Forced air induction ?

[Frank Catt]

Scene at Goodwood Tuesday -- any ideas ? Frank

[Frank Catt]

Another pic

[Paul Bearman]

Hi Frank,
Looks like Robin has gone for more blow thsn suck. That's something I keep telling the wife!!!
Like to know more about the idea.
All the best, Paul.

[Kalun D]

at's not a cooling fan mate, at's an eletronic blower ehh!!!!!!!!!!


you could even du a madd maxx and hav a switch on da dash to turn it off when ya didn't need da xtra juice, then when da badd biker pukes wuz after yu, yu could just "flick da switch".... later duudz.

[John Lind]

There are a pile of electric superchargers out there these days. They mostly seem like the one on the link below, but this looks like a home grown version

http://www.esuperchargers.com/

If you believe the advertising its gets a 1-2 PSI manifold pressure increase and so should give a few HP. It looks like its mounted on Carbies so I wonder if they lean out when the fan is swithed on. When you set up a real supercharger with carbies downstream they have to be specially set up for "blow through". Otherwise the extra pressure in the venturi stops the carby sucking fuel properly and it leans out. These electric pumps are probably so weak you could just set it up a bit rich and it would be OK.

Regards

John

[Peter D]

Well, blow me down !! (so to speak).

If I ever get my car thru rego, I will put a pressure probe near the intakes to see what happens over the speed range with the standard MK1 rear clip.

My suspicion is that the fan-assist might be a help off the line, but might "get in the way" at higher road speeds.

I can see some intersting problems with mixture on a carb setup, but things might be able to be tweaked on an EFI ?

Kind Regards,

Peter D.

[JP]

Frank,

Its not April!! [img]/ubbthreads/images/graemlins/grin.gif[/img]

But never the less I'm sure some believe in such bollocks!

Best,

J.P

[dave harris]

This reminds me of a guy that used to roadrace Karts in the unlimited class - He was quite the "inivator" and always seemed to win - one race he would show up with two carbs mounted on a custom manifold and just when everyone figured that was the way to go - he'd show up with THREE mounted somehow - this drove everyone to try to make this work (which never did since he had "dummy" carbs for #'s 2 and 3 anyway!) - these antics screwed with his competition so bad that it took them months to figure out he was playing them (all the time he was winning!!).

So, maybe this is just his way of screwing with his competition?

[Mark Clapp]

I think it's a shame to hide those carbs, and the "fan box" is just plain ugly on such a sexy car with such a detailed engine. I guess IF it works and IF you are just worried about racing, then maybe. [img]/ubbthreads/images/graemlins/crazy.gif[/img]

[Ian Anderson]

I cannot see it working
It looks like about a 10 inch fan
from this website http://www.merlinmotorsport.co.uk/catalogue/fans.htm

A 10 inch fan gives 575 cfm
575 cfm *12*12*12 = 993600 cubic inches per minute
993600 cubic inches per minute into a 302 inch motor will allow a max rpm of 3290 - after that the fan blabes will be restricting the airflow

Likewise the 11 inch fan max rpm is 4577

Interesting but I would think little or no gain

Ian

[Steve Toner]

Perhaps it's just a cover to keep people from dropping rocks into the carbs when the car is sitting. I use a piece of carboard myself. Some people have nice plastic covers that fit onto the air horns. Some use plastic balls and just set them in there...

[Neal]

You've got it all wrong... Air is drawn past the fan causing it to rotate and generate a positive voltage that is used to charge the electrical system. Remove the alternator and gain mega horsepower as there is no parasitic drag. [img]/ubbthreads/images/graemlins/grin.gif[/img]

[David Morton]

I think it maybe just for cooling the top end after the car has been parked. It cannot possibly be used to give any performance advantage as the passage of air in the venturi's would far exceed the output of such a fan and it would therefore be an impediment. The carbs will probably
get their air around the side of it. I once saw a Mallock GT40 which had a similar cooling set up but provided for by an electric blower in the left area of the engine bay above where the battery normally sits (not in gtd though).
Dave M

[Lynn]

I think someone just sat the oil cooler on the top of the carbs and Frank thought, "let's get a picture or two of this. It'll drive the lads on the forum mad!"

Fess up, Frank! That's what you did, right?

Regards,
Lynn

[Frank Catt]

David Morton got it dead right, and JP was well on the ball as well. The unit is in fact a cooling unit which I built to slip over the webbers as soon as the car comes off the track, and which stops fuel vaporisation from heat soak from the engine. We have seen a few carb fires when hot engines have been restarted due to fuel being boiled in the float chambers and expanding onto the butterflies, which ignites as soon as the engine is turned over to start, this simple unit has worked well and we have never had a problem since. Got a few of you thinking though ! Frank

[MK -IV J6]

Frank
I'd make sure that that fan is electrically "Non Arc" and grounded. (Rated for explosive enviroment)
Best

[Frank Catt]

The cooling unit is a "sucker", not a "blower" ( sorry Paul !) and removes hot air up and away from the carbs very quickly. Frank