Diesel Porn - Page 2 - PeachParts Mercedes-Benz Forum

KarTek · #16 01-27-2016, 01:09 PM

Did you send your pump to Goran or did you buy a performance pump outright?

How much is the European shipping?

Dan Stokes · #17 01-27-2016, 02:56 PM

Quote:

Originally Posted by vstech

mmmm I like it.

what were the costs? is there a discount if you already have an M pump?

Mine was right at $1200 including shipping and expenses. Goran suggested that he supply the pump and do the mods so there was only one set of shipping charges, customs fees, etc. - he felt that any gain would be pretty much overcome by the shipping and fees. Kar-Tek - he wrapped it all into one price so I can't separate out the shipping. I paid with Paypal and it was just 1 number.

The price isn't all that bad if you look at the price of, say, a Holley Dominator for an Otto-cycle race engine. As in all race mods, there is MORE that can (and eventually will) be done.

Dan

charmalu · #18 01-27-2016, 08:13 PM

Good score Dan, be interesting to see your ETA at the finish line compared
to the stock MW Pump.

HMMM...would one of those make my 240 a bit faster?

Charlie

m1tch · #19 01-28-2016, 03:11 AM

I am going with 8mm elements in my EDC pump soon

vstech · #20 01-28-2016, 07:05 AM

Quote:

Originally Posted by Mxfrank

Lets get the math right, so we can appreciate the engineering! An 8mm valve has a cross section that's more than double a 5.5mm valve. Its more like going from 650cfm to 1300!!! You will need more boost. (And think about that radiator)

can someone explain this in more detail? obviously 5.5 to 8mm is not more than double, but the area of the circle obviously is a quad factor increase, not linear... how is the increase such a drastic increase?

5.5 area is 8.6394

8 area is 12.5664

so, still seems linear... about a 33% increase in area...

Dan Stokes · #21 01-28-2016, 08:34 AM

Have to ask one of the math guys - that's why I wasn't an engineer! I'm assuming that the stroke remains constant though I really don't know that. Seems like you would have to modify the cam that operates the plungers to change stroke so I'm thinking they don't do that.

Don't forget "pi"!

Dan

babymog · #22 01-28-2016, 08:51 AM

I think you're using the formula for circumference.

5.5mm dia. area is 12.5mm sq.
8mm dia. area is 50.25mm sq.

Area of a circle = pi x Rsquared

... or do I rely too much on CAD?

t walgamuth · #23 01-28-2016, 09:22 AM

Its pi r squared. I get 23.5 mm2 for the 5.5 and 50.26 mm2 for the 8 mm. Double the area. I believe in piping there is also another factor which favors the larger pipe size even more than the simple area.

vstech · #24 01-28-2016, 10:05 AM

I forgot the squared... Had everything else right...

Yup, more than double the area... That explains it.

Pipe seems to flow much more than the size increase for the huge increase in area of the tube from the minor increase in diameter...

funola · #25 01-28-2016, 10:08 AM

Quote:

Originally Posted by t walgamuth

Its pi r squared. I get 23.5 mm2 for the 5.5 and 50.26 mm2 for the 8 mm. Double the area. I believe in piping there is also another factor which favors the larger pipe size even more than the simple area.

pi r squared is volume, not area! pi d is area

Architects don't deal with volumes?

dude99 · #26 01-28-2016, 10:34 AM

Quote:

pi r squared is volume, not area! pi d is area

No, PIr^2 is area, PIr^2 x H is volume, and PId is circumference

funola · #27 01-28-2016, 10:41 AM

Quote:

Originally Posted by dude99

No, PIr^2 is area, PIr^2 x H is volume, and PId is circumference

I stand corrected. Isn't volume what matters in this case? Isn't it the bore and stroke of the element, volume of fuel injected that matters?

vstech · #28 01-28-2016, 10:51 AM

Quote:

Originally Posted by dude99

No, PIr^2 is area, PIr^2 x H is volume, and PId is circumference

speaking of volume, what's the stroke on the elements? I bet the volume is a lot higher than 2X...

funola · #29 01-28-2016, 10:58 AM

Second thought, stroke is controlled by the cam, not the element, so stroke should stay the same? Unless the cam was reworked.

Alec300SD · #30 01-28-2016, 11:07 AM

Better fuel atomization and more fuel with less rack travel.

A win-win, better fuel economy with a better burn and more power on tap when you want it.

Saving up to do the same as Dan Stokes.

Going from 5.5 mm diameter elements to 8 mm diameter elements you get a 2.1+ times factor increase in volume for the same pump stroke.

(4.0 x 4.0 ) / (2.75 x 2.75) = 16 / 7.5625 = 2.11570247933. (My calulator only has 12 digits). LOL.