What's teh ebst bang for buck that allows high hp? The Nippo Denso claims up to 500 hp, but if I want 500 rwhp, then I'd need something larger, so are how much hp can the skyline pumps do? the supra pump? or is the HKS in pump the best that you can do, while also the most expensive (another case of ya get what ya pay for)? Any info etc. would be helpful, especially you big hp guys, boostd7, crispeed, etc. Thanks

Spyder420
01 MR2 Spyder
FD shoppin if toyota keeps screwin with my warranty

 

pluto (Steve Khan) dynoed at 582 hp at the wheels with the RP competition before and fuel pressure loss.

 

Any other opinions? looking for something that supports 30 psi of boost really well (HEY CRISPEED!!), and if crispeed were to respond, what numbers should one expect at the wheels from 30 psi on a T-78 agressive street port, fmic, intake, catback, resonated mp, dp, and fuel tuning to a safe but very aggressive mixture (12 or so I guess)??? any response would be appreciated. thanks

Spyder420
FD shoppin, F toyota

 

I've been slogging through the fuel pump muck for a couple of weeks. Here's what I've found...

First order of business is to visit http://www.rceng.com. See the technical pages, check out the calculators, and determine how many pounds of fuel the motor needs per hour (injector sizing). Next, divide that number by 6 to get the gallons per hour needed to feed the injectors (pump sizing). All the equations are there. Even I could work them!

There is some good general info at http://www.scuderiaciriani.com/rx7/fuel_pump.html

There is a pump v. pump comparison at http://www.wvinter.net/~flanham/wlanham/fuel/pumps.html

The most popular (and cost effective) setup of late has been the 2x550's and 2x1600's. By my calculations (please correct me) this setup can support 504bhp (428RWHP) @ 40psig (rail pressure) and 80% duty cycle with a BSFC of .65. I think this calc is off because I'm using a turbo motor BSFC, but a flat rail pressure of 40psig (rail pressure should rise w/ boost).

I'm not sure how compensating for boost (1 psi of fuel pressure for every 1 psi of boost) affects the calculation. The increased pressure changes the calculation in two different ways. First, it obviously *increases* the HP capacity of the injector (because it increases the volume of fuel per injector cycle, and fuel atomizes better at increased pressures), and second, it *reduces* the flow volume of the pump.<sigh> Guess it depends on the pump? Anyone comment on this?

Now for the pump. To size the pump, take the 504 lbs/hr, divide by 6, and get 84 gallons per hour. Correct me if I'm wrong, but by this calculation, the following pumps are undersized for this application: Bosch models 10208, 10209, and 10210, Walbro GSS-341, the Cosmo pump, and the 3rd and 4th gen Supra pumps. Seems like I'm missing something, because 84GPH is the world of -10AN fuel lines and the SX & Weldon pumps??? What gives? Guess there's not too many people out there making 428RWHP.

But wait! There's more. There are several X Factors:
If your car was sitting perfectly still all the time like it sits still on a dyno:o you'd be done . But, you accelerate, you stop, you can pull 1+ G's in the corners - right? <yeah, right!> I read somewhere that some tuners will *double* their pump figures to compensate for the pump pushing against the extra weight of the fuel created by the g's generated by the motion of the car. This is probably overkill. But wait, there's more...

Fuel pressure is normally measured at the rail. Makes sense 'eh? Well, the pumps numbers are measured at the pump outlet. I have not researched this yet, but there is likely some pressure loss across the system due to curves, bends, etc in the lines. If there is, then the amount of loss becomes important. But, I'm not sure how to compensate for this, or if it needs to be compensated for. Maybe an EFI pro can shed some light on this?

My leanings thus far: the pump, is NOT the place to skimp. But, I'm not sure how much is enough. I'd rather not pay for -10 and -6 lines if I can help it. OTOH, I'd rather spend my money on fuel lines than rotor housings:\

All best,
Steve C.
http://www.se-rx7.com/members/2ndgen/stevecappelli.html

 

Here are a couple of things I have learned about fuel pressure:

There are two different pressures that are important. One is the "gauge pressure", which is the fuel pressure relative to the atmosphere that shows up on a fuel pressure gauge. The other important pressure is what I call "effective pressure", which is gauge pressure minus your manifold (boost) pressure.

When calculating fuel flow, use the effective pressure. This is the pressure across the injector. If your gauge says 55 psi, but you are at 15 psi of boost, the injector will flow like it has 40 psi behind it.

When determining your fuel pump requirements, use gauge pressure. The fuel pump will have to overcome your boost pressure on top of feeding your injectors. This becomes a particularly important point if you are running a lot of boost.

Your effective pressure can actually be higher than the gauge pressure when your car is idling, or any time that you have vacuum in the manifold. If you are setting your fuel pressure, be sure to account for this, either by disconnecting the vacuum line to the fuel pressure regulator while you make the adjustment, or by simply making an adjustment and then driving the car to see what the pressure is when your manifold pressure is zero. You may also be able to run the fuel pump with the motor stopped and make the adjustment that way.

There are several different kinds of fuel pressure regulators. Some do not respond to changes in manifold pressure, and simply hold the fuel pressure constant no matter what the manifold pressure is. Most turbo cars come with a 1:1 (one-to-one) regulator that holds the effective pressure constant by matching the changes in the manifold pressure. For example, if the base pressure (at zero manifold pressure) is 40 psi, the gauge pressure will increase to 50 psi when your boost gauge reads 10 psi. Many aftermarket regulators are 1:1, but have an adjustable base pressure. Another kind of regulator is called a Rising Rate Fuel Pressure Regulator (RRFPR). Instead of matching the boost pressure, a RRFPR will increase the fuel pressure by some multiple of the boost, like 2:1 or 3:1. For instance, with a 2:1 RRFPR with the base pressure set to 40 psi, the gauge will read 60 psi at 10 psi of boost.

When you have multiple regulators in the system, they should be plumbed in series. This way, the regulator that wants the pressure highest wins. There is no adding them up, it is just the highest one that wins. For instance, of you have the stock 1:1 fuel pressure regulator (FPR) with a base pressure fixed at 40 psi, and you have a 3:1 RRFPR with a base pressure of 20 psi, the fuel pressure gauge will read like this:

(Boost), (Gauge Pressure), (Who wins?)
0, 40, stock FPR wants 40, RRFPR wants 20, stock wins
5, 45, stock FPR wants 45, RRFPR wants 35, stock wins
10, 50, stock FPR wants 50, RRFPR wants 50, its a tie!
15, 65, stock FPR wants 55, RRFPR wants 65, RRFPR wins!

RRFPRs come in several configurations with various adjustments. Some allow you only to change the rate at which the fuel pressure rises, but have a fixed base pressure. Some allow you to set the base pressure and the rate. I have even heard of some that seem to allow you to set the base pressure and rate, and also the pressure at which the rising rate takes effect.

RRFPRs are popular for fuel management of turbo kits for cars that start out in NA form. You usually need a pretty hefty fuel pump for these setups because the pressure needs to be increased by a substantial margin.

Popular wisdom suggests that 85 psi of effective pressure is the maximum you want to run or the spray pattern goes bad or the injectors stops working (can't open against the pressure?) or something like that. I imagine that you might run into trouble with fuel lines or even the injectors themselves being damaged if you run gauge pressure much over 100 psi. However, the limiting factor is most often the fuel pump, as it gets very expensive to get a pump that can flow enough fuel at pressures this high. It would likely be less expensive to buy bigger injectors.

Ignore fuel pump ratings given in HP. A rotary burns more fuel than a piston engine for the same amount of power, so the numbers you read for fuel pumps in domestic car magazines don't apply. You really need to figure out what kind of fuel pressure you are going to run, and then choose a pump that can flow enough fuel for the HP you expect to make AT THAT PRESSURE. Also, the fuel lines and junk can take as much as 20 psi, so add that onto your target pressure before you make a decision. It is a good idea to have a safety margin in there, too, for when your battery is low or it is hot out. You just need "enough" pump to cover your expected running conditions and the margin of safety, any bigger than that will not improve your car's preformance. You need to have an adequate pump to be able to tune your car and have it run consistently.

A fuel pressure gauge can alert you when your pump is inadequate because the pressure will start to drop under high boost at high RPM. Unfortunately, in-car fuel pressure gauges are expensive because they have to be electronic. It isn't safe to run a fuel line into the car to the gauge, so you have to spring for an expensive gauge. It may be tempting to plumb a fuel line into the car for a much-less-expensive mechanical gauge, but it isn't safe and it won't pass a tech inspection at a race track.

Okay, I lied, this is EVERYTHING that I know about fuel pressure. I hope someone finds it useful.

-Max

 

I have the Walbro GSS-341 but have not installed it yet. According to Wade Lanham http://www.wvinter.net/~flanham/wlanham/fuel/pumps.html
<TABLE border=1>
<TR><TD></TD><TD colspan=2>BOSCH<BR>(10208,10209,10210) at 13.2v</TD><TD colspan=2>WALBRO<BR>GSS-341 at 13.5v</TD></TR>
<TR><TD>Pressure</TD></td><TD>GPH</TD><TD>Amps</TD><TD>GPH</TD><TD>Amps</TD></TR>
<TR><TD>0</TD><TD>66</TD><TD>5.5</TD><TD>86</TD><TD>5.0</TD></TR>
<TR><TD>20</TD><TD>62</TD><TD>6.9</TD><TD>79</TD><TD>6.1</TD></TR>
<TR><TD>50</TD><TD>54</TD><TD>8.7</TD><TD>65</TD><TD>8.5</TD></TR>
<TR><TD>70</TD><TD>50</TD><TD>10.0</TD><TD>57</TD><TD>10.2</TD></TR>
<TR><TD>100</TD><TD>43</TD><TD>11.7</TD><TD>34</TD><TD>13.2</TD></TR>
<TR><TD>120</TD><TD>33</TD><TD>13.0</TD><TD>12</TD><TD>15.5</TD></TR>
</table>
I will have a street ported engine, PowerFC, intake, downpipe, high flow cat, cat-back, IC on stock twins at 14psi with 850cc primaries and 850 secondaries. Do I need a RRFPR? How about if I go to a T78 or T04E?

 

How do you install an external pump? Do you leave the stock one there and the external is extra? Do you remove the stock pump and replace with a filter of some kind? It seems to me that if you are going with an external pump you would also be running a purge tank, fuel cell, an8 lines etc.
-Jedon

 

I agree with wankawankal. SX external pump. But I am having
fuel starvation problems due to crappy tank baffles. I am getting
some air problems between 1/4 and 1/2 tank so I am going to
a bottom sump pickup with the SX external pump. Anybody
else have baffle problems under hard acceleration or cornering
with a diff cure? 93RX7. Factory tanks Pt#s diff for every year
why? anybody!

 

Hey Xcessive!
Do yourself a favor and get rid of that SX Fuel pump.
The SX fuel pump was overated and most users have found that out the hard way by now. The pump always seem to fall short just around 400RWHP in a turbo car may it be piston or rotary!
It's not that it cannot support higher power but in a non turbo motor you don't normally run above 45psi. Anything above 45psi and the SX pumps would fall short. Besides that they have serious problems staying running for extended periods especially during idle conditions because they over heat and shut off.
If you want a streetable high volume/pressure external pump go with the Aeromotive 1000 pump. The only other pump better than that would be a Weldon but most of the high volume ones are not streetable.
As for in-tank designs a dual pump set-up would provide enough fuel to satisfy most needs.

crispeed
87TII
9.20@150mph

 

Ok!
This is my personal formula that works for me when it comes time to choose a pump.
First off you need to determine HP requirement. Once you figure that out divide the HP by 10. The result would be the GPH(gallons per hour) requirement to support that HP. For example let's say you are developing 600hp, divide by 10 and that would = 60 GPH.
Now you're looking for a pump that can flow 60 gallons per hour.
That's the easy part now here comes the difficult and the most over looked requirement! The pump must be able to support the GPH at the OPERATING FUEL PRESSURE LEVEL! So with that in mind you're now looking for a pump that can support for example, 60 GPH at 70 PSI of fuel pressure. Fuel pressure is dependent on boost pressure in a turbo application. So if your base pressure at 0 inches of vacum, is at 40 psi and you're running 30 psi of boost pressure, 40 + 30 = 70 psi.
You also have to give yourself a safety margin to work with when determining pump requirement. The operating Fuel Pressure should be increased by 10 or 20%.
With all this in mind the required pump to support 600 HP at 30 PSI of boost pressure would have to flow at minimum 60 GPH at 70 PSI of fuel pressure or with a saftey margin in place, 60 GPH at 84psi.
The Weldon fuel pump in my car can support 180GPH at 85psi!
This is the main reason why all fuel pumps should be provided with a flow chart.
When determining fuel pump size there're many factors that one must take into consideration. That's the reason why you just can't rate a pump by just one factor but by a combination of of all.
Another important factor determining fuel pump size would be G-forces the pump would have to operate against. That normally would affect, for example, a car that has a high rate of acceleration such as what it would experienced in a drag racing enviroment. That is one of the main reasons why very quick 1/4 mile cars would mount the pump and fuel cell in the front of the car. In that location the G-forces would aid in the operation of the pump!

This is based on what I've experienced
Others may differ!

crispeed
87TII
9.20@150mph
650RWHP/520RWTQ
T-72@35psi
2600lbs

 

I just created a web page to help figure out what kind of power you can make with different injectors & fuel pressure, etc. I added a section at the bottom to help determine fuel pump requirements. Check it out:

http://www.maxcooper.com/rx7/how-to/...tem/calcs.html

Let me know if there is anything that doesn't work right or needs improvement.

-Max

 

Crispeed I will get the aeromotive 1000 pump as you said. I have been running a cosmo in tank pump and a airtex inline
booster pump together to get enough fuel at 20psi, barely enough!
Thanks for the input Xcessive

 

So for now I have stock twins so could not possibly have over 400rwhp. I will run (4) 850cc injectors with a Walbro pump, with a PowerFC for management. I already have all this stuff so don't try and talk me out of it :-)
If I go single I will need (2) 850 (2) 1300 and a RRFPR to get ~ 450rwhp with a T04e, T78 or T04s?
Thanx for all the info!
-Jedon

 

That tied lots of loose ends together

Related stuff...

The Aeromotive has -10 fittings. Is there is a less expensive alternative to braided steel that is safe? Recommendations?

Also, what size "hard line" does -10 equate to, 5/8 ?

I checked-out Aeromotives' site last night...
Nice catalog http://www.aeromotiveinc.com
No prices
Anyone know of a dealer?

All best,

 

Wow, what a great thread! I went with the Aeromotive 1000 pump and the SX filter ... I'll probably do braided line, but what do you guys think of Aeroquip AQP Socketless hose and fittings? Seems like that would be a simple way to do it, but not sure if it is safe. Opinions?

Ryan

 

Ryan, Go with the russle lines and fittings, they may be expensive as **** but they are the best and they are worth it. I spent about $250 on hoses and fittings

 

Steve, if you are looking for the pump and accessories you can get them here

FILTERS: $70 at http://www.precisionte.com/cgi-local...515991.3980410

REGULATOR: $139 at http://www.precisionte.com/cgi-local...515991.3980410

PUMP:$299 at http://speedunlimited.com/cgi-bin/we...rv0Ka0190067jq

I have the 1000 hp pump, 2 Fuel filters, and the Regulator. I love the quality of their stuff. Definately the best **** out there, they even have a 2000 fuel injection fuel pump!!!!! Have Fun

 

Yup, -10=5/8". Every "-" = 1/16th of a inch. So a -8 would be 1/2"


One thing I don't get is why the fule lines are so large on fuel pumps?? Ok so you're flowing 60gph for 600hp (crispeeds formula) thats only 1gpm, with -10 lines thats only a velocity of a little more than .5 feet per second. I can't see how fuel moving through a line @ a rate of .5 FPS has any restiction? Any comment?

 

Good info, but the Denso pump and 582 rwhp??? I don't think so.

 

weldon 2035 would by my guess as to the pump your running!!!
have you had to rebuild it yet? i noticed the brushes wear out pretty fast..
i like the aremotive pro pumps, cheap and reliable..

 

and p.s - run a freakin surge tank guys!

 

I run a cell with a Big Bosch pump(one down from the 044), -6/surge tank/-6/return to cell. Out of the surge,big SX filter/ -10/A1000/-10/Aeromotive FPR/parallel into the the two rails / -6/ rails -8 back to the cell.

 

Guys, please look at the dates of when this thread started...4 years old!

 

Soooo what a good thing...I have 780 and 1600 and the Cosmo intank with an MSD booster but looks like I will be way short to hit 20PSI with the TO4R.I needed to know this as we are putting together everything now.
I will search, but if you guys know, where and how would I do a surge tank.Dont answer if there are other post that address the specifics of how and where I'll get it.
But>>>>Which pump makes the least wining ? Man my Bosch on the GT race car just screames and I dont care for that not on my daily driver.
Thanks