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+--- Thread: M vs MW pump (/showthread.php?tid=1033)
M vs MW pump - kmaser - 01-14-2010
I'm sure this has been asked before but I have searched and didn't find exactly what I was looking for, there are some posts about the M pump being better to modify than the MW pump (MYNA Modified ). I was wondering if there is a large advantage to swapping out an un-modified MW pump for an un-modified M pump on my 617a as I have both. I have already removed the ALDA from my MW pump so I am thinking that both pumps would then be doing basically the same thing as far as boost compensation goes, also the M pump is from a N/A 617 which is 88HP ? so will this pump supply enough fuel for the 617a ? and also was the M pump ever installed on 617a's for any other market such as europe ?
Thanks for any help
RE: M vs MW pump - ForcedInduction - 01-15-2010
(01-14-2010, 09:23 PM)kmaser I was wondering if there is a large advantage to swapping out an un-modified MW pump for an un-modified M pump on my 617aNo. They both have the same fuel delivery limitations. So you're better off pulling the rack limiter in the MW and saving the M for Myna.
Quote:and also was the M pump ever installed on 617a's for any other market such as europe ?No, all 617's with a turbo in europe were basically an American model without an EGR.
RE: M vs MW pump - tomnik - 01-15-2010
Just from technical side:
MW is older design, our MW55 the smallest of the MW seize.
The design is stronger for higher pressures, higher specific power (hp/cylinder).
I’d say this IP is more expensive and was replaced (in the passenger car sector) by the cheaper M.
For the 617a the MW is the only turbo IP. There are Ms and (non turbo) MWs on the non turbo 617. Also here the early 617 still had the MW (non turbo).
Element swap and adjustment of a MW is less complicated because for balancing the cylinders (quantity and timing) the barrel has to be turned and shimmed only.
To do this correctly on the M the rollers have to be exchanged in case of different timing. This means measuring the difference and replacing the concerned roller, which means taking out the cam. Common procedure here is not to do this and risk uneven run.
If done correctly this job is time consuming and I bet not every pump is adjusted like that.
The separation of fuel and oil circuit is done by o-ring on MW (barrel/housing) and metal/metal also barrel/housing on M. In case the housing side is damaged on the M the surface has to be redone resulting in a lower position of the barrel which alters the timing. This has to be compensated with a smaller roller…
One big difference is the assembly of the element in the pump. The MW barrel (hardened material) has the thread for the DV holder integrated. So the forces are within the barrel only. Forces here are sealing and fuel pressure.
On the M these forces go via the (alu cast) housing and it sometimes happens that the barrel deforms and the plunger gets stuck when the DV holder is tightened. Also there is the sensitive alu thread in the housing.
This might be the reason why the MW can handle higher pressure.
Due to the design the elements for the MW are more expensive and alternative seizes are rare.
Tom
RE: M vs MW pump - kmaser - 01-15-2010
Tom,
I am hoping to get 150+ HP out of my 617a and as much torque as possible, I have an intercooler ready to go in and would most likely stick with the Air Research KKK? turbo for now. All I have read on this boards points to the IP being the biggest restrictor of making HP so I want to get bigger elements now as that's where I will eventually end up anyway. I am interested in either the 7.5mm elements for the M pump or the 6.5MM holley elements for the MW pump, I am just trying to find out from someone who has experience with a modded IP which would be best for my needs. I am not looking for fast 1/4mile times as the 617a is in my G-wagen with 35" tires, even as it is now it's not bad off-road in Low range but really struggles to keep near 100km/h on the hills. I am following the thread on the elements being brought to the U.S. with great interest as it would allow for pump mods without shipping costs to Myna and am waiting to hear on costs.
Kurtis
RE: M vs MW pump - tomnik - 01-16-2010
Clear answer: For the 617a: MW IP mods.
Using a n/a 5cly. M IP was simply because the Fins didn't have suitable MW elements. And then all the mess with ALDA...
The perfect combination (for me with 617a) will be: Holly IP, VTG with stand alone controller, available in 4-5 weeks and a w/a intercooler out of an AMG bi-turbo.
The 6mm Holly should be on the bench right now, the owner is waiting for it so results should come up shortly.
The first 7.5mm Floyd will go into an extreme modded car, not comparable with yours. This will be the second swap in the US.
Tom
RE: M vs MW pump - kmaser - 01-16-2010
Sounds like I will wait for the holly elements for my MW pump, which VGT turbo would you recommend for the 617 ?
Kurtis
RE: M vs MW pump - ForcedInduction - 01-16-2010
I wouldn't bother with 6mm elements. Its only enough to support around 180hp and even then you're back to the "injection takes too long" problem the 5.5mm elements have at 145hp.
RE: M vs MW pump - tomnik - 01-17-2010
the 6mm MW mentioned were the last set for a stock engine.
Only 6.5mm for the future.
Tom
RE: M vs MW pump - kmaser - 01-17-2010
Tom, thanks for the helpful responses i will definitely want the MW6.5mm elements for my pump so please let me know as soon as they are available !
Kurtis