LS7 Head Has Been Outdone!
Originally Posted by PREDATOR-Z
open your mind Padiwan
If those deliver as promised you'll wish to have the $$$ to get some.
If those deliver as promised you'll wish to have the $$$ to get some.
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I really don't see these heads taking off anytime soon, for the simple reason that they are extremely expensive, and there are much cheaper ways to make more power.
It also doesn't seem like the best design to have the pushrods at different angles, operating 2 valves at a time. Thats a lot more stress on all the components, including cam, valve springs, pushrods, ect.
It also doesn't seem like the best design to have the pushrods at different angles, operating 2 valves at a time. Thats a lot more stress on all the components, including cam, valve springs, pushrods, ect.
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With the ETP heads, the flow numbers do equal proportionate power.
IE: ET Canted valves flowing 422CFM out of the box, in a max config should be able to do greater than 900HP. There are already alot of 800HP combo's using this head...
IE: ET Canted valves flowing 422CFM out of the box, in a max config should be able to do greater than 900HP. There are already alot of 800HP combo's using this head...
Teching In
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There are only two operating motors I know of with this type of head on them.
1. Nelson Racing Engines Supercharged 406
32v SC Video
2. SAR's NewMad 502
Mal
1. Nelson Racing Engines Supercharged 406
32v SC Video
2. SAR's NewMad 502
Mal
I wouldn't get to reve'd up about them. They did this with the LT-1 stuff a few years ago. I think maybe one set made it out. I doubt they will ever surface in the hands of the average guy.
Typical ohc 4 valve bullshit...if someone made a head that flowed 600 cfm there are those who would get excited about it. It is hype that will never come to be. There are much easier ways to get efficiency and hp out of the 4 stroke engine.
Originally Posted by ChucksZ06
Typical ohc 4 valve bullshit...if someone made a head that flowed 600 cfm there are those who would get excited about it. It is hype that will never come to be. There are much easier ways to get efficiency and hp out of the 4 stroke engine.
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Good luck spinning 10K rpm with a pushrod based engine that is pushing more seat pressure and overhead mass than the biggest springs and valves in a tradional LSX head. Get out your 1/2" unobtanium pushrods and let me know how it goes.
Originally Posted by briannutter
Ahh, but that's what RPM is for. I'm thinking 500ci spinning 10000k rpm and sounding like a motorcycle engine. As for the manifold, I figure a guy that can afford these is probably going to go sheetmetal, but they had to give it "some kind" of intake manifold pattern. There have been heads out like these before, most notably the Cyril Batten b4 heads that were fitted to big block chevy's. The same billet head stretched out two more cylinders for Batten's v12 design. If I remember right, his v12 utilized bb chevy bore spacing, bb ford main journals, bb chevy rod journals, custom cranks and rods. one aluminum one was 777ci, his magnesium block one hit 1000ci easily. The only problem is the v8's and v12's were HUGE in width, although not that much wider than a 426 hemi. It took work to shoe-horn them into cars. The other issue is the blocks had to be ordered without head studs to accomodate the Batten pattern. On top of the heads, a guy had to buy a block....but check out the v8 that I used to own and was sold to the gentleman that went to Bob Norwood for fitting in an impala ss
http://www.hotrod.com/techarticles/1...s_engine_swap/
http://www.turbomagazine.com/tech/02...nycar_integra/ is an example of the v8 head on a billet 4cyl. block.
http://www.hotrod.com/techarticles/1...s_engine_swap/
http://www.turbomagazine.com/tech/02...nycar_integra/ is an example of the v8 head on a billet 4cyl. block.
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Originally Posted by xfactor_pitbulls
Good luck spinning 10K rpm with a pushrod based engine that is pushing more seat pressure and overhead mass than the biggest springs and valves in a tradional LSX head. Get out your 1/2" unobtanium pushrods and let me know how it goes.
Originally Posted by LiENUS
The valves and springs are lighter as well as running less seat pressure. Due to the two valves you don't need nearly as much seat pressure to keep them controlled, where a system like this really stands out is when you put a turbocharger on it...
Originally Posted by DrkPhx
You just posted 4 times in a row..slow down. 
Originally Posted by xfactor_pitbulls
Yeah you are right, but multiply everything by two per one pushrod. Also add the additional friction of the shaft mount tieing everything together. With the type head, I would also assume that the pushrod length will be longer to accomodate all the extra hardware. Again, hurting deflection. If it was driving direct by a timing chain, as in the mod motors, this stuff wouldnt be an issue, its not though. You cant compare tradional overhead cam stuff to this adapted pushrod hyybrid.
I also wonder why they went to 1.4:1 rockers. I understand the theory that it will take less lift to generate the same power with 4 valves vs.2, but would the extra lift from the 1.7:1 rocker hurt flow and power? Wouldn't the stock 1.7:1 ratio make even more power? Does the intake charge become turbulent at higher lift? Or what happens when you have 4 valves at higher lift? Does the divided intake port cause efficiency problems at the 1.7:1 lift?
Last edited by 1CAMWNDR; Apr 13, 2007 at 09:06 AM.
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From: Cleveland
Yeah pushrod 4v is a bit wierd. I'm not trying to defend it, but I don't *automatically* dis it either until I see results.
As for RPM, I don't know why everyone thinks 10k rpm is such a big deal or barrier. 500ci Pro stock turns 9500rpm with the biggest longest valves you've ever seen. Cup motors turn similar rpm for 500 miles w/ flat tappets. Comp elim. motors turn a lot tighter than that. 500+ lbs of seat pressure fixes a lot of problems. 4v makes it easier, but I'd agree with Cary that it's not *always* better; but, if you put a company with equal amounts of engineering talent into designing a 4v and 2v piece for a given shortblock though..the answer is clear.
At any rate, LT5 zr1's are part of LS ancestory. Cossie Vega as well if you're gay. I'd regard "4v" and "arao" to be two different subjects. If you dis the company, that's one thing. To dis the technology is another.
The guy on the LT1 forum is getting a bit of flack from a few guys for trying something new, but he should be congratulated for fabbing and designing a cool piece..99% of the people on this forum buy cookie cutter parts and shouldn't be throwing stones.
I mentioned over there, we'll compare power between that engine, a couple other ls and lt engines of the same displacement and compression, and equal intake valve closing points. Overlay that with a Rippie or Lingenfelter built zr1 motor for kicks.
As for the legality of this engine in racing. The problem with the Batten 4v BBC heads is they were billet and not cast...otherwise they would have been legal in IHRA pro mod at least. As for the street markets...There's plenty of Bahrainians, raps stars, and drug dealers to sell too.
As for RPM, I don't know why everyone thinks 10k rpm is such a big deal or barrier. 500ci Pro stock turns 9500rpm with the biggest longest valves you've ever seen. Cup motors turn similar rpm for 500 miles w/ flat tappets. Comp elim. motors turn a lot tighter than that. 500+ lbs of seat pressure fixes a lot of problems. 4v makes it easier, but I'd agree with Cary that it's not *always* better; but, if you put a company with equal amounts of engineering talent into designing a 4v and 2v piece for a given shortblock though..the answer is clear.
At any rate, LT5 zr1's are part of LS ancestory. Cossie Vega as well if you're gay. I'd regard "4v" and "arao" to be two different subjects. If you dis the company, that's one thing. To dis the technology is another.
The guy on the LT1 forum is getting a bit of flack from a few guys for trying something new, but he should be congratulated for fabbing and designing a cool piece..99% of the people on this forum buy cookie cutter parts and shouldn't be throwing stones.
I mentioned over there, we'll compare power between that engine, a couple other ls and lt engines of the same displacement and compression, and equal intake valve closing points. Overlay that with a Rippie or Lingenfelter built zr1 motor for kicks.
As for the legality of this engine in racing. The problem with the Batten 4v BBC heads is they were billet and not cast...otherwise they would have been legal in IHRA pro mod at least. As for the street markets...There's plenty of Bahrainians, raps stars, and drug dealers to sell too.
Last edited by briannutter; Apr 13, 2007 at 09:35 AM.
500 lbs of seat pressure helps valve float (which we are not talking about). Really the additional seat pressure does nothing but hurt the pushrods. If you want to use exotic alloyed and LARGE diameter pushrods I can see it getting to 8500rpms. With THIS specific application, I dont see it turning 10K rpms without a ridiculous amount of money that is not needed on supporting hardware.
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From: Cleveland
Originally Posted by xfactor_pitbulls
500 lbs of seat pressure helps valve float (which we are not talking about). Really the additional seat pressure does nothing but hurt the pushrods. If you want to use exotic alloyed and LARGE diameter pushrods I can see it getting to 8500rpms. With THIS specific application, I dont see it turning 10K rpms without a ridiculous amount of money that is not needed on supporting hardware.
2.) When's the last time you saw a set of proper pushrods wear out.
3.) Alloys get thrown out most 2v needs to Ti to turn over 7500rpm anyway.
4.) Let's throw money out of the equation, because there's plenty of people that could afford "the best" whether it's 2v or 4v.
5.) Let's also throw out poweradders...that's not really the point because a guy could always put a power adder on a 4v engine too.
The real issues are this:
RPM: One issue is the valve float. Two small valves are better than 1 big one (every thing else being equal).
Flow: for a given bore size, 4v outflows two when designed correctly. Otherwise they'd be running 2v's in F1 and motorcycles right?
The big UNKNOWN issue here is the rocker arrangement. A Superstock Chrysler Hemi guy could chime in. Or A valvetrain design guy with the proper software could calculate the loads.
I don't know and you don't know.
Keep an open mind though. There's two types of people. The first type saw catheral ports for the first time and thought they were "skinny". The next type took the time to measure the cross-sectionals and based *potential* off the engine off that.
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4.) Let's throw money out of the equation, because there's plenty of people that could afford "the best" whether it's 2v or 4v.
The all billet Dart LS block, $6k no problem.
All billet Wilson intake $3k, throw that on too thanks gotta have that.
$2k forged Lunati crank, pocket change what's a motor w/o one.
$10k heads whoa that's crazy.
If they cost $3-$4K he could not keep em in stock. The only question would be "How much faster would I go with 'em?"
Mal