Re: Cubic inches and boost
[Re: SRT6776]
#2205535
11/30/16 10:50 PM
11/30/16 10:50 PM
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Joined: Dec 2007
Posts: 486 IL
knyech1
mopar
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mopar
Joined: Dec 2007
Posts: 486
IL
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I was always told that boost motors need swept volume (stroke) for most power. Hellcat was set-up for overbuilt-durability, you'll see guys putting stroker cranks in them soon enough though. I'd be investigating the 400" boosted BES 3rd gens over the stock stuff That applies for both NA and boosted because you are getting more displacement. The problem, as stated previously by another user, is the fact that you run into higher rod angles with the lower rod ratio you create. That, along with the higher cylinder pressures, can cause large side loading on the pistons and cylinder walls. For 5.7 and 6.1 blocks (which are already notorious for cracking because of thin cylinder walls) this should be taken seriously. On top of that, you reduce dell time and increase piston speed with a stroker...
knyech1-
'71 Sassy Grass Demon 340/904. Pump gas, 1.61 60ft, 7.439 1/8 @ 95mph, 11.824 1/4 @ 111mph
"Not too bad for a pump gas 340, full of used parts and hillbilly ported stock heads." - V.B.
'03 2500 5.9L HO 6-spd on 35's. 395hp/755ft-lb at tires.
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Re: Cubic inches and boost
[Re: hudsonhornet7x]
#2205548
11/30/16 11:08 PM
11/30/16 11:08 PM
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Joined: Dec 2007
Posts: 486 IL
knyech1
mopar
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mopar
Joined: Dec 2007
Posts: 486
IL
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From what I have read, srt cranks are good to 1000hp. The factory oiling is what does them in at high rpm. There are guys on other forums running TT 6.4L in the 1200hp+ range with stock cranks. Can you say breaking the tires loose at 80mph? I would look into the pistons a little before you use them; call Manley and ask them a couple questions. Your crown thickness needs to be thick (at least 0.230") to accommodate the higher cylinder pressures and the first ring needs to be about 0.280" min from the top of the piston so it doesn't get fried. Wrist pin is often overlooked in high hp boosted applications so you might need a thicker walled pin; the pins take quite a beating in there. Learn from others' experience.
knyech1-
'71 Sassy Grass Demon 340/904. Pump gas, 1.61 60ft, 7.439 1/8 @ 95mph, 11.824 1/4 @ 111mph
"Not too bad for a pump gas 340, full of used parts and hillbilly ported stock heads." - V.B.
'03 2500 5.9L HO 6-spd on 35's. 395hp/755ft-lb at tires.
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Re: Cubic inches and boost
[Re: knyech1]
#2205591
12/01/16 12:01 AM
12/01/16 12:01 AM
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Joined: Dec 2005
Posts: 9,719 Home
SRT6776
I hate internal combustion engines!
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I hate internal combustion engines!
Joined: Dec 2005
Posts: 9,719
Home
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I was always told that boost motors need swept volume (stroke) for most power. Hellcat was set-up for overbuilt-durability, you'll see guys putting stroker cranks in them soon enough though. I'd be investigating the 400" boosted BES 3rd gens over the stock stuff That applies for both NA and boosted because you are getting more displacement. The problem, as stated previously by another user, is the fact that you run into higher rod angles with the lower rod ratio you create. That, along with the higher cylinder pressures, can cause large side loading on the pistons and cylinder walls. For 5.7 and 6.1 blocks (which are already notorious for cracking because of thin cylinder walls) this should be taken seriously. On top of that, you reduce dell time and increase piston speed with a stroker... NA is different - its not ever going to get the same volumetric efficiency as a forced air engine. Engine is just an air pump - more in, more out = more power.
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Re: Cubic inches and boost
[Re: hudsonhornet7x]
#2205633
12/01/16 12:49 AM
12/01/16 12:49 AM
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Joined: Feb 2011
Posts: 4,302 Nebraska
72Swinger
master
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master
Joined: Feb 2011
Posts: 4,302
Nebraska
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The bigger the engine, the bigger the supercharger/turbo needs to be to make the same boost. In a boost application like this, a 420"+ engine wont make much more power than a 390"+ engine. Why does Goss ONLY have 404" when he could easily be using 440" engines? Its been said A LONG time ago in Gen III land that for NA build as big as you can afford, high boost builds seem to take ALOT more power with a crankshaft 3.80 or smaller and a rod 6.20 or longer because of block strength when you get over the 1000hp mark.
Mopar to the bone!!!
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Re: Cubic inches and boost
[Re: 72Swinger]
#2205644
12/01/16 01:09 AM
12/01/16 01:09 AM
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Joined: Dec 2005
Posts: 9,719 Home
SRT6776
I hate internal combustion engines!
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I hate internal combustion engines!
Joined: Dec 2005
Posts: 9,719
Home
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I hear you, and that's why I'd LOVE to know the specs on his engine (bore/stroke/heads). BTW he's having blocks made in the UK that can handle the power and he's selling them. The word of that needs to get out.
Last edited by Malicious�; 12/01/16 01:10 AM.
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Re: Cubic inches and boost
[Re: hudsonhornet7x]
#2205647
12/01/16 01:12 AM
12/01/16 01:12 AM
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Joined: Feb 2011
Posts: 4,302 Nebraska
72Swinger
master
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master
Joined: Feb 2011
Posts: 4,302
Nebraska
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It is, the wet blocks are $5500. For me a stock 6.1 block does just fine, but if these can hang at 2500hp, that is a whole new engine market for these radial guys.
Mopar to the bone!!!
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Re: Cubic inches and boost
[Re: hudsonhornet7x]
#2205656
12/01/16 01:24 AM
12/01/16 01:24 AM
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Joined: Feb 2011
Posts: 4,302 Nebraska
72Swinger
master
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master
Joined: Feb 2011
Posts: 4,302
Nebraska
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Yep I agree, I have a set of Apaches under my bench that will eventually replace my CNC'd 6.1's currently on top.
Mopar to the bone!!!
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Re: Cubic inches and boost
[Re: SRT6776]
#2206109
12/01/16 10:15 PM
12/01/16 10:15 PM
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Joined: Dec 2007
Posts: 486 IL
knyech1
mopar
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mopar
Joined: Dec 2007
Posts: 486
IL
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I was always told that boost motors need swept volume (stroke) for most power. Hellcat was set-up for overbuilt-durability, you'll see guys putting stroker cranks in them soon enough though. I'd be investigating the 400" boosted BES 3rd gens over the stock stuff That applies for both NA and boosted because you are getting more displacement. The problem, as stated previously by another user, is the fact that you run into higher rod angles with the lower rod ratio you create. That, along with the higher cylinder pressures, can cause large side loading on the pistons and cylinder walls. For 5.7 and 6.1 blocks (which are already notorious for cracking because of thin cylinder walls) this should be taken seriously. On top of that, you reduce dell time and increase piston speed with a stroker... NA is different - its not ever going to get the same volumetric efficiency as a forced air engine. Engine is just an air pump - more in, more out = more power. So how is NA different?? Larger swept volume = more cubes = more air space = more power so I'm not sure what you mean when you say they are different. Boosted engine obviously have a better volumetric efficiency but that wasn't the topic of conversation.
knyech1-
'71 Sassy Grass Demon 340/904. Pump gas, 1.61 60ft, 7.439 1/8 @ 95mph, 11.824 1/4 @ 111mph
"Not too bad for a pump gas 340, full of used parts and hillbilly ported stock heads." - V.B.
'03 2500 5.9L HO 6-spd on 35's. 395hp/755ft-lb at tires.
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Re: Cubic inches and boost
[Re: 72Swinger]
#2206113
12/01/16 10:21 PM
12/01/16 10:21 PM
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Joined: Dec 2007
Posts: 486 IL
knyech1
mopar
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mopar
Joined: Dec 2007
Posts: 486
IL
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The bigger the engine, the bigger the supercharger/turbo needs to be to make the same boost. In a boost application like this, a 420"+ engine wont make much more power than a 390"+ engine. Why does Goss ONLY have 404" when he could easily be using 440" engines? Its been said A LONG time ago in Gen III land that for NA build as big as you can afford, high boost builds seem to take ALOT more power with a crankshaft 3.80 or smaller and a rod 6.20 or longer because of block strength when you get over the 1000hp mark. +1 Exactly what I am saying about higher rod ratios. These engines don't like high cylinder side loads. Hellcat and 6.4 are stronger, but at a certain power level you need to be thinking about things like rod ratio because of stress issues. Again, be careful because Apache and 6.1 heads are made of 316 (unlike the hellcat heads that are made of a more durable 356-T6) and are known to flex and lift under high cylinder pressures.
knyech1-
'71 Sassy Grass Demon 340/904. Pump gas, 1.61 60ft, 7.439 1/8 @ 95mph, 11.824 1/4 @ 111mph
"Not too bad for a pump gas 340, full of used parts and hillbilly ported stock heads." - V.B.
'03 2500 5.9L HO 6-spd on 35's. 395hp/755ft-lb at tires.
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Re: Cubic inches and boost
[Re: knyech1]
#2206164
12/01/16 11:30 PM
12/01/16 11:30 PM
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Joined: Feb 2011
Posts: 4,302 Nebraska
72Swinger
master
|
master
Joined: Feb 2011
Posts: 4,302
Nebraska
|
The bigger the engine, the bigger the supercharger/turbo needs to be to make the same boost. In a boost application like this, a 420"+ engine wont make much more power than a 390"+ engine. Why does Goss ONLY have 404" when he could easily be using 440" engines? Its been said A LONG time ago in Gen III land that for NA build as big as you can afford, high boost builds seem to take ALOT more power with a crankshaft 3.80 or smaller and a rod 6.20 or longer because of block strength when you get over the 1000hp mark. +1 Exactly what I am saying about higher rod ratios. These engines don't like high cylinder side loads. Hellcat and 6.4 are stronger, but at a certain power level you need to be thinking about things like rod ratio because of stress issues. Again, be careful because Apache and 6.1 heads are made of 316 (unlike the hellcat heads that are made of a more durable 356-T6) and are known to flex and lift under high cylinder pressures. My current engine is NA and staying that way. Just would like to get it up around the 700hp range on pump gas.
Mopar to the bone!!!
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Re: Cubic inches and boost
[Re: 72Swinger]
#2206199
12/02/16 12:06 AM
12/02/16 12:06 AM
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Joined: Dec 2007
Posts: 486 IL
knyech1
mopar
|
mopar
Joined: Dec 2007
Posts: 486
IL
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The bigger the engine, the bigger the supercharger/turbo needs to be to make the same boost. In a boost application like this, a 420"+ engine wont make much more power than a 390"+ engine. Why does Goss ONLY have 404" when he could easily be using 440" engines? Its been said A LONG time ago in Gen III land that for NA build as big as you can afford, high boost builds seem to take ALOT more power with a crankshaft 3.80 or smaller and a rod 6.20 or longer because of block strength when you get over the 1000hp mark. +1 Exactly what I am saying about higher rod ratios. These engines don't like high cylinder side loads. Hellcat and 6.4 are stronger, but at a certain power level you need to be thinking about things like rod ratio because of stress issues. Again, be careful because Apache and 6.1 heads are made of 316 (unlike the hellcat heads that are made of a more durable 356-T6) and are known to flex and lift under high cylinder pressures. My current engine is NA and staying that way. Just would like to get it up around the 700hp range on pump gas. Bada$$. Very possible with these new engines. Can't wait to get my junk done
knyech1-
'71 Sassy Grass Demon 340/904. Pump gas, 1.61 60ft, 7.439 1/8 @ 95mph, 11.824 1/4 @ 111mph
"Not too bad for a pump gas 340, full of used parts and hillbilly ported stock heads." - V.B.
'03 2500 5.9L HO 6-spd on 35's. 395hp/755ft-lb at tires.
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