Lowering Pump inlet restriction. (Eheim 1250)
 

After reading a Procooling article (which used my system from over a year ago as an example) about resistance on the pump inlet, I've been thinking of how to reduce it.

Some of you may be familiar with the Eheim 1250's inlet structure. I has the threaded inlet tube (Where barb screws in) attached to a plate with an O-ring seal, that forms the inlet wall of the impellor chamber. This is held on by a ring that you twist into place until it locks.

My questions?
Is the inlet wall of the impellor chamber important to the pumps function (I assume it is essential)?
How come such a large benefit can be had from lowering restriction, when the actually size of the inlet is 3 small slots?

I plan to do something similar to what pHeatus did with his pump using a PVC piece, but I'd like to not have it permanent (ie glue), so I'd like to machine a piece to actually function as the locking ring as well as a mini res on the inlet. Would this give much benefit, as the inlet would not have a barb on it at all, rather it would just be in free water.
How big a restriction free area is best? 5cm, 10cm before tubing?

I'm going to refer you to a French product review that's just too similar:
http://adnpc.net/dossiers/42/lire.php

Note the advantages and disadvantages.

Not really "disadvantages", as far as my french skills go.
The plastic "colour" doesn't mean a thing unless you have win-dozes.
And bleeding is easy if you can move the pump.
Real issues would be with trapped air.

looks like a nice product. too bad I have zero french skills.

Anyone make something like that in the states?

Interesting.

There's an Innovatek push-on reservoir for the 1046 and 1048 - made who-knows-where (Germany? Taiwan?) but available in the states AGB-O-Matic Reservoir .
I've used four of 'em so far (mated with 1046s). No problems.
Replace the inlet compression fitting. The reservoir's threaded for 1/4" BSPT - and you can 1/4"BSPT to 1/2" tubing adapters at McMaster for about $5 for a bag of 10 (made by Eldon James Corp - probably available elsewhere).

If nothing else, these make systems ridiculously easy to bleed - just pour coolant in. The pump inlet is under a couple of inches of water, so no inlet restriction.