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What are the benifits to the dohc comparde to the sohc? Is there that big of a difference in preformance?
Benifits of dohc
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My head flows 250 cfm w/ 8 valves. What does a full race 2rz push? Twice as many valves means what? More rpm I thought, but obisousy not what are the benifits to the dohc?
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What can you tell by a pic of a motor? I can't guess your cfm with a pic only. LC tech articles will back up my 250 cfm for a stage 5 22r head 86 and up. What dose your head flow? I know you can't see much but that is my truck under my name. It was just a mock up but that what it is going to look like when I'm done.
With plenty of money for professional head work, a 2 valve head can be made to flow plenty...enough to match or exceed a 4 valve head, but only at high RPM and with the right camshaft profile.
The 4 valve head will always have a more smooth, wide powerband. It will be the engine you like to drive on the street because it will make enough low RPM power to get out of its own way.
For circle track racing, a 2 valve head is fine because you're at high RPM constantly.
The 4 valve head will always have a more smooth, wide powerband. It will be the engine you like to drive on the street because it will make enough low RPM power to get out of its own way.
For circle track racing, a 2 valve head is fine because you're at high RPM constantly.
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sohc is good for low end torque , but falls off up top . dohc doesnt make as much low end torque but makes more top end power . im sure a stock for stock head the dohc outflows it by quite a bit . some needs to get a hold of luis im sure he knows what a worked 2rz head flows .
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what the hell is a mock up!? does that mean the motor doesn't exist?> because I have a mock up of what my truck will look like- but the key word is WILL, as in NOT CURRENTLY... therefore you really don't know what the head will flow like because you don't have it on a flow bench, currently... hell, LC has been known to f-up their flow charts and info- and frankly until I see your motor, I have have to doubt everything you say!
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There are so many factors that affect this debate it's hard to say whether one design is "better" than the other. That said, for most street applications, the basic packaging of four-valve heads means more surface area inside the combustion chamber meaning more flow.
Of course, I've got a Corvette Z06 parked outside that is a two-valve design that flows PLENTY--about 360 cfm at .600 lift.
Other concerns, such as the ability to include variable valve-timing systems, the positioning of spark plugs, and valvetrain weight also factor in. All things being equal, the four-valve design will usually come out on top in terms of performance, but things are rarely equal: I'd take my stock 2RZ over a stock 22RE anyday, but that doesn't really tell you anything.
Of course, I've got a Corvette Z06 parked outside that is a two-valve design that flows PLENTY--about 360 cfm at .600 lift.
Other concerns, such as the ability to include variable valve-timing systems, the positioning of spark plugs, and valvetrain weight also factor in. All things being equal, the four-valve design will usually come out on top in terms of performance, but things are rarely equal: I'd take my stock 2RZ over a stock 22RE anyday, but that doesn't really tell you anything.
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Mock up means ,I bolted everything together to make sure it would all fit. I had to pull it to put a roll cage in. And no my motor is not currently together the head is at Jet hot getting coated (Thermal barrier coatings) along w/ my turbo exaust housing. How can you tell cfm of a head when it is together? I have never heard of being able to do this. And when I went to buy my head I went to Louis first. He quoted me over 500cfm for a 22r race head. LC quoted me 250 cfm, I posted that on CT and no one could believe the # Louis had on his web sight, so I went w/ LC. If their folw bench is wrong then I was ripped off. But with the info I had I made the best choice for my situtation. And by the way my motor could be running right now, I just preferr to do everything possible before I put it together. You should understand that since you are now having to beef up your engine. If you want to drive down this weekend (or tonight) to SD I will show you all the recipites and parts, that way you can assure yourself that I am for real. Anyone who can put together something like I have will take their time, I have put over 10,000 into that truck and I am not made of money. Another $5000 and I'll be drifting, so dought me all you want, I know what I have and how much I've spent, plus I'm not trying to build a little puss engine that won't hold up, I want the best, and I can wail until I can afford it.Racer_X said:
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I have one last thing to say before I get out of this stupid thread . they have people making over 400hp at the wheels on a stock 2rz .do that with a 22re im done .
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