MM, so what is the correct way to add injectors?

 

I currently have the setup that way (380/380/480) and its been fine, although maybe MM 'mucked' around with it to make it work.

From my understanding, you want to keep the Primaries and Secondaries at the same ratio and keep the Primaries low for idling purposes, which usually will mean keeping those two as they are. The Primary 2 slot can be as large as you want and come on only when needed, but if you switch from the yellow, things get complicated because the primary 2 and secondary share the latency table.

Easiest solution to meet all those: Stock Primary, Stock Secondary, Yellow Modified Primary 2

 

That is basically correct. The secondaries are best kept at 125%-ish of primaries, and the sec and p2 share a latency table....

So in a perfect world you up all three, keeping the ratio the same, along with latency. But it gets expensive. So most of us run big P2's and deal with the small latency issue.

 

^ This.

 

Thing is - I have not had to do any "chicanery" . Could it be that the difference between 280 and 380 is not enough to upset the balance ?

 

When you transition into boost at a low RPM, do your fuel tables deviate more from your actual output lambda than they do after 4500 RPM?

 

you can tune around most anything. The issue arises when you change something significant enough and the amount of tuning required to dial it back in.

 

I have a 6% rich spike at 4000 relative to 3500 and 4500 so I guess the answer is yes .

 

And there it is.

 

Ok . I guess there is a small amount of tuning around it then .
I kinda like the idea that the P1s (which inject direct into the port) are supplying a little bit more of the total fuel .

 

The fuel that gets there from the P2s is just the same.
I like the idea that fuel getting into the chamber somewhat equally from both sides of the rotor leads to a more even burn.

 

The P1s are right on the port whereas the P2s are up stream somewhat .


which you would only get if you made the secondaries larger - not the P2s .

 

Doesn't really matter. In fact, I'd posit that the mixture is more homogeneous with the added distance.
It isn't like the P1 position is really "direct injection".


Not exactly. As a result of the OE staging strategy, the secondaries get leaned on pretty hard as the P1s get trailed off. Also, the air path is different.
You can see the result of fuel delivery if you dissect a very low-mile, undamaged turbo motor.

 

This is one of the areas that was giving me fits when trying to tune myself with my uncapped P2s. In the end I got it "close enough" but never really completely "got" it. It would be so much easier if the staging of the injectors was directly tunable.

 

True - I'ts as close as Mazda could get it without going the whole hog . I would have to believe there was a benefit to doing that though , as it would have been far easier for them to just mount all the injectors further upstream. What is the layout with the S2 engine ? The P1 is now 400ccs (same as what I now have ) but is the other injector a P2 or in the secondary air channel ?


which is what ?

 

great in theory, but probably not valid due to the air flow not being equal from both sides, within a certain range is likely to be inconsequential regardless

The primary injector positions are placed for emissions/efficiency purposes.



.

 

But they are equal under these relevant circumstances because of the location/shape of the ports.
This becomes apparent when you look at a low-mile motor as I suggested.

 

What's apparent is that you theorized your belief rather than actually tested it out in detail in a controlled environment with definitive feedback, such as a Superflow engine dyno. I can only surmise that you don't have any direct experience tuning with the 4 injector S2 intake manifold on a 6-port engine. Going back to you original statement, a more even burn is defined less by appearances and more by calibrated data.

You're pretty d@mn good at what you do, but don't confuse your Cobb AP talent with operating at the top of the world class rotary/Renesis knowledge base. There are people who have built, tuned, tested and torn down multiple hundreds of Renesis engines let alone decades of prior 13B experience.

 

You might have just opened a new orifice on your neck there with that one...

 

Just going through this with the uncapped yellows ATM . From the results i'm getting It seems they don't flow as much as they should . What settings did you have when you were "close "

 

Oh .... not again ....


Did you guys uncap your P2's on your own?

I like what these guys do ... http://kgparts.com/index.php?page=rx8modinject

Apparently they flow test them afterwards and send you a matched pair!

I am leaning towards this....

Can AT injectors be uncapped in the same fashion?
In that case, could you do this set-up, with increasing all of them at the same time as Kane said:

primary: yellow
secondary: stock blue
P2: uncapped blue

 

My injectors that KG flowed at 900cc had to be scaled more like 750cc to get things in line. I had initially offset them with the Maf scale which caused all kinds of wonkiness.

 

Yes - I've uncapped my own . (after the shop i gave 1 to totally destroyed it trying to get the cap off - fucktards )

if you have 4 blues why not go
P1: yellow
sec : blue
P2 : blue

that gives you the scenario Kane spoke of . Not sure it's that much of an issue though .

 

I mean ... i dont have 4 blues, BUT I have spent $160 on worse things http://www.discountfuelsystems.com/s...ry,universal:0)

Esp with how much I have put into this turbo build already, combined with the fact that I want to go bigger in the future...

However, can someone explain why the following is?






Also, what exactly does the latency table control? From what I understand it has something to do with the firing mechanism of the injector (hence the pressure vs battery volt. relationship) However, is this atmos pressure or fuel line pressure?

Finally, if I go for the yellow, blue, blue setup, can I just copy the table from my currently secondary/P2 injectors over into the primary table and get an A/T table for the sec/P2? Should be doable since the tables are NOT rpm based.....

Jeff, can you hook me up with that ^?

 

It has to do with transition.

The PCM normally knows when and how to bring the sec's online and drop the duration on the P1's - if you mess with this ratio, it won't work right. This is firmware, cannot be tuned out on the AP.

If you go Yellow, Blue, Blue, you should be able to copy "Yellow" Latency Map onto P1 along with the size, to get close. You will still need to scale. And also you could get the Auto settings if Jeff was willing to send them. Only a pro-tuner can tune auto's?

The latency is the amount of time to physically move the pintle open in injector. IE Injector ON time where no fuel is flowing.