slo

iTrader: (1)

I'm looking to find out what the max sized streetable primary injector is for pump gas. I have heard of many people running 1000CC primarys and claiming they where no harder to tune, and once tuned where just as streetable as 550CC injectors.

Is that true? how about 1300's

Claudio RX-7

iTrader: (1)

In my opinion you dont really need more than 850cc primaries and 1600cc secondaries for a street car. That is enough fuel flow for a lot of power. Also, how much boost are you gonig to run anyway?

slo

iTrader: (1)

In general I agree with you, 850 1600 if all else is up to the task is capable of making allot of power.

What I want to do is use the largest streetable primary injectors to push the staging bar as far into boost as possible, as part of an idea, basicly immagine 2 physicly seprate fuel systems, designed pretty much as standard fuel systems, (as in tank or fuel cell, pump, lines plumbed to the engine, fuel rail, injectors, pressure regulator, return line) one of them will be the stock fuel system, feeding injectors inb the primary spot. One will be an auxillary fuel system fed by the largest fuel cell I can fit in the FC spare tire well. The stock tank will use pump gas, the fuel cell will use E85 or alcohol which is available to me localy. I'd like to push the transition up to about the 300 whp mark if possible.

brooklynfc3s

iTrader: (1)

seems to me that what you really want to do is run an alcohol system as a complete secondary fuel system. I think you could probably use 1000cc primary injectors, without serious idle or cruise issues. My question to you though is how late do you want to stage the secondaries? Why would you want to use them so late? If you're going to use alcohol at all you'd be better off injecting when you come into boost. like say after 5 psi.

slo

iTrader: (1)

I'd like to use them past wastegate pring pressure, at about 10 PSI. At and below that it won't be making enough power for it to be usefull.

slo

iTrader: (1)

Actually that gives me an idea, I could start using them at about 5PSI, then I could use 87 octane in the primary tank..... HMMM

brooklynfc3s

iTrader: (1)

nah man use 93 and be safe

slo

iTrader: (1)

e85 which is what I would be injecting is 105+.. in any case we don't even have 93 in cali we only got 91. Dave (RIP) mad well into the 300 HP level on 87 with no alcohol injection.

moremazda

iTrader: (4)

That seems like a lot of headache, why not just use E85 as the primary fuel???

slo

iTrader: (1)

Its only avilable at one station near my house, but most importantly, the factory tank would need to be replaced with something made of SS or coated, and the hard lines would need to be replaced.

Every part that comes in contact with fuel would need to be replaced, which I wouldn't mind doing, but the availablility thing is a killer.

moremazda

iTrader: (4)

^^ true, but you have to do all of that for the secondary fuel system.... so just do it for the primary...

And if you use the E8 you can setup dual mapping and tune one map for 91 and the other for E85.

slo

iTrader: (1)

I think that the cost would be similar if not equal to the secondairy injection idea, and with the secondairy injection Idea I would have more flexibility. If E85 was at half the gas stations I would probably just do a full conversion to use it. There is an RX3 using pure e85, that is tuned to the edge, even beyond what you could tune with c16 because of the very low exhaust temps.

moremazda

iTrader: (4)

double post

moremazda

iTrader: (4)

my point exactly and you then have only one fuel system in the car.

with dual mapping, switching between the two fuels is as easy as flipping a toggle switch, the only complexity would be having to wait until the tank is completely empty before switching to the other fuel