Ok if you have 2 identical motors and you put 2 different blowers on them one small say a 250 and the other a 8-71 and they both have 10 pounds of boost are they going to run the same or is the one with a bigger blower going to make more power ?

The 8-71 will be turning slower than the baby blower to make that 10#, slower equals less heat, less heat=more power.

Your results may vary.

Ok but heat aside so 10 pounds is 10 pounds regardless of size so same power is produced. Correct ?

quote:

Originally posted by smokinjeff:
Ok but heat aside so 10 pounds is 10 pounds regardless of size so same power is produced. Correct ?

I would say no.

While 10 lbs is 10 lbs, it is a matter of how you're getting it. Like bender said the 250 will make more heat due to the number of revolutions of the smaller rotors it takes to achieve 10 lbs of boost, thus increasing the intake charge temp.

Therefore a 250 blower will make less power than the 8-71 that would take less revolutions of the rotors to make the same 10 lbs, with a cooler intake air temp.

I would say a more interesting question would be .... If you are running alcohol is the 10 lbs made by the 250 blower vs 8-71 cooled enough to be negligible as far as intake air temp goes.

10 pounds is 10 pounds.How much oxygen does that 10 pounds contain? Think of nitrous bottle. If you have 800 lbs pressure and need 900, what do you do. Heat the bottle.Then you have 900 lbs pressure.Do you have more nitrous? No. Boost is same in away, it is just a pressure reading.

Ever had hard time getting your breath on extremely hot day? Less oxygen in the air even if more volume.

Larger blower moves more cfm per revolution and if you do so with less friction even better. Reason screw blowers beat the hell of out old peter built design roots blower. Less drag is also great. I good 14-71 hi helix takes a pull bar to turn and a screw blower can be turned by hand. I think 350 to 400 hp use to be number for HP required to spin hi helix.

People get to worried about boost number. A engine runs on fuel, oxygen and something to make it go boom.

I would much rather have 45 lbs of 75* air than 49 lbs. of 130* air charge. This is why intercoolers are on higher boost turbo or the run alcohol to keep air temp down.

One or the other of those two blowers is going to require more energy to create the 10 lbs of boost. One of them is going to weigh more than the other also.

Thanks Guys. I was just thinking and have time to do so as I’m on the tractor preparing land to plant Cotton this year. Not enthusiastic about it as expenses are so high the risk vs reward does not look good. Might just need 6 lucky numbers just so I can keep racing.

quote:

...expenses are so high the risk vs reward does not look good.

You have my support and well wishes (which is worth 0). None the less best of luck!

quote:

Originally posted by smokinjeff:
Thanks Guys. I was just thinking and have time to do so as I’m on the tractor preparing land to plant Cotton this year. Not enthusiastic about it as expenses are so high the risk vs reward does not look good. Might just need 6 lucky numbers just so I can keep racing.

Around here it is tobacco as number one crop. Lots of prayers for hail storm little before harvest time.. Cpl have just said hell with it. Funny thing is they all c0mplain there is niot money in it and they still do it yaer after year.then buy 100k worth of new stuff after harvest and sell.LOL

I spend most of hunting season thinking race car parts and/or design while sitting in tree waiting for Bambi's granddaddy to walk by.

Thanks Canted Valve. The issue for me is many things. We don’t have as much underground water that we once had.( We are in a drought). Expenses have risen yearly but not so much for crop prices. When prices would be up the following year everything we buy would go up but would never come back down when crop prices drop. I call it the jack effect. Expenses go up but never back down. Profit per acre decreases so you need more acres to offset At my age I don’t want to add more risk. I should quit racing but it’s my escape even though I don’t race a lot. I can’t imagine a life without the friendships I’ve made because of racing. I will be able to tell stories of my life instead of just saying I worked. Everyone in the country is getting hit with high cost of living. It looks like this administration is trying to put everyone in a hardship and struggle to just survive. I hope for all who reads this can weather the onslaught because it doesn’t look like it’s going to turn around anytime soon. Sorry this was so long and off subject, after all I told you I was bored.

I agree Jeff.

quote:

Originally posted by smokinjeff:
Ok but heat aside so 10 pounds is 10 pounds regardless of size so same power is produced. Correct ?

Yes, sort of. In reality, you will have to deal with the heat, friction, and efficiency of a smaller blower vs the big one.

Being a nice guy and willing to help a fellow racer out, I'll give you my address and you send me one of each of the blowers in question I'll let you know my results!