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injector opinions (yes i searched)

Posted: June 20th, 2007, 11:35 pm
by mazdax3speed
so i saw the equation of (HP*.55)/# of injectors then times 10.5=injector cc
but that seems way to low for me

i have a tubular manifold, going for a GT28r, have 3" turbo back exhaust and SAFCII, shooting for 240-250whp. Somebody had recommeded getting RX7 550s, but everbody on here seems to say that is to much, and maybe DSM 450s are better. is this true, and if so do they fit the BPT fuelrail, im not looking to get my fuel rail boared out like the nissian injectors

thanks, i did use the search but its so broad as to what everybody seems to be running,

Posted: June 21st, 2007, 4:53 pm
by Mnemonic
u dont need 550s to run 250whp use teh dsms

Posted: June 21st, 2007, 10:03 pm
by mazdax3speed
ive pretty much decided on the DSMs after looking at some more setups, im just still curious if they fit the stock fuel rail (BPT) or if i have to get the fuel rail boared out or somthing. but i guess ill figure out once i buy um

Posted: June 22nd, 2007, 4:52 pm
by Mnemonic
they will thats what justin is using i believe

Posted: June 23rd, 2007, 12:09 pm
by mazdax3speed
thanks, im pickin some up today

Posted: June 24th, 2007, 2:57 am
by Limegreen mx-3
i say go with 550cc in the long run since in my opinion u have such a small whp range 550 will get u there no problem. 440 will get u at ur set goal but if and in by any change u want a lil more u'll end up buying another set of injecters why spend double the cash.

on my setup i bought 550cc but realize i wanted more power and well bought 880cc know i want even more and im again buying 1000cc injecters. i plan on makeing a 600whp mx-3 she be a trailer queen. thats thats about 900 i spend on just injecters if i had just bought the 1000 in the first place i could be spending that wasted money on other parts. (note) i am running with a standalone system so i can control 1000cc injecters on my setup. i have a 450whp street setup goal.

DSM and mazda injecters are roughly the same i belive i have the mitsu 880cc on my mazda fuel rail.

Posted: June 24th, 2007, 10:25 pm
by mazdax3speed
^^thanks for the info, im only tuning on SAFC2 i might have already setup some DSM injectors, but i have 2 TurboII friends who use 550s, and both cars happen to be down...and will be down for a while, so i can snag those if need be and resell the DSMs
i appreciate it, i really wanted to make sure they fit tho first, and it seems like they do

Posted: June 25th, 2007, 8:27 pm
by JWMotorsports
440's are pushing it on that turbo with only a S-AFC. We had a MX-3 with a BP, small Mitsubishi 16G, S-AFC with Miata RC 440cc injectors, and BP ECU. I belive we ran out of fuel at only 10psi of boost. The reason is your still limited to the stock ECU's injector control range and you won't get an honest 50% control range...annother words your 440cc injectors will be limited. The only solution you can get to idle with out washing the cyl walls is a standalone and big low impedance injectors. That is the other thing you need to measure. The stock ECU can only run high impedance injectors and if you hook DSM injectors to it with out the resistor box you may fry your injector drivers on the stock ECU as I believe the DSM injectors are low impedance.

High Impedance is 12ish ohms or higher resistance
Low Impedance is below 10ish ohms

Posted: June 29th, 2007, 1:44 am
by mazdax3speed
i guess that leaves me with the 550s, but 87-88 and 89-91 are different. one style is low and one is high, im not sure which is which yet tho (talking RX7s) it seems like with these my idle will suck beyond belief on SAFC but that ultimately itll be all good uptop and ill be free to crank the boost

Posted: July 11th, 2007, 4:08 pm
by mazdax3speed
im going with RC 550cc's

thanks for the help

Re: injector opinions (yes i searched)

Posted: March 26th, 2008, 1:24 am
by RS_OBD'oh_2
Sorry to jump on your thread here.... I was just wondering if these bad boys would work out ok? They are Hi Z 370cc for the dsm. This would save a guy over 100 bones by not going to RC, and no hassle with the resistance box.

(For the B6 Dohc)
Any info would be great, Thanks.

Edit: Just found 410cc... was not aware they existed.
http://cgi.ebay.ca/Accel-40lb-410cc-Fue ... dZViewItem" onclick="window.open(this.href);return false;

Re: injector opinions (yes i searched)

Posted: March 26th, 2008, 10:41 pm
by RS_OBD'oh_2
So, I'm still unsure of what the deal is. I see many BP guys using the DSM injectors... but as far as I can tell we need to splice in the DSM injector clips, is this correct or no?

Re: injector opinions (yes i searched)

Posted: March 27th, 2008, 7:10 pm
by nos92mx3
in order to run a dsm injector in our cars you need to install an inline resistor to each injector or grab a resistor box from an early (?) 90's honda.
You can go to radio shack and grab the resistors..
get like a 10 watt 10 ohm resistor, shouldnt be more than a few dollars

Re: injector opinions (yes i searched)

Posted: March 28th, 2008, 9:13 am
by RS_OBD'oh_2
nos92mx3 wrote:in order to run a dsm injector in our cars you need to install an inline resistor to each injector or grab a resistor box from an early (?) 90's honda.
You can go to radio shack and grab the resistors..
get like a 10 watt 10 ohm resistor, shouldnt be more than a few dollars
Oh, sorry dude. I must not have been typing what I was thinking. These 410cc and 370cc injectors that I listed above are not low resistance. I was just asking if the clips need to be replaced or not.

Re: injector opinions (yes i searched)

Posted: March 28th, 2008, 8:06 pm
by nos92mx3
hmm my oem mazda injectors fit onto a dsm injector with a bit of a push, i dont see a problem using the stock ones...