Bigger injectors?

dac69er

Super Moderator
Was looking at getting the Mazda rx8 440cc injectors for my build.

Anyone have any good or bad experiences with them?

I understand the spray pattern probably isnt optimal for our cars, I didn't know if this really made that much of a difference in reality?
 
i've run these injectors over the years on emu...stock 295cc, mazda 360cc, mazda 460cc and subaru sti 565cc
the stock 295cc and subaru 565cc have been perfect on idle, cruise, and full throttle (boost)..these had several holes at the bottom of each injectors to create fine spray patterns

the mazda 360cc and mazda 460cc have been good on full throttle ,,however they occasionally caused a "jerking/judder" on idle and cruise for some reason...these had "one" hole at the bottom of each injector,,so the spray pattern was not the best

all were cleaned and flow tested before installation
 

dac69er

Super Moderator
i've run these injectors over the years on emu...stock 295cc, mazda 360cc, mazda 460cc and subaru sti 565cc
the stock 295cc and subaru 565cc have been perfect on idle, cruise, and full throttle (boost)..these had several holes at the bottom of each injectors to create fine spray patterns

the mazda 360cc and mazda 460cc have been good on full throttle ,,however they occasionally caused a "jerking/judder" on idle and cruise for some reason...these had "one" hole at the bottom of each injector,,so the spray pattern was not the best

all were cleaned and flow tested before installation
That was my concern.

I have some Toyota 370cc injectors that match the spray pattern of the stock injectors, but they may be a bit too small for 1.4 bar boost.

Do the Subaru ones require different plugs and/or a resistor pack?
 
That was my concern.

I have some Toyota 370cc injectors that match the spray pattern of the stock injectors, but they may be a bit too small for 1.4 bar boost.

Do the Subaru ones require different plugs and/or a resistor pack?
yeah..you will need bigger injectors than 370cc for your goals

the Subaru 565cc injectors were a direct fit to the 4e/5e fuel rail and same impedance (no resistor packs required) ----all you need to do is remove two of the black plastic spacers (one from each side) that are used to secure the injectors to the fuel rail...they come in pink and medium blue...if you go this route, try to get some genuine ones from the subaru forums, those guys are always upgrading and sell them cheap...i'll have to search for the year/model Subaru sti they came from...
be very careful with ebay...they sell a lot of cheap fake Chinese knock offs.
 

dac69er

Super Moderator
yeah..you will need bigger injectors than 370cc for your goals

the Subaru 565cc injectors were a direct fit to the 4e/5e fuel rail and same impedance (no resistor packs required) ----all you need to do is remove two of the black plastic spacers (one from each side) that are used to secure the injectors to the fuel rail...they come in pink and medium blue...if you go this route, try to get some genuine ones from the subaru forums, those guys are always upgrading and sell them cheap...i'll have to search for the year/model Subaru sti they came from...
be very careful with ebay...they sell a lot of cheap fake Chinese knock offs.
Thanks for the info. I will stay away from the Chinese stuff

If you have info on what model Subaru or what part number I'm after, that would be a huge help :)
 
Any other options out there from anyone else?

Been looking at the Bosch injectors. Seem to be pretty good value for brand new injectors that are allegedly direct fit (just need to replace the plugs or buy an adapter).

https://cpfuelandrace.com/products/toyota-starlet-gt-galanza-v-4e-fte-4x-550cc-bosch-ev14-fuel-injectors-uscar-connector?currency=GBP&variant=41451988418758&utm_medium=cpc&utm_source=google&utm_campaign=Google Shopping&gclid=Cj0KCQiAveebBhD_ARIsAFaAvrFjaSxOLPHh6PlXBOo-10ySQub89u_rl4GZb73rNuEO_qceGvuBHxgaAgH3EALw_wcB

Thanks

i guess you have to do some research on them...the price seems good...you have to make sure spray pattern and atomisation are good too,,as that will be important to the quality of your tune
 

dac69er

Super Moderator
i guess you have to do some research on them...the price seems good...you have to make sure spray pattern and atomisation are good too,,as that will be important to the quality of your tune
Got some "hopefully" genuine pink Subaru 550cc injectors on the way.

Will get them prepped to fit and then send them away for a clean and test.

Will let you know how I get on with them.
 

SKINY

Lifer
Pooburu injectors would have to be pink lmfao
Make sure they are not clogged up with Vape juice too :)
 

dac69er

Super Moderator
i've run these injectors over the years on emu...stock 295cc, mazda 360cc, mazda 460cc and subaru sti 565cc
the stock 295cc and subaru 565cc have been perfect on idle, cruise, and full throttle (boost)..these had several holes at the bottom of each injectors to create fine spray patterns

the mazda 360cc and mazda 460cc have been good on full throttle ,,however they occasionally caused a "jerking/judder" on idle and cruise for some reason...these had "one" hole at the bottom of each injector,,so the spray pattern was not the best

all were cleaned and flow tested before installation
Hi, I'm having a little bit of trouble getting the car to run right with these injectors. It's ok now I have played around with the lag time to get the fuelling about right. Im struggling now with the revs dropping when coming down to idle, it will often stall.
I'm no tuner, but I want to make it driveable enough to get to the tuner!!!!!

Any advice to help me out?
 
like yourself, i'm not much into tuning, but i do play around with the emu if i'm forced to.
are you running a wideband? if so, what afrs are you seeing before/when this happens.
it sound like over fuelling or ignition related in those cells ---in the emu maps, i know fuel is pulled in the idle/cruise areas with those bigger injectors
if you're running a full standalone, it could also be as simple as a setting somewhere---but i'm not too clued there
 

dac69er

Super Moderator
I'm running a power FC.
Never had troubles changing injectors before. These Subaru ones seem to be a bit of a pain to get right.

When I first changed them over, it was running 10 afr on idle and 18afr on boost!!!!

It's alot better now, but I'm still having trouble with it dropping back to idle.

Do you have an option of adjusting the injector lag times in the emu? I. Just wondering what times your tuner set them too?
 
yes, emu has before/after injector size and before/after injector lag time...unfortunately, with emu, what we did is just play around with the before and after injector sizes until we got a decent idle afr,,,we ended up using incorrect before/after injector sizes too to achieve the 14.7 idle,,,,then went about tuning,,,that's the life with piggybacks, always some improvising,,smh
so there are zeros in the before and after injector lag time cells...somehow that works for the emu piggyback...less variables to mess about with

a long time ago we tried to input injector lag times as well, but it we ended up just using the before/after injector size cells
 

dac69er

Super Moderator
Ok, no worries. Will just have to have a fiddle about myself so it's driveable and then Take it to the tuner to get running properly
 
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