Mythbuster: continuing project thread of my 1303 '75

[effvee]

Originally Posted by Wally

Cheers!

In the meantime, I started on the revamp of the 2,2 engine beginning with the new central cooling lay-out:

Walter, why the change in shrouds? I thought you liked the horizontal setup better. Was there a difference in CFM of the two?

[Wally]

Originally Posted by effvee

Walter, why the change in shrouds? I thought you liked the horizontal setup better. Was there a difference in CFM of the two?

Yes, I like the horizontal set-up A LOT! However, at very high RPM, it doesn't always stay on when the ecu activates the Rev-cut or fuel-cut.
It has shown to be good for 7700 RPM easy, but not combined with sudden soft- or hard-cuts in the ignition.

Air distribution is naturally very good with the horizontal set-up, but with the arrival of this centrally positioned cooling system from MSS with his shroud, I think there is a better chance cooling will be close to evenly spread with this one as well.

CFM (total air moved) is dependant on a lot of other things. Pulley size has a huge part there and the Riechert pulley is much larger (172mm?) then the vertical set-ups (most are 145mm as is this one, also to clear the DS pump), so you know which one will move more air...

Also the fans are different. 12 blade fans displace less air then the older 11-blades, so thats different as well.
Your question about CU.ft/min sort of suggests that more CFM cools better, which is still questionable. Lots of variables.

So, ...my track use with very high rpm with lots of iginition cuts more or less lead me to a vertical set-up again, but I think only by actually using the system and seeing what it does or doen not do on a certain engine, can give an idea of how well something works.

[spannermanager]

Originally Posted by Wally

. but I think only by actually using the system and seeing what it does or doen not do on a certain engine, can give an idea of how well something works.

X Two for that, ive come across cases where the motor was overcooled and needed the smaller pulleys to bring it back into 'the zone', and it picked up A LOT of power.