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Hi, i know there are many injector questions, so this post would help some get their questions answered. My question is whether 440 is large enough, and if 550 is overkill for N/A applications. Help me! :dontknow:
 

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Bluewind said:
Hi, i know there are many injector questions, so this post would help some get their questions answered. My question is whether 440 is large enough, and if 550 is overkill for N/A applications. Help me! :dontknow:
440 IS PERFECT IF YOU WANT TO STAY N/A , BUT IF YOU EVER WANT TO GO NOS OR EVEN TURBO/SC THEN YOU MIGHT AS WELL GET THE BIGGER ONES .. YOUR GONNA NEED THE K PRO TO TUNE IT PROPERLY AND SOME M&H SLICKS TO GET YOU DOWN THE STRIP :thumbsup:
 

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NSTLLMNGR said:
440 IS PERFECT IF YOU WANT TO STAY N/A , BUT IF YOU EVER WANT TO GO NOS OR EVEN TURBO/SC THEN YOU MIGHT AS WELL GET THE BIGGER ONES .. YOUR GONNA NEED THE K PRO TO TUNE IT PROPERLY AND SOME M&H SLICKS TO GET YOU DOWN THE STRIP :thumbsup:
who makes the injectors??are they peak hold injectors??or saturated??
 

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ECU Tuner
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Bluewind said:
Hi, i know there are many injector questions, so this post would help some get their questions answered. My question is whether 440 is large enough, and if 550 is overkill for N/A applications. Help me! :dontknow:
The 440s and 550s offered for the RSX seem to come from RC Engineering, which offers those two sizes in its saturated injector lineup, so I think that is the technology used.

As for what size is large enough, that's one for the performance experts out there, like Jackson or Hondata.

There are many formulas and rules of thumb out there as to what size injectors are adequate for an engine. I think the stock Type-S uses 310 cc injectors. One rule of thumb I saw somewhere was to divide the flow figure by 5 and then multiply by the number of injectors to get the maximum hp capability of a setup. 310/5 = 62 times 4 = 248. By that same rule, 440s would be adequate up to 352hp. If we assume those are flywheel hp and assume a 15% loss to the wheels, the max numbers for those two injectors would be 210 and 300 wheel.

Some of the injector calculators out there seem more conservative. Injector.com's calculator, assuming industry standard values, suggests that 440s would be good for about 268 hp and the stocks only about 190. If that is wheel hp, and my guess it is, it might explain why engines approaching 200 whp tend to get a bit lean. 550s, on the other hand, would be good for up to 330 whp.

Some sources also suggest that simply getting larger injectors is not always the best idea unless they are a) needed and b) properly matched to corresponding ECU programming. Which gets you back to trusting the experts who know all the exact definitions and how they apply to real world situations.

From what I can tell, the stocks are good for perhaps 20% more power. Anything above that would appear to require larger injectors (though higher fuel pressure might extend the stocks a bit). I'd say that any NA app should never need more than 440s (though Nitrous might, I am not familiar with it), and 550s would definitely be gross overkill for NA.
 

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No one interested in this topic? I think it's quite relevant and I wish someone who truly knows this stuff would join the discussion and provide some definite answers. In addition to the issues raised above, I also wonder

a) what would be involved in getting peak&hold injectors, what their benefit might be, and

b) whether 370cc injectors might not be a good compromise for those who are getting close to maxing out the stock 310s but don't need the 440s. (After all, MSD Ignition states, "If the induction system has been left stock and the ECU cannot compensate for the increased fuel volume, unburned fuel will all but pour into the exhaust.")

c) MSD Ignition further states, "if you make slight changes to your engine combination you may be able to compensate without having to replace all of the injectors by increasing the fuel pressure," so it'd be interesting to know in which scenarios increased fuel pressure might be a better solution than replacing injectors.
 

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Honda4Ever
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I think this is a very relavent topic, although I have no prior knowledge of said topic, I would like to know how to upgrade my fuel system properly.

I currently have Hondata #4, I/H/HFC/E and would like to get Toda someday.
 

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Larger injectors aren't a basic performance mod -- you'd have to be pushing the limits of your current set to warrant an upgrade, and you'd need an ECU program that takes advantage of it. Just dropping a set of 440s onto a Toda kit will not affect anything.

Usually you only hear people talking about upgrading them for FI setups, in which case the correct size usually comes with the kit. There's been talk lately of JRSC with 550s because they've been modifying the kit to push more boost with a new pulley. I believe Hondata said that 550s were good through 9 lbs. CyberNation would probably also have information about that, but if you had their kit, they'd include the correct size, so it wouldn't be an issue.
 
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