Blower motor questions

[tmaxxman21]

I have a 6-71 on a gm performance 350 crate motor. It's under driven 12%. I wanna build a decent sbc. Where should I get the internals?

My motor runs great. I drive it on 100 mile trips. But I wanna stomp on the throttle without worrying about dropping the crank haha

 

[RPM]

I have good several good things about Big Al. http://www.bigalstoybox.com/shorthblocks.htm

Be sure to get the good crank, billet drive hub with a double keyway.

 

[tmaxxman21]

I do have a big Al's blower.. So I should look that way

 

[Screaming Metal]

Its best if you don't turn wrenches to get a complete longblock assembly, thats built for a blower. If you do it otherwise, theres a list of parts, must haves, if you will if you plan on hanging your foot off in it at times.
Its suggested heavily that you go with a steel crank. Double keyed,as Ron said. Good rods are a must and also quality pistons. You have to run low compression if your not planning a race motor with race fuel and detination fighting measures, such as water injection, etc.
What I explain to the Customers is that a blown motor 'thinks' its several times bigger than it is, depending on boost levels, because the fuel and air is forced into the cylinders under 'pressure' or 'boost'. That, in turn, puts a tremendous strain on the crank, rods and pistons. Not only at the rod throws and mains, but on the snout of the crank. It takes 50 to 100 horses to power that blower....run the belt too tight, you'll snap the end right off your crank. Have it slapping too much, the same.
A 6-71 puts more of a strain on your crank than a 4-41, 8-71, even more. Bigger=more stress at a lower rpm and a LOT MORE at Drive pressures above 3800 rpm's. On race cars running 12-71's, the whole block twists slightly because of the torque.
Just a little FYI before going blown, especially in a big way.

 

[Golly]

don't forget a good fuel supply system. Good electric pump , filter and 1/2'' line to the motor. and make sure your cooling system is up to scratch too. Once you've had a good running blown motor you'll never go back!

 

[Hot Rod Todd]

Some will suggest that blowers on a bucket arent really necessary for street driving, but dont believe them for a moment!!!!

Some thoughts to consider tho:
Put in a decent ignition system
Blowers build heat so upgrade your cooling system to the best you can afford
A bigger blower, run lightly makes less heat than a small blower thats overdriven to get the same power
Its torque that spins the wheels and not the HP
112-114 degree overlap on the cam works pretty well.
Double keyway the crank always
A cast crank will last about 5 years if you go drag racing as well as driving on the street(ask me how I know this)
A steel crank, decent rods and forged pistons under 8.0:1 is pretty standard stuff for a street driven blower motor.
Pat Gandahls book on street blowers says any heads will be fine as the blower pushes the air thru regardless, but decent aftermarket heads will breathe better

My personal view is that all buckets with blowers should do at last one run down the quarter mile while in your ownership. That way when somebody says how fast, you can just smile at them knowingly......Its much cooler than saying "its real fast" when you dont really know in all truth.

 

[GT63]

Definitely get this book if you're thinking about a blower.

http://www.amazon.com/Street-Superc...94&sr=1-1-spell&keywords=street+supercharginh

 

[old round fart]

When people ask me how fast my car was, I would tell them"It will do a half hour in 28 minutes".

 

[sstock]

Once you have been blown, everything else sucks

 

[409T]

Its torque that spins the wheels and not the HP

Amen!

 

[Screaming Metal]

Amen!

You'll notice that when you go to do a burnout with a blower atop your motor, that, you don't push as heavily on that Go pedal. Thats a big grin maker right there.
Blower motors start making tons pf horses and torque earlier, if tuned right. One of the main things for the Blower motors is your timing.
This, these days is a direct influece of the crappy gas we have now. You cannot run a blower motor lean. if you do, you'll torch a piston or a valve.
Backfires, aviod them at all costs if at all possible. That means have your timing really close to start with. Your compressing alot of air and fuel into a small space under that blower. Also between the rotors and the carb bases. There is a explosive territory there....so be careful.
Compression and ignition are also super critical. A stock ign. system isn't up to snuff here. If you look at the motors at the drags, the Altereds and the TF's, among others run dual distributors and and dual plugs....
This is because they're blowing the flame out inside the cylinders.
Though you might have a low static compression ratio, with high boost pressures with alot of overdrive, you can blow that flame out in a street motor at high RPM's, with fairly stock heads. So when that dredful miss occurs....often, a better ignition is often the answer....
I'm talking about 6500RPM, which the nonblowns don't consider Hi-RPMs.

Last but not least....any serious blower motor....you have to change your spark plugs. For every 75 to 100 horses, you have to go to a colder plug.

And That E85 in a blower motor....just let me say....it can be problematic, at best... It just doen't have the octane. And sometimes it won't have spark rattle that warns you. Alcohol can absorb water. Water will fight detonation somewhat.
That slight cooling effect, along with not enough octane to do the job, caused a person, not long ago to have a massive meltdown while showing off in a street car.
Wasn't my setup, but i was the one that diagnosed the rubble afterwards. Nice $6500 street motor down the drain. He opened it up with crappy fuel in it....