Corvair fan project (horizontal mount)

[Piledriver]

For a variety of reasons, I have decided on attempting a horizontal fan housing setup on a T4, using a modified Corvair fan.

Up to this point I have been severely hijacking Type4unleashed build thread, as his new Reichert Tuning lay-down fan housing prompted me to action.

What I have in mind will likely look a LOT like his, except without the 911 fan and alt.

Racer Chris has been using a similar Corvair-fanned setup with much success for some time, so I'll be trying to pick his brain for all I can get

The main reason _I_ am attempting this is for packaging in my 914: I want to put my dry sump tank down low, ~block level, and keep the lines as short as possible.

It's also likely I'll be able to stuff the GT17 in on the other side up front.

If it happens to look kickass and work better than stock cooling (it should) all the better.

To kick things off, I'll try and post 2 pics, one displaying why the Corvair fan needs cut down to ~9 inches, and one showing the initial mock up of the CB drysump install on a block.

Fan (unmodified, ~11" diameter) no optical illusion--it's touching the block:

corvair-fan-std-top.jpg

Modified CB pump and manifold block for external oil pressure bypass. Pump is modified to NOT have the inter-stage passages, the stock output for the T4 oil filter comes off the scavenge pump. The 1/2" pipe port above it is for a Swagelock adjustable pressure relief, which will dump to the tank.

The passenger side motor mount is unmodified, drivers side needs an easily "doable" few mods.

EDIT: Much better description of the pump mods/pics in the drag racing forum, as well as explanation of using it as a "stage and a half" wet sump pump for 3/4 rocker box and/or turbo scavenging.

pump-block1.jpg

Edit2: Reattached images the bitworms ate

[Unkl Ian]

Did you ask Chris if his 'Glas shrouds were for sale yet ?

Is this for a race car,or street ?

[Piledriver]

Street. High mileage/mostly highway, occasional AX perhaps. Will have a bypass oil filter setup on top of the 2 Obergs...

As to AX, I'd like to try it... but with the dry sump/turbo/IC/Corvair cooling system etc, It would probably put me in some nasty fast class.

I'd like to make my own shroud, at least give it a shot.

(Unless the ones Chris uses are cheap, which I doubt)

I'm also considering using my old York AC compressor clutch to drive the fan (on the end of the crank, modified hub) as a fan cut out.

Nice big healthy compressor clutch...

[Unkl Ian]

Crankshaft harmonics might be hard on a compressor clutch.
But it's still sounds like an interesting experiment.

[NextGen]

Hey Pyledriver, this is going to be interesting. I like the fact that style leaves loads of room in the engine bay. The only problem is don't rev the engine if you are trying to drag someone off a red light. The fan blows down with such force it lifts the rear and you lose traction.


OK back to earth. THe wild right angle belt is going to fun to play with.

Joe

[Piledriver]

... THe wild right angle belt is going to fun to play with.

Joe

I think the Corvair guys, Even Joe Lociero had the fix for that ages ago... Spring loaded idler pulley.

Have considered attempting going serpentine, since it's all "out there" anyway.

I think it could work better.

Still have to cut this fan down, first attempt showed me there are ancient cracks at the edge of the fan at the blade roots. (still usable, only go in ~ 1/4", cutting 1 1/2-2" off diameter)

Interesting bit of trivia--- The straight bladed fans were originally going to be molded Delrin.

It was redone in aluminum as Delrin gives off formaldehyde gas when exposed to sulfuric (battery) acid droplets, and almost gassed out the driver on one of the prototypes.

With by moving or properly venting the battery, wouldn't have been an issue... Would have had much less mass, and probably eliminated tossing belts by itself.

[Wally]

Pile,
Nice project!
Did you ever think of using the stock type 4 fan in a horizontal position?

Greets,
Walter

[Piledriver]

Pile,
Nice project!
Did you ever think of using the stock type 4 fan in a horizontal position?

Greets,
Walter

Thanks!

Yes, but its squirrel-cage blower airflow characteristics (unsurprisingly) work GREAT for stock app, more flow <4600 RPM, then stalls pretty hard. It would probably be a great choice in a split bus app if the housing works well cooling wise. it IS the ~right size... Would need a different bearing setup...

A centrifugal fan will have less flow down low, and possibly MUCH more at high RPM, and can handle far more backpressure. It just works ... different.

It IS a compressor. It can be set up to generate significant pressure in the plenum. The stock T4 fan style cannot, nor can a single stage axial, at least not efficiently.

(much depends on housing/clearances, again, think turbo compressor, same rules)

[Piledriver]

Interesting read.
http://autoxer.skiblack.com/fan.html

has some airflow data for the (stock) corvair fan, and some observations.

The restrictor mentioned (power disc) goes on TOP of the fan, under the pulley, and starves the fan at high RPM... and is easy, but the probably the wrong place to restrict the fan. Larger outer edge overlap gives you benefits in peak pressure/stall speed...

Note the idea at the end where the fellow has a duct from the decklid to the fan.

Might be a great place for an intercooler...

Can (potentially---The carbs could use cool air) remove all the other engine compartment sealing sheetmetal, the fan intake is all that must be sealed... Perhaps the fan could provide?

[MASSIVE TYPE IV]

Some recent developments with my axial fan arrangement have changed it's position from the typical vertical fan placement for several reasons.. Mainly for better positioning of the air charge and for a better transition of charge air into the fan in a beetle application. Big tracks should be made with this arrangement over the next 35 or so weeks..

I also have an engine that is going to be using the horizontal set up from Riechert (mainly for packaging and the overall application) so we'll be able to gain crucial data during this engine's testing that will be done in the latter part of 2007..

[jonas_linder]

Nice Pile!!

It was about time you got yourself your own post

I like the oilpump but I don't fully understand how you have done it though, more pictures?!

[Piledriver]

Thanks for the input, Jake, at least I know I'm in good company!

I think a serpentine drive would be more efficient, FWIW.

Nice Pile!!

It was about time you got yourself your own post

I really WAS trying to be on topic, I figured Type4unleashed could give the Corvair fan a shot cheap/easily, as he had the Reichert fan/drive setup anyway, and didn't have a 911 fan/alt setup yet.

I like the oilpump but I don't fully understand how you have done it though, more pictures?!

Will post some more pics as time permits, oiling setup really should have its own thread...

If you are familiar with the std CB drysump pump, the in-the-block scavenge stage comes OUT through a small passage in the upper stage, via the filter side of the pressure (outer) stage, right at the same level as the horizontal bit of a 914 motor mount... would require a complete rework of the mount to make it work.

I plugged that output, and drilled the "stock" one that goes to the oil filter boss in the usual location.
(will add a setscrew in the outer plug over the main gallery to keep the inner plug "staked")

The pressure (outer) stage ALSO routes oil (via internal passages) to the "normal" oil output port via an internal passage.

I installed an aluminum plug in the outer pump body (inside), and am using a full flow cover. It clears the stock fan housing. One could PROBABLY install an output fitting in the body, but it's close, and I only have one pump to play with

IOW, the oil path on the inner stage is ~like stock, and the oil path on the outer stage is straight in and more or less straight out.

2 small passages and 4 90 degree bends are eliminated... and it fits, which was the main point.

The pump body exterior has spent some quality time with a belt sander, getting rid of the useless extra metal bosses so the pump will fit between the motor mounts.

(Will add pics to this explanation ASAP, gotta go to work)

[mikeG15]

This is a nice project, I like the idea of the horizontal fan but the drive belt arrangement is very inelegant.
I'm working on a geared drive using a Tecumseh right angle bevel drive from a heavy garden mower. This would work well with the Corvair fan which as I understand it works in either direction of rotation. I'm using a 911 fan which requires the gearbox to be modified to reverse the output direction.

[NextGen]

Mike that geared right angle drive sounds like out of the box thinking but.. How will it do with RPM's, the Rotating Mass, the fact that belts can be replaced and adjusted. Is the drive gear driven and does it has a sealed system for lube. Also it may be loud, which to me fine. Just things to think about . It may work great.

Question, I forget, does the Corvair have the alt on the fan or is it stand alone. THe reason I ask is because if it is stand alone you have no way of knowing if the fan belt broke, no idiot light.

Joe

[Piledriver]

Mike that geared right angle drive sounds like out of the box thinking but.. How will it do with RPM's, the Rotating Mass, the fact that belts can be replaced and adjusted. Is the drive gear driven and does it has a sealed system for lube. Also it may be loud, which to me fine. Just things to think about . It may work great.

Question, I forget, does the Corvair have the alt on the fan or is it stand alone. The reason I ask is because if it is stand alone you have no way of knowing if the fan belt broke, no idiot light.

Joe

The gen/alt is one of the idler pulleys on a Corvair.

I'm going to see how it works, and if so, see if I can go serpentine belt.
It would have a lot less loss, assuming it han handle the twists.

Ony 3-4 projects at a time

The gear drive is a neat idea though... Just sounds much harder to change on the side of the road.