Blower for a 500hp
#11
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Thread Starter
Here is the link to the blower i am looking at. So let me know what you think is the price right good choice for my motor ect.
http://forums.boatfreaks.org/showthr...ghlight=blower
http://forums.boatfreaks.org/showthr...ghlight=blower
#12
Charter Member # 55
Charter Member
$4250 seems overpriced for used. Full retail on the Blower kit is $3300 new. The rest of the stuff brand new is maybe $2000. BTW, is it a Marine carb??????
Its maybe 20% off of brand new.
Its maybe 20% off of brand new.
#13
Registered
Platinum Member
Not new but it will get youstarted.
http://www.offshoreonly.com/forums/s...-up-cheap.html
Probably need a smaller upper pulley for that engine and those heads to make boost.
Realy, you don't need heads that big and that is going to be a good cam. If you are going to spend the cash, you should just call or PM rmbuilder and let him get you a custom cam that will do what you want.
750HP out of a 250 blower and that displacement is going to be real hard to do without using a tiny pulley on top and a giant pulley on bottom. That creates a lot of heat and that takes away from reliablity.
600 is a very reasonable and reliable expectation for that setup you are considering. Maybe a few more.
If you are going for the extra power, I highly suggest the intercooler also.
1 Dominator actually makes a little more and better power in the mid range than dual carbs on an engine that small.
If you are doing a total rebuild and starting from scratch, use JE piston #257949. This is a very low compression piston, 7.8:1 and use the smallest pully they offer on that blower kit with an 11-1200 Dominator and have Bob build you the right cam and I think you might get into the mid to low 700's. This should yield around 6-7lbs of total boost at WOT. You will need a longer rod for that combo though, but that is a good thing as this will give you a better angle on the piston travel and allow more rpm's safely.
I have used a very similar combination on a 468CI engine with a net 650+- HP at 5800rpms. You will have plenty more CI's to play with so it should get you there. IMO you shouldn't need bigger than a 330 +- head. Go with a silod roller for a little more power.
Good luck.
http://www.offshoreonly.com/forums/s...-up-cheap.html
Probably need a smaller upper pulley for that engine and those heads to make boost.
Realy, you don't need heads that big and that is going to be a good cam. If you are going to spend the cash, you should just call or PM rmbuilder and let him get you a custom cam that will do what you want.
750HP out of a 250 blower and that displacement is going to be real hard to do without using a tiny pulley on top and a giant pulley on bottom. That creates a lot of heat and that takes away from reliablity.
600 is a very reasonable and reliable expectation for that setup you are considering. Maybe a few more.
If you are going for the extra power, I highly suggest the intercooler also.
1 Dominator actually makes a little more and better power in the mid range than dual carbs on an engine that small.
If you are doing a total rebuild and starting from scratch, use JE piston #257949. This is a very low compression piston, 7.8:1 and use the smallest pully they offer on that blower kit with an 11-1200 Dominator and have Bob build you the right cam and I think you might get into the mid to low 700's. This should yield around 6-7lbs of total boost at WOT. You will need a longer rod for that combo though, but that is a good thing as this will give you a better angle on the piston travel and allow more rpm's safely.
I have used a very similar combination on a 468CI engine with a net 650+- HP at 5800rpms. You will have plenty more CI's to play with so it should get you there. IMO you shouldn't need bigger than a 330 +- head. Go with a silod roller for a little more power.
Good luck.
Last edited by jeff1000man; 12-13-2008 at 07:30 PM.
#15
Registered
Thread Starter
I have already purchased the cam and lifters. They are actually already in the motor. The motor is already put back together. The stock heads have been freshened up.
This was a mix up between me and the motor guy so i only want to take apart what i should. Like if you guys say you really should change the pistons then i will, but if what i got will work then i wont mess with them.
As for the inter cooler i really do not want to have a scoop i have 6 kids and a Ole lady that's always laying back there or something. I was told to use the chiller. That i would need the scoop.
For the heads i have not purchased a set yet so i am open to suggestions i think i want to use brodix not sure what size. If buy using the blower and heads i would only see 600 hp i wont buy both i will buy heads or blower. To me the money spent for 600 hp or a little more is not worth 7000.00 I thought the heads would give my 575 hp and with the blower and heads i would be 700 to 750.
I was also looking at this setup but not sure, so if you guys think this is a better deal please speak up.
http://cgi.ebay.com/ebaymotors/ws/eB...m=140287151756
What kind of hp with a good set of heads with no blower? Arre the heads a absolute must with the blower, or would the stock heads be fine. I am not so worried about hp just wana run 80 I was thinking it would take around 700 hp to get there.
I just want to do this right the first time no short cuts. If you cant tell i am pretty new to all of this so i apologize if i am asking allot of dumb questions. I just have no one else to ask except the good people of oso. I THANK ALL THAT ARE HELPING ME!!!!
This was a mix up between me and the motor guy so i only want to take apart what i should. Like if you guys say you really should change the pistons then i will, but if what i got will work then i wont mess with them.
As for the inter cooler i really do not want to have a scoop i have 6 kids and a Ole lady that's always laying back there or something. I was told to use the chiller. That i would need the scoop.
For the heads i have not purchased a set yet so i am open to suggestions i think i want to use brodix not sure what size. If buy using the blower and heads i would only see 600 hp i wont buy both i will buy heads or blower. To me the money spent for 600 hp or a little more is not worth 7000.00 I thought the heads would give my 575 hp and with the blower and heads i would be 700 to 750.
I was also looking at this setup but not sure, so if you guys think this is a better deal please speak up.
http://cgi.ebay.com/ebaymotors/ws/eB...m=140287151756
What kind of hp with a good set of heads with no blower? Arre the heads a absolute must with the blower, or would the stock heads be fine. I am not so worried about hp just wana run 80 I was thinking it would take around 700 hp to get there.
I just want to do this right the first time no short cuts. If you cant tell i am pretty new to all of this so i apologize if i am asking allot of dumb questions. I just have no one else to ask except the good people of oso. I THANK ALL THAT ARE HELPING ME!!!!
Last edited by ubet28; 12-13-2008 at 11:05 PM.
#17
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#19
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#20
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Thread Starter
I was also looking at this setup but not sure, so if you guys think this is a better deal or choice Please speak up.
http://cgi.ebay.com/ebaymotors/ws/eB...m=140287151756
http://cgi.ebay.com/ebaymotors/ws/eB...m=140287151756