rx7superman

My friend and I both have the same pumps and are having the same problems. The cosmo pump, although he still has the twins. This is the second time I bought this pump and it just sucks. The first time used from ebay and it went bad around 150 miles later. I thought maybe the person who had it before me jacked it all up. But I just bought a new one and not even 70 miles later it is just not cutting it or perhaps it just is'nt enough for my setup. But then why is my buddy with factory twins having the same problems? I'm running 12-14psi on the T-78 with 110 octane......Has anyone else had these problems with their single or twins?

87GTR

iTrader: (61)

cosmo pump is not must more than the FD pump which it does not flow enough you need the supra TT pump.

lok33

yeah get the Supra TT one

88fc3sw/HX83

The supra only flow a little more than the cosmo, get the GTR fuel pump. I have a BRAND NEW one for sale, PM me if you're interested

rx7superman

I'm just going to go with an fuel cell and weldon or barry grant pump. Thanx for the input though.

rynberg

The Cosmo pump ~ Supra pump.

The only reason that the pump isn't flowing enough is because of the stock wiring. Read here and read carefully, especially point #5:

http://www.newwave.net/~flanham/wlan...l/fuelfaq.html

rx7tt95

The Walbro GSS341 high pressure 255lph pump will flow enough for a T78 on pump gas with stock wiring assuming all wiring is in good working order.

tkbang

what do you mean by not enuff? did you car detonate at high rpm? you can always check the fuel pressure and tune the car

rx7superman

Its really wierd.....It will start to go bubububu backfiring like crazy around 6700-6900 rpm and then shuts off. A little after the turbo spools up to full boost. Then the oem battery light comes on and the display from the microtech says check battery....but that might be because the car shut off. I believe the wiring was done correctly when I had the Microtech installed. I changed spark plugs (platinum NGK's) and I have brand new Magnecor plug wires with an MSD 6A running on the trailing.

87GTR

iTrader: (61)

the supra pump out flow the Skyline GTR pump hands down.

87GTR

iTrader: (61)

here is the flow data chart for the cosmo ver the supra pump.

I have some for supra vs walboro and HKS skyline GTR pump the stock supra pump clearly out flows all of them.

you need to rerun the power wires to the fuel pump as the stock factory wire does not provide good enough voltage.

mmonaco

Or run two walbros in parallel!

tkbang

87GTR, i thought vr4 is abb. for mitsubishi 3000GT?

mmonaco

VR4 is a model the the 300GT, being the TT one.

88fc3sw/HX83

Seriously, I think you better do some research! Here is an excerpt taken from
http://www.stealth316.com/2-fuelpumpguide.htm#j8

"Conclusions
The A'PEXi BNR32 fuel pump 404-A011 (an upgrade pump for the Nissan Skyline GT-R) is the highest flowing in-tank fuel pump at line pressures up to 75 psi and at 13.5 volts. At present I am not aware that this pump has been installed in any 3S car. However, it is installed in some Mazda cars that use a factory Denso fuel pump nearly identical in form factor to the 3S factory Denso fuel pump. The relief valve opens at about 75 psi, limiting use to boost pressures up to 30 psi if base fuel pressure is set at 45 psi. With available flow measurements at only 13.2 volts, we do not know yet how this pump performs at lower or higher voltage. Nevertheless, if this pump is installed with a re-wired electrical circuit (providing at least 13.2 volts during WOT operation), injectors up to 720 cc/min can be supported. List price in the 2003 A'PEXi online catalog is $499.00. I have seen it advertised at online stores for $360 to $410.

The Denso fuel pump 195130-1020 (the Supra Turbo MKIV pump) is one of the best in-tank upgrade choices if you are using injectors up to 550 cc/min and are providing at least 13.5 volts to the pump. When higher voltage is supplied, the Supra pump is good for injectors up to 880 cc/min. At 13.5 supplied volts no other in-tank pump flows significantly more fuel up to 70 psi line pressure or 27 psi boost. It is a direct drop-in replacement; all other non-Denso choices require some modification to the assembly. It is as quiet as the stock pump. Best of all, it can cost only $180 at Conicelli Toyota. One disadvantage of the Supra pump is its relatively heavy current draw and large decrease in flow as supplied voltage lowers. Good, heavy-gauge wiring (meaning re-wiring the fuel pump electrical circuit) is a requirement to get the most out of this pump.

The Walbro 341 model (also called the 255 lph HP) flows about 10 to 40 lph less than the Supra Turbo pump up to about 70 psi, when 13.5 volts are supplied to both pumps. However, at 12 supplied volts, the Walbro 341 outflows the Denso 195130-1020 above 55 psi line pressure (compare John Cribb's Supra pump data to the Walbro charts). The Walbro 341 is an excellent choice for 450 cc/min injectors, especially if the fuel pump has not been re-wired. It can be used with 550 cc/min injectors if 13.5 volts are supplied. Some slight modification to the pump assembly is required and it is not as quiet as the Denso pumps. The price is even less than the Supra pump at $100 to $150.

Whatever pump you decide to go with, the Cosmo and 300ZX/Skyline pumps are also good choices, the voltage at the pump is critical for good flow. Check the voltage at the pump. If it is below 11 volts try the resistor/relay by-pass modification first to see if voltage increases to 11.5 to 12 volts. For more current you will have to re-wire the circuit and maybe add a step-up voltage regulator. "

rx7superman

Thanx guys!

JunpoweR

iTrader: (1)

ok guys where is the fuel pump resistor relay located??
in a 1990 gxl FC3s thanks

GoodfellaFD3S

iTrader: (213)

Re: the skyline pump, you guys are both right. 88fc3sw/HX83 is referring to the Apex'i BNR 32/33, which are upgraded pumps for a skyline. 87gtr is referring to a stock skyline pump.

I'm not surprised the cosmo pump isn't enough for you. supra pump with stock wiring probably won't be either. Lots of good info in this thread I started not too long ago:

https://www.rx7club.com/showthread.p...stem+ramblings

GoodfellaFD3S

iTrader: (213)

You dragged this thread back from the dead to ask that? Why not start a thread about it in the 2nd gen section

fastcarfreak

I know this is an old thread, but i figure i would add my 2 cents in because this is the setup i have. I have found that the cosmo pump flows more than enough for what the t78 has to throw at it. I have already found myself throwing boost up to 30 psi at it and it doesnt seem to have a problem.

GoodfellaFD3S

iTrader: (213)

Hey Adam,

30 psi? who is tuning you? great big ***** you have, my friend .

You may want to verify the pump you have. a true cosmo pump will not handle that kind of power.

fastcarfreak

yeah, we managed to hit 30 psi(although it doesnt stay there, goes back down to around 25 psi). I kept the tune that steve kan gave me for driveability and up to around 17 psi. Steve told me my timing map would be good to around 25 psi so i just tuned my fuel map myself from 18 - 30psi with the aid of my father driving (its nice to have a father who isnt afraid to do multiple 60 - 135 mph pulls. I use the safety of c16 fuel and my duel stage water injection. The AFR stayed between 10.8 - 11.4 with 15 degrees of timing. No detonation just smooth acceleration I wish there was a dyno to put the car on around here.

I took my cousin along for my first non 4th gear acceleration test. Started at about 30 in 2nd gear. stepped on it, got a little wheel spin so used a bit of throttle control, shifted to 3rd gear and i could swear i immediately had to shift to 4th. Didnt even realize at that point which gear i was in and found my hands doing the shift movement for myself into 5th gear in which i let off at around 6500 rpm or around 175 mph absolutely insane. Especially the short stretch of road that it was done on with its 55 mph speed limit. needless to say, my cousin (who drives a slow *** 350z), couldnt get enough of my car, and i was shaking after we came down to the speed limit...

Adam

darkphantom

iTrader: (2)

The Bosch 040 Is A Expensive Pump $200. But Will Out Flow All Of Those Fuel Pumps 64 Gal Per Hour. (700hp)

Howard Coleman

iTrader: (6)

i run a cosmo pump bought from SR in 99.

i run 850/1600 injectors to 88% injector duty cycle and digitally log my fuel pressure so i KNOW i have enough pump.

for all of you that already have a pump upgrade but are running on the edge and considering an upgrade i have a suggestion:

Kenne Bell Boost A Pump (BAP)

that's the key to having no pump worries for me... as soon as i hit boost the BAP solenoid triggers the module and my pump gets zero to 50% increased voltage. i run +20%.

$200.00 check out the Kenne Bell tech-rich site...

i have been running my BAP for 3 years w no problems.

howard coleman

fastcarfreak

yeah, one of the tuner mags did a test with this fuel pump amp on a variety of common import used pumps a couple years back. With this unit, the cosmo out performed all the other pumps using the same amp. I think they found that it would be able to support like 750 horsepower (flywheel) with the amp.