Stock NA1 motor...who is running anything OTHER than OEM fuel injectors?

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I have a stock C30A. I am looking at all these posts (very informative) about the topic but they seem to be older and I presume potentially outdated.

Is anyone else running non-OEM injectors and if so, will you please share the results?
 
So, what I (think) I have learned (thanks Larry, Honcho and others) is that if I am unwilling to reprogram my engine management system, then I am limited to stock injectors. That lead me to see where I could find a second or replacement set.

As I cross-reference injectors (OEM, 240cc) on various sites, I see that quite a few Acura's use the same injector. Can that really be true? If other models use the same injector, does that mean that one could buy a set from another vehicle (i.e. not pay the NSX tax) and use them? Surely spray patters do not differ if the part number is the same.
 
So lets just double check to confirm: injectors have nothing to do with how much horsepower you will achieve. They are only sized to match the airflow, which we could call the end result as an, air fuel ratio.

My point is simply this. Throwing fuel by itself at an engine is not enough to significantly raise your horsepower output. Oh sure it will change, but it could go up OR down, and it will not go up much at all ultimately (you might gain 2% or 15%, but if you want real increase like 100% or 200% it will not happen with fuel by itself)

You need the airflow. You need to work on the airpath. Think of breathing in and exhaling. Air follows the same path in as it does out into the lungs. But this is not true for engines. You have one side dedicated to the intake and one side dedicated to the exhaust. If you put an air filter over your face you expect to breath cleaner air but it may also be harder to draw breath also. The idea of cleaning the air is a great one for both humans and engines of course, but the way it is done can have an effect on performance. Now imagine that instead of breathing through a filter on your face, you install air filters into the ROOM in which you reside, which is also perfectly sealed otherwise, such that only filtered air can enter. You will no longer notice a difficulty breathing, because filtered air is being offered to you the same way it would have been if the filter wasn't there. This would be like installing a large box with enormous filters around another small cone filter feeding the throttle body. There are rates, numbers, but I want to apply a variable to any situation, such as a cruise ship engine, so try to imagine how air would behave differently if you moved much more of it using larger tunnels. Think now of the engines airpath in the head, that is, the port leading right up to the combustion chamber. The Intake runner of the head. If the human lung is the combustion chamber, then that intake runner is the trachea. If the lungs did not have to deal with the next 90* turn of the pharynx and mouth then it would be easier to get air into and out of the lungs, just like an engine where the intake manifold and throttle body are necessary and also have turns for the air. ( and the nose is a pseudo air filter device, but we also filter our air with by other means such as trapping particulate with sticky saliva.) The amount of air necessary for life determines the size and shapes of all the tubes, such as the trachea, imagine if your trachea was twice its size now. The air would move slower but you might breath easier, especially if your air requirement suddenly increased due to exercise. When you exercise you breath "harder" because your demand for air has increased. This would be like installing a better camshaft on an N/A engine. The air is the same density as before but now we need more of it, we can top the cylinders off and increase our VE. To increase VE is the reason for the camshaft swap. A supercharger by itself is able to compress air, but that compression only happens because it is trying to move more air into the engine than the engine needs to be at same place it was when naturally aspirated (when the atmosphere was the only pressure). The difference in pressure between the port leading up to the head (intake runner in the head) and the difference in pressure inside the cylinder when the valve opens is what drives the air molecules into the cylinder, whether supercharged or not. In fact if you think backwards through the airpath, you will notice that the atmosphere is still the ultimate reason air molecules get into the engine, since the atmosphere is feeding the compressor wheel of the supercharger. Also, if we enlarge the intake manifold, the air can be adjusted to move the same rate as before we did anything. Air molecules have a weight, and are subject to invisible forces such as sound, and these properties are often engineered into the factory intake equipment you see on a vehicle, taking advantage of the weight of air molecules to time the valves with respect to the piston to fill the cylinders as much as possible at any given RPM. This is the number we measure as volumetric efficiency "VE". A 100% VE means you are filling the cylinder completely with fresh air molecules. By timing the valves right you might attain an even higher number, think of a tunnel ram or GM's Tuned Port Injection (85-92 technology). Honda especially has done a great job designing engines that do this sort of thing, and many of their engines already produce 100%VE+ with OEM equipment. This is why I do not think it is necessary to play with the OEM air path much, if at all. The only real option you have once the engine's VE is already nearly 100% is increase air density (more air molecules per unit volume).
 
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So lets just double check to confirm: injectors have nothing to do with how much horsepower you will achieve. They are only sized to match the airflow, which we could call the end result as an, air fuel ratio.

My point is simply this. Throwing fuel by itself at an engine is not enough to significantly raise your horsepower output. Oh sure it will change, but it could go up OR down, and it will not go up much at all ultimately (you might gain 2% or 15%, but if you want real increase like 100% or 200% it will not happen with fuel by itself)

You need the airflow. You need to work on the airpath. Think of breathing in and exhaling. Air follows the same path in as it does out into the lungs. But this is not true for engines. You have one side dedicated to the intake and one side dedicated to the exhaust. If you put an air filter over your face you expect to breath cleaner air but it may also be harder to draw breath also. The idea of cleaning the air is a great one for both humans and engines of course, but the way it is done can have an effect on performance. Now imagine that instead of breathing through a filter on your face, you install air filters into the ROOM in which you reside, which is also perfectly sealed otherwise, such that only filtered air can enter. You will no longer notice a difficulty breathing, because filtered air is being offered to you the same way it would have been if the filter wasn't there. This would be like installing a large box with enormous filters around another small cone filter feeding the throttle body. There are rates, numbers, but I want to apply a variable to any situation, such as a cruise ship engine, so try to imagine how air would behave differently if you moved much more of it using larger tunnels. Think now of the engines airpath in the head, that is, the port leading right up to the combustion chamber. The Intake runner of the head. If the human lung is the combustion chamber, then that intake runner is the trachea. If the lungs did not have to deal with the next 90* turn of the pharynx and mouth then it would be easier to get air into and out of the lungs, just like an engine where the intake manifold and throttle body are necessary and also have turns for the air. ( and the nose is a pseudo air filter device, but we also filter our air with by other means such as trapping particulate with sticky saliva.) The amount of air necessary for life determines the size and shapes of all the tubes, such as the trachea, imagine if your trachea was twice its size now. The air would move slower but you might breath easier, especially if your air requirement suddenly increased due to exercise. When you exercise you breath "harder" because your demand for air has increased. This would be like installing a better camshaft on an N/A engine. The air is the same density as before but now we need more of it, we can top the cylinders off and increase our VE. To increase VE is the reason for the camshaft swap. A supercharger by itself is able to compress air, but that compression only happens because it is trying to move more air into the engine than the engine needs to be at same place it was when naturally aspirated (when the atmosphere was the only pressure). The difference in pressure between the port leading up to the head (intake runner in the head) and the difference in pressure inside the cylinder when the valve opens is what drives the air molecules into the cylinder, whether supercharged or not. In fact if you think backwards through the airpath, you will notice that the atmosphere is still the ultimate reason air molecules get into the engine, since the atmosphere is feeding the compressor wheel of the supercharger. Also, if we enlarge the intake manifold, the air can be adjusted to move the same rate as before we did anything. Air molecules have a weight, and are subject to invisible forces such as sound, and these properties are often engineered into the factory intake equipment you see on a vehicle, taking advantage of the weight of air molecules to time the valves with respect to the piston to fill the cylinders as much as possible at any given RPM. This is the number we measure as volumetric efficiency "VE". A 100% VE means you are filling the cylinder completely with fresh air molecules. By timing the valves right you might attain an even higher number, think of a tunnel ram or GM's Tuned Port Injection (85-92 technology). Honda especially has done a great job designing engines that do this sort of thing, and many of their engines already produce 100%VE+ with OEM equipment. This is why I do not think it is necessary to play with the OEM air path much, if at all. The only real option you have once the engine's VE is already nearly 100% is increase air density (more air molecules per unit volume).

Thank you for the thoughtful response, Kingtal0n. I should have made myself clearer.

I am looking to see if there are other injectorsbeside OEM that I can use for my normal, daily-driving use. I have no desire to increase or amend performance, efficiency aside.

I am trying to save a buck or pay similar money and get the best quality I can. I just want to know what my alternatives are.
 
you might consider cleaning and calibrating your oem ones. i had this done as part of a mechanical refresh,and they improved the spray pattern,two were just dripping.it was done here-
http://www.rceng.com/
 
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And that I would say stick to OEM. When you change to another injector manufacturer, there are variables inside the injector, such as resistance, latency, and overall design, including performance of the nozzle and any number of other variables that may change. That means your OEM computer and sensors are no longer working to fuel the engine the way it was from the factory, since the injectors will not perform similar to factory injectors. They might perform close enough that you will not notice a difference, but just like the intake manifold in your vehicle, if you change it to something else, it still might work with the OEM equipment, but performance overall will not be optimal without additional tuning. And even if you did "tune" the engine, who is to say that it will ultimately perform better? Lets say you found a superior injector that offers a finer atomization and your fuel injector duty cycle drops .2% across the board because less fuel condenses on the cylinder walls at lower rpms (pretend the oem injector had poor atomization). How will you even notice unless you performed hours of data-logs prior to the installation of the new injectors?
 
And that I would say stick to OEM. When you change to another injector manufacturer, there are variables inside the injector, such as resistance, latency, and overall design, including performance of the nozzle and any number of other variables that may change. That means your OEM computer and sensors are no longer working to fuel the engine the way it was from the factory, since the injectors will not perform similar to factory injectors. They might perform close enough that you will not notice a difference, but just like the intake manifold in your vehicle, if you change it to something else, it still might work with the OEM equipment, but performance overall will not be optimal without additional tuning. And even if you did "tune" the engine, who is to say that it will ultimately perform better? Lets say you found a superior injector that offers a finer atomization and your fuel injector duty cycle drops .2% across the board because less fuel condenses on the cylinder walls at lower rpms (pretend the oem injector had poor atomization). How will you even notice unless you performed hours of data-logs prior to the installation of the new injectors?

Bingo
 
And that I would say stick to OEM. When you change to another injector manufacturer, there are variables inside the injector, such as resistance, latency, and overall design, including performance of the nozzle and any number of other variables that may change. That means your OEM computer and sensors are no longer working to fuel the engine the way it was from the factory, since the injectors will not perform similar to factory injectors. They might perform close enough that you will not notice a difference, but just like the intake manifold in your vehicle, if you change it to something else, it still might work with the OEM equipment, but performance overall will not be optimal without additional tuning. And even if you did "tune" the engine, who is to say that it will ultimately perform better? Lets say you found a superior injector that offers a finer atomization and your fuel injector duty cycle drops .2% across the board because less fuel condenses on the cylinder walls at lower rpms (pretend the oem injector had poor atomization). How will you even notice unless you performed hours of data-logs prior to the installation of the new injectors?


Interesting.

Thanks for the follow up.

One follow up question then. The injectors I see from tuner shops, the ones that claim to be OEM and fit a cross-section of other models...if those all have the same part number, I should be in good shape. Right? At that point, I have an injector that is rebuilt and calibrated as well as being OEM for 1/5th the price.
 
Silly questions, but that little plastic-esque part at the end of the injector (at the nozzle)...if that breaks, I am toast, right? At least for that injector? One of mine, after removal, was so brittle it cracked and i could easily snap off part of that end part.
 
+ 1000 on the injectors. Have them cleaned or replaced, not upgraded. I only know from those who post here and not from a personal experience. Save your money for a ctsc or a turbo kit if looking for more umph.
There should also be a wealthy stock of Oem injectors in many of our garages from upgraded fuel systems. Why not post a wtb part thread. It does wonders.
 
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If you are using the stock PR7 ECU, then please stick with the factory 240cc injectors. The start, cold cycle and idle trims are carefully calibrated by Honda from 100's of hours of testing for those injectors. Using anything else will virtually guarantee starting, idling and running problems. You can get other injectors to work, but so far no tuner has been able to replicate Honda's reliability. The best advice is to have them cleaned and balanced by a company like RC Engineering. You will not believe the difference in idle, starting and VTEC with fresh injectors. I did it ~ 90,000 miles and am kicking myself for not doing it earlier.

If you go with an aftermarket ECU, this opens up your choices for injectors. A big favorite would be the RDX 410cc. I would only upgrade injectors if you are contemplating more than bolt-on mods.
 
If you are using the stock PR7 ECU, then please stick with the factory 240cc injectors. The start, cold cycle and idle trims are carefully calibrated by Honda from 100's of hours of testing for those injectors. Using anything else will virtually guarantee starting, idling and running problems. You can get other injectors to work, but so far no tuner has been able to replicate Honda's reliability. The best advice is to have them cleaned and balanced by a company like RC Engineering. You will not believe the difference in idle, starting and VTEC with fresh injectors. I did it ~ 90,000 miles and am kicking myself for not doing it earlier.

If you go with an aftermarket ECU, this opens up your choices for injectors. A big favorite would be the RDX 410cc. I would only upgrade injectors if you are contemplating more than bolt-on mods.

Thanks for that feedback Honcho.

I actually had RC do my injectors and the ones I was referencing above had one with a pintle cover broken (old set). I called RC and they are able to fix this one. So, off to the FS board and list them as ready to be rehabbed!

As to larger injectors, etc. I am staying stock. I put my refreshed ones in and the car leaps out of the ground at starts. :)

As an aside, I bought a car (parts car) that had an SoS ECU, one of the first models done with flash chip technology. SoS rep claimed I could plug and play and get up to 10whp with stock setup. Does that sound right?
 
As an aside, I bought a car (parts car) that had an SoS ECU, one of the first models done with flash chip technology. SoS rep claimed I could plug and play and get up to 10whp with stock setup. Does that sound right?

Yes and no. :) The problem with chips on the NSX is that each engine is hand-built. The build variance between engines is often more than +/- 10 whp, so depending on your engine, the SoS chip (or any other chip for that matter) may not do anything at all. From an anecdotal standpoint, this has been confirmed over the years by owners whose experiences have run the gamut from "oh my god it's so much faster" to "I dynoed it and I gained 1 hp." That is why I recommend in-person tuning on the factory ECU. For example, if you can find him, Brian from Propseed can tune your car and your specific engine to gain power on that specific configuration. In that instance, you are looking at more like + 20 whp and tq. I was going this route before I sold my NSX (and now I'm tuning my GT-R on a Ecutek lol).

Now that Matt (sr5guy) has released the full cracked PR7 ecu definition, hopefully some more tuners will start offering factory ECU tuning services.
 
I am one of many on NSX prime who have upgraded to the Honda RDX injectors buying the kit provided by Prospeed that includes a remapped chip with adjusted fuel delivery (injector pulse widths/fuel map). Pretty much everyone who has done this has seen a modest but definite gain in torque and power across the full rev range. For example here are my before/after dyno charts...

The reasons behind the improvements is the finer atomization of the fuel due to the many tiny holes in the RDX injector head, and the alignment of the rdx injectors spray profile just happens to align particularly well to the NSX combustion chamber ...

My engine is otherwise a stock NA1 except for GTLW exhaust and Top Speed headers

BTW I did an injector clean just before the first dyno run. small improvement, but nothing compared to RDX improvement
 

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I am one of many on NSX prime who have upgraded to the Honda RDX injectors buying the kit provided by Prospeed that includes a remapped chip with adjusted fuel delivery (injector pulse widths/fuel map). Pretty much everyone who has done this has seen a modest but definite gain in torque and power across the full rev range. For example here are my before/after dyno charts...

The reasons behind the improvements is the finer atomization of the fuel due to the many tiny holes in the RDX injector head, and the alignment of the rdx injectors spray profile just happens to align particularly well to the NSX combustion chamber ...

My engine is otherwise a stock NA1 except for GTLW exhaust and Top Speed headers

BTW I did an injector clean just before the first dyno run. small improvement, but nothing compared to RDX improvement

Sparky, did you have any issues with startup once you installed the RDX kit? I installed it yesterday and am getting no power at the injectors. I talked with Brian and hes sending me another chipped ECU thinking thats the problem. Im wondering if there is anything else to check? This is what we did, car woudnt starts, put a meter on the injector wires and got no reading. Sprayed a little starter fluid in the intake and car started so I know its fuel at the injector or in path to.
 
Sparky, did you have any issues with startup once you installed the RDX kit? I installed it yesterday and am getting no power at the injectors. I talked with Brian and hes sending me another chipped ECU thinking thats the problem. Im wondering if there is anything else to check? This is what we did, car woudnt starts, put a meter on the injector wires and got no reading. Sprayed a little starter fluid in the intake and car started so I know its fuel at the injector or in path to.

the ecm only only controls the ground side of the injectors, the power is supplied through the resistor bank, and is always present (assuming a good main relay)
 
The only issue I had was my fault, I didn't follow instructions properly for the resistor and had a rough idle problem. Fixed it easy enough when my brain was back in gear. In general ECU faults are rare, so I would double check everything - again.
 
My RDX kit had a rough idle at times but very rare, some others reported it a lot more often. I have since gone for an aftermarket ECU and when we installed that we connected it to the existing loom so I could always reverse it if needed and we found quite a few pin-outs were loose when we grabbed the loom while the car was idling and it made the car hunt like the idle issue, so we tightened them all up and have not had an issue with the new ECU but we believe we would have had we not found those lose connectors.
 
I think some people here are taking huge risks by having an ecu tuned off site for 10 hp give or take. There are a lot of "things" that can go wrong here. Just my opinion. I prefer to keep my cars brain Oem and not feed it drugs. But to each his own. All mods are cool in my book. I just read far more problems with this mod then good.
 
... we found quite a few pin-outs were loose when we grabbed the loom

can you explain a little more about loose pins scammy, and how you tightened them. I assume you mean pins in the 4 large connectors that plug into the ECU? I don't see how can they can be tightened ... ??
 
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can you explain a little more about loose pins scammy, and how you tightened them. I assume you mean pins in the 4 large connectors that plug into the ECU? I don't see how can they can be tightened ... ??
Yep those are the ones coming from behind your right ear (RHD) its a very tedious job you have to de-pin (pull them out of the plastic plug) and press the tab down with a pick (like a minature ice pick) and then plug them back in they will be firmer in the hole now. we tested it a few times and whenever we grabbed the plugs we got the idle hunting up and down after we did this she was solid so installed the new ecu into our old loom
 
Thanks for that ... although I'm surprised they come loose at all, and also surprised you managed to extract them without a special tool.
Connector pins are usually held in by a one-way "barb" that lock the pin into place on insertion, and each barb would need to be pushed back, in a *very* tight space, to permit removal. Perhaps these pins lock in place differently? I'd better have a closer look!
 
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I found in my car my EGR wire contact would not grip the pin in the ECM, thus a CEL for the EGR system. You test it with a spare pin and see if it is grips the contact and is not loose. I had to replace that contact. The Miata uses the same connector so I had plenty new contacts on hand. I also replaced the connector shell. To remove the contact, you open the back hinged cover, use a very small straight screw driver insert from the front next to the contact (not in it, this will damage it) turn 90*, pull the wire/contact out from the back. To reinsert, just push it back in until lit clicks in. Test it by gently tugging on the wire, it should not come out.

here is is a photo during the shell change.

image.jpg
 
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