The name implies it's hydraulic and mechanical. Does that mean there are no electronics associated with said system?

Consider a Benz M119 5.0L engine, with hydro-mechanical VVT on the intake cams.....say one were to run an standalone EMS, like a Megasquirt, is there a need to electronically control such a system?

Is it easy enough to simply disable the VVT all together.

This is purely bench racing, but a pipe dream as well.....please entertain me.

Megasquirt Benz V-8! Ah Myles, you sure do keep it up on the downbeat...

Older audi v-8 is where the curly black chest hair is at.

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alkun
Megasquirt Benz V-8! Ah Myles, you sure do keep it up on the downbeat...

Older audi v-8 is where the curly black chest hair is at.

Gold chains too.
And a silk shirt opened at the collar.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Always wit da collar popped!

I kno....an outlandish dream....wish I had the $$$ to support it.

Saw a late 90's SL500 in the JY yesterday, with a good M119 V8 engine....

If you know MBZ V8's....you'll know that motor is da Shizz. Just wondering about alternative means of managing it....as in MS...

So far, I'm still quite unclear what "hydro-mechanical" means in terms of operating VVT

Ya'llz ever seen me wear a collared shirt? My pitbull rocks the gold chain better than I can.



Edited 1 time(s). Last edit at 03/27/2012 05:52PM by Mylesofsmyles.

Pulling from dark corners of my memory the hydro mecanical system did not need any controling it worked by changes in oil pressure to pull something some way to change the valve timing.

I think honda used a solinoid to open an oil gallery, if audi did the same I would think a simple power on at x rpm would make this work from the ECU or from a dedicated system only doing this task.

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In the long run reality always wins.

What Derek said.

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Robert.

"You are way too normal to be on Rally Anarchy." Eddie Fiorelli.

On a honda, the v-tech is not really "variable", just a second set of longer lobes are engaged at a specific RPM. 2 cams in one kinda deal.

True variable valve timing is infinite, within 7-15' usually and needs electronic control to operate correctly. Higher end ECU's will have a output for this. Megashit likely not.

Variable valve timing is pretty much useless in race engines unless it's a highly restricted formula like Group N. It's the last thing I'd worry about.

ALLDATA shows an electromagnetic clutch type thingy on one of the cams. It looks like a variable cam phasing unit.

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Robert.

"You are way too normal to be on Rally Anarchy." Eddie Fiorelli.

On the MB engine, it is an electrmagnet, that pulls a plunger out of the front of the cam, alowing the cam to change timing in reference to the chain through a helical cut gear.

Audi and VW use a pretty neat and simple system, one cam is driven by the belt, the other cam is driven by a chain between the 2 cams with the chain about 4 or 5 links too long, and the tensioner is controlled up/down through a solenoid in the oil circuit. Move the tensioner up so the the chain is straight at the bottom, to moving it down so the top it straight nets 40 degrees or so of timing.

I have a job waiting at work, current M5 V10 with VANOS faults. It uses an engine driven high pressure oil pump to supply 60 BAR of pressure minimum to the cam actuators. It only makes 50 BAR, so 15 hours of labor later to change the pump and oil lines that run from the pump in the pan to the cam actuators INSIDE the engine... Oh yeah, it han no timing covers..... one piece block assy...

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Gravel Spray
On a honda, the v-tech is not really "variable", just a second set of longer lobes are engaged at a specific RPM. 2 cams in one kinda deal.

True variable valve timing is infinite, within 7-15' usually and needs electronic control to operate correctly. Higher end ECU's will have a output for this. Megashit likely not.

Variable valve timing is pretty much useless in race engines unless it's a highly restricted formula like Group N. It's the last thing I'd worry about.

Why would VVT be useless in a rally engine? I could see your point for a track car where you are likely have it pinned in the high rpms most of the time. But most rally drivers are all over the rev range during a rally due to driving error or road conditions this seams like the type of situation where a VVT system would shine since it allows you to run a bigger cam without the abrupt fall off of power when you are out of "power band". And it would allow the motor to be quite civil at idle or an transits which are not bad features.

If you think having a second set of lubes come in is going to make your head snap back you're going to be dissapointed. More of a gimmick than anything else.

Neil Brown Engineering in the UK did a lot of developement work on Honda Group-A rally engines in the late 90's and early 2000's. They tossed all the V-tech garbage in order to make room for large cams and very large valve springs. With a careful selection of CR, cam, port shape and combustion chamber design you can have an engine that is VERY yanky down low and still screams like a mofo up top.

The only time I have ever seen true variable valve timing worth while at all is the Subaru system used in a Group N car. The oversquare Subaru engine is poorly suited for a inlet restricted turbo application and the variable cam timing helps eek out a "touch" more bottom end. In any other application it's a waste of time.

I fully agree with Pete. My Golf was a high reving monster and I had no issues.

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In the long run reality always wins.

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Gravel Spray
If you think having a second set of lubes come in is going to make your head snap back you're going to be dissapointed. More of a gimmick than anything else.

I can tell when Evan Moen's ITR goes into the high lobes (VTEC KICkED IN Y0! okay that's out of my system) because the exhaust kinda gives a half-backfire and the exhaust note changes. A lot.

And he's got a blower on top of that.

---

Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

Quote
Gravel Spray
On a honda, the v-tech is not really "variable", just a second set of longer lobes are engaged at a specific RPM. 2 cams in one kinda deal.

True variable valve timing is infinite, within 7-15' usually and needs electronic control to operate correctly. Higher end ECU's will have a output for this. Megashit likely not.

Variable valve timing is pretty much useless in race engines unless it's a highly restricted formula like Group N. It's the last thing I'd worry about.

The new hondas are i-VTEC, which have both VTEC and variable cam timing on the intake cam.

Quote
Gravel Spray
Neil Brown Engineering in the UK did a lot of developement work on Honda Group-A rally engines in the late 90's and early 2000's. They tossed all the V-tech garbage in order to make room for large cams and very large valve springs. With a careful selection of CR, cam, port shape and combustion chamber design you can have an engine that is VERY yanky down low and still screams like a mofo up top.

The only time I have ever seen true variable valve timing worth while at all is the Subaru system used in a Group N car. The oversquare Subaru engine is poorly suited for a inlet restricted turbo application and the variable cam timing helps eek out a "touch" more bottom end. In any other application it's a waste of time.

Neil Brown is making engines for Matt Neal and the likes in BTCC, not rally. They have MANY restrictions and specific power requirement. One of the restrictions were cam timing and the vtec was considered part of it and banned, and along with rpms, compression, valve lift, and throtle size limitations. Also, taking off the vtec means less weight on the valvetrain. And with the powerband matched with the correct sequential box ratios for each individual track makes things not too hard to actually "develop".

Also the Evo 9's with their Mivec in Group N made them the car to have in PWRC vs the Subarus and the Evo's are undersquare.

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Cosworth
the Evo's are undersquare.

the all alloy things 2010 and onwards are now "square" at 86 x 86 (like GMs XE,
Ford's DOHC 16v in MkV Escorts---in the rest of the world,
Toyota's 3S-GE, and 3S-GET
Nissan's SR20DE and DET, Citroens XU10
Honda K20 fambly
and
The Subu-yota new 2,0;

They said they wanted room for bigger valves..

Seems 86 x 86 is a pretty good compromise between bore for valve area, and combustion efficiency.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.