700HP Blower vs. NA
01-18-2011, 03:58 AM
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Thank you for the responses. I'm looking at an American Offshore NSX 26 with a 502 and B&M 420 blower. The engine was originally built (setup) by American Offshore I believe in 1996 and had a major rebuild in 2006 adding aluminum heads. The current owner runs 100 octane. The octane requirement is concerning but I've always been a big fan of this boat and it's concept. I'm not sure how do go 100 mph in a single engine boat more safely and economically than this setup.
01-18-2011, 06:54 AM
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Thank you for the responses. I'm looking at an American Offshore NSX 26 with a 502 and B&M 420 blower. The engine was originally built (setup) by American Offshore I believe in 1996 and had a major rebuild in 2006 adding aluminum heads. The current owner runs 100 octane. The octane requirement is concerning but I've always been a big fan of this boat and it's concept. I'm not sure how do go 100 mph in a single engine boat more safely and economically than this setup.
01-18-2011, 08:57 AM
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700 H.P. blower motor, easy to build, and will last with routine maintaince. 700 H.P. N/A motor a little more involved. Blower motors tend to make torque at a lower rpm, hence the bad reputation as drive brakers. A N/A motor, will tend to make torque in a higher rpm range.
Both, if making the same h.p. will push the boat the same speed on the top end. IMO the blower boat pulls harder on the low end.
Would check with the owner about the octane fuel he is running. He may be doing it to try to be safe. Unless the 420 blower is making alot of boost, 100 octane seems a bit high. Especially running Aluminum heads.
Both, if making the same h.p. will push the boat the same speed on the top end. IMO the blower boat pulls harder on the low end.
Would check with the owner about the octane fuel he is running. He may be doing it to try to be safe. Unless the 420 blower is making alot of boost, 100 octane seems a bit high. Especially running Aluminum heads.
01-18-2011, 09:07 AM
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Thank you for the responses. I'm looking at an American Offshore NSX 26 with a 502 and B&M 420 blower. The engine was originally built (setup) by American Offshore I believe in 1996 and had a major rebuild in 2006 adding aluminum heads. The current owner runs 100 octane. The octane requirement is concerning but I've always been a big fan of this boat and it's concept. I'm not sure how do go 100 mph in a single engine boat more safely and economically than this setup.
01-18-2011, 09:59 AM
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blowers/big cubic inch
i have read all the post here on this topic w/intrest.i have had one blower motor,and a quite a few n/a motors.not one thing was said about gas consumption.....yea,i know you should,nt say that word around performance boat,but i did.heres why.i think a roots stye blowers are hard as hell on fuel.when your not running boost,the blower is useing up h/p.which uses more fuel.i know fuel is the cheaspest part of boating,but when its five dollars @the pump,something to think.i am not dissing blowers ,realy i like them,but as said.if they are not tunend right,they can be not such a good thing.i am no expert by no means.just my 2cent.
01-18-2011, 12:20 PM
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Problem is that people bolt blowers on motors, who have no clue, and fry their engines in 1 hour.
Their is two trains of thoughts on this. Most of it depends on what you have to start with for a base. For example, lets say you have a 502CI merc. To get 700HP N/A out of it, you will need to run really good flowing heads(expensive), 9.5:1 or higher compression, solid roller camshaft with lots of lift and duration, very high valve spring pressures, and probably turn the engine to 6000+RPM to even get close to 700HP.
Or, you can leave the stock 502, put some cometic head gaskets in, a good valve job, a mild hyd roller camshaft, install a blower, and make 700HP.
The blower setup would more than likely last longer, and idle better around the docks. My vote is for blowers, as long as they are properly tuned and setup.
Their is two trains of thoughts on this. Most of it depends on what you have to start with for a base. For example, lets say you have a 502CI merc. To get 700HP N/A out of it, you will need to run really good flowing heads(expensive), 9.5:1 or higher compression, solid roller camshaft with lots of lift and duration, very high valve spring pressures, and probably turn the engine to 6000+RPM to even get close to 700HP.
Or, you can leave the stock 502, put some cometic head gaskets in, a good valve job, a mild hyd roller camshaft, install a blower, and make 700HP.
The blower setup would more than likely last longer, and idle better around the docks. My vote is for blowers, as long as they are properly tuned and setup.
