larger secondaries, or additional injectors?
 

what do you say? larger secondaries or additional injectors. and please dont give a 2 word answer, please explain your logic in giving the answer, the ups and downs of each or why you personaly picked your "way"
i am planning on going with additional injectors run by a haltech f5 controller with the "secondary" fuel system running its own lines, pump, and filter from the tank. would this be a good choice? my reason in going this route is that i do not want to change my ecu from a pettit to something like a apexi pfc.

bring on the comments please...

larger secondaries. :)



if you really really do not want to change your ECU, than adding more injectors is the only way to go. you will need a new GReddy elbow, injectors, and a new fuel controller (Apex S-AFC, HKS AFR...etc.).

why dont you wanna switch to a PFC?? financial issues?? well, rigging up two extra injectors to run with your Pettit ECU will cost roughly $600. so a PFC/1300 secondary setup will not cost that much more than keeping your Pettit and running additional injectors. and i dont think tuning the PFC is an issue for you, living in NJ. there are many shops around there.

you can keep your Pettit ECU and run additional injectors, but i would reccomend buying a PFC and run 1200 or 1300 secondaries. much easier route.

just my .02

I think joeD said it best

here is a pic of rotaryextreme's setup:

http://www.rotaryextreme.com/enginebay2.jpg

i dunno...but wont this put you at very high risk for possible leaks and engine fires??

i see your point if i werent in a different boat than you speak of. i have access to a haltech f5, i have plenty of extra injectors, i have an extra fuel pump, and lines are not all that expensive. so what would i "need" to buy...almost nothing. i can plumb the injectors into the plenum if i were that hard pressed for cash. ( i am not) i just dont feel the need to go spend upwards of 1300 for a pfc. i feel i could use that cash for something other than changing my ecu. (read larger single turbo) i just dont feel i need to go the pfc or a haltech e6k type route at this stage in my car's progress. plus the comment about living in nj, you are right, but i will be doing it myself. so no labor cost...

How big are you wanting to go on your secondaries. Someone (it's in the ECU forum if you want to look for it) mentioned they did some testing, and using a M2 or Pettit ECU should be fine up to 1100 on secondaries.

i was not sure of this yet. i have (for additional injectors) 460's that would bring me to 1310
550's that would bring me to 1400
and 850's that would bring me to 1700 when combined with the stock secondaries.

Um Jesse Lau has a manifold with injector bosses welded in.. that way you could run 4 extras and it would be super accurate! thats what i will probably do in the future,,,

well the pfc is a pos so rule it out right now..theres no one to tune it on the east coast so its a waste of time...
i dont know shit abt how the f5 would work..if it could be reliable- or hold up to what your planning on doing with the car..
also if you go single your gonna wana play with the timing..wich e6k will do
well kieth look @ it this way
you can bandaid it or do the open heart surgery and have no worries

haltec e6k for 1300- 500 for the pettit being sold
so 800 for unlimited tunablity and no wories

but its all abt where your goin with the car

ohh i vote larger secondaries:D

I guess the real question is, what boost is he trying to run?

rxrotary2_7,

What are you planning on doing with your car? Are you just wanting larger injectors for the hell of it or are you going to be running more boost? What boost level are you planning on running?

Are you on stock twin turbos? If so, 13 or maybe 14 PSI is about the most you'll want to run on those (unless you don't care about throwing money away), and I would imagine you won't need 1400 or 1700 on secondaries for that.

yea dont leave out the most important part of the equasion kieth:D

I was under the impression that the Greddy elbow with the additional
injector bosses was a POS? Basically just another marketing ploy
by the "name" brand to get more money out of the consumer for a
part that doesn't really work that good ...

I believe you would be better served by larger secondaries. I've heard
from several different sources that it is not very efficient to place the
xtra injectors so far "up stream" - such as in the case of the Greddy
elbow. You want the injectors on the manifold side of the throttle
body, and not vice-versa.

What do you guys think? Please correct me if I'm wrong....

Cheers,
GEB

You couldn't pay me to run a stock ECU! With the adjustability from the user end of any of the aftermarket systems you are way better off. Also the aftermarket ECUs make the engine run so much smoother. I don't like have the injectors that far away from the intake ports for mixture reasons .... I don't want to see all the fuel go to one rotor and not the other ... hence creating a lean rotor/rich rotor situation which would not show up w/ wideband O2. Others might disagree with me and say they have been doing this for a long time ... but it makes ME nervous.

Since you already have everything to run the extra injectors then go for it. There are a few guys that uses the Pettit ECU with additional injectors controlled by the HKS AIC or Greddy Rebic to run more then 15 psi on the stock twins. You can also run larger injectors then use the HKS super AFR or the AFC to fine tune it. I've heard conflicting stories aboutt his setup, one person say it will not run smooth in the upper range and the other say it'll fun smooth.


Tony S.

first off, i don't know what weed you've been smoking, but how about you try some of mine! I've got the best in the world, and it's straight from weed city! HAHA, anyways... honestly, I think the PFC is not a pos. In fact, I really like it. Yes, there are people who tune the PFC. KD rotary does it, so does performance motorsports--just to name a few.

I run larger secondaries but here is an argument for additional injectors.

Many Japanese tuners believe in additional injectors because they feel that the fuel is atomized better with more smaller injectors. Instead of a a huge injector dumping fuel in they feel that smaller injectors in groups have a better chance of mixing the fuel and air better.

But, additional injectors are harder to tune but easier to install. For a while I was using a HKS AIC with two additional 550cc injectors. I still have them on my car but just not used. I switched to 1300cc secondaries when I installed my PFC. But, at least i know i have more fuel then i will ever need for the street (4x550cc 2x1300cc).

When i switch to the FCON V Pro i could actually run larger injectors and additional injectors off of it. FCON S can do it too.

neither bacon or myself would use kd...i think i can speak for the both of us on this...

one question for everyone
what system did adam swaratttiiiee( or how ever its spelled) use. i know he was the fastest around at one point and i KNOW he ran additional injectors. i see the point you are all making, but for some reason i dont feel this is a band-aid job as opposed to open heart surgury. i think it is just a differnt way of doing it. i am not sure of my future goals with this car, i just want more fuel to be on the "safer side" to run more boost. i should just leave the damn car alone, and concentrate on my rx2, but we all know its hard to leave any car as it is for very long.

I am not opposed to additional injectors ... it is just where you put them!

after the TB? is that where you would? what would cause one rotor to recieve more fuel than the other?

wasnt adam running a haltec...and aditional injectors?

well kieth youy still havent answered what your doin with the car..if your just gonna run over 15psi on stocks id say aditional injectors are fine..but if you plamning on going single and running a decent mount of boost id go standalone :D

ohh marcros11-
yea kd "tunes" the pfc but not with the powerexcell software wich to the best of my knowledge is only avable to xs enginering since its all in japanese and runs on japanese based windows software....
but not knocking dave but i havent seen ANY high hp single application
come out of his shop tuned with a pfc...
pfc has hidden menues dave CANNOT acess without powerx-cell

Yes I would want them in each runner. Really it is all about air flow and mixture of the fuel that is key. Our throttle bodies have 3 openings and the bottom one splits into 2 runners. I've just heard of various flow problems on many engines(piston) where one side goes lean and the others don't just from engine design. I don't have any supporting evidence on the rx-7 ... but just something I would stay away from unless I could monitor both exhaust ports with EGT probes.

no adam used a EFI box..and greddy injector controllers...early on

please take a look at this thread and tell me what you think.


https://www.rx7club.com/forum/showth...threadid=21519