Fuel injectors: the good, the bad, and the ugly.
 

Hi, i'm may be looking to get a new set of injectors for my fc to replace my (most likely) defunked "Venom" injectors. I need a minimum of 720cc of fuel flow (aprox 69#) i wouldn't mind even going to 750cc or 800cc for the extra buffer. My engine management consists of Rtek 1.8 coupled with Apexi AFC Neo tuned via wideband (dyno/freeway tune)

I plan on posting a poll for every ones opinions on the various injector brands and types.

the brands i can think of ATM are:
Venom: mostly junk (modified stock injectors)
Delph/multeci: unknown/stock Garbage motors products
sard: factory s5
deatschwerks: 750cc peak&hold only?
bosch gen1: old fords and euro cars saturated
bosh gen 2/3: newer fords and many other cars saturated
denso: factory s4
RC engineering: #1 quality and reputation
Greddy/trust: mixed reviews
others??


I've seen some posts of ppl running delphi injectors in their 2gens, the good points are that they are for peak and hold systems, they are fairly cheap. However i have experience with the multec injectors and they are garbage so i'm debating on trying a set (almost anything can be better then my venoms). I'm also not sure if their body actualy fits the stock fc fuel rail and injector bungs on the intake manifold. some clarification would be nice.

thanks for the input.

Rc

I only have experience with denso, rc, injector dynamics, and fords 1680cc injectors.
They all fit the stock rail. They all do their jobs as expected. I havent had a failure from any if them. If I were to chose one and stick with them, it would be ID. They have what I need, high impedance, great fitment to stock rails and great reputation. They also use the new bosch design.

Heard great things about ID"s and the strict tolerances..
RC's are in my car right now,but I am switching to ID's in the spring.

should take venom off the list, i have personally dealt with a car that had them lose calibration over a short period of time.

Does the new Bosch design atomize the fuel well?

I have bosch, and I'm happy with them. That said, if I were looking today, ID would be my choice. I've seen a car running ID2000s all around idle and drive around with no problems and drag guys swear by them.

Don't forget Marren Injectors

about how much do the ID's run? 300per pair or more.

any idea about the delphi? what do the 750cc plus bosch injectors come out of?

I have actually had good success with the venom injectors in the past.

Though I currently use ID since they are very high cc and still saturated.

I have actually had good success with the venom injectors in the past.

Though I currently use ID since they are very high cc and still saturated.

my 1000cc from ID cost $230

+1 for the marrens
,, if you need rochy/ multechs in 800 or 1000 at least these versions are blueprint paired
( getting around the very ambiguous variances in the mass produced multech batches )
and fit straight into stock rails ( choose the "import" versions to get 11mm tops )
-and allow you to bin the dodgy plastic mazda atomiser cups

PS
i can get the 1000's to idle as good as stock,, even with a micro
,, fine enough to tune for 19 inch vacuum on mild ported engines

for each injector?

for a pair.

http://cgi.ebay.com/ebaymotors/Delph...#ht_2917wt_939

any idea with this injectors??? fitment & performance?

multech body ( ball plug and seat design ),, 11mm tops,, 1 % blueprinted
pretty much same as the marrens ( multech 2 ) ( which are 800 and 1000 ) [ and around $100 US each ]

multechs do not cope well with injector clean solvents
( the plug design is supposedly self cleaning , multech2 are much improved,, ID them by the wider base spray difusser )

the main issue is batch variances ,, the 1% stuff means they are flow matched
( blueprinted )



they can have some issues fitting the primary rail locations on rotaries due to the bulky body
i find you may have to use a mazda base rubber ( or two if delete the atomiser )
to lift them so they do not foul the block with the bottom of the injector body

personally i find the best combo is 4 x 1000 marrens
,, for easy fit,, for overall price
and as they are finite enough for a normal idle,, and stage well with primitive ecu staging ( micro ) and still flow well past 400 rwhp

i have put them in a fair few cars and never had issues

however with the Rtek you probably need to keep the groupings within those sizings that suit the ecu staging

PS
some multechs don't like high fuel rail pressures and they are prone to seal shut at above 60 psi fuel rail pressures
i highly suspect these are the ones with the hi ohming motor windings

the ( 95 lb, 1000cc ) marrens i have used are fine at 15-20 psi boost
( up to 65 psi fuel rail pressures )
NB .... these are the low ohming ( 2.0 ohm ) peak hold versions

the saturated injectors dont like high pressure?? i know some gm cars with the original multecs and the multec2s run a pressure spec of 60psi nominaly +/-5psi

I have 4x1000cc Injector Dynamics Injectors and my car holds idle at 750rpms like a rock. Now thats a true testament to how precise those injectors are made that they can function perfectly at such a tiny pulse width. My tuner also recommended them, so that's another vote.

Nice. What mods you running?

yeps,, recalls seeing a display on a test bench with some GM saturated multechs where they stopped working at 60 psi base pressure
pretty sure it may be still up there on youtube ,, suspect the author is on one of these websites also

again,,
will state that the later ev1 mutechs with the wide base spray difuser and peak hold type
( the 800 and the 1000 )
don't appear ( in application on medium boosted 13bt ) to have many of the faults of the earlier GM sized multechs
( like sealing shut or burning the winding regularly )

yes, this is what IDs are, they are nothing more then "matched" bosch, no modifications done to them whatsoever. The data I think they admit to is 1:10 are slightly off from the others, so you get matched to each other not to a standard and there is no dumpster full of injectors that they reject.

been around a long time, and will continue to do so long after most have come and gone. They also sell the new style bosch injectors

There are no modification to the ID2000's. The 725's, 850's, and 1000's are modified. Here is a pic for you:

http://www.fullfunctioneng.com/tipcomparo

WTF is this 1:10 ratio you keep bringing up? I don't understand what that means... ID's are matched dynamically in batches of more than 200 injectors at a time. There is a standard and they do have waste from each and every batch that does not meet their standard. Not sure where you got that misinformation from...

Greddy injectors are rebadged Denso

Haltech e6k for engine management.
RB Rev II Exhaust, random cone intake, 255lph Fuel pump, BNR Stage 4 turbo, Stock Block, stock TMIC (yea I know...)

I was making 240hp @ 12psi (I think, it's been a while and that boost number might be wrong by a few psi) on the dyno before my engine took a shit. My tuner said I could have reached 300hp easily (around 20psi if I recall properly). I could probly make around 320-340 with a FMIC just because the intake temps were getting retarded with the TMIC. Just too much air for the thing to work properly even with ice and a fan on it.

The Injectors themselves should be good up to about 500hp before they run out of juice, so I have plenty of fuel, which is always good to know on a rotary :)

I got it from this:

maybe I read that wrong, but it seemed like you were saying that there is deviation for every 10th injector, thats 1:10 correct?

I wasnt aware of the modifications to the 1000s- can you go into more detail as to what exactly is done to them?

Do you provide the testing sheets with each pair or set of injectors? I had a pair but got them from another vendor and I didnt ask for one but it seems to be a big selling point of yours.

That chart shows how 10 randomly selected injectors match up out of a batch of 100 (unmatched and straight from Bosch). This is to show how much deviation can be present when you do a "grab bag" approach which is what that article is trying to address.

stage 4 at 12 psi :icon_no2: lol
they are way more efficient at 15+psi. Though on the tmic, that is going to be pushing it. At 17psi a stage 4 will push around 350hp

so they are then matched to each other, gotcha.

what are the modifications done to the 750s and 1000s?

if you read what I wrote, you would notice that the reason I didn't run more boost was because my engine exploded during tuning... thus the guessing at numbers and lack of a dyno sheet.

i also found some accel injectors. they also look like repainted denso injectors however...

dropped the injectors off to get flow tested, initial results are not too hot. only 5% variance 25%DC and the spray pattern of two of the injectors were garbage

They don't go through much trouble to re-badge them, mine still have the desno part # in plain sight.

so do the injector dynamics come peak and hold or all saturated

any idea on trickflow fuel injectors? I know trickflow is a big name with the mullet heads (mostly ford guys) and there products like aftermarket heads/intake quality enough to use on their race cars.

Injector Dynamics are all saturated.

not going standalone any time soon soooo ID is out =[

Rtek 1.8 will handle id 720cc injectors, or any 720 injectors, as for 1000cc, I dont see why not it wouldnt work, it should. Its within the safc adjustment range.

I agree. The only reason not to go with ID injectors imo is cost.

if you're poor, then get something else. But I went ahead and spent the extra ($460 for new 4x1000cc) and never looked back. They even have the added benefit of using different o-rings that are much thicker and stronger to reduce fuel leaks. I know I have had a lot of issues with tearing those damn injector o-rings and getting fuel leaks on my LIM. Maybe I'm the only one, but that was a big plus for me.

also, I know I sound like a spokesperson for ID or something. I'm not. I'm not affiliated with them in any way. I just like their product.

EDIT - you will be able to tune out the extra fuel from bigger injectors using your SAFC easily. I know because I've done it.

s4 car bros, peak and hold injector drivers

remove the resistor pack...

the drivers are not the same, especially if you examine the wave form on a scope.... removing the resistor pack would not solve this problem......

whats up with the "5" under my screen name lol?

It will work. If it works for countless others with no problem, it will work for you.

.... knowing what i do about how injectors work and the differences in how the drivers wave forms are it seems like a poor idea. The accuracy of the injector timing and duty cycle would become compromised, IE run like garbage...

generally the difference is unnoticable.

*shrug*

Seems like one of those things that "matter" on paper, but not so much in real life....kinda like pulsation dampeners.

yea wtf? Sharingan has one too

I want one!

... I think... unless they mean something bad lol

EDIT - actually a lot of people have them... wonder what that's all about

its a 5 year member ship thing, I want my 10 year next year!!!

is it?

*looks at his join date*

fuwaaaa


owning the same rx7 for 5yrs should earn somthing....