Offshoreonly.com - 454 rebuild with blower... Pistons and clearances.

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They don't so much compress the air , but can ram it into a space faster than can escape. They do not like back pressure. I maintain several large roots blowers as part of my responsibilities. Your both right , they dont actually compress the air but it has the same effect.

Quote:

Originally Posted by Bawana (Post 4255002)

Mike, thats like saying a piston does not compress................ Is it not?

a piston in a cylinder moves air,without a cylinder head with closed valves would there be any compression?

Quote:

Originally Posted by mike tkach (Post 4255012)

the correction factor on the dyno i use does not get calibrated by the operator,the computer is hooked up to a devise that feeds the info and the computer makes the correction factor.i assure you the dyno i use is accurate and repeatable.if your dyno operator changes the calibration to produce the numbers you want to see,RUN FORREST RUN.if i may ask,how much dyno experiance do you have?

The correction factor is to simulate that the conditions are X everytime, and there are a couple different formuals that can be used, one of these formulas your dyno uses to take current conditions and make adjustments to the output to simulate the X conditions. I never mentioned changing the correction factor, nor does my guy try and hit numbers at all. My point was a good dyno operator can minipulate the machine to make damn near any number you want. You can also do a quick blast while the motor is cooled down, but the oil is still hot to make more power on that pull. Ny guys dyno is known to be on the conservative side.

Ill give you a good example, and this is an example that Bob gave me the other day. He spoke of a builder that his dyno is very conservative, on any given day you could put a motor on it, and then take to another dyno and run it and the motor would make 30-40hp less on his dyno then the other, its just the way its set up. And in reality the "number doesn't matter, the dyno is a tool to tune, make sure there aren't any issues with the motor, and also to find where peak power is.

A good question is in order to make 691hp 667ft lbs with this set up, what do you think this motor is making NA to get those numbers?

i don,t know how much power it would make n/a because it will not be run that way so it was not tested that way.looks to me like you have all the answers.good luck with your build.for me to say how much power it would make would be speculation and i see no need for that.

Quote:

Originally Posted by mike tkach (Post 4248051)

i just finished a build very similar to what you are doing,it is scheduled for the dyno wednsday.it is 1 of 2 for another oso member.it is standard bore 454,8.5 to 1 compression ratio,afr 305 heads and a bob madera cam.it has wet exhaust so the cam is pretty conservative and it has to run on 89 oct fuel.it has a 177 blower that makes around 4 lbs boost.i am looking for 625 to 650 hp but more important to the owner is reliability.add in,it has scat h beam rods with arp 2000 bolts because they did not cost much more than rebuilding the stock gm rods with new bolts and they are a way better rod.also has morell hyd roller lifters.imo this engine should go 250 to 300 hrs before it needs the isky valve springs replaced and hundreds of hours before needing a refresh.i will let you know how it does on the dyno if you are interested.edit in,im no expert but i did stay at a holiday in express last week.

Mike do you have a dyno sheet on this build??? If so could you post it. I m interested in timing, egts, and afr's... Thanks

Quote:

Originally Posted by Bawana (Post 4255109)

Mike do you have a dyno sheet on this build??? If so could you post it. I m interested in timing, egts, and afr's... Thanks

I'm sure everyone would like to see the make believe sheets.

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Originally Posted by Black Baja (Post 4255114)

I'm sure everyone would like to see the make believe sheets.

really.

Quote:

Originally Posted by ealesh33 (Post 4255049)

A good question is in order to make 691hp 667ft lbs with this set up, what do you think this motor is making NA to get those numbers?

My guess, which is all that it is, would be somewhere in the area of 550-575HP. The little blower at 4lbs of boost, is probably netting around 100-125HP max.

[QUOTE=MILD THUNDER;4255120]:food-smiley-007:

Thanks guys