Vvt???

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Dec 17, 2007 | 03:25 AM

DCRB

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From: Portland, Oregon

Vvt???

OK so here's something that i've been wondering for a while; do our areo's (atleast the 3.0l) have Variable Valve Timing? you know, like vtec (or i guess fords version, ztec).

I ask this because when i'm driving, ocasionaly i like to listen to just the engine, specialy when feel like pondering things, i notice that through 1st, 2nd, and sometimes 3rd, my aero sounds like it has a power band that kicks in around 2500 rpms. it sounds like i'm steping on the pedal, but thats just it-i'm not. my foot doesn't move, i just accelerate slowly, and it will start to go, but then all the sudden it takes off real quick, and then shifts. i also notice this soemtimes when i'm going UPHILL. it's not downshifting, it just gets... louder and more responsive, as if the valves are opening up more.

its kind of hard to explain, its more of a you'd have to sit in my aero and listen to what i'm talking about sort of thing. maybe i'll make a video some time.

Dec 17, 2007 | 11:14 AM

TallPaul

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From: Metro Detroit (Redford)

I have a '92 Aerostar with 3.0. I don't think there is any fancy valve apparatus. My 3.0 hits it's torque peak around 3600 rpm and hp peak is around 4800 IIRC. I think it is just that there is not much power below a certain RPM. Mine struggles to get up speed from 0 to 20 mph. At that point, the engine has reached about 3000 rpm and will take off. I think what you are experiencing is the same thing, but later 3.0s (not sure when started 93 or what) had a wider power band so this would probably kick in at 2500 maybe. That's why I think a 4.55 rear end would do these Aerostar 3.0's a world of good. Give it more umph out of the hole.

Also, variable valve timing theoretically should smooth things out so there is no power surge, that is the timing varies per engine speed to keep power up at all speeds.

Dec 17, 2007 | 01:50 PM

Pablo-UA

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From: Kiev, Ukraine

VVT is a good idea, but VVT engine is MUCH more expencive and expenses difference is not covered with fuel economy. And to have better low rpm. torq. I'd like to prefere bigger engine. Cheapper and better.

New DOHC engines with VVT, turbo and many other modern features appeared on European market, becouse we pay for bigger engine more taxes and more insuarance payments. But everibody wants to have more horsepower. As result, on market appeare small engines, but 200 HP with 1.8 L engine!

Dec 17, 2007 | 08:30 PM

93nighthawk

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From: Mitchell, SD

Nope, no VVT on the 3.0L or 4.0L

Dec 17, 2007 | 08:42 PM

Aeroman59

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From: Kitchener,Ontario,Canada

I think VVT only appears in OHC motors.

However some of our motors (EEC V.... OBD-2) have computer controlled ignition timing, & sequential fired injectors which are variable on engine load , vacuum, throttle position, engine temp, RPM's, road speed, etc. My engine analyzer shows up to 44* ignition advance under some conditions. On 96 & later Aero's all major engine functions are computer managed together with transmission shifts. A very reliable system, IMO, hard to beat & low pretty low maint.

ATB Aeroman.

Last edited by Aeroman59; Dec 17, 2007 at 08:52 PM.

Dec 18, 2007 | 12:45 AM

Pablo-UA

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From: Kiev, Ukraine

There is VVT on Toyota engines. They have better torque at 1000-1300 RPM, but like other DOHC engines maximum torque is at 3500-4000 RPM. VVT is a way to make torq.-rpm characteristic more flat, but all DOHC have top torque at hight engine speeds. Yeah, DOHC VVTi 1.8-2.0 engines have the same perfomance as Ford 3.0 V6, but they are more expensive, difficult to maintane and repare, have shorter life, they are not so reliable like OHV engines and VVT is oil pressure controlled feature, there are VVT related problem when oil pressure is lower ore highter then norma, oil is old/dirt, and it is cold outdoors.

Some ingeneers think, that it is time to build engines with elctronically controlled valves (w/o camshaft).

Dec 18, 2007 | 01:09 AM

Bear River

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From: Salt Lake City, Utah

With DOHC engine, the high rpm powerband is not something that is inherent with the design. Rather, ever major manufacturer makes the ports too big. If they make smaller higher velocity intake ports, the powerband shifts to a lower rpm, and the peak torque increases. The peak HP will decrease to some extend, depending on the actual sizes. I'll taken bottom end torque any day.