Blower size?
12-12-2011, 07:10 PM
#41
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Huber 1350 transmissions, and big shaft #4's. Can I turn up the boost enough to make 850 with iron heads and no chiller though? It is sounding like I need to either run aluminum heads or run the chillers to get the boost high enough to get the HP results I am seeking?
With 8:1, iron heads, no chiller, I'd keep the boost at 6, maybe 7psi if the tune is right. I think you'd be making a honest 750HP per side, and boat would probably run really nice. Blower motors make some impressive torque, that will put a smile on your face! My buddy did some 509's, that did 800HP, but he had a chiller, and I think they were around 9-10psi on the dyno.
Granted a different boat, but a buddy of mine has a 1990 Top Gun with a pair of 800s. Konrad drives mounted about 4" or so below the bottom. Pretty much runs mid 80's. I'd expect your boat to run about the same #'s with 750s. To get to 100mph, you'll probably need a pair of 1000's, maybe 1100's.
12-12-2011, 10:12 PM
#42
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Huber 1350 transmissions, and big shaft #4's. Can I turn up the boost enough to make 850 with iron heads and no chiller though? It is sounding like I need to either run aluminum heads or run the chillers to get the boost high enough to get the HP results I am seeking?
Darrell.
12-13-2011, 06:44 AM
#43
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Since we are on the subject, lets talk about chillers for a minute. This is a subject that comes up often between a buddy and me over beers. He runs a 9:1 iron headed 8-71 509CI with chillers. His plan is to increase boost to 8psi.
So, if we compare two builds Lets say you have one engine and you want to run 7-8psi.
502CI, 9:1, iron heads, a basic build and you put a 10-71 on it.
502CI, 8:5:1, aluminum heads, properly selected blower cam, proper steps taken in the build for a good quench, polished combustion chambers, and bolt a 10-71 on it, no chiller.
Now, with both of the above setups, running say 7psi, and the blower is underdriven, since we know overdriving creates alot of heat. It is understood that compressing air in itself raises the air temperature, but how much at a level of 7psi? And which engine would have a larger safety factor from detonation? The aluminum headed lower compression blower specific build, or the iron headed higher compression intercooled setup?
Im pretty sure that the intercooler helps alot with a mini blower, like on a 177 or 250 blower driven at say 2:1 ratio. Im sure the air temps after the blower can get quite hot. But how much heat would be generated by a bigger blower running at say 10% underdriven? Is there enough heat in the intake air temp to allow the chiller to make a substantial drop in temperature?
I know that in say my Semi truck, I have a intercooler, well, a air to air cooler. However, at full load and wot, I peg the boost gauge at 32PSI. Or like the guys who run Turbo Buick Grand Nationals, with intercoolers and 18+lbs of boost. I can definitly see the need to cool the air when it's compressed to those levels. Granted its probably not the heat generated by the compressor itself, but the heat from the compressed air.
Even if with the above 10-71 setups, detonation wasnt a issue, how much power would be gained/lost with a intercooler. I've seen where some have lost speed when adding a chiller, so they overdrive the blower a bit more , to get it back. And i've also seen where turning the water feed on to the intercooler on the dyno netted about 20hp with no other changes. However, i'd be curious to see if that 20hp would come back if he had removed the chiller completely, as to not have that restriction in the intake.
DMOORE, the only reasons i can see not to run a chilller, would be cost, clearance issues, and if you sprung a leak in the core and filled the engine with water.
Reasons i can see you NEED a chiller, would be increased boost levels desired, small compressor overdriven, higher static compression, lower octane fuel, iron heads, or when running water thermostats or boating in very warm waters.
I know lots of guys running roots blown stuff without chillers and no issues, and i know lots of guys running roots blown stuff with chillers, and no issues. I guess it comes down to the overall build and how its setup. Would love to hear some proffessional input on this topic! Just another think to talk about over some beers!
So, if we compare two builds Lets say you have one engine and you want to run 7-8psi.
502CI, 9:1, iron heads, a basic build and you put a 10-71 on it.
502CI, 8:5:1, aluminum heads, properly selected blower cam, proper steps taken in the build for a good quench, polished combustion chambers, and bolt a 10-71 on it, no chiller.
Now, with both of the above setups, running say 7psi, and the blower is underdriven, since we know overdriving creates alot of heat. It is understood that compressing air in itself raises the air temperature, but how much at a level of 7psi? And which engine would have a larger safety factor from detonation? The aluminum headed lower compression blower specific build, or the iron headed higher compression intercooled setup?
Im pretty sure that the intercooler helps alot with a mini blower, like on a 177 or 250 blower driven at say 2:1 ratio. Im sure the air temps after the blower can get quite hot. But how much heat would be generated by a bigger blower running at say 10% underdriven? Is there enough heat in the intake air temp to allow the chiller to make a substantial drop in temperature?
I know that in say my Semi truck, I have a intercooler, well, a air to air cooler. However, at full load and wot, I peg the boost gauge at 32PSI. Or like the guys who run Turbo Buick Grand Nationals, with intercoolers and 18+lbs of boost. I can definitly see the need to cool the air when it's compressed to those levels. Granted its probably not the heat generated by the compressor itself, but the heat from the compressed air.
Even if with the above 10-71 setups, detonation wasnt a issue, how much power would be gained/lost with a intercooler. I've seen where some have lost speed when adding a chiller, so they overdrive the blower a bit more , to get it back. And i've also seen where turning the water feed on to the intercooler on the dyno netted about 20hp with no other changes. However, i'd be curious to see if that 20hp would come back if he had removed the chiller completely, as to not have that restriction in the intake.
DMOORE, the only reasons i can see not to run a chilller, would be cost, clearance issues, and if you sprung a leak in the core and filled the engine with water.
Reasons i can see you NEED a chiller, would be increased boost levels desired, small compressor overdriven, higher static compression, lower octane fuel, iron heads, or when running water thermostats or boating in very warm waters.
I know lots of guys running roots blown stuff without chillers and no issues, and i know lots of guys running roots blown stuff with chillers, and no issues. I guess it comes down to the overall build and how its setup. Would love to hear some proffessional input on this topic! Just another think to talk about over some beers!
12-13-2011, 07:29 AM
#44
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Hey Rob, is there any particular reason 850HP is your number? Only reason I ask, is because I think you would be pleasantly surprised even if you were only 750HP per side with your new setup. You should pick up some speed considering your drives are not mounted in the basement any more. Sometimes just getting the drive height dialed in is like adding 100hp a motor.
With 8:1, iron heads, no chiller, I'd keep the boost at 6, maybe 7psi if the tune is right. I think you'd be making a honest 750HP per side, and boat would probably run really nice. Blower motors make some impressive torque, that will put a smile on your face! My buddy did some 509's, that did 800HP, but he had a chiller, and I think they were around 9-10psi on the dyno.
Granted a different boat, but a buddy of mine has a 1990 Top Gun with a pair of 800s. Konrad drives mounted about 4" or so below the bottom. Pretty much runs mid 80's. I'd expect your boat to run about the same #'s with 750s. To get to 100mph, you'll probably need a pair of 1000's, maybe 1100's.
With 8:1, iron heads, no chiller, I'd keep the boost at 6, maybe 7psi if the tune is right. I think you'd be making a honest 750HP per side, and boat would probably run really nice. Blower motors make some impressive torque, that will put a smile on your face! My buddy did some 509's, that did 800HP, but he had a chiller, and I think they were around 9-10psi on the dyno.
Granted a different boat, but a buddy of mine has a 1990 Top Gun with a pair of 800s. Konrad drives mounted about 4" or so below the bottom. Pretty much runs mid 80's. I'd expect your boat to run about the same #'s with 750s. To get to 100mph, you'll probably need a pair of 1000's, maybe 1100's.
12-13-2011, 09:06 AM
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What blocks? I would not recommend aluminum heads on a GM 502 with that much boost...or anything past 750hp with those blocks.
Last edited by Back4More; 12-13-2011 at 09:18 AM.
12-13-2011, 09:36 AM
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12-13-2011, 09:53 AM
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These engine's started life as carb hp 500's. Are these blocks not going to take that much horsepower? This would be the first I have heard on this topic. Also why no aluminum heads on this block at that boost level? I do plan on staying with the iron's, but I am wondering about the logic on that as well?
12-13-2011, 01:56 PM
#48
a custom 10:71 will fit, call Littlefield and tell him you want the blower with more forward bias, this will allow suffiecient distributor clearance, and you can run 10% under which will give you a lower charge air temp and still make plenty of boost... run a roller cam that has around 250 deg duration @ .050 on a 114 grind, with 8.0:1 compression, she will live and you'll be a happy camper!!
