As I understand the high impedance injectors started with the S5 give or take. I have been considering RX8 injectors as the are a newer design but not sure if it would be better to go with FD instead. The engine is a streetported GSLSE with a S4 intake, a S5 turbo is part of this equation as well. Haltech 750 for control if that is of consequence. Is there a other Denso I should be considering?

 

I think you're on the right track if you want to stay with an OEM type fuel rail. Otherwise you can get Bosch EV14s and something like a Full Function Engineering or JDL Manufacturing fuel rail setup on that intake manifold.

Rx8 Injectors have a very nice, modern spray pattern. Realistically that turbo needs roughly 2600cc/min total of fuel to really max it out. Modern Injectors are DEFINITELY the way to go as their control is substantially better than anything that came on these cars.

I'd love to help dial you in on the Haltech. Let me know if you have any questions.

 

I had my eyes on the EV14s. I wasn't sure about the fuel rail though. The JDL FC set is in my budget. question is would that fit the NA manifold for the secondaries? I would assume the primary rail would fit. If not I am not against going with a turbo intake manifold. Need to do some more digging on that one.

 

Almost positive that's a NO. Connect with me as needed. I'm here to help.

 

My reading had led me to these options:

(4) Injector Dynamics 11mm EV14 1050cc injectors (1050.11.03.60.11.2) which as I understand will fit in the stock Denso location

or

(2) Rx8 Yellow 450cc in the primaries and the Injector Dynamics 1050 in the secondaries.


discuss

 

I have the same engine specs (GSLSE Street port with s4 intake) but I am running a megasquirt. I am finishing my build so haven't got it out on track but as is I am running all 450cc rx-8 injectors as both primaries and secondaries.

Let me ask this for the sake of this conversation: Why does everyone run such large secondaries? It seems the general consensus is to run close to 1,000cc secondaries. The megasquirt manual has a rough table for HP to injector size requirements. According to this table 4 450cc injectors should be good for ~300hp. Since even a good street port build will only be around 200hp why such large secondaries?

 

BSFC. Brake Specific Fuel Consumption. basically the amount of fuel per hp. the 6 port rotary is pretty bad here, and then the forum recommended AFR's tend to be on the rich side, which doesn't help.

so? so we need larger injectors.

4x 450 is basically what a stock NA came with, and its plenty for an NA (even with stock injectors, and stock fuel pressure, ~13:1 AFR at 150rwhp is only like ~75% injector duty), or for that matter 2x 1050 would be ok too

the 4x1050 or 450/1050 would be a great setup for a mild turbo, but its HUGE for an NA

 

If you can find a set of the previous ID725 “long body” injectors they fit in the primary position and will maintain proper spray pattern for the necessary idle flow rate. They didn’t have the stainless pintle though, which is why everything converted to short body style.

Just the same I was kind of bummed that they dropped those, but did manage to buy some before they changed to all short bodies just for that purpose.

 

What about those nutty plastic diffusers? Do they have a place with modern injectors?

 

No. The plastic diffusers were needed with the old school injectors. With the newer technology in the ev14 injectors you get better spray patterns and atomization without the need for diffusers.

Personally I'd get rid of them, they're one more thing to break down and damage the motor.

 

Thanks!