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-   -   Blower or not?? (https://www.offshoreonly.com/forums/general-q/173316-blower-not.html)

obsessioncatsass 11-15-2007 01:31 PM

Blower or not??
 
I have a 10 meter fountain with #3 drives. It has fresh 540 aluminum head motors built for blowers, but they dont have blowers on them. Runs about 85 MPH. The compression is only around 8 to 1. How much power can I gain by raising the compression up to around 10 to 1? and can I still run pump gas? Or should I just install blowers???? I want reliability. What would u recommend for a blower for a motor of this size? I have willys 950 CFM carb on the motor now and would like to use them on the blowers if possible. Any imput would be appreciated.

excalibur32 11-15-2007 02:01 PM

Adding blowers would be the thing to do with your compression ratio. Also the easiest thing too!

ghittner 11-15-2007 02:54 PM

You are losing a TON of power. Add the blowers it would be the best option and far outweigh the gains of higher compression. You are right where you want to be as far as compression for the blowers. You will get hundreds of horsepower and you can run 8 to ten pds boost on pump gas with that set up. Keep your timing coservative with the blowers and they will live a long time. 30 Deg max. Ideally you should run dual 750-850's for best fuel distribution. An 8-71 will be perfect and a 10-71 would be better if it would fit. You can spin the 10 slower and create less heat.

tomas_wallin 11-19-2007 08:39 AM

Make sure your motors are built for the amount of HP you will produce with the blowers first of all!

WildWarrior 11-19-2007 09:04 AM


Originally Posted by obsessioncatsass (Post 2336934)
I have a 10 meter fountain with #3 drives. It has fresh 540 aluminum head motors built for blowers, but they dont have blowers on them. Runs about 85 MPH. The compression is only around 8 to 1. How much power can I gain by raising the compression up to around 10 to 1? and can I still run pump gas? Or should I just install blowers???? I want reliability. What would u recommend for a blower for a motor of this size? I have willys 950 CFM carb on the motor now and would like to use them on the blowers if possible. Any imput would be appreciated.

I would throw 6 or 7 lbs of boost to those mills and run 4- 850 to 950cfm carbs.Best bang for the buck !
I have a set of low hr Blower Shop 8-71s if you need them,all they need is snout's ,I used the 8-71 snouts on my new Hi helix 14-71s.

Edward R. Cozzi 11-19-2007 11:56 AM


Originally Posted by ghittner (Post 2337021)
You are losing a TON of power. Add the blowers it would be the best option and far outweigh the gains of higher compression. You are right where you want to be as far as compression for the blowers. You will get hundreds of horsepower and you can run 8 to ten pds boost on pump gas with that set up. Keep your timing coservative with the blowers and they will live a long time. 30 Deg max. Ideally you should run dual 750-850's for best fuel distribution. An 8-71 will be perfect and a 10-71 would be better if it would fit. You can spin the 10 slower and create less heat.

I agree with almost everything here, but I think 8 to 10 lbs. of boost is a little much for pump gas without sacrificing some engine longevity. Be careful in this respect.

obsessioncatsass 11-24-2007 01:28 PM

Wildwarrior, How much you want for the 8-71's How much would the snouts cost. Give me your number and i will call you about them, Thanks

WildWarrior 11-26-2007 05:53 AM


Originally Posted by obsessioncatsass (Post 2346520)
Wildwarrior, How much you want for the 8-71's How much would the snouts cost. Give me your number and i will call you about them, Thanks

Please send me an E mail as you have that feature turned off on OSO and mail can not be sent to you .
Thanks!
Glen

ECeptor 11-26-2007 04:47 PM

Increasing compression from 8:1 to 10:1 will give you about 6.5% more power all other things being equal according to this article - The Power Squeeze

obsessioncatsass 11-28-2007 10:45 AM


Originally Posted by WildWarrior (Post 2347993)
Please send me an E mail as you have that feature turned off on OSO and mail can not be sent to you .
Thanks!
Glen

I dont think I can send email because im not a paying member, im just registered. Im not real computer savy.

WildWarrior 11-28-2007 03:14 PM


Originally Posted by obsessioncatsass (Post 2351206)
I dont think I can send email because im not a paying member, im just registered. Im not real computer savy.

Can call me at the shop 717-417-2900
Thanks!
Glen


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