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Re: What to Build to compete with a SR20 BBC
[Re: moparmafia]
#1695460
11/21/14 04:00 PM
11/21/14 04:00 PM
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Joined: Nov 2004
Posts: 6,890
North Alabama
Monte_Smith
master
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master
Joined: Nov 2004
Posts: 6,890
North Alabama
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I have nothing against HEMIs or Wedges, have owned plenty of both. But it is like anything else, there is always a better "tool" for the job. If the "job" in question is a large cubic inch motor, a wedge is just a better choice and that's just the way it is. A HEMI chamber, is a HEMI chamber and it was designed for a smallish bore. So when you go to say a 4.560 bore HEMI, you either open the chamber some, or you have the same dome on your 4.560 piston, that you do on your 4.250 piston. They are somewhat hard to make compression in anyway, so if you do open the chamber for the larger bore, now it is REALLY hard to make compression. Compression in a HEMI consists of one thing, DOME and a lot of it. In a big motor that just means even MORE weight, to what is already about the heaviest rotating assy there is.
Guys who build 600+ inch HEMIs do it because they are HEMI guys and are looking to get all they can from that combination. And that's fine, good for them and if that is what they want, that's great. But if your goal is to make the MOST HP per inch that you can and your choice is a 650" wedge, or a 650" HEMI, the wedge will win out every time.........
Let me point out, this is NOT just a Mopar to Mopar comparison. This whole thread was started because a guy wanted to build a Mopar wedge, to compete with a Chevy wedge, and given the rules package, it was stated that it could NOT be done, which is true. So then all the HEMI worshipper start talking about that.
Horsepower is very simple..........It boils down to how much air you can move at a certain rpm. You think the A/HEMI guys turn their motors 10k because they want to, or think it sounds cool........hell no, its because they HAVE to, so the head will move the air. HEMIs have huge ports and flow lots of air, but not with low air speeds. That is why they respond so well to boost.
So now, lets say we have 650 inches and how much more air we need to move to make that extra power. Yeah, we make the port bigger and the bore is bigger, but you still need LOTS of air speed to generate the flow to make the power.
So, you take a wedge head that flows 550 and a HEMI head that flows 550, put them on the same size short block..........the wedge wins everyday, if by nothing more than a MUCH lighter rotating assy.
Monte
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Re: What to Build to compete with a SR20 BBC
[Re: Monte_Smith]
#1695461
11/21/14 07:29 PM
11/21/14 07:29 PM
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Joined: Aug 2008
Posts: 78
Canada/USA
ragingram
member
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member
Joined: Aug 2008
Posts: 78
Canada/USA
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Quote:
I have nothing against HEMIs or Wedges, have owned plenty of both. But it is like anything else, there is always a better "tool" for the job. If the "job" in question is a large cubic inch motor, a wedge is just a better choice and that's just the way it is. A HEMI chamber, is a HEMI chamber and it was designed for a smallish bore. So when you go to say a 4.560 bore HEMI, you either open the chamber some, or you have the same dome on your 4.560 piston, that you do on your 4.250 piston. They are somewhat hard to make compression in anyway, so if you do open the chamber for the larger bore, now it is REALLY hard to make compression. Compression in a HEMI consists of one thing, DOME and a lot of it. In a big motor that just means even MORE weight, to what is already about the heaviest rotating assy there is.
Guys who build 600+ inch HEMIs do it because they are HEMI guys and are looking to get all they can from that combination. And that's fine, good for them and if that is what they want, that's great. But if your goal is to make the MOST HP per inch that you can and your choice is a 650" wedge, or a 650" HEMI, the wedge will win out every time.........
Let me point out, this is NOT just a Mopar to Mopar comparison. This whole thread was started because a guy wanted to build a Mopar wedge, to compete with a Chevy wedge, and given the rules package, it was stated that it could NOT be done, which is true. So then all the HEMI worshipper start talking about that.
Horsepower is very simple..........It boils down to how much air you can move at a certain rpm. You think the A/HEMI guys turn their motors 10k because they want to, or think it sounds cool........hell no, its because they HAVE to, so the head will move the air. HEMIs have huge ports and flow lots of air, but not with low air speeds. That is why they respond so well to boost.
So now, lets say we have 650 inches and how much more air we need to move to make that extra power. Yeah, we make the port bigger and the bore is bigger, but you still need LOTS of air speed to generate the flow to make the power.
So, you take a wedge head that flows 550 and a HEMI head that flows 550, put them on the same size short block..........the wedge wins everyday, if by nothing more than a MUCH lighter rotating assy.
Monte
I know we are getting way off the OP topic but I'm guessing Monte that you are not considering the Prostock Hemi stuff a "hemi" head? Only the old and true Hemispheric chamber heads? Cause I'm pretty sure the Prostock Hemi stuff will out preform a Wedge head on a 650 platform.
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Re: What to Build to compete with a SR20 BBC
[Re: ragingram]
#1695462
11/21/14 07:53 PM
11/21/14 07:53 PM
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Joined: Jun 2008
Posts: 577
Arkansas
Adrielp
mopar
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mopar
Joined: Jun 2008
Posts: 577
Arkansas
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Quote:
Quote:
I have nothing against HEMIs or Wedges, have owned plenty of both. But it is like anything else, there is always a better "tool" for the job. If the "job" in question is a large cubic inch motor, a wedge is just a better choice and that's just the way it is. A HEMI chamber, is a HEMI chamber and it was designed for a smallish bore. So when you go to say a 4.560 bore HEMI, you either open the chamber some, or you have the same dome on your 4.560 piston, that you do on your 4.250 piston. They are somewhat hard to make compression in anyway, so if you do open the chamber for the larger bore, now it is REALLY hard to make compression. Compression in a HEMI consists of one thing, DOME and a lot of it. In a big motor that just means even MORE weight, to what is already about the heaviest rotating assy there is.
Guys who build 600+ inch HEMIs do it because they are HEMI guys and are looking to get all they can from that combination. And that's fine, good for them and if that is what they want, that's great. But if your goal is to make the MOST HP per inch that you can and your choice is a 650" wedge, or a 650" HEMI, the wedge will win out every time.........
Let me point out, this is NOT just a Mopar to Mopar comparison. This whole thread was started because a guy wanted to build a Mopar wedge, to compete with a Chevy wedge, and given the rules package, it was stated that it could NOT be done, which is true. So then all the HEMI worshipper start talking about that.
Horsepower is very simple..........It boils down to how much air you can move at a certain rpm. You think the A/HEMI guys turn their motors 10k because they want to, or think it sounds cool........hell no, its because they HAVE to, so the head will move the air. HEMIs have huge ports and flow lots of air, but not with low air speeds. That is why they respond so well to boost.
So now, lets say we have 650 inches and how much more air we need to move to make that extra power. Yeah, we make the port bigger and the bore is bigger, but you still need LOTS of air speed to generate the flow to make the power.
So, you take a wedge head that flows 550 and a HEMI head that flows 550, put them on the same size short block..........the wedge wins everyday, if by nothing more than a MUCH lighter rotating assy.
Monte
I know we are getting way off the OP topic but I'm guessing Monte that you are not considering the Prostock Hemi stuff a "hemi" head? Only the old and true Hemispheric chamber heads? Cause I'm pretty sure the Prostock Hemi stuff will out preform a Wedge head on a 650 platform.
I'm pretty sure he wasn't considering the Pro Stock heads in this explanation. Also, even though, the heads have been branded with the "Hemi" moniker, its more of a splayed valve head than a hemi.
Adriel Paradise
Substation Design Engineer III
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Re: What to Build to compete with a SR20 BBC
[Re: ragingram]
#1695463
11/21/14 11:20 PM
11/21/14 11:20 PM
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Joined: Nov 2004
Posts: 6,890
North Alabama
Monte_Smith
master
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master
Joined: Nov 2004
Posts: 6,890
North Alabama
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Quote:
Quote:
I have nothing against HEMIs or Wedges, have owned plenty of both. But it is like anything else, there is always a better "tool" for the job. If the "job" in question is a large cubic inch motor, a wedge is just a better choice and that's just the way it is. A HEMI chamber, is a HEMI chamber and it was designed for a smallish bore. So when you go to say a 4.560 bore HEMI, you either open the chamber some, or you have the same dome on your 4.560 piston, that you do on your 4.250 piston. They are somewhat hard to make compression in anyway, so if you do open the chamber for the larger bore, now it is REALLY hard to make compression. Compression in a HEMI consists of one thing, DOME and a lot of it. In a big motor that just means even MORE weight, to what is already about the heaviest rotating assy there is.
Guys who build 600+ inch HEMIs do it because they are HEMI guys and are looking to get all they can from that combination. And that's fine, good for them and if that is what they want, that's great. But if your goal is to make the MOST HP per inch that you can and your choice is a 650" wedge, or a 650" HEMI, the wedge will win out every time.........
Let me point out, this is NOT just a Mopar to Mopar comparison. This whole thread was started because a guy wanted to build a Mopar wedge, to compete with a Chevy wedge, and given the rules package, it was stated that it could NOT be done, which is true. So then all the HEMI worshipper start talking about that.
Horsepower is very simple..........It boils down to how much air you can move at a certain rpm. You think the A/HEMI guys turn their motors 10k because they want to, or think it sounds cool........hell no, its because they HAVE to, so the head will move the air. HEMIs have huge ports and flow lots of air, but not with low air speeds. That is why they respond so well to boost.
So now, lets say we have 650 inches and how much more air we need to move to make that extra power. Yeah, we make the port bigger and the bore is bigger, but you still need LOTS of air speed to generate the flow to make the power.
So, you take a wedge head that flows 550 and a HEMI head that flows 550, put them on the same size short block..........the wedge wins everyday, if by nothing more than a MUCH lighter rotating assy.
Monte
I know we are getting way off the OP topic but I'm guessing Monte that you are not considering the Prostock Hemi stuff a "hemi" head? Only the old and true Hemispheric chamber heads? Cause I'm pretty sure the Prostock Hemi stuff will out preform a Wedge head on a 650 platform.
The current Pro-Stock HEMI, is not a HEMI at all. It is basically a "wedge" chamber that is twisted in the head casting to oppose the valves...........Plus the current GM head IS a true wedge head and obviously does quite well.
If you just saw the pic below and could not tell how it was oriented in the head........what type chamber would you call it
Monte
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Re: What to Build to compete with a SR20 BBC
[Re: Adrielp]
#1695465
11/21/14 11:34 PM
11/21/14 11:34 PM
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Joined: Oct 2011
Posts: 515
geezer acres rest home
dakotawilly
mopar
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mopar
Joined: Oct 2011
Posts: 515
geezer acres rest home
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im going to go out on a limb here and say i think theres a way to get close to the actual hp with a very well ported set of brewers or b1 pso heads,but to even get near the ballpark would take a very talented builder,porter,and a rather large investment.my guess would be $60,000 minimum. when you consider the parts,labor,r&d,and so on just to get to ,or close to that level and then any possible improvements would be marginal to none to begin with.you would at best be starting out at the maximum level you could EVER be at.and to think,you were going to retire on that chunk of change....
SFI 25.5 depends,no leak,even at 213 mph....
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Re: What to Build to compete with a SR20 BBC
[Re: B1MAXX]
#1695467
11/22/14 06:40 PM
11/22/14 06:40 PM
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Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
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I believe 650 CID is about it in a raised cam siamese bore hemi block, still going to need a dome to get over 9 to 1 compression or so. I am not a total purist as some here would believe so I don't think it would be a sin to fill in the sides of a hemi head a little like the eagle, apatche, and 6.1 heads in order to get more compression with less dome. It can certainly be done without hurting the flow. Also the chevy heads in this discussion are not wedge heads no matter what universe you are from. As far out of kilter as those valves are I would not even call them a twisted wedge, as a matter of fact the more "Hemi like" they keep making these heads the more flow they keep getting. They are splayed valve heads and they still need a BIG bore to match the flow of the Hemi valve arrangement (witch is the real important part a lot more than the chamber shape)  Of course none of this matters to the discussion because the Hemi is not allowed in the guys class  wonder why 
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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