Variable Valve Timing for Pushrod engines
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From: Tullahoma TN
Variable Valve Timing for Pushrod engines Check this out guys!
http://www.hotrocker.com/
What do you think besides it being too damn expensive?
http://www.hotrocker.com/
What do you think besides it being too damn expensive?
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From: Nawf Carolina
Re: Variable Valve Timing for Pushrod engines Hmm, interesting. An LS1 system would probably cost about, what, $1500 or so with very minimal gains for drag racing. Of course if its your street car, then you could run a much more radical cam while having a suitable idle, and still have good drag performance. If you went with a custom designed system and did a lot of road racing where a larger amount of the powerband was used, I could see a big drop in lap times.
In 1903 Daimler-Benz had a 60 hp racing pushrod engine that used variable length pushrods for variable cam timing.
J.
[ January 18, 2002: Message edited by: Crazyquik ]</p>
In 1903 Daimler-Benz had a 60 hp racing pushrod engine that used variable length pushrods for variable cam timing.
J.
[ January 18, 2002: Message edited by: Crazyquik ]</p>
Re: Variable Valve Timing for Pushrod engines Only looked at the test results. The system produced great low end torque in the 1500 - 2500 range. It might make drivability better with a high stall converter or M6's tooling around in high gear, but no useful performance gains.
too bad.
too bad.
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From: Nawf Carolina
Re: Variable Valve Timing for Pushrod engines Thats pretty much what variable valve timing is for, increasing driveability. If you have it set up right, it could be used to flatten the powerband up top out, but your drivability would be unchanged.
There is an misconception that VTEC makes great power, it doesnt. You could take a non VTEC engine and cam it to make similar power, but it'd be very very peaky and virtually undriveable down low. Variable valve timing allows you to have a "race" profile and a "street" profile. It doesn't make more power, it just makes more livable power. It could possibly make a 230 duration cam streetable in a stock cube LS1.
There is an misconception that VTEC makes great power, it doesnt. You could take a non VTEC engine and cam it to make similar power, but it'd be very very peaky and virtually undriveable down low. Variable valve timing allows you to have a "race" profile and a "street" profile. It doesn't make more power, it just makes more livable power. It could possibly make a 230 duration cam streetable in a stock cube LS1.
Re: Variable Valve Timing for Pushrod engines I guess that was my thought. The Test I want to see is exactly what you describe. take a 228/228 cam and combine it with the system and show me what you got. They probably held the cam constant.
I understood that some variable valve systems rotate the cam timing plus or minus X degrees. Sorta like the effect you would get by dropping a cam in with a bunch of degrees of advance (plus) or retard (minus) so effectively extend the power band.
I understood that some variable valve systems rotate the cam timing plus or minus X degrees. Sorta like the effect you would get by dropping a cam in with a bunch of degrees of advance (plus) or retard (minus) so effectively extend the power band.
On The Tree
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From: Carrollton, TX
Re: Variable Valve Timing for Pushrod engines You guys don't understand the premise of such a setup.
This would allow us to run a cam with say 240-250 degrees @.050" and act like only a 220 @.050" camshaft for lower engine speeds.
I think its a great idea.
This would allow us to run a cam with say 240-250 degrees @.050" and act like only a 220 @.050" camshaft for lower engine speeds.
I think its a great idea.
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From: Lincoln Park Mi
Re: Variable Valve Timing for Pushrod engines YOu guys ever see that engine with no throttel blade? all incoming air was controlled by the valve timing and lift. if you wnated to go faster the valves just opened up longer and farther. was in a hot rod or somethin a year or two ago. being designed around a big block chevy
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From: Freeland, MD
Re: Variable Valve Timing for Pushrod engines This is potentially a GREAT idea. If it were to work, torque could be gained over the entire powerband, and really extreme power bands could be accompanied by good low-RPM performance and drivability.
Before I were to do this, I would want to see how durable these rockers are, how they interact with the springs/lifters, how to handle this in the PCM . . . Bringing something like this to the LS1/6 could take some work.
Before I were to do this, I would want to see how durable these rockers are, how they interact with the springs/lifters, how to handle this in the PCM . . . Bringing something like this to the LS1/6 could take some work.
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From: new england
Re: Variable Valve Timing for Pushrod engines Price is very fair if this system delivers. Jesel shaft systems are 900 to 1100 bucks. They dont have VVT either. Freak brought up very interesting no throttle system, that would be worth investigating too. Torque band would be much flatter with no throttling to hurt air flow and distribution.Id like to see both these systems
work out.
work out.
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From: Nawf Carolina
Re: Variable Valve Timing for Pushrod engines It would greatly help driveability and all around performance yes, but as far as drag strip performance no. If you've got a huge converter, you're rpms might never be under 5000 after the launch, and shifting at 6200 or 6400. Here this system wouldn't show much gain (it could if engineered for this application though). Now in road racing if you're using 3500-6500 there would definently be a gain.
Yes, potentially we could run 250@.050" duration hydralic cams in stock displacement cars and have a good idle this way. But think how many rpms you're going to have to spin to use the power. More duration isn't always better. We've got a decent amount of displacment, so we've got a pretty flat torque curve to start with.
[ January 19, 2002: Message edited by: Crazyquik ]</p>
Yes, potentially we could run 250@.050" duration hydralic cams in stock displacement cars and have a good idle this way. But think how many rpms you're going to have to spin to use the power. More duration isn't always better. We've got a decent amount of displacment, so we've got a pretty flat torque curve to start with.
[ January 19, 2002: Message edited by: Crazyquik ]</p>
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From: Freeland, MD
Re: Variable Valve Timing for Pushrod engines Yeah Crazyquick, you have a point. There would not be much change at the dragstrip, especially for high stall auto guys. On the other hand, this could be huge for the straight street cars and the dual street/strip cars.
On The Tree
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From: Carrollton, TX
Re: Variable Valve Timing for Pushrod engines I can tell this system was designed by a true engineer, because it don't look "pretty".
They need to clean up on the aestatics of the kit.
Later.
They need to clean up on the aestatics of the kit.
Later.
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From: LaConner WA
Re: Variable Valve Timing for Pushrod engines This system would obviously work great for lift #'s ,but I wonder how much it would actually vary duration @ .050 ? I'm thinking a little ,but not enough to make a hot cam seem like a mild one around town . I also seriously question the differance of 50 ft/lbs of torque based solely on a change in lift ,not to mention the change in torque peak rpm by 1500 rpm's depicted by the chart . I do wonder what the actual differance in .050 #'s would be tho. If we knew that then we'd have a better grasp of its potential.
Certainly is interesting tho
Certainly is interesting tho
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From: Nawf Carolina
Re: Variable Valve Timing for Pushrod engines I've heard you gain a degree or 2 from 1.6 rockers to 1.7s, is that right? So thats 7 to 13 degrees difference from 1:1 to 1.65:1. They make a 1.2:1 - 1.85:1 version also.
