, or Variable Valve Timing with intelligence, is an automobile variable valve timing technology developed by Toyota.VVT-i, introduced in 1996. It varies the timing of the intake valves by adjusting the relationship between the camshaft drive (belt, scissor-gear or chain) and intake camshaft. Engine oil pressure is applied to an actuator to adjust the camshaft position. Adjustments in the overlap time between the exhaust valve closing and intake valve opening result in improved engine efficiency.
Easy right? Wikipedia is your friend! LOL Need to see it in a video? Look bellow! Thanks to Jonathan J. Gautier for the link.
The VVT gear This is an area of concern for those that are not informed. Can it go bad? Yes it can. IF you unplug the VVT solenoid and plug it back in while the car is running, yes it can go bad. It will strip the gears inside! The other problem is that it leaks. Most likely its already 15+ years old!. These are easy fixes, buy a new one if you are not sure of it's health. (Come on! If this was a non VVTi engine you would have spent money for a HKS or Titan gear anyways!)
Other parts that you want to check for optimum VVT reliability is the oil control filter. this one is located in the the upper banjo bolt of the VVT oil feed line. (Thanks Toyota for placing it there)
The VVT solenoid This little thing controls oil to the gear to advance and retard the cam timing. This, paired with the factory ECU and cam and crank sensors, is what makes the magic happen. Change the factory ECU with one of our EMS packages, add some E85, bigger injectors and your choice of Turbochager (Comp turbo, BW, Garrett) on stock internals. We have had great results on 100% internally stock engines.
This dyno Graph is from a 100% internally stock block/head 2jzgte with a Comp turbo 67mm Turbo. The off boost drivability of this car is nice. This kind of response on the street is killer. It has plenty of torque where you need it, when you need it. It is all done with a factory R154! No fancy parts, just good old heavy shock proof!
The engine setup Well it looks like this...
We use coil on plug from the TT engine with the igniter. No DLI yet, until we start to eclipse 750+ whp. A better ignition system will gain more ponies but hey, the stock system works! The EMS we use for this car is our very own modded AEM EMS and our own harness. It controls AICV just like stock ecu, giving you great start ups everytime.
So far we have seen what the VVT system can do in stock longblocks, but what can it do for heavily modified cylinder heads and built blocks? Well the System doesn't know if it's on a stock engine or a fully built longblock. It doesn't.
The Test We had built a non VVT engine for a customer over 4 years ago. This block and head combo has made over 900 whp before. All supertech valve train, dual springs, beryllium copper seats, shimless buckets and GSCS2 cams. The block has Tomei pistons and Manley turbo tuff rods. ACL bearings and billet main caps finish off the block to create a bullet proof engine. Now, 4 years later, when we want to remove the head, and install a built VVTi head with the same components as the non VVTi head. Setting up the VVTi head with the same cam profile and duration was an easy task thanks to GSC power division. The port job was also done by the same machine shop and they had the flow numbers from the first one so it was easy to match. So to top things off, the leakdown of the old head bolted to the block was 3% across the board. Why is it important to check this? It tells us that the engine is healthy and that the head is performing at its best. Once the VVTi head was bolted down, we rechecked that the leak down was the same... and it was! We then started our back to back test. Using the same intake and turbo manifolds as the non VVTi engine, same Turbo, same gas in the tank and the same boost levels it was going to tell us once and for all what the difference was. The difference was jaw dropping!
The Difference between a VVTi (solid red line) and non VVTi (light red line) cylinder head shown above, on the same car, same block, same compression (8.5:1), same tank of e85, and same boost levels, with the same lift and duration on cams, shows the gains at 5000 rpm. Torque went up by 276 ft lbs and whp increase by 269 hp! Another aspect that increased was the MPG! It went from from 16 ish to 21 mpg on e85! Now the car didn't drive like the typical lag monster Supra Brent was used to.
The magic questions?... What does it do against a similar built stroker? What if the stroker had higher compression?
BAM! blue line is the stroker! We built both cars, we used the same dyno.
Do you think VVTi is worth it yet? What if it had a 10.5:1 compression block, stroker? Nitrous? quick spool valve? Maybe it will need to run a full MT ET street all the time! If torque wins races why not use VVTi? Is it hard to tune? No, the System is easy to setup depending on how much you want out of it and how aggressive you want to set it. At this point, is safe to say that we need more ignition. The TT coils and HKS DLI can't handle the overlap and blows out the spark.
The Non VVTi engine bay
The VVTi engine bay.
Here you can see the Air induction box that Leilani and I made. I know it doesn't have anything to do with the topic but I wanted to show it to you... Also the big ETS 6 inch Intercooler core, functional AC, as well. Just before we finished the air box, Speedhunters came by the shop to snap some pics of the Scrapyard Scamp (also VVTi powered) and wanted to feature Brent's car as well. http://www.speedhunters.com/2015/01/the-eternal-supra-refining-an-icon/
Brent was responsible for making this VVTi project happen. He is always willing to push the envelope of his car. Once we knew that the engine was healthy enough to take all the abuse we could throw at it, we knew that the only way it can go was up! AEM was also great help. Beau Brown of BBR tuning made this thing come true as well. His skills are second to none.
8+ years of messing with VVTi and these are some of the VVTi projects we have worked on.
2JZGTE powered by A comp turbo 6767 using a MS3pro EMS owned by Dave Buckshaw!
Rodel's undisputed, show stopping A70
NA-T VVTi :)
Kenny bells, whipples, AWD E85 Evo's and lots of dead snakes and horses! Julio's Supra now on E85 and over 600 whp!
Silent killer! Stock looking, wastegate recirculated 4 door Supra! 25 MPG to boot and stock ecu!
Went from Non VVTi to VVTi. Original shop sold a busted 2jz to this customer. We made it right. Also made a new harness and routed it in the right place. Using an AEM V1 for A 7MGTE!
Dsport Cover, project Soristo/SC300! on AEM Infinity 10
Auto, VVTi, Single turbo E85 on AEM V2!
AEM Infinity 10 tuned by BBR tuning, owned by Brent Huckaby. Comp turbo 7483 Turbine!
We didn't work on this one, but it's engine porn! VVTi as well so why not! 1200 HP Daigo Saito's Drift car
We have proved that VVTi is worth having in any application, from street to strip, road racer to drift car, this technology is amazing just as the bullet Proof JZ engines. Now that we have discombobulated the JZ engine tuning Mantra, will JZ VVTi find its self in your engine bay? Don't take my word for it, Nissan guys are using them as well!