Hey guys.
Well, a little while ago I discovered that there is an allowance for inlet cam gear adjustment from the factory.
For some reason, possibly emissions etc, Nissan has handily made the VVT assembly adjustable, but it is very hard to do, involving removing the pulley each time you want to adjust it.
That is until I made up a ring which, with slight modification to the standard pulley allows adjustment from the front of the engine in a matter of seconds; with the cam gear cover off of course.
Now, until now, nobody had tried them on a car with any sort of dyno charts to prove anything.
Until now.
On the weekend, an R33 which shall remain nameless, and a workshop who shall also remain nameless tried one of my little wonder rings, and made some fairly significant gains by advancing the inlet cam a little.
The peak power remained the same, but the power through the rev range was increased by a very reasonable amount. How’s 20rwkw sound?
In the lower range, off boost, power was also increased, and then when the car began to boost, power was up everywhere.
The power flattens out at the very top, but stays up and doesn’t nose over.
Car has following mods. Intercooler, highflow turbo and Wolf3D and other supporting stuff.
The procedure with the tune was as follows.
Adjustable exhaust cam gear was added, power run up. Exh gear adjusted to about 4 degrees. Pretty standard stuff on an R33.
The top made was the Black line.
Then the inlet cam gear was adjusted. Can’t say how much by at this stage.
But you can see, with each amount of adjustment, the power curve moved across, until the final one made the 20rwkw at about 4500rpm
Nothing was changed on the tune, no adjustments were made with timing or anything.
Just the pulley was adjusted.
The VVT was still active, and the changeover points, to my knowledge, are very close to stock, they were only adjusted to fine tune the turbo.
Obviously soon, I will be spinning my car up and trying it with a stock turbo but with Tomei Poncams, and seeing what we can see.
Also, I will be making the adjusters up to a commercial quality, with adjustment marks and zinc plating them for longevity, and a batch will be made up.
I would like somebody in Melbourne to try one of these with stock management and stock turbo etc just to get a grip on the power gain possible with everything stock. I will supply an adjuster free of charge, but I will need you to spin the car up on a dyno, which I can arrange in Croyden.
Any volunteers?
Here’s the dyno charts, see for your self and make your own decision.