boosted_D

iTrader: (1)

*** THIS INFO IS BASED ON FLOW CHARTS FOUND FOR WALBRO RECIPROCATING PUMPS, AVAILABLE IN 190,210,225 LPH*** The numbers shown are taking into onsideration that walbro intank pumps have similar flow charaturistics as I could not find any such charts specifically for intank pumps.

So I see a lot of stuff out there with people saying the stock pump or a 190 or a 255 can support X amount of HP.

I dont seem to find flow ratings for stock honda pumps.

Just want to see everyones input on HP capabilities with

Stock pump, walbro 190, walbro 255.

From what I can find, the stock pumps are somewhere around 130 lph.

According to walbro's website and chart for calculating what pump is needed for X HP. There is a chart that shows at 50 psi fuel pressure, you need 30 Lph of flow for every 100 crank HP.

Lets base this on stock honda fuel pressure of roughly 40 psi. Making this adjustment, at 40 psi, you need 30 Lph of flow for every 80 crank hp.

Based on this info, at 40 psi.

Walbro 190 LPH will support : 506 crank hp or about 422 whp at 15% loss from crank to wheels.

Walbro 255 LPH will support : 680 crank hp or about 578 whp at 15% loss from crank to wheels.

Any disputes to these findings?

There is a lot of people out there who say a 190 is only ok for about 280 hp, and that a 255 is good for about 500 hp, according to calculations based on walbros charts, these "guesses" that are out there seem to be pretty far off from the truth.

And what about a stock pump? If they really do flow around 130 Lph.

They would be good for:

about 346 crank hp, or 294 whp at 15% loss from crank to wheels at 40 psi.

4genaccordfreak

The only way to know the stock pumps capabilities is to flow test several pumps and get a base average flow rating. Then do the math.

Granted the stock pump is not designed to hold fuel pressures above stock (40-45psi), it possibly could, but for how long? nobody knows...

The Walbro intank pumps are so cheap nowadays and have proven themselves as 80-90% reliable in most cases, that it is just common place to change up to it for peace of mind. Also for room to grow your setup without having to swap it out.

For most turbo (honda) setups, the majority of people will steer towards the 255LPH as it gives the broadest range of usage from stock engine requirements to an (ESTIMATED) 600+ whp.

liam821

this

lsturbo33

I think it was Turbo magazine. Several years ago they did an article where the flow tested oem gsr, walboro 255 replacement for gsr, supra, skyline...The flow tested a bunch of pumps at different voltages and gave flow numbers. I have it at the house somewhere but I'm sure it can be found on the web.

figi fg2

have seen 255lph go to 600horse maxed out, if you plan on pushing close to that kind of power and not building a fuel system spring for the new 400lph walbro, it fits with minor modification to the hanger, after about 650whp the factory fuel lines become limiting factor

hybrdthry911

http://webpages.charter.net/hybrdthr...mp_web_app.htm

boosted_D

iTrader: (1)

This a cool chart, it will show the pumps flow capability at any given fuel pressure.

For example, at 40 psi, the walbro 190 LPH is capable of flowing 300 lb./hr.

But how do you turn this data into useful hp or whp capabilities?

what kind of power will this "300 lb./hr." flow rate support?

4genaccordfreak

^^
There is no calculation/formula to do it with math.

There are too many variables to take into consideration when seeing what (horsepower) a fuel pump will support.

Everyones setups are slightly different, from fuel feed line diameter, to injector size, to fuel pressure setting, to air/fuel tuning and even elevation and air density will significantly change the (horsepower) number any specific component can support.

In the HONDA world of forced induction, there are mostly "General" rules of thumb.
IE:
-Any power level potential above 200whp will likely require a fuel pump/injector upgrade

-Any power level potential above 300-350 will likely require a fuel pump above 200LPH and an injector size above 450cc

-Any power level potential above 500whp will likely require dual fuel pumps (either dual-intank or intank-inline), injector size above 800cc, a larger than stock fuel feed such as a -6, -8AN and fuel pressure settings above 60psi.

-Anything after the above is completely custom dependant on setup

The above rules of thumb a just GENERAL and like I said before, ALL SETUPS ARE DIFFERENT and these rules will stretch either direction.

scmil95eg

Very simple young grasshoppa: divide by BSFC.

BSFC for a stock N/A Honda is ~.46
(that means it takes .46 lb/hr to make each HP at the crank)

So 300/.46 = 652 crankshaft HP

No offense, but I'd disregard the post above. I didn't fuel $100,000 engines based on "rules of thumb." lol Everything can be calculated.

scmil95eg

Before someone asks, here's a few general BSFC's:

.45 - .48 [gas, stock N/A]
.48 - .52 [gas, modded/heavily modded N/A]
.55 - .65 [gas, turbo/supercharger]
.6 - .75 [E85, N/A]
.8 - .95 [E85, turbo]
1.1 [methanol, N/A]
1.3 - 1.6 [methanol, turbo intercooled]
1.5 - 1.8 [methanol, non-intercooled turbo/supercharger]

Step 1: pick a fuel pressure
Step 2: see what your pump flows at that pressure in lb/hr
Step 3: divide by applicable BSFC
Step 4: smile about KNOWING how much power your pump will be good for

boosted_D

iTrader: (1)

Scmil95eg: Thank you for your knowledge, it actually solidifies my original numbers up top.

The whole point of this thread was just to put real solid facts out there about what pumps were capable of what power levels.

There is soooo much speculation out there about this subject.

Most people "think" a walbro 190 LPH is only good for like 300 hp or less, when in reality the stock pump is capable of more than that, and a 190 is good for deep into the 400's, while a 255 should be good for like 600+.

4genaccordfreak

Calculations USUALLY only work in a perfect world. What works in the REAL world is mostly through trial and error

No person in the right mind WOULD fuel $100,000 engines based on rules of thumb. OBVIOUSLY

My statements were in very generalized terms of what I and many others have seen work EFFECTIVELY and safely in the past.

To the OP, try putting up numbers past the 600whp mark with a single Walbro 255LPH.

Then come back and tell us all how well your motor turned out after it leans out and you melt all your internals.

boosted_D

iTrader: (1)

I realize that beyond 600 would require more than a single 255, my aim was more at pointing out that a 255 is not REQUIRED for many set ups.

I do plan to go into the 400 whp territory with my current 190 pump though, and I'm confident it will be just fine.

scmil95eg

Maybe I was a little harsh, but your post couldn't be more wrong. There are many things in this world that I don't know about, and you won't ever catch me posting misinformation about those things. Please respect that and do the same. For everyone's benefit.

scmil95eg

lol - you should quit before you look even worse.

What do you think requires guessing? I'll help you out. Anything you need to know about engine requirements - just throw it at me.

Do you really think people pick out 900+ cubic inch engines with 3000 HP goals and just "guess" on how to get there. Or blow a few up during a "trial & error" process?

Doesn't happen. Want to know why? Because everything can be calculated before the first part is purchased. This isn't rocket science or anything new.

4genaccordfreak

Granted I agree with you that everything can be calculated. Maybe my post was interpreted the wrong way, since the majority of us do not have engineering degree's or have the opportunity to work in an environment where money in R&D is no object.

I was answering the OP's post about Walbro fuel pumps in HONDA forced induction applications. Forgive me if I do not have Top Fuel dragster, F1 or NASA Rocket booster fueling experience.

Are you confirming the fact through your math equation that 1 Walbro 255LPH fuel pump will flow and hold enough pressure to maintain a 600+ WHP forced induction setup.

According to your math it will. According to years of trial and error it will NOT. Why do I see many, if not all Honda's above the 500WHP mark running dual setups or a very large external pump. We aren't talking about world class race teams here. Even their engineers get their equations wrong or need to adjust for the environment, track conditions, fuel being used etc.

Gloat all you want about your vast knowledge about engine requirements. It looks like you've been spending too much time studying the books and equations and not enough time studying in the field. Testing and tuning isnt always about math and calculations. Any and all calculations need to be tested through trial and error. Anyone can do a calculation and the result will be different since very few have the exact same specifications, engine builds, parts quality and most importantly tuning quality.

You are also comparing apples to oranges talking as if a HONDA 300-500WHP setup requires the same R&D as a 900+Cubic inch 3000-5000whp engine that a pro race team can push for the final thousandths of a second quicker than the next guy.

This ISN'T rocket science. Although you are making it out to be way more complicated than it always HAS BEEN! Everyone has to do their own research, find out what works and what doesn't. That being said, I never posted any MISINFORMATION since my "rules of thumb" were so general that you can't even consider them as incorrect. The fact that I stated there is no equation for determining flow/horsepower rating is because not everything calculated works the way it should. It is all dependant on the rest of the setup, like I stated several times in my previous posts.

This thread is going no where but into a pissing match

This is the internet and whether or not the OP or anyone else wants to take this thread as factual information is there call/problem.

/my rant

/my inclusion in this discussion

hybrdthry911

If you know the bsfc of the engine then you can calculate the fuel requirements at a given power level. The program allows you to enter the bsfc at peak power to find how much fuel you need. It also features an estimator using afr and some common estimated calculations. Obviously having a little extra fuel is never a bad thing.

Spawne32

iTrader: (3)

I thought the stock pump was 90lph?

boosted_D

iTrader: (1)

The stock pump really could be anything from 90 to 130+ lph depending on what car it came in, honda used different pumps in different cars.

So an aftermarket pump is definitly advisable for any forced induction set up.

That said, it is a commonly known fact that over time, a 255 can weaken the stock FPR and cause overrun, this results in a raise of base fuel pressure, and causes cylinder wash out and rich idle conditions.

Thats why its important for people to know that a 190 will be a good choice for a 350-400 whp set up. It will provide enough fuel, and wont ever overrun the stock FPR.