Doctor_25

Does anyone know the ratio of injector cc's to hp for rotary...if there is one
(E85 turboed if that makes any diference)

iceman4357

iTrader: (2)

Howard has a lot of good info on his site:

E85 Appraisal for Turbo Rotary - Coleman Precision Rotaries

fendamonky

iTrader: (6)

It's probably a safe bet to take whatever flow amount you need for 93 octane, and just double it for e85. It's not exact, but it should get you close to slightly over. It's always better to be slightly over the required fuel potential needed, than under it.

I was initially thinking of running ID2000 cc injectors as my primaries, and ID2600-XDS as my secondaries with a flex fuel sensor so I can safely swap between pump and e85. That should be enough to power 500-600 I'd guess.

peejay

It is also going to depend on stock/street port or bridge/peripheral.port. The bridge/peripheral engines have a lower peak powr BSFC, so they need less fuel.

Richard Miller

I have been trying to get a stronger understanding of the fuel system. In conversations about fuel requirements and boost applications the injectors are discussed as being a static 1050 for an example. Yet when I read ID's website I see the flow rate varies upon fuel pump psi. For example an ID1050x is rated at 1060cc @ 43.5 psi and 1305cc @ 65psi. Does this mean that I should calculate, for instance 43.5 base at 0 psi (vacuum) with 1060 cc and with the regulator running lets say 21psi boost would bring the fuel pressure to 65psi and therefore we would reach the 1305cc per injector ( at full duty cycle) or 1109cc at 85% duty cycle.

peejay

The fuel pressure is still 43.5psi, you have 21psi in the manifold fighting the 64.5psi in the rail.

This is why fuel pressure regulators are referenced to manifold pressure.

Doctor_25

Im going to do a pretty big street port, and eventually mill a semi pp into the housings, when I start trying to increase power more

scotty305

iTrader: (2)

2000cc injectors have a reputation for crap idle quality on piston engines, even running E85. I can't imagine they will be pleasant on rotaries either. Not everyone agrees but I would rather deal with a car that makes 'only' 300-400hp and is easy to drive than having a lot of power and poor manners.

fendamonky

iTrader: (6)

Really? I've heard the opposite about the ID2000's. I'm guessing it boils down to tuner and ecu capability?

There is no real good reason to intentionally undersize your fuel potential if you're looking to run flex fuel, regardless of your power goals. I have both an EFR 7670 and 9174 that I plan on swapping between. The 7670 will be in the 330-430ish range for twisty back roads and auto-x (lots of fun!) while the bigger turbo will be for higher speed use. I had ID1000/ID2000 injectors for pump gas and "only" 360whp ish. Way more injector than needed but the driveability was still perfect. I think the same theory applies when talking about e85 potential.

R-R-Rx7

iTrader: (24)

I would go for 4 secondaries 1700 or 2000 and 1000s primaries instead of oversizing the primaries to 2000s. That means a different intake manifold and rail but i think you ll have a much better idle and enough fuel for e85

fendamonky

iTrader: (6)

^ Oh, agreed on just going with 4x secondaries. The 2000/2600 is just an option if you don't want to change out the intake manifold. Though, it looks like the 2000cc ID's aren't listed any more so if buying new it would need to be 1700/2600. I've spoken with folks that said they have had zero issues tuning idle with 2000cc injectors using pump fuel, I'm not a tuner though so I can't say I've done it personally.

I ended up opting to completely replace my UIM/LIM and just get a pro jay manifold. I'll be running 4x primaries and 4x secondaries for 14k-15k total cc's of injector potential. Since we're building the harness from scratch anyway we might as well future-proof the hell out of it!

R-R-Rx7

iTrader: (24)

FIC and some other companies still offer the 2000. ID is the choice for a lot of people but i have used the others and i have been pretty happy in numerous builds for a very long time.
for a closer to a "stock" functioning intake manifold xcessive is a very widely used option

As for pro-jay they are coming out with a similar "street" version but noone knows when they ll be done

TeamRX8

iTrader: (2)

2x is a bit over the top; it only needs 41% more theoretically, in reality a bit less

1.5x will more than adequately cover it
.

Carlos Iglesias

iTrader: (6)

Running my old Motec M4, I must've been an anomaly: 900rpm velvety idle on ID2000 primaries. Maybe the fact that it was Paul Yaw himself that tunes my car might have had something to do with it... or maybe not.