RX7Club.com - Mazda RX7 Forum - Optimized AI (Alcohol) System Component Location (FD)

sometimes jobs magically fall together on an optimised basis and other times they fight you and end up butt ugly...

fortunately my AI install turned out to be the former to the degree i thought it might be helpful to share it. i don't have pics currently and since a picture is worth 10,000 words this is going to be lengthy.

my install is 100% methanol. as such it is important to recognize that any leaks can catch fire and potentially fry you or your FD. water or a 50/50 mix of water and alcohol don't burn so system components may differ.

let's start with the container. 4 gallons is an excellent size. and you will want a "fuel cell". most AI vendors do not sell cells w their kits. i examined sizing, capacity, build quality, and found what i think is the right item. the cell comes w foam inside so as to decrease fuel slosh. (you don't want to your car to sound like a Maytag on the wash cycle.)

http://www.jegs.com/webapp/wcs/store...tegoryId=29395

the cell is 12X12.5X8.5.

now we trot out the qualifier that will be operative for this entire post... what worked for me might not work for you as we may have differing needs.

i do not carry a spare tire.

the spare tire wheel well (STWW) was always my fuel cell target/location. Alcohol weighs 6.6 pounds per gallon, and i love rear weight. (my car has 54% rear weight). i am very weight conscious as to car design. as far back, as low as possible and as far to the passenger side is the rule.

looking at the STWW.... remove the tire and you are looking at a 4 inch high protubence in the middle of the well. if left unremoved it would raise the fuel cell 4 inches. an absolute no no. remove it. locate cell so outport faces forward and sloped top faces rearward. bonus, the hatch will close. i bought the fuel cell mount kit (Jegs/Jaz PN 0547400-005-03). it is not specifically made for this cell but can be modded a bit and will make life a bit easier.

i used a sheet of the pink house insulation and carved a piece to function as a foundation for the cell between the floor of the STWW and the cell. since it was pink i covered it w black duct tape. using a U shaped piece from the mounting kit i situated it half way up the fuel cell's height w the flanges pointing rearward. i used the second piece on the slanted top and welded it to the main section. the inboard (laterally) flange connects to a bolt that runs back just beneath the rear plastic hatch and bolts to the chassis. the outside flange bolts to an angle iron that bolts to the floor. another strap fits the rearward face. done.

their are 4 connections to the cell.

1. air vent. a fitting supplied by Alkycontrol screwed into the airvent on the cell and connects to a dash 3 aeroQ line that runs rearward thru the vent holes in the plastic hatch moulding, turns toward the pass side of the car and T's into the rubber sunroof drainline near the B piller.

BTW, all fittings w an alcohol system should be BRASS.

2. low alcohol sending unit screws supplied by Alkycontrol fits this cell perfectly after re-arranging the foam. 2 wires run to the side and down w the ground wire. to the driver's side and eventually up to the dash.

3. Alkycontrol furnishes replacement Stainless Steel bolts for the filler assembly at the fuel cell. plated mild steel can get corroded by methanol. a final connection is fixtured as the bolts are installed in the form of a ground wire from one of the bolts.

4. the alcohol output line runs out of the cell and thru a hole i drilled thru the side of the STWW. silicone it to seal. the line runs forward to the rear suspension frame and turns toward the driver's side and passes thru the frame toward the pump.

now it starts to get really neat.

when Mazda was busy designing the FD they knew that we all would be doing AI so they designed the perfect pump location and i accidentally found it.

Pump Location

ideally.... the pump should be below the fuel cell so gravity helps. when last we visited the install the fuel line snaked alongside the rear steel lateral suspension frame. it then passes over the PPF and heads downward between the rear of the PPF and the diff. it runs laterally toward the center of the car just at the bottom of the halfshaft to meet the pump's 90 degree input fitting.

mounting the pump.

cut a piece of aluminum so it is 7.5 by 5.375... i used .14 inch thickness. my Alkycontrol pump came w a rectangular base w rubber insulators. tilt your piece of aluminum so the long way is east west. locate the pump on the mounting plate so the input/output faces east. locate the pump base plate so it is .5 of an inch from the east and .625 from the south. drill 4 holes mount the pump on the baseplate.

the baseplate mounts on 3 corners. use some 3/4 X 1/8 inch mild steel. you will use the bolts that locate the plated steel body brace for 2 of the baseplate bolts. the inboard strap is 6 inches long and runs straight back to the pump mounting plate. the outboard strap ties of the other end of the frame brace and needs a Z bent into it. the other corner bolts to the black steel frame. reference measurement... outboard edge of pump body to PPF 4 inches.

now you get to put the black plastic protective piece back on... notice it covers the pump. trick.

electrics (weatherford) run under inboard strap and frame brace and thru ABS hole in floor (driver's rear compartment). methanol pump output line runs straight forward under frame brace to Alkycontrol filter thru filter and into the outside fuel breather line which you removed from the car. the line literally snaps into the OEM line clips and you then reinstall the black plastic cover for the lines. is that cool or what.

all the way up to where the fuel lines emerge from the plastic cover and head for the engine. my lines then enter a NOS Y fitting (not brass... none available so a maintainence item) ((edit: have now used it a year and no degradation)) split in two and head up under the elbow. my nozzles are located in the silicone coupler between the elbow and intercooler pipe. nozzles located at 6 oclock and 3 oclock. two M10 nozzles... 600 rwhp. one M15 for 550-500 rwhp.

that's the mechanical plumbing.

Control systems....

the Alkycontrol system uses an on/off (Gain) progressive ramp control dial, a test button and LED in a module i placed on top of the area between my steering wheel and the dash.

in addition, the system has a separate module that controls at what boost you want the spray to start (Turn On), and at what pressure (Initial) rate. BTW, i have found that spray starts within 100 PIM points, that's less than a tenth of a PSI!

the third module is a pump controller module. the primary function of this module is to disapate heat soak and decrease the chance of a blown fuse. i know of no other system that uses a separate module in this manner. Julio Don principal of Alkycontrol is an Electrical Engineer. draw your own conclusions. i did.

getting back to system location...

my battery is located in the passenger compartment. the pump, yippie, is not far from the battery. it made sense to locate the pump controller in the same compartment. in order to do this use a 30-40 amp relay in the compartment. i used the really nice OEM relay from my junked ABS unit. yippie no cost. i located the other control module on an electrical line in the same compartment. you generally don't adjust it that often. i extended the lines from my Gain controller along the driveshaft tunnel back to the passenger's compartment. if you do it similarly i suggest you measure and ask Julio to fab the proper line length as there are a number of lines some shielded.

the system is run off your 3 bar MAP sensor. you need to splice into it to the Gain module.

the output to the pump runs from the pump controller laterally over the driveshaft tunnel and into the driver's compartment thru the unused ABS elec hole to the pump.

if you go the Alkycontrol route you generally mount the components, measure your needed line length and Julio makes them for you using braided stainless lines and hydraulic brass fittings.

there will be 2 LEDs to mount. one for low alcohol and one that starts red when the system starts spraying and turns green at a set psi. i run a boost sensitive J&S knock sensor/retarder and have the retard dial next to the Gain module on just behind my steering wheel. i fixtured the 2 LEDs on the mounting bracket for the J&S.

that's about it. my fuel cell is black w an attractive red and chrome fill assembly. it matches my rear carpet. i cut the carpet so the cell protudes 4 inches and looks nice.

of course the real fun starts w the alcohol.

any additional fixturing ideas of course welcomed here.

let's try to keep this thread on topic which is component location.

howard coleman