Actually talking to a company that makes custom flow injectors. I sent them an used OEM injector and they are seeing what can be done to remanufacture it to higher flow levels. If they are not able to increase the flows and still retain OEM like spray patterns, performance and reliability they have OBDII and OBDI B-Series Honda injectors that they currently sell that flow up to 650CC. I am pretty sure the RC injectors are OBDI B-Series fitment (which requires the spacers and OBDI connectors). These would require the spacers on the fuel rail - but should use the OEM S2000 OBDII connectors.

Once I move to larger injectors I will still retain the supplemental injector as a small amount of fuel injected into the air stream prior to the plenum serves as an evaporative cooling charge.

 

Very nice with the upgraded stock injectors.

Sending them 4 OEM injectors and getting 4 flow matched injectors with the same reliability and increased performance over stock

What is the price to upgraded an OEM injector

You are correct on the fuel rail spacer and injector plugs for RC injectors.

 

Just got off the phone with J&S

There timing box is not currently compatible with the S2000 unless the car is rewired to a wasted spark system.


Wonder if this can be done at the ECU harness

 

What is the benefit of increasing the 4 main injectors vs using a bigger 5th injector? Have you found a problem with using a bigger (800-1000cc/min) 5th injector?

If you increase the 4 main injectors, will you have to expand the injector map to cover the entire rpm/pressure range? Using the OEM injectors you are only have to map the area under boost.

 

The scaling ability inside the ULT allows you to use a larger injector and the ULT will scale back the pulse width.

So before you even start changing maps the car will run as though it has stock injectors.


In other words

You upgrade your injectors 20% larger then stock
once you have inputted the values for your stock injectors and what size you are currently running the ULT will scale back the inputted pulse width by 20% before any maps are applied for the output.

Hope that made sense


The advantage to using 4 larger injectors instead of a supplemental is a more accurate air fuel mixture to each of the cylinders.

Using a larger supplemental injector at the TB can lead to a situation where the fuel is not uniformly mixed in the intake plenum so each cylinder does not get the same amount of fuel.

Disadvantage to using 4 larger injectors instead of the supplemental setup is the supplemental setup adds added cooling due to longer evaporated cooling effect.

 

As Mark stated - there is a larger risk of not getting equal fuel to all cylinders. I am also told that the larger flow injectors do not atomize the fuel as well once they get over 600-700 CC.

Still not ruling out the larger supplemental injectors but want to look at larger OEM injectors also.

Mark - not sure what the price will be on the injectors. Their B Series Honda 525cc OBDII injectors are $299 a set.

 

Correct me if I'm wrong, but the S2000 injectors are not single pintle style right? They have several smaller holes? Who even makes higher flow injectors of that style?

 

I can see where large amounts of fuel through the supplemental injector might be more difficult to distribute evenly. On my set up right now, about 25% of the total fuel delivery (@7500 rpm & 10 psi boost) comes from the supplemental injector. Not sure if this is causing any problems but I am seeing some inconsistency in AFRs.

What horsepower are you targeting and what is the total injector capacity you think it will take?

 

I will be going for 330whp with 550's for now

340-345 when I change out the exhaust.

They should be sufficient for now, if it becomes necessary to increase the total pulse with to over 85% I will run up the fuel pressure a small bit.


I prefer to use a smaller injector with a higher fuel pressure instead of automatically bumping to the next available injector size.

 

where is this at ? I figured it would have been released already.