GLH with variable Valve timing!

[rgl10]

That is an interesting unit. I was just using air since with the turbo I can store some boost in a reservoir and mod my BoostButton cal to control a solenoid to move it. The thing I've found though is that full boost comes on in my motor about 3500 rpm and this is close to the rpm range that the cam needs to switch to retard for better top end power. I really think I could just hook a vacuum hose straight to the intake manifold and under idle and cruise conditions use full 5 degree cam advance for good throttle response and smooth idling. Then any time I wanted good top end hp it would retard the cam 5 degrees when I went into full boost. No complicated controls needed at all if a person went this route.

[Reaper1]

The problem with linear actuators is that a lot of the time you need a PWM controller, AND/OR you have to figure out how much it will move after power is turned off. We ran into this issue with our SAE Formula Hybrid car. We were using an electric linear actuator to move the sheaves on the CVT and getting accurate control was difficult. Something I came up with, but never got tried was to apply a quick burst of electricity to the actuator motor to act as a brake so it stopped exactly where you wanted it. Again, timing of this could be troublesome and the actuator might not work in a linear fashion at different load levels. I suppose a load sensor could be used for compensation (some actuators might even have this built in...we never got that far).

Personally I'd look into an oil controlled actuator that used differential oil pressure on opposite sides of the piston. This can be VERY accurate and if I'm not mistaken this is how most OEM systems sort of work.

One thing I'm concerned about is the diameter of the idler rollers. I don't know if there are bearings inside of them, but if there are I'd be looking at their load rating and service rpm.

Still...VERY cool!

[rgl10]

I bought the rollers for a WRX STI timing belt setup. I figured they would hold up beyond what I will put on them, time will tell I guess. Also this vct system I'm working on is just going to be an on and off type at first. If you wanted to scrape ever bit of power out of a vct system you would need to tune it on a dyno over dozens and dozens of pulls. Our nearest dyno is 3 hours away so that won't work for me. (however this summer I'm planning on building my own version of the homemade dyno just so I can do all those pulls for myself)

[Reaper1]

Cool! I just started looking through the build thread. After I posted I saw the bearings. I think what you have will work fine, especially in an on/off type of application.

BTW, not totally related to the VCT, but what the heck is that big box looking thing that the A/C lines go to on the passenger side of the engine bay? That's not something I'm familiar with at all.

[rgl10]

Thats my heat exchanger for the water to air intercooler. I'm trying to get all that posted up in my project build but just haven't got there yet. I wanted to keep a/c so it does double duty, cools the car and cools the water for the intercooler. When I push the throttle past 3/4 the a/c clutch kicks out but the water keeps flowing through the intercooler. It has a two gallon reservoir in the cowl so it can go for a while without the compressor running. As soon as I back off the gas the compressor kicks back on and cools the water again.

[vipernbox]

I am really going to have to look into that I/c setup

Did you build the intercooler? What are the specs on it? How much air flow before it becomes a restriction? The cooling power is impressive.

[rgl10]

I bought it from ebay. I have less than 350 dollars in the whole system. Take a look at this thread. I'm being lazy I guess but I will post all this in my project log over the next day or so. I just hate to post it all here and then again in my log.

http://www.turbo-mopar.com/forums/sh...48#post1023948

[Aries_Turbo]

this is awesome. ive been sketching up a system just like that for years but never got around to building it.

looks like I may have to get to the garage and fire up the welder.

I wanted to use a RPM based control system though. low RPM's and its advanced and as it raises to high rpm, it retards. use something like an arduino to control a stepper motor worm gear drive so that its ridgid.

pretty sweet.

Brian