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Old 05-14-2008, 07:07 PM   #1
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Default Walbro normal v. HP

Aside from the flow at higher pressure and a few bucks is there a difference between the 190 and 190HP? (namely I don't see why not to get the HP unless there are other factors I am missing, like reliability or something else)

{my search showed that most folk seem to get the HP but I was not sure if there were reasons beyond the rating that would distinguish the two. For example if the Normal was more reliable at my required flow, I would choose it instead - I run whatever pressure the stock FPR puts out}
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Old 05-14-2008, 07:17 PM   #2
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Since you are in the Megasquirt forum, I assume you are planning a Megasquirt build. That being said, you don't need either pump- the stock one will be fine.

Apart from that, you're not missing anything.
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Old 05-14-2008, 07:21 PM   #3
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Since you are in the Megasquirt forum, I assume you are planning a Megasquirt build. That being said, you don't need either pump- the stock one will be fine.

Apart from that, you're not missing anything.
Sorry, I should have given more details:
MSPNP, 91 Turbo, running <215rwhp (slightly higher aspirations), 550 injectors. I am worried that the current fuel pump may be failing (sometimes running lean at high boost, it is intermittent and thus hard to diagsnose). Replacing the stock pump is an inexpensive possible solution so I thought I would try it (and the Walpro's seem well liked).

Dave
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Old 05-14-2008, 07:29 PM   #4
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Well, then either one will be fine. The HP version is simply rated to produce "label" flow (190LPH) at a higher pressure, but of course you're running stock pressure. For the life of me I can't seem to locate a flow chart for either of these pumps...

The "issue" with Walbros, so to speak, is with the 255 models. Allegedly they will push more fuel that the stock FPR can effectively bypass, causing rail pressure to increase.
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Old 05-14-2008, 07:38 PM   #5
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i bought a walbro 190, non hp
it will maintain 50psi @ the rail (at 10psi of boost/550cc injectors) where the 140k mile stocker would not anymore

no problems with it, i just got it for headroom (if necessary) and it was cheaper than stock.

braineak has a good link to buy these cheap in his diy sticky
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Old 05-14-2008, 07:40 PM   #6
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Thanks, I was looking at this chart for comparative flow numbers :
http://www.autoperformanceengineerin...l/fpspecs.html

I had heard the HP might have a lower life rating than the Normal version but that may just be at the higher pressures.
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Old 05-14-2008, 07:40 PM   #7
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Quote:
Originally Posted by Joe Perez View Post
Well, then either one will be fine. The HP version is simply rated to produce "label" flow (190LPH) at a higher pressure, but of course you're running stock pressure. For the life of me I can't seem to locate a flow chart for either of these pumps...

The "issue" with Walbros, so to speak, is with the 255 models. Allegedly they will push more fuel that the stock FPR can effectively bypass, causing rail pressure to increase.
This one?
Attached Thumbnails
Walbro normal v. HP-graph-walbros-01.gif  
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Old 05-14-2008, 07:45 PM   #8
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Quote:
Originally Posted by Joe Perez View Post
Well, then either one will be fine. The HP version is simply rated to produce "label" flow (190LPH) at a higher pressure, but of course you're running stock pressure. For the life of me I can't seem to locate a flow chart for either of these pumps...

The "issue" with Walbros, so to speak, is with the 255 models. Allegedly they will push more fuel that the stock FPR can effectively bypass, causing rail pressure to increase.

Ahhh Joe you kinda answered something I was thinking about....I have a 255 but didnt install because I also read (after buying--noooooooooob) that the stock pump would be fine (w/ MS).

Now that everything is put together, the stock pump doesnt seem to be doing all that well (I've heard a couple others having the same luck lately??? weird). Injectors rehabbed by Witchhunter, and are 460's...but I seem to have to dump alot of fuel in the cells in order to not run too lean (and even now am kinda borderline)...

Anyway, I heard the 255 unneccesary, noisy, etc...but didnt know it was literally too much to handle... Any more details on this? I didnt want to have to buy another fuel pump, but better to know this now rather than AFTER installing the 255 and having issues...

Thanks sorry for the partial jacking
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Old 05-14-2008, 07:55 PM   #9
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Aseer nailed it- those are the graphs I was looking for.

190 lph is 50.2 gph.

Here's the "standard" 190 chart. It's capable of delivering 50gph against ~40PSI:



And the 190"HP" version. Ditto:



But, the knee point on the HP is much further out. At 100 PSI, it's still flowing ~31 gph, whereas the "standard" pump is only moving about 15 gph. By 120 PSI, the HP is still flowing ~23gph, whereas the "standard" pump has crapped out altogether.


And here's the 255. Waaaay more flow at the lower pressures:




We actually don't need huge amounts of flow. Assuming .6 BSFC, 250HP is only about 25 GPH. The base 190 will deliver twice that at "normal" pressures. Those using a RRFPR would require the HP version to make serious power, but those of us running proper civilized engine management and correctly-sized injectors need it not.

Is it true that the 255 will literally out-flow the stock FPR? I have no idea. Never tried it, never plan to.
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Old 05-14-2008, 08:19 PM   #10
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Yea I posted right after the graphs were on there, and was doing some math..
Prob understood Scott's forumla wrong in the DIY thread, but I basically got that the 190HP was good to about 430hp...
If my math is even in the ballpark, I can just stop right there and let logic tell me that that its more than enough for my application, and can easily see how the 255 would be WAY to much...
Am I on the right page?? Not that the explanations in this thread (or others) aren't good enough for me to go get myself the recommended pump, but wouldnt mind knowing about the formula at the same time...
You guys prob know it by heart, but this is what I'm referring to:

[B]"[To convert Gal. / Hr. to Lbs / Hr. - multiple by 6

Multiple that by .80 (duty cycle) and divide by .55 (BFSC) and see how much B.H.P. the pump is capable of flowing for.
/B]
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Old 05-14-2008, 08:35 PM   #11
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Pretty much. Except that the .80 correction for duty cycle is relevant to injectors, not pumps.

We'll run your math on the 190lph. First, let's assume that we're at 20PSI of boost, so fuel pressure is actually gonna be 65PSI on the stock FPR. At 65PSI, it looks like the 190 will flow about 40 GPH, or 240 lbs/hr. Omit the duty cycle correction, and I'm gonna be a real pessimist and divide by .65 for BSFC, that gives us enough fuel for 370HP.

It'll do.
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Old 05-14-2008, 10:13 PM   #12
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I find that a number of places offer the 190, the 255 and the 255HP but far fewer seem to offer the the 190HP (and not under the GSS family part number that the others are). Is the 190HP not part of the GSS family, is it a currently supported model (sometimes this can indicate a discontinued model)? I can get the 190HP from a few places but I am curious as to why the model family seems different.

{I am looking for this on the Walbro corporate site but no luck so far}
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Old 05-14-2008, 10:52 PM   #13
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Quote:
Originally Posted by Joe Perez View Post
For the life of me I can't seem to locate a flow chart for either of these pumps...
someone didnt read my faq.
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Old 05-15-2008, 01:06 AM   #14
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Much better clarification Joe, thanks so much...
Ok, looks like yet another bit of cash to fork out..but well spent!
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Old 05-15-2008, 01:12 AM   #15
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someone didnt read my faq.
FAQ? We don't need no stinkin' FAQ!
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Old 05-15-2008, 10:41 AM   #16
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FAQ? We don't need no stinkin' FAQ!
well that's where all the flow charts for pumps are
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