NotARaCist

iTrader: (1)

For those of you who aren't subscribed to Import Tuner (can't say I blame you), they recently ran an article about fuel pumps. They brought a shitload of them over to RC and had them flow tested. All the science behind the testing is sound, so I won't clog up this thread with it unless someone REALLY wants it. Long story short, they tested flow rates at given fixed pressures with variable voltages, which is exactly what a fuel pump has to deal with when it's being used in a car. Below are the published test results. As a point of reference, a stock 92-00 Civic fuel pump is run at ~45 PSI and flows ~41 gal/hr.

Walbro 255


Knockoff Walbro 255


CNT Racing 300


Bosch 044


Knockoff Bosch 044


Aeromotive Stealth FP 340


Knockoff 340


Deatschwerks DW200 (255LPH)


Deatschwerks DW65C (265LPH)


Deatschwerks DW300 (340LPH)


AEM High-Flow (320LPH)


Denso Evo IX MR (190LPH)


Denso Supra TT OEM pump (260LPH)


UNISIA JECS 02-05 WRX pump (130LPH)


So what do all of these numbers mean to us? The first thing to consider is that the highlighted lines are all 45 PSI. That's important, because that's roughly what any of our Hondas should be running with a stock fuel pressure regulator. Assuming you're running a stock fuel system, that's the only line you need to worry about.

The next thing to notice is the bypass valve. It's a small valve built into the fuel pump that opens to prevent catastrophic fuel system failure. The OEM bypass valve cuts open at 75 PSI. The Walbro 255 valve opens at 95 PSI. The rest of the pumps all open "somewhere above 100", but they only tested up to 100, so no opening valves.

Some notes that the charts don't show:

Yes, the fake Walbro 255 flows "better" than the real 255. No, it's not a better fuel pump. First off, the release valve didn't open. Not good. Second, notice the amp output - more than double what the Walbro 255 used. The people testing the pumps also said that the amp output was VERY flaky. This is important for two reasons. First off, higher amp output means hotter fuel, and hotter fuel means less power. Fuel temperatures contribute directly to IATs, and everyone with basic FI knowledge knows that higher IATs = lower power, period. Second off, flaky amp output is BAD. It means the fuel pump is completely and totally inconsistent, so you can't trust it to give constant flow, ever. If you're thinking about buying a knockoff Walbro, just stop.

CNT is one of those companies no one has ever heard of. The guys who tested it were impressed. It flows HUGE numbers, comparable to the Aeromotive Stealth FP 340. At 45 PSI, it can handle 900 horsepower. I'll be seriously considering one of these pumps when it comes time for me to get a new pump. If anyone has a CNT Performance pump, please chime in and let us know what you think!

The Bosch 044 is ancient technology, but it still works. Personally, I don't think the 044 is very impressive, and I don't know why anyone would use one over an Aeromotive (or a CNT, now that I know they exist).

The Aeromotive is rated at 340 lph, so it's expected to flow the best of them all...and it does. There's just no denying it. The off-brand 340 flows insignificantly less, but it has the same problem as the knockoff 255 - irregular, inconsistent voltage.

Are you pushing one of these pumps to the limits in these sheets? Do you want to fight the case for knockoff fuel pumps? Are you using a CNT pump? Let's get some fueling discussion going!

ls joker

good read

ferio-ichi3

Good info!

DDTECH Lulz

CNT performance pump is impressive and cheap!

http://www.cntracing.com/CNT-Racing-...-p/500-842.htm

wantboost

iTrader: (2)

glad you posted this. this reinforces my argument against knockoff ****... while it might be cheaper you never know what you're getting in terms of quality and performance vs the original part the walbro 255 just elaborates my point. we all know how well the walbros perform... and you can tell just how **** the copy is. while it does flow more the amperage draw is through the roof, that pump with OEM wiring would either kill the relay or melt the wiring trying to draw 16 amps, what also worries me is that the check valve never opened, if the copy was a non high pressure unit then it should open around the same point as the real one. I've seen knockoff pumps either have a bypass that stuck open or one that never opens. both situations will cook the pump the 044 is another perfect example... the Bosch 044 is a tried and true pump. in typical cheap **** copy form the knockoff doesn't come close in matching the performance of the original. at 100psi the copy is down 150lbs/hr which is a huge difference... they shouldn't even be marketed as an 044 copy, they only are because the physical appearance of the pump is the same. anyone that doesn't know better will buy the copy (potentially thinking it's real, although price should be a dead giveaway) and hate it, never knowing the true difference between the two

another example, the knockoff 340. only 1/10th of an amp difference at 100psi yet the knockoff flows 56lb/hr less than the real deal, roughly supporting 100 less hp

if you also notice the bulk of the knockoffs flow less across their operating range.. I'm still baffled as to how the knockoff 255 flows more... the amount of voltage it pulls indicates it's fairly inefficient as a pump so I don't know why it flows more... although at 95 and100psi during the test the real 255 had an open bypass valve, reducing flow and causing an amperage increase. the fact that the knockoffs bypass never opened can explain the higher flow at the higher pressure levels

this just reinforces my point of view


don't buy cheap eBay/Chinese knockoff parts

Runnerdown

I don't understand the comments about the fake 255 flowing more. It looks like flow is only higher at 90-100 psi. Which nobody ever goes to anyway.

93ls10.0

I ran a knock off 340 for 6 month could never get the fuel right. changes injectors, wb sensor ect everything I could think of. finally said f it and changed the pump to a stealth and every thing worked perfect. was never sure if it was the voltage or just the flow but I through it in the garbage.

NotARaCist

iTrader: (1)

Most definitely, and the most important part about the knockoff pumps isn't even the flow - it's the amperage, like you mentioned. Their flows are comparable, but the amperage is caused by shitty internal components. The pump is working harder and pulling more power, which means it's going to burn out sooner, it'll put a LOT more stress on the wiring and electronics supplying it, and it'll heat up your fuel a lot more.

I keep harping on the heat thing, because it's EXTREMELY important. Last time I looked into it, the rough estimate is 4 horsepower lost per 1 Kelvin temperature increase. When you're talking about a pump drawing twice as much power as it should be, you're talking a good 5-8 K increase in temperature, which kills off 20 to 35 horsepower. That's a pretty big loss just from saving a couple bucks on a fuel pump.

Everything above 75, the knockoff flows more fuel.

Yep, you couldn't get the fuel right because of the heavy fluctuation in amperage.

I'd seriously like to hear from some people who are running the CNT pump, or know someone who is. I don't even care if it's in a non-Honda application. Their website doesn't list a "plug and play" option for anything before '06 in the Civic world. Evidently it also has a 1 year warranty. They also MSRP for ~$30 less than a Walbro 255, while flowing more...I'm seriously thinking about buying one.

ferio-ichi3

Racist, hows your build coming along?

NotARaCist

iTrader: (1)

I'd rather keep this thread on-point. I updated my build thread for ya

underrated

iTrader: (3)

Nice find!! No deastchwerks love huh?

hardcore97

i have a dw in my car, was hoping to see it on the list

NotARaCist

iTrader: (1)

They said they brought over 20 pumps to be tested, and will be continuing the article next month. I saw at least one DW pump in the picture, so I'm hoping they'll follow through and give us more numbers. If they do, believe you me they'll go ITT as soon as I get them.

wantboost

iTrader: (2)

I'm debating using a Bosch 044 to feed my surge tank setup then have my a1000 feed the motor. because the Bosch isn't pressurized it flows a **** ton of fuel, enough to supply the a1000 at what will be 75+psi at full boost feeding 8 injectors, roughly 850cc@42psi base.

the problem with the a1000 and similar pumps can't prime themselves so they have to below the lowest point of the tank.

LightningTeg

You have to remember under boost the fuel pressure rises 1:1. So if you are running 30lbs (like me) and base pressure of 50lbs, thats now 80lbs. Alot of people will bump up their fuel pressure to get more out of their injectors and run into this issue of diminishing returns with the pump.

I had to stop around 470whp on a 255 with my 1000's and 570whp with a Walbro 400/450.

wantboost

iTrader: (2)

pretty much, i know some people running 60psi base on walbros.

I'm still amazed at how many people have said they will use a stock pump on their turbo setups. while the OEM pump might flow 41gal/hr it's at a very low pressure (42psi I think) so if you don't have the regulator increase pressure with boost in theory it might work.

the problem is the stock pumps flow rate drops off sharply with pressure increase, combine that with stock wiring, on top of the age of the pump as well as the amount of time/miles on the pump and it's easy to see how high and likely failure of the stock pump is.

a walbro 255 with install kit is only 89 dollars, don't be a cheap **** and risk destroying your motor and wasting hard earned money because after spending thousands upon thousands of dollars you couldn't spend another 89 on proper parts

do it right or don't do it at all

NotARaCist

iTrader: (1)

After scratching my head for a second over LightningTeg's numbers, there's something I just realized that's worth mentioning about those spreadsheets. The BSFC (Brake Specific Fuel Consumption) constant they used for those "maximum horsepower" numbers is .55. If you're sizing up for a turbo application, you should be using a BSFC of .65. Why they decided to use .55 is beyond me, since you're supposed to use .50 for NA, .60 for superchargers, and .65 for turbochargers. What this means is that rather than dividing the flow rate by .55, you actually need to divide by .60 for SC applications, and .65 for TC applications.

TL;DR version - For a turbocharged motor, divide their BHP number by 1.18179 to get an accurate BHP value. For a supercharged motor, divide by 1.09085.

I don't remember if I said this in this thread, or another one. The stock 92-00 fuel pump can theoretically support 400 BHP. Would I trust it anywhere near that? **** no. Just like people consider 200-225 the safe limit for stock D series rods and pistons, that's what I consider the safe limit for a stock 92-00 fuel pump (99-00 SI owners, that means you too!)

Freemananana

iTrader: (3)

I liked the explaination. Honestly, the knockoff numbers looked good to me. The flow rates seemed on par. But the heat is a big issue. Probably lead to premature fuel pump failure. And that's no good.

Natural Aspirations

I'm running the DW300, wish it had made the list

NotARaCist

iTrader: (1)

Premature failure and power loss!

Like I said above, they tested a LOT of pumps, and at least one DW pump was in the list. They said they'll be continuing the piece next magazine, and when they do, I'll be posting more numbers. Don't worry, they'll come eventually.

Natural Aspirations

Thanks for sharing!

Schister66

**Added to the Forced Induction FAQ**

Lets keep the discussion going (and on topic)

Runnerdown

Yeah, this I do realize. But I bet 95% of people don't push more than ~80 psi on the 255's so I'd still label the genuine a winner. Between that and the amp draw/heat it's a no brainer. Sad part is that lots of people probably have gotten duped on the knockoffs unknowingly.

OneBadTurboCRV

Not only that but not everyone uses a rising rate fuel pressure regulator. All of this must be taken into consideration let alone the fuel being used and if the pump is compatible (mainly singling out knock-offs).

wantboost

iTrader: (2)

I've always wondered how a turbo motor would run at a fixed fuel pressure (no pressure increase under boost)

I know the benefit of letting pressure rise under boost effectively increases the injectors maximum output

I imagine it would take a little work to establish a good baseline between fuel flow and fuel atomization if staying with a static fuel pressure.