Boost numbers and opinions needed
09-29-2018 | 06:32 PM
#12
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From: chicago
3lbs more of boost will likely net you 75-100hp. Been there and done it on the dyno with a similar combo.
theres alot of factors that go into what amount of boost is safe. An 454 with locked timing, 177 blower, 9:1, single carb, warm coolant temps, small cam, will not tolerate the same boost as a 8:1, 8-71 equipped underdriven healthy cammed dual carb setup with a timing curve.
its all about managing cylinder pressures, and what octane is available. Your air intake temps shouldnt be very high, and with the right tune, 7-8psi should not be an issue at all.
i run 9psi on my 468s, 8:1, iron heads, superchillers, etc. Id run more, but im already spinning the engines to 6200-6300rpm with the props i have. With 10psi, id be probably in the 875-900hp range, and 6500rpm wot range. Pretty sure sooner or later im gonna push the crank out of the stock block.
theres alot of factors that go into what amount of boost is safe. An 454 with locked timing, 177 blower, 9:1, single carb, warm coolant temps, small cam, will not tolerate the same boost as a 8:1, 8-71 equipped underdriven healthy cammed dual carb setup with a timing curve.
its all about managing cylinder pressures, and what octane is available. Your air intake temps shouldnt be very high, and with the right tune, 7-8psi should not be an issue at all.
i run 9psi on my 468s, 8:1, iron heads, superchillers, etc. Id run more, but im already spinning the engines to 6200-6300rpm with the props i have. With 10psi, id be probably in the 875-900hp range, and 6500rpm wot range. Pretty sure sooner or later im gonna push the crank out of the stock block.
09-29-2018 | 06:59 PM
#14
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Joined: Jul 2017
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From: Sodus MI
So that being said and knowing my build...do you think I should wait for chillers to try upping the boost or do it now and tune accordingly for the higher boost?? Again I don't want to run it on the ragged edge and hurt it and I repsect everyones opinions...just trying to not have to jet this thing a hundred times hahaha
09-29-2018 | 07:38 PM
#15
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From: St. Pete Beach, FL
All else equal 5-8psi would add 15% more power. In reality it will be less due to the blower not being perfectly efficient.
Assuming a 500hp base engine, 5psi = 670hp, 8 psi = 772hp. 500x(1+(boost/14.7))
Assuming a 500hp base engine, 5psi = 670hp, 8 psi = 772hp. 500x(1+(boost/14.7))
09-29-2018 | 07:47 PM
#16
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From: St. Pete Beach, FL
3lbs more of boost will likely net you 75-100hp. Been there and done it on the dyno with a similar combo.
theres alot of factors that go into what amount of boost is safe. An 454 with locked timing, 177 blower, 9:1, single carb, warm coolant temps, small cam, will not tolerate the same boost as a 8:1, 8-71 equipped underdriven healthy cammed dual carb setup with a timing curve.
its all about managing cylinder pressures, and what octane is available. Your air intake temps shouldnt be very high, and with the right tune, 7-8psi should not be an issue at all.
i run 9psi on my 468s, 8:1, iron heads, superchillers, etc. Id run more, but im already spinning the engines to 6200-6300rpm with the props i have. With 10psi, id be probably in the 875-900hp range, and 6500rpm wot range. Pretty sure sooner or later im gonna push the crank out of the stock block.
theres alot of factors that go into what amount of boost is safe. An 454 with locked timing, 177 blower, 9:1, single carb, warm coolant temps, small cam, will not tolerate the same boost as a 8:1, 8-71 equipped underdriven healthy cammed dual carb setup with a timing curve.
its all about managing cylinder pressures, and what octane is available. Your air intake temps shouldnt be very high, and with the right tune, 7-8psi should not be an issue at all.
i run 9psi on my 468s, 8:1, iron heads, superchillers, etc. Id run more, but im already spinning the engines to 6200-6300rpm with the props i have. With 10psi, id be probably in the 875-900hp range, and 6500rpm wot range. Pretty sure sooner or later im gonna push the crank out of the stock block.
The cam is bleeding some cylinder pressure though in your hypothetical scenario.
09-29-2018 | 08:02 PM
#18
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From: Sodus MI
Well a hypothetical 100 hp gain is worth it enough for me to try...If my baby big block made 750+ I wouldn't know what to do with myself hahaha
I guess detonation would be my biggest thing to watch?? And I'm still researching the best way to recognize and combat detonation since especially in a boat from what I understand you will never hear it...I plan to tune my WOT air fuel to mid 11's and pull my plugs after 1 or 2 WOT passes...I assume detonation will show on the plugs??
Like I said I'm going to research it more but other than detonation what should I really be concerned with when upping the boost to 8 lbs and how would I detect said problem?? Sorry for the rookie questions like I've said in other threads related to this build I'm new to the blown bbc game and don't have the money to trial and error this thing hahaha
Thanks guys!!
I guess detonation would be my biggest thing to watch?? And I'm still researching the best way to recognize and combat detonation since especially in a boat from what I understand you will never hear it...I plan to tune my WOT air fuel to mid 11's and pull my plugs after 1 or 2 WOT passes...I assume detonation will show on the plugs??
Like I said I'm going to research it more but other than detonation what should I really be concerned with when upping the boost to 8 lbs and how would I detect said problem?? Sorry for the rookie questions like I've said in other threads related to this build I'm new to the blown bbc game and don't have the money to trial and error this thing hahaha
Thanks guys!!
09-29-2018 | 08:04 PM
#19
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From: Sodus MI
I assume that holding this thing pinned for like miles at a time is a quick way to make a lot of scrap metal so with no chiller right now would say 1/4-1/2 mile WOT pulls after tuning be realistic??
09-29-2018 | 08:06 PM
#20
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Joined: Jan 2006
Posts: 3,865
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From: St. Pete Beach, FL
Well a hypothetical 100 hp gain is worth it enough for me to try...If my baby big block made 750+ I wouldn't know what to do with myself hahaha
I guess detonation would be my biggest thing to watch?? And I'm still researching the best way to recognize and combat detonation since especially in a boat from what I understand you will never hear it...I plan to tune my WOT air fuel to mid 11's and pull my plugs after 1 or 2 WOT passes...I assume detonation will show on the plugs??
Like I said I'm going to research it more but other than detonation what should I really be concerned with when upping the boost to 8 lbs and how would I detect said problem?? Sorry for the rookie questions like I've said in other threads related to this build I'm new to the blown bbc game and don't have the money to trial and error this thing hahaha
Thanks guys!!
I guess detonation would be my biggest thing to watch?? And I'm still researching the best way to recognize and combat detonation since especially in a boat from what I understand you will never hear it...I plan to tune my WOT air fuel to mid 11's and pull my plugs after 1 or 2 WOT passes...I assume detonation will show on the plugs??
Like I said I'm going to research it more but other than detonation what should I really be concerned with when upping the boost to 8 lbs and how would I detect said problem?? Sorry for the rookie questions like I've said in other threads related to this build I'm new to the blown bbc game and don't have the money to trial and error this thing hahaha
Thanks guys!!
