austinramsay

Sorry to add to the 500hp threads, but i have some questions and my brains about to explode reading all these threads haha. So my goal is 500rwhp obviously, but here's the setup i plan to run based on what ive been researching.

I already have a greddy t78 turbo, apexi pfc, hks twinpower, 3mm apex seals, street port, and am on 13psi of boost. Im currently redoing my fuel system with top feed rails, id 850 primaries, and id 2000 secondaries.

My first question is about which fuel pump to run. I know the 044 is enough for 500hp, but im not sure whats required for installing one since its not an in-tank (what do you do with everything in the gas tank, what modifications are required?). Would running two fuel pumps be better? In order to do that, youd have to buy http://www.rx7store.net/Dual_Pump_As...y%20walbro.htm something like that to run 2 correct? Would i need bigger fuel lines all the way up to the rails from the tank?

Another question is fpr, this might sound dumb but what do you need a pressure regulator for? I know its necessary but what exact purpose does it serve?

I plan on running an aem water/meth kit. Im curious what does the water do? What does the methanol do? Is water just for cooling, and meth is for octane boost (less detonation)?

After the fuel systems good, with the rest of my setup i should be good to go right?

Howard Coleman

iTrader: (6)

T78.... no compressor map. compressor is 7.58 aver sq inches. i have seen it make 680 on a piston engine. the compressor is within a hair of the size of a GT4088, not the smaller 4088r...

it makes 72 pounds which squares well w 680 piston rear wheel.

so let's assume 72 pounds max (around 30 psi)

that's 540 rotary rwhp.

your fuel is fine.

fuel pump... i suggest you look carefully at the new Walbro gas intank pump... much stronger than the 044. part number 9000262. a 21st century design and priced right, hard wired you are in business. i do suggest you add a digital fuel pressure sensor and log fuel pressure thru your Datalogit.

for more fuel pump info see my thread in the single turbo section:

Fuel Pumps 2013

you do not need to change the OE steel lines for your app.

a fuel pressure regulator delivers two necessary functions:

it allows you to set base fuel pressure

it maintains base fuel pressure versus the vacuum or boost pressure in the manifold.

for example, say you set base fuel pressure at 5 Bar or 43.5 psi.

if you are in boost, say 20 psi, the regulator adds 20 psi pressure to the fuel pressure so you maintain a net of boost 43.5.

if you are in vacuum, idling, and at minus 8 psi the regulator will deliver 35.5 psi. 8 + 35.5 and you are back to maintaining 43.5.

AI is necessary. since the engine is of small displacement yet is capable of making monster power very high combustion chamber pressure and heat is generated. water and or meth cools the process allowing the engine to live. a combo of water and meth works well as does water or meth.

500 rwhp requires a strong clutch. since the engine is compact the frictional surface of the flywheel is small requiring more spring pressure than a typical V8. at 500 hp you may need a 2600 pound pressure plate... not alot of fun.

or spend big bucks and get an Exedy double disc cerametallic which has double the frictional area and therefore can use a friendlier spring pressure, around 2000.

you will need a good ignition... you can probably get by w stock coils and an HKS Twin Power or could step up to the Mercury Marine coils.

10 heat range spark plugs or colder

1/2 oz 2 cycle oil to a gallon of gas for street, 1 oz for track/dyno

good luck,

howard