which fuel pump for 500 rwhp?
 

i have read most of the fuel pump archives and still am up in the air as to which fuel pump i will need. i plan to make just over 500 flywheel hp at 17 psi. street and road racing primarily but i wouldn't rule out a few trips down the quarter mile. i currently have a cosmo which, depending on who you listen to, is either junk or will make 500 rwhp. my question is directed to the guys on the list making 500 flywheel hp... what are you using? i will be powering 4300 cc's of injectors and run a power fc.

Howard,

My car dynoed at 400 rwhp on a 105 degree F day with intake temps over 65 Celcius... so on the street with no heat soak it is probably pretty close to 500 flywheel HP. :)

I run the Nippon Denso pump that RX-7store sold me (I think it's the Supra pump???). At any rate, I have had no problems running 550/1600s at stock fuel pressure.

Many others use that same pump for under 450 rwhp and have had success with it.

If you didn't mind spending more and working a little harder to install it I think there are other good options (don't ask me what though). But it's hard to beat the 15-30 minute job to use the ND pump :) Couple of screws... a few hose clamps... done.

Brian

The Nippon Denso is good for 500flywheel, but craps out before you can get to 500 rwhp.

K

What have you guys seen from the Walbro pump???

STEPHEN

I'd like to know more about this topic too. I'll do a search on the 3rd Gen section as well. If anyone has experience to add to this thread, please do so. I'm also in need of a fuel pump but cannot decide which one I want for my XS TO4E boosting 1 bar.

http://www.rx7.com/cgi-local/3catalog.cgi?cat=11&part=1

I have this fuel pump from RX7.com(RP).

Seems to work fine with my XS T04e kit.
Currently running 15-20psi boost. Will be trying 25psi in the next month.


Ken

I

I also posted in the 2nd Gen forum on this very topic. I need a pump just a little bigger than the Walbro. The only other pumps that I could find verifiable flow rates for were the Aeromotive and SX pumps that are 3 1/2 times the price and three times the flow rate. Is there not something in the middle for 500rwhp?

I have the SR ultimate fuel pump (apexi) and it flows more than any other in tank I've found. 74GPH @ 43psi....which is more than enough for 500rwhp.

74GPH @43psi is the flow at idle , what would happen when you boost say , 15psi and your fuel pressure regulator closes ?........... your fuel pressure would now be 43 + 15 psi and that 74GPH would surely fall to some "un known " flow , just make sure you have enough injectors that are also properly sized to keep the flow up and the pressure down.

I think I can answer that...
http://www.maxcooper.com/rx7/parts_i...exi_bnr32.html

At 13.2v and 58 psi, mine flowed about 81 gal/hr.

-Max

That's no help at all. The SR flows less than the pretty SX pumps and costs $80 more. Is there a less expensive option?

E6KT2,

If you don't want an intank pump then go install your SX external and let us know if an intank might be worth the extra $80.



Howard,

The Rx7 Store Apexi pump will support your horsepower goals as will SRMotorsport big intank pump (Apexi pump), they are not the same pump but both will easily support 500hp.

Everyone has a rising rate fuel reg, which is 1 for 1.

1:1 is sometimes called rising rate, but should not be, in my opinion. Rising rate would be better defined as >1:1, since the rate of fuel flow would increase for a given duty cycle when the boost rises. 1:1 merely maintains the same flow rate for a given duty cycle no matter what the manifold pressure is.

I prefer:

"Adjustable FPR with manifold reference" for 1:1 regulators with an adjustable base pressure.

"Rising Rate FPR" for a regulator with a rate that is higher than 1:1, where the rate is usually adjustable.

These two are really different beasts, and should have distinct names.

Some regulators have both an adjustable base pressure and rate, and even allow you to set some kind of offset pressure at which the rate begins to rise.

-Max

I think 3 or 4 of us argued about this before, and yes Max you are right they do need to refined in terms of purpose and operation, under the technical terms laid out, just about every regulator is a rising rate, the question is ,what point in particular is the rising rate, fuel pressure, fuel delivery from what point, or differential pressure across the injector..
The 1:1 is merely to maintian the the differential flow across the injector in terms of fuel flowing from a high pressure to a lower pressure , in other words fuel pressure versus manifold pressure, which injector capacity is dependent on to determine a flow rate for the injector at a given differential..

Fuel pressure manifold pressure pressure differential
40 psi 0 psi 40
41 1 psi 40
42 2 40

etc etc..
With the adjustable or non 1:1 ratio such as FMU with the 2:1 etc
40 0 40
42 1 41
44 2 42
as manifold pressure rises at a fixed injector duty cycle fuel flow will increase,
Some regs are only activated at positive manifold pressures and won't work on their own they are meant to be used in conjunction with the stock fpr for fueling in sub atmosheric conditions..

A couple of us with TII's in my neck of the woods have been using the Malpassi regulator, and it has been working, but both of us have noticed that they both had some problems;
1) the regulators do not hold pressue, they bleed to zero as soon as the pump stops,
2) the base fuel pressure changes daily, even with the manifold pressure reference line disconnected, I have seen fluctuation of up to 15 psi in base fuel pressure, which throws the tuning for a total curve sometimes, I have the FJO wideband as does another Malpassi user, we have both caught the malpassi going out of whack with the widebands, one day, you are backing out the garage with a perfect glass smooth idle at 13.5:1, the next day its a lump 11:1, the next its a stalling 15:1 idle, and you find your fuel pressure sitting at 18 psi..
I am going to the aeromotive or the SX regualtor next, with motors costing what they do, you can be screwing around with questionable fuel system parts IMHO..Max

Re: which fuel pump for 500 rwhp?
 

Toyota JZ80 Supra fuel pump made by Nippon Denso.

B

.

I bought the Ultimate Pump from Ray at www.srx7.com . I make 440 rwhp (approx. 506 flywheel hp) and I'm sure it is good for more. I also ran some -6 line from the pump to the fuel rail.

618 RWHP aeromotive 1000 fuel pump. never a problem or for yours you could use 2 walboro 255s.

GOOD LUCK

I was going to mention the PTP dual Walbro 255 pump setup that they were selling. You could pick that up. Or seeing as it's Howard that's asking, I'm sure you could fab up your own setup that mimics theirs. Glad to see a lot of the guru's in this thread.(not me!!) I have a feeling that there's going to be some great info in here by the time it's said and done.

Zach

I have use a Tomei intank pump flows 280 lt/hr and a load more after doing pumpo wiring. I have 478 rwhp at 1.2 bar running too rich with duty cycle at 68% before I performed my fuel pump rewiring, with 850 pri 1680 sec injectors.

wishing someone luck from over 2 years ago :scratch:

As a laymen I did another variation.changing from the in tank cosmo FP to Gothem's single in tank FP
(maybe the same or a Supra),I made several grounds in the fuel system and hot wired with relay to the battery with a heavier gauge wire.
I am hoping that the high quality grounds and better power source would reflect in the max potential of the in tank pump.
I dont want to hear the external wine of a race pump.
However I have stayed with the original fuel lines and used the Areomotive rising rate FPR. This feeds 780 primaries and 1600 Secondaries.
Can one of you guys tell me what will be my short commings of this fuel set up?
I would like to tune to 20 PSI on the ported , TO4R setup.
I really liked not making a whole new fuel system.

Here's what I did....
2 nippondenso FPs wired with 10gauge wire.
2 - 3/8th" fuel lines, one going to each fuel rail, also 1 3/8th return line
1000cc pri, 1600cc sec
1:1 fuel reg