Yellow Streak

Well, to clarify, I mean 380 CC at 46 PSI. I was told that the stock Honda injectors are 330 CC at 46 PSI or 360 CC at 60 PSI (which is what RC tests them at). If you compare apples to apples, a set of RC 440 CC injectors would only flow 385 at 46 PSI (if the calculators on the internet are correct).

I have no idea what the Comptech FMU has as a base fuel pressure. If it is 60 PSI when seeing no boost, then they would flow 440. I haven't heard of anybody that could tune out enough fuel at idle with 440s to make the car idle properly. It may be possible if you set the narrow throttle settings low enough and pull out a ton of fuel, but I am looking for a simpler installation/tune.

I am looking for an injector that is slightly larger than stock so I don't need to run as much fuel pressure. And, before anybody gets into a rant about AEM/larger injectors versus V-AFC and FMU, I am not changing to an AEM and big injectors for a motor running 7 PSI. There is no need for the investment in time or money. The car runs great and is tuned very well. My only goal is to reduce the amount of fuel pressure necessary to make it run as well as it does now.

-YS

Jenner

I'm running stock fuel pressure with my 755cc injectors and the AEM EMS is pulling out fuel at idle and non boost settings and adding fuel under boost. Works great.

I don't have an answer/solution for you for larger injectors + idle. e-manage or AEM EMS are the only paths to do that that I know of, and I don't reccommend the e-manage at all.

What will your goal of reducing the fuel pressure do for the system? If it runs great and is tuned well, why do you want to change it?

Yellow Streak

[QUOTE]Originally posted by Jenner
[B]I'm running stock fuel pressure with my 755cc injectors and the AEM EMS is pulling out fuel at idle and non boost settings and adding fuel under boost. Works great.

Jenner

The way I see it(in my limited knowledge) is that you need to increase the injector size as you lower the fuel pressure, in order to have the same amount of fuel at a given rpm/boost.

By increasing the injector size, any area that isn't in boost, or idle for example will need to have fuel pulled out. This works with a VAFC down to idle, but idle is too rich and you have no way to tune it.

So you are stuck. Can't reduce the fuel pressure without bigger injectors, can't idle with bigger injectors without fuel management computer.

Yellow Streak

[QUOTE]Originally posted by Jenner
[B]The way I see it(in my limited knowledge) is that you need to increase the injector size as you lower the fuel pressure, in order to have the same amount of fuel at a given rpm/boost.

RCR S2

There's no way to reduce fuel without a standalone ECU or a custom electronics box that reads the fuel PWM signal from stock ECU and provides a clone+ajustment based on the VAFC input. Even then, you'll have a slight delay as it is impossible to have it real time.

Uber-s2k

Looks like a potential FAQ addition to me

Steve

cbender

For those of you following this thread, I thought I'd post a recent exchange with ChrisD that might be of use to you:

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cbender wrote on 06-07-03 12:33PM:

Is it worth buying the AEM EGT sensors (one per cylinder) to give the AEM the ability to read individual cylinder exhaust temperatures or can I simply rely on my EGT gauge (mounted in the downpipe) to monitor my exhaust temperatures for all cylinders combined?

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ChrisD replied on 06-07-03 12:35PM:

Personally I think that individual EGT sensors per cylinder are overkill for what you are planning on doing. I even think they might be overkill for what I'm doing. If you have one EGT gauge as it is, I doubt you'll need 4 more. Chris

cbender

Here's another question, ChrisD:

If I'm only planning to run relatively low levels of boost (certainly no more than 8-9 psi on race gas, MAX), can I use the stock map sensor instead of buying a 3 bar one and avoid having to buy the following:

GM 3 Bar map sensor + pigtail: $10 bucks?
GM boost solenoid: $15 bucks
GM boost solenoid pigtal: $5 bucks

Thanks,
CB

ChrisD

[QUOTE]Originally posted by cbender
[B]Here's another question, ChrisD:

If I'm only planning to run relatively low levels of boost (certainly no more than 8-9 psi on race gas, MAX), can I use the stock map sensor instead of buying a 3 bar one and avoid having to buy the following:

GM 3 Bar map sensor + pigtail: $10 bucks?