Increase Fuel Pump Capacity 50% for Free.

Okay, this article doesn't apply to everyone, but we all love risky, warranty voiding modifications to squeeze unintended performance out of a product. Don't worry, this doesn't involve fancy five axis CNC port work...while this modification can be performed by anybody with a drill and hammer, we suggest you leave this modification to an expert.

As of this writing, the TI Automotive F90000267 is the standard fuel pump to run on high boost street/strip cars running ethanol blended fuel. While this is currently one of the highest performing electric pumps available, the safety relief valve is a weakness that needs to be considered if you're pushing your fuel pressure past 80 psi.

TI Automotive publishes the following performance curve for a new F90000267. Detailed performance data between 80-90 psi is not provided, but the change in the slope of the performance graph indicates the relief valve may actuate anywhere in between 80-90 psi and still be in specification.

Broken-in pumps perform better than new pumps; however, repeated actuation of the relief valve causes degradation in the relief spring. In order to find out "which one" wins, we took a used pump (that had spent some time at high pressures) and tested before / after the modification. As you can see, performance before relief valve actuation is better than the new pump, but performance after the relief valve could be unsafe for some cars...especially if the valve is allowed to degrade under repeated actuation after the initial tune.

APPLICATION

Thanks to Tony and his crew at T1 Race Development for pushing us to get more out of these pumps and proving out the effectiveness of these changes. He was gracious enough to provide the following screen before/after captures from a couple R35s at his shop:

HOW TO MODIFY

First off, you have to completely remove the fuel pump from the hanger/module. If you are using one of our cartridge based modules, it is best to plan ahead an purchase an o-ring kit for reassembly...the o-rings will likely tear when you take everything apart.

Drill a 4.5mm hole as shown...(but try to do a better job of getting the hole on center...CNC is our thing...not necessarily hand tools):

Use a M4 screw to find the depth of the spring seat, then adjust the jam nuts so you can press the spring seat down another 1.5mm.  (FYI, two turns on a M4 screw = 1.4mm)  Done.

Here's what you did.  There is a spring behind the ball...you simply pressed down the spring so that the ball doesn't spring open at 80-90 psi.

WILL THIS BENEFIT YOUR APPLICATION?

This won't help everybody...this is only valid if you're pushing the pumps beyond 80 psi. Remember, in a boost referenced application, the fuel pump operates at base pressure + boost pressure + system losses.  (do you monitor the loss across your fuel filter...like this?)

DOES THIS PUT THE PUMPS AT RISK?

Absolutely forget a pump warranty...but you're probably used to hearing that if you're using 80 psi of fuel pressure. By the way, TI Automotive is planning a future revision in the F90000267 to increase the blowoff pressure to 110 psi. Until then, this is the best way to accommodate high base+boost cars.

E85 Attack on Metals and Rubbers

In regards to the blog title, we are more specifically interested in the materials used inside automotive fuel tanks. (NOT marine tanks) This includes fuel pumps, filters, tanks, level senders, fasteners, wiring, etc. There are tons of disinfomation scattered across the internet on this subject...based on ignorance, misdiagnosis, and corporate interest. So, let's set it straight:


Concern #1: Corrosion

The big concern is galvanic corrosion.  In layman's terms, this is where dissimilar metals are immersed in a conductive solution (electrolyte) that causes at least one metal to corrode.  (corrosion of metal in salt water)  In automotive fuel tanks, we typically have a combination of steel, aluminum, copper, brass, and stainless steel.

The concern is that E85 could possibly have a similar affect as filling your fuel tank with salt water.  In order to analyze this concern, let's look at the electrical conductivity of our suspects:

LIQUID                                           CONDUCTIVITY (S/m, higher number is more conductive=BAD) 
water                                0.0005 to 0.05
seawater                           4.8
gasoline                            0.0000000000000001
E85                                   0.0000000000074
glass                                 0.00000000001

(fellow nerds:  pardon my omission of scientific notation in the table...but I felt the presence of all the zeros helps correlate the relationships)

Indeed, E85 has a higher conductivity than gasoline.  However, it is hardly enough to be a concern.  E85 has similar conductivity to glass, which is often used as an insulator.  Therefore, E85 is not an electrolyte and galvanic corrosion cannot occur.  This is why we don't bother to fool our customers with "anodizing" or "coating" for E85 compatibility with our in-tank fuel modules.  If someone is selling you this, beware.


Concern #2: Chemical Compatiblity with Rubber and Seals

Many hoses and o-rings are commonly made from NBR, nitrile, or Buna-N rubber.  It is cheap and has descent chemical and temperature resistance.  NBR is shown to have "good" chemical resistance to gasoline and E85.  However, in our experience, NBR is not adequate for E85, especially in elevated temperatures in high performance automobiles.

In terms of seals, stick with Viton.  If you're buying o-ring type fuel fittings, make sure they have Viton o-rings.  That is, unless you're okay with risking your expensive motor over $20 in o-rings.

SAE J30R10 Fuel Hose
This submersible hose is generally constructed from reinforced rubber core with a flourocarbon inner and outer shield.  The flourocarbon shields are supposed to "protect" the core from gasoline.  Otherwise, the fuel will permeate (or soak in) the rubber core, causing it to expand and weaken the bond with the reinforcing fabric.  Safe?  Read on:

First of all, the SAE J30R10 hose specification does not include E85.  Let me repeat that:  SAE J30R10 is not for E85.  The ethanol molecule is MUCH smaller than "gasoline" molecules, which allow E85 to permeate easier than gasoline.

Let's assume the flourocarbon shields could prevent the permeation of E85.  Even so, there is no flourocarbon "shield" on the ends of the hose, because the hose has been cut.   If the hose end(s) are submerged, the fuel will permeate through the end of the hose, past the hose clamp, into the pressurized region, causing the rubber to expand, separate from the reinforcement, and eventually lead to failure.

Simple, avoid the use SAE J30R10 hose in E85. 

P.S.  race gas does the same thing to SAE J30R10 hose ;)

E85 and Fuel Filters, The Truth

Paper (cellulose) filter elements is the most practical way to filter your fuel to 10 microns...which is required by fuel injector manufacturers.  Now, some companies are saying paper filter elements cannot be used in E85.

The truth is:  it's been done for many years.  We've been doing it for several years ourselves.

First of all, none of the "high performance automotive" companies that sell aftermarket fuel filters actual make their own filter elements.  Only a few companies in the U.S. make these filters...so, we are likely buying our filter elements from the same company as our competitor.  (that says "don't run E85.")

FUEL FILTER DESIGN
I started with a military spec aircraft fuel filter...the one that caught my eye is good for almost 1400 liters/hour, then I designed a housing around it.  I took the mil spec for the filter and improved it for E85, which included a Viton o-ring and alcohol compatible epoxy.  The company that manufactures our filter element for us even validated it for E85.  Voila, an E85 compatible fuel filter...wasn't that easy?

SO WHY WOULD A COMPANY PROPAGATE FALSE INFORMATION ON E85 FILTER COMPATIBILITY?
The truth is, their fuel pumps can't handle E85.  They even tell their customers to change fuel filter socks every 10 hours!!!  (because their pumps keep burning up)  Since their business relies on selling fuel pumps, they NEED you to run gasoline.  I think they are buying time to figure out how to make their pumps E85 compatible, then they will give the OK to filter E85 with cellulose.

In the meantime, it is okay to use paper filter elements in E85, provided the manufacturer says it is "E85 Compatible."  And my shameless plug, Fore Innovations fuel filters are definitely E85 compatible, if you add the Viton o-ring option.

So, in the meantime, here are some pics of the production of our 10 micron, cellulose element, E85 compatible filter.