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How big of an injector will I need?


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Guys' date=' ive been told my 420s will be too small for my hp goals. My goals are an extremely lofty 400hp. I would like to have injectors that will support that plus some, i dont like doing things twice. I am also prepared to do the oring fuel rail thing.

 

Thanks guys - Evan[/quote']

 

My 370s are supporting something close to 350hp, or 313 at the wheels. Of course, I don't know for sure what my duty cycle is currently, or if my corrected dyno numbers are close. But I am running 12:1 a/f ratio, so unless you plan on drowning your engine in fuel, 420ccs should get you 400 hp to the crank easily.

 

Shane ran high 11s at 118mph in his 240 with the 420cc injectors and the JWT setup. Not sure what his race weight was, something like 2600lbs...

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Hey Even Gabe here From Mobile.. Ivans friend. Well J taylor on this site dynoed his Z at 388 RWHP with 370cc injectors. I think that was about maxing them out though. So I am thinking that 420s should do you fine for 400 RWHP. Are you going down with Garret and Ivan for the event? I met you at the montgomery event. I am actually about 80% done with turboing my Z.. I cannot wait to have boost.. Take care man. Hope to see ya soon.

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Just thought I'd chime in on this one since I've been doing the research too...

 

To get a rough idea of fuel flow and horsepower available from the injectors, it's not hard to figure out. Use this equation:

 

Number of Injectors X Flow in Pounds, divided by 0.55 (represents approx 85 % duty cycle)...

 

i.e. Using Ford 42# injectors...which happen to be 418cc/min...you would get

 

42x6=252 ... 2520.55=458.18181... Therefore:

 

Ford 42# injectors (418cc/min) would yeild a possible 458 hp @ 100% Duty Cycle...of course these numbers are RAW and not gospel, but they'll get you close enough.

 

Hope it helps.

 

For a quick reference chart, go to SDS EFI TECH PAGE

Warren

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yeah, what custom lock said! when your putting injectors on a 6 cylinder, a general rule of thumb is that what ever size injector you have is how much horsepower they will safely support. Its pretty crude, but as you can see by the formula, thats about how it goes. If you wanted to be on the safe side, get some DSM turbo injectors, I beleive they are 450cc. should be enough for a little extra cushion as well...

 

McAdam

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early RX7's from a N/A motor are 460CC low ohms. 11mm O-ringed at the top and you will have to drill out the intake for the tips but, it's nothing major at all. you will do best with a custom rail for the O-ring type of injectors. i have heard of ppl clamping hose on them but, that's just not the way i work.. good luck.. pallnet

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early RX7's from a N/A motor are 460CC low ohms. 11mm O-ringed at the top and you will have to drill out the intake for the tips but, it's nothing major at all. you will do best with a custom rail for the O-ring type of injectors. i have heard of ppl clamping hose on them but, that's just not the way i work.. good luck.. pallnet

 

 

I use these exact RX7 injectors. The Nippon Denso p/n is 195500-1350.

 

I had them cleaned and flowed prior to putting them on my car. They actually flow 440cc at at 43.5psi fuel pressure. For some reason everyone thinks they are 460cc.

 

Instead of drilling my intake I just took some 80 grit sand paper and sanded a few thousands off the plastic pintle caps and they slid right in. Before I made my o-ring fuel rail I did use the hose clamp method. :oops:

 

It's worked well until I got sick of looking at the old fuel rail.

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Jamie T, here's a link that has some decent injector information. As usual my injector p/n 195500-1350 is listed as a 460cc. As I mentioned above, it tested at 440cc at 43.5 psi.

 

http://www.rotaryresurrection.com/injector.html

 

http://www.robietherobot.com/storm/fuelinjectorguide.htm

 

I may be selling mine to upgrade to 680cc injectors if anyone is interested.

 

Regards,

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