A couple of people have asked me what the difference in flow is, between the Bosch '044 MS, and Walbro 255lt pumps.

The graphs below have been produced from tests carried out by FSE/Sytec, on their own in house flow bench, and are not figures produced by the manufacturers.

This is for the Walbro 255lt, and covers the 340, 341, and 342 pumps.
http://www.wallis2000.co.uk/uploads/Walbro34X.jpg

Bosch '044 pump.
http://www.wallis2000.co.uk/uploads/Bosch044.jpg

The pumps both flow a similar amount, until you get over 6 bar, but at 5bar, which is a good base line, the Bosch flows 3lts pm, and the Walbro 2.8lts pm.

Just out of interest, the DTW engine dyno uses the Bosch '044 pumps, and on each of the engines I've run there, we had to use two pumps when we reached circa 500bhp, because we started to lose fuel pressure. Of course one pump is fine for most people.

Thanks JF, and Wallis for sorting the images.

Mark.





[Edited by R19KET - 12/17/2003 6:48:19 PM]

Images are in paintshop pro format, they need saving as jpg.

NP mark..

I've deleted the psp images off my server to save space.

David

And here is my bosch pump for comparison, which cost me £150 for a pair or there abouts.

Hmmmmmm.

http://www.fuelsystem.co.uk/2549091.gif

Paul,

Your Bosch are very good VFM. Seeing the graph you posted also made me realise I'd posted what I assume is the lower voltage graph. This is the graph for the '044 at 13.5volts

http://www.wallis2000.co.uk/uploads/044.jpg

Mark. He who needs some IT lessons !

[Edited by R19KET - 12/18/2003 12:40:40 AM]

We've had a lot of reliability probs over on the SXOC with bosch pumps. Most folk are going for the walbro 255 these days.