Fueling Last Update: May 4, 2009 11:01 PM

Parts You Need:

The stock Miata fuel pump is not capable of fueling the LS1. The popular choice is to use a Walbro 255 pump. The 1999+ Corvette fuel filter and regulator is an excellent part to use as it both filters the fuel and regulate the pressure to the 58psi that the LS1/2 requires. The pump and filter/regulator are said to be good up to 650hp so this can even handle a fair bit of engine modifications. Two other extremely nice things about the vette filter/reg is that it will bolt up to the stock Miata filter location and since it regulates the pressue close the the tank, the return line is short. Below are the items I used:

Corvette filter/regulator: GM Part number for 1999+ vette filter regulator is:
10299146 $50 shipped from http://www.gmpartsdirect.com

15ft of Russel 6AN SS braided hose and a handle of Russell fittings, $200 shipped from Summit.

6an fuel hose - RUS-632080 - Qty. 1
Fuel rail - RUS-640860 - Qty. 1
EFI fitting - RUS-640850 - Qty. 3
90 deg swivel - RUS-613160 - Qty. 3
Straight - RUS-610020 - Qty. 1
 
You will need to cut the 15ft. of hose into 3 lengths. The tank to filter lines require two 40 inch peices and the filter to engine depends on how you route it but 15ft will cover all the line you need.
 
2 equal lengths will run from fuel pump cover to the Corvette fuel filter (make sure to note the feed and return lines). At the end of both lines, attach a 90 deg swivel to 6an fitting. A fuel rail fitting will thread into the swivel for the feed line and the EFI fitting will be used for the return. Attach them to the filter.
 
The other side of the filter will required a special plug-in fitting. Racing Concepts provided this fitting to me. You will use a EFI fitting to attach to this supplied component. The fuel rail fitting will need the 6an straight to attach it to the fuel line that will run to the fuel rail. At the fuel rail, use the remaining 90 deg swivel and EFI fitting to connect to the factory LS1 fuel rails.

Walbro 255 fuel pump $99: http://www.autoperformanceengineering.com/html/fpapps.html I used the standard 255 (P/N FPM008) but you can use the high pressure one (FPM009) too, it is a little more efficient.

Fuel Pump Install:

This is the stock fuel pump assembly. Note how the pump feed goes into a flared tube on the assembly.

miata fuel pump

Close up of the stock pump.

miata fuel pump walbro 255

Here is the stock pump (top) vs. the new Walbro 255 pump. The Walbro is a little taller than the factory one so it will not seat into the flared hose. The Walbro pump comes with a hose that is used to attach the pump feed to the modified assembly.

This is where I cut the flared fitting off. I HATE taking a hacksaw to my car but its for the greater good.

Beyond the point of no return... I hope this works.

miata walbro 255 install

Horray!, it fits.

Note that the flared tube is now replaced with a short fuel line hose.

Fuel Filter/Regulator:

miata fuel filter

This is the stock fuel filter. It is behind a plastic splash gaurd on the rear passenger side of the car.

ls1 miata corvette fuel filter regulator

This is the Corvette fuel filter and regulator installed in the stock Miata fuel filter location.

AN fittings sure do look nice.

Fuel Line Routing:

There is not an AN fitting for the fuel pump assembly connections so I have double hose clamped the lines. The best solution is to weld on AN fittings but I haven't gotten around to it yet.

This is how I routed my fuel line and battery cable wire. I used insulated clips that I screwed into the body and then used a couple zip ties here and there for a little tighter of a fit.

In this picture, I had not recieced the special connector to the fuel filter/reg so the hose is just hanging.

To prevent the fuel line from contacting and hard corners (the engine especially has sharp machined edges), I used a rubber insulated clip on a bellhousing bolt to facilitate the turn from the trans tunnel to the engine bay.