Thread: Making A Small Block 350 As Fast As It Can Be

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Huffer on huffer off ,is real easy for air to get thru.Basically a pipe,since said huffer is not gunna sit on top of intake,none of the oem style on off huffers sit on the intake,thats for the movies,the real ones are crank driven.I am not sure of the correct name of this valve is ,but heres how it works. You have a 4 inch pipe with a spring operated door{diverter} which opens under low pressure{no boost}apply the boost and the pressure in the pipe forces the trap door closed which seals the system and you are boosted,cut the boost trap door opens allowing fresh air thru the trap door into the carb.with the boost off there is no draw thru the huffer to worry about.picture a drain trap and a cross over pipe on the top .the top is where fresh air goes in unboosted.hit the boost and the top pipe is sealed via the trap door and then the huffer sucks the air thru the bottom of the the drain{instead of the top} around to the same spot only thru the huffer this time

Originally Posted by shawnlee28

Huffer on huffer off ,is real easy for air to get thru.Basically a pipe,since said huffer is not gunna sit on top of intake,none of the oem style on off huffers sit on the intake,thats for the movies,the real ones are crank driven.I am not sure of the correct name of this valve is ,but heres how it works. You have a 4 inch pipe with a spring operated door{diverter} which opens under low pressure{no boost}apply the boost and the pressure in the pipe forces the trap door closed which seals the system and you are boosted,cut the boost trap door opens allowing fresh air thru the trap door into the carb.with the boost off there is no draw thru the huffer to worry about.picture a drain trap and a cross over pipe on the top .the top is where fresh air goes in unboosted.hit the boost and the top pipe is sealed via the trap door and then the huffer sucks the air thru the bottom of the the drain{instead of the top} around to the same spot only thru the huffer this time

What???OH MY!!!!

Originally Posted by Don Shillady

Erik, I went back to an old post from when I joined the Forum and found it was still there but condensed to only active members as of now and edited quite a bit with three pages repeated so it looks like the comments from Streets are gone due to a combination of his departure, and changeover of the Forum software. Nevertheless, Streets claimed he once had a T-bucket with a 350 that had a huffer on it with an airconditioning clutch on the blower pulley and he could turn it off and on. The discussion was about mpg and he claimed he could run a 2.73 rear gear with the huffer on for traffic light fun and then turn it off for highway use. He mentioned this several times in posts so there is a good chance he actually solved this problem and got it to work. Probably he is on some other site but I do not know how to reach him to check on this. Anyway I need to work on the car today since this is the end of Summer for me and the Fall schedule will have less time for the car so I need to work on it NOW! Saturday I will go to the Richmond NSRA National at the RIR Fairgraounds which is only a few miles from where I live and yesterday and today has seen a parade of rods coming in on I-95 (300 yards from my home) and I-64 and here I am with only a garage car. I hope I can make to the Richmond National next year with a running car. Does this Forum have any representative or contact person at such NSRA events?

Note in edit mode: Erik I read you post after I submitted mine. Yes, you have pointed out the main problem as how to get the engine to breath when the blower clutch is not engaged. I am already gettirng weary of this idea due to it's difficulty but since one might only want to run a 6 psi boost or even as low as 4 psi, maybe the blower case could be "over-clearanced" so it would leak better when the rotors are not turning but still provide some boost when the clutch is engaged. Still it would be a gamble to possibly waste a $2500 blower case.

Don Shillady
Retired Scientist/teen rodder

One point is if you over clearanced a blower case like you talked about I think it would become more inefficient.In other words you would have to drive it that much faster to get the same effect or boost thus spinning the blower faster and "beating" the air and making a hotter fuel and air charge.

sounds cool .like a blower on demand. i really thing it would work crappy. it would be a lot of work to find and make a pulley set up and aE clutch that could take and drive a 3 inch belt and take the shock when in engaged ?? at any speed and deal with the blower mass and if the blower is rotors are lined then it would suck big time to get any air / fuel .i would think it would be very unresponsive with the drive belt not engaged . so i would think it is a mad max only thing

Herre is how it was done in 1918 ,I am sure it can be improved upon.crude picture at best,but this is the crank ,gear,driven set -up.This diagram only shows the on off air flow of said huffer and route

it would be a blow thru

Yeah,I saw no difference in the old designs than a modern turbo,supercharger type setup.Other than the fact you could shut it off.But how well it actually worked ???? they aint around no more! !!anything that works usually sticks around in some form. Heck ford is changing the cam timing with oil pressure ,I am sure some electronics and solenoids would make it work.Although the old motors were about 50 ,60 hp and the forced air uped that to 100 to 120 hp.50 percent increase on an very inefficient design.14,760 cc 4 cyl motor may of had sumthing to do with it too!!

Originally Posted by erik erikson

One point is if you over clearanced a blower case like you talked about I think it would become more inefficient.In other words you would have to drive it that much faster to get the same effect or boost thus spinning the blower faster and "beating" the air and making a hotter fuel and air charge.

Not quite so neccesary ! As has been pointed out, the blower rotors will spin quite freely with the vacume from the running engine. I have actually run engines with a blower insyalled and the belt removed, taken them for a drive, very streetable can get 60 to 70 mph out of them and that is just with moderate accellerator even though a little shy on power. The blower just windmills on the engine vacume. I also point out that the 671 had stock clearaces. And the engine ran at below normal operating temperature on the water guage.

Originally Posted by southerner

Not quite so neccesary ! As has been pointed out, the blower rotors will spin quite freely with the vacume from the running engine. I have actually run engines with a blower insyalled and the belt removed, taken them for a drive, very streetable can get 60 to 70 mph out of them and that is just with moderate accellerator even though a little shy on power. The blower just windmills on the engine vacume. I also point out that the 671 had stock clearaces. And the engine ran at below normal operating temperature on the water guage.

Engine vacuum spins the rotors?
Very streetable?The blower windmills?A little shy on power?What brand of supercharger was it?I have used Dyers,BDS,Weiand,Kuhl and none of them spin as loose as you say un-less they are worn out.I would guess you have never been around a "roots style "blower.

Originally Posted by DennyW

http://shell.deru.com/~sgn1/AW11/Scnotes.htm

Denny found it.
It was used on a car 15-20 years ago.
The mr2 is no longer made.
The engine made 145 hp at full boost.
Now if we could only make this work on a 6-71 hmmm.

I was working on the car and got the tack rail bolted on and one side mount for the top bow adapted to the Bebops body which came without them while you folks were working on this. DennyW has indeed found an example of a commercially engineered on/off huffer, but the air flow valve is an added technical detail that might not be easy to fabricate. Let's go back and ask Southerner to give more details on his experience running with a disengaged blower. He did say 6-71 so that would seem to be a Roots type and the example Henry Rifle gave is encouraging for the relative ease of rotation of the rotors when not driven. So the question really is where to get the clutch and I guess one would look at whatever is the largest AC compressor unit. I burnt out two small AC clutches on a Voyager wagon which had a relatively small unit, so they are not overly sturdy even for their intended use. Maybe a starter solenoid/Bendix could be modified to pull in a clutch but a stronger clutch would require more current if it is an electrical type. Then there is the cart centrifugal type which might be adjusted to engage at a set rpm range like a torque converter, say at 2500 to 3000 rpm. That way you could cruise in high gear on the highway without the blower for better mpg but still have the blower engaged when accelerating in the lower gears. I have plenty left to do on my car just to get it running and maybe someone here will build an on/off huffer while I am doing other things and thinking about this. Who wants to build one? Actually I kind of like the idea of the centrifugal clutch that turns on the blower at 2500 rpm, I'll think about that.

Southerner can you give any more details?

Don Shillady
Retired Scientist/teen rodder

Originally Posted by erik erikson

Engine vacuum spins the rotors?
Very streetable?The blower windmills?A little shy on power?What brand of supercharger was it?I have used Dyers,BDS,Weiand,Kuhl and none of them spin as loose as you say un-less they are worn out.I would guess you have never been around a "roots style "blower.

Ah have been around heaps of roots style blowers, being a diesil mechanic for many years I have had plenty of opertunity to convert jimmy 471's and 671's to chevy use. If given an option I will choose a blower every time over other hop up tricks. I was refering to a 671 blower that did not have any teflon in the rotors or end plates. It's only a street blower so it does not need to produce massive amounts of boost. So therefore the clearances are loose. To be honest I still use the diesil specifications when setting them up. Just that I turn either the gears or the rotor support shoulders rather than using the thin shims to get the c and cc clearances.

Ok Ill let the cat outa the bag,1938 mercedes 540 k has all the parts you need for clutch operated roots type blower!!!I will take a pic and post it shortly!!!

Originally Posted by shawnlee28

Ok Ill let the cat outa the bag,1938 mercedes 540 k has all the parts you need for clutch operated roots type blower!!!I will take a pic and post it shortly!!!

I think we might be "beating a dead horse" on this one.

Here it is!!!