1600cc

[Mirage2LTurbo]

Unless your goal is to make over 700hp I would stick with 950cc injectors or smaller. I would also try to size my injectors to supply the proper amount of fuel for X hp and stay under 75psi of peak pressure. Most high performance fuel pumps for reasonable prices cannot handle the abuse of rail pressures above 80psi and have dramatically drop in flow.

I run a base fuel pressure 22psi so I can properly regulate my fuel at idle and low engine speeds due to the TEC IIs limited fuel map(8x8). I am using an Aeromotive 4 port bypass regulator somewhat designed for carb applications with a heavier spring.

Need more matrix

www.autronic.com

 

[Kevin Jewer]

Larger injectors will be open for a much shorter time. No more fuel is pulled from the rail than the engine is using, regardless of injector size. If no more fuel is being taken from the rail, why do we need more flow/pressure to backfill it?

 

[Mirage2LTurbo]

If you are running -6 line, you are going to have to flow x volume to maintain y psi. If you run a -10 line, you're going to have to flow more fuel to maintain the same pressure.

a injector will consume the same amount of fuel as b injector, like 95GSX said, they will just be open shorter.

 

[Kevin Jewer]

If you are running -6 line, you are going to have to flow x volume to maintain y psi. If you run a -10 line, you're going to have to flow more fuel to maintain the same pressure.

Only in an open-ended system. In a closed system like ours (pressure regulated), the above statement doesnt apply.

 

[Mirage2LTurbo]

Correct. The pump only has to supply enough fuel to overcome what the injectors expend to maintain the fuel pressure.

 

[crankbender]

I dont understand this line of thinking at all. Wether you have a 200 lph pump or a 400 lph pump, 1600cc injectors at a given duty cycle always require the same fuel flow from the pump. I cant see how a higher flowing pump would dampen the pulsation from large injectors. I'm certainly open to a more in depth explanation if you're willing.

My statement was in response to this.

I think its worth mentioning that if he is running 1600 injectors, but really only needs say 850s, then he only needs enough pump to "support" 850s. The pump has to be appropriate for the power goals, not the injector size. Now, I dont see why anyone would buy injectors this large, even if they are cheap. More "normal" large size injectors arent that expensive these days. But if the management system can do it, go for it I guess.

The problem is that if your fuel pump can only keep up with 850 cc injectors when the 1600 opens up the system will naturally fall in pressure to increase flow.

Your fuel pump requirements are based on the injectors....it gets really tricky when you have to figure out how many are open at any given time.

 

[crankbender]

No dynos, but the buttdyno is saying 400ish+ whp on 1 bar. Keep in mind that IDC is not linear, turbo dynamics my son Trust me, I have plenty of flow. I'm only running 37psi base, which isn't really a big deal, I'll never run out of injector. If I get close, I'll bump up the base pressure and go from there, but 5psi isn't going to move my IDC anything incredible. Think about it, I'm using 780cc's of injector.. what kinda power is that good for? I have an incar fuel pressure gauge, it is fine under WOT.

1 bar is 14.5psi, not 17 I should be on 18-19 this weekend though, I'll post up how it goes

I know what 1 bar is I donno if 17 was a typo or if I was just using it for a reference. My point was why is your engine using so much fuel with such a low boost pressure. (PS please don't call me son I find it degrading not mad just letting you know). This is why I asked about your mods to let the engine breathe. On the other hand you may have a restriction after the fuel pressure gauge (on your fuel filter correct?) but before the injector. This is why I asked about the flow in the return line.

It just seems odd that you are flowing 750cc with your setup when others seem to be flowing less. I donno if I trust butt dynos .

 

[Mirage2LTurbo]

A 800cc injector opeating at 80% IDC fows the same amount of fuel as a 1600cc injector open for 40% of the time. As long as you are not outrunning parts in your system, there is no pressure drop. What do you mean it gets tricky to figure out when th einjectors are open? You look at your logger, or in my case my laptop, and see pulsewidth and IDC, and you can tell exactly when it's open.

Why would you run ANYTHING on the return line? There is nothing on it, btw. 750cc injectors flow for what, 425whp or so? The PT67 on a 1 bar should be making that to two wheels. That's why it's using so much injector, it's flowing a SHITTON of air

 

[GRNDSM]

>A 800cc injector opeating at 80% IDC fows the same amount of fuel as a 1600cc
>injector open for 40% of the time. As long as you are not outrunning parts in your
>system, there is no pressure drop.

True, but… larger injectors allow you to lower your base fuel pressure. Pump’s capacity at lower fuel pressure is higher. So larger injectors will allow you to run a SMALLER pump.

In the above example, you might be at

800cc @ 80% IDC at (lets say 45psi).
1600cc @ 40% IDC at same 45psi or
1600cc @ ~46% IDC at ~38psi

Those 7psi of lower base fuel pressure will increase pump’s capacity from 5-10% (depending on boost level).

I can’t believe I am making a case for using larger injectors… Hell must be freezing over .

Leon
RR

 

[Mirage2LTurbo]

>A 800cc injector opeating at 80% IDC fows the same amount of fuel as a 1600cc
>injector open for 40% of the time. As long as you are not outrunning parts in your
>system, there is no pressure drop.

True, but… larger injectors allow you to lower your base fuel pressure. Pump’s capacity at lower fuel pressure is higher. So larger injectors will allow you to run a SMALLER pump.

In the above example, you might be at

800cc @ 80% IDC at (lets say 45psi).
1600cc @ 40% IDC at same 45psi or
1600cc @ ~46% IDC at ~38psi

Those 7psi of lower base fuel pressure will increase pump’s capacity from 5-10% (depending on boost level).

I can’t believe I am making a case for using larger injectors… Hell must be freezing over .

Leon
RR

Good point, but also take into account that injectors are measured at 43.5psi, so if you are running higher or lower fuel pressure than that, they aren't 1600cc injectors anymore, they become 1700 or 1500 (for argument sake only, numbers are not right ) So you can help your fp along and lower the base pressure, but you're taking away from the topend of the injector if you're running close on IDC. Bump up fp, you gain injector, bu then you need a bigger pump to support it

 

[GRNDSM]

>Bump up fp, you gain injector, bu then you need a bigger pump to support it

This became operant to me during my last tuning session. I was running out of my injector capacity at 45psi (110% IDC). I bumped the fuel pressure all the way up to 54psi, eventually lowering my IDC to “just” 98%.

That would have been OK, if my fuel pump could actually keep up with fuel demand at such high pressure (54+27=81psi). But it didn’t go anywhere near that high, it would top out around 65-70psi…

Needless to say, I am overhauling my fuel system:

- Cosmo Pump feeding Paxton (same as A-1000) pump
- Through –8AN lines
- Into a fresh fuel filter
- to 1000 cc injectors

I think that between 1000cc injector and now hugely increased fuel pump(s) capacity. I should have ample fuel supply.

Oh, I have also added an AEM fuel pressure sensor, so I will be able to log the fuel pressure along with everything else.

Leon
RR

 

[Mirage2LTurbo]

>Bump up fp, you gain injector, bu then you need a bigger pump to support it

This became operant to me during my last tuning session. I was running out of my injector capacity at 45psi (110% IDC). I bumped the fuel pressure all the way up to 54psi, eventually lowering my IDC to “just” 98%.

That would have been OK, if my fuel pump could actually keep up with fuel demand at such high pressure (54+27=81psi). But it didn’t go anywhere near that high, it would top out around 65-70psi…

Needless to say, I am overhauling my fuel system:

- Cosmo Pump feeding Paxton (same as A-1000) pump
- Through –8AN lines
- Into a fresh fuel filter
- to 1000 cc injectors

I think that between 1000cc injector and now hugely increased fuel pump(s) capacity. I should have ample fuel supply.

Oh, I have also added an AEM fuel pressure sensor, so I will be able to log the fuel pressure along with everything else.

Leon
RR

What engine management you on? I'm running the A-1000 pump, love it.. it's a bit loud, but the exhaust quickly drowns that out

 

[GRNDSM]

I guess you didn’t look at my profile . I am now on AEM EMS. I was considering using AEM to only turn this pump on when I went into boost (or something like that), so that it would not be on most of the time, but I am concerned how much my Cosmo pump will be able to push through this monster of a pump.

Leon
RR

 

[Mirage2LTurbo]

I guess you didn’t look at my profile . I am now on AEM EMS. I was considering using AEM to only turn this pump on when I went into boost (or something like that), so that it would not be on most of the time, but I am concerned how much my Cosmo pump will be able to push through this monster of a pump.

Leon
RR

Sump it and only run an external.

 

[GRNDSM]

>Sump it and only run an external.

Not really an option, at this point:

1) I do not have enough time (I need to have it running with-in a week or so).
2) I would like to convert to a fuel cell, but I make everything much more complicated than it has to be, so it is not such a quick thing for me .
3) Everything I read suggested that this pump (A-1000) likes to be below the gas tank. That is out of the question if you are going to sump your tank.

So I figure that I will finish off this season running on A-1000 pump being fed by a Cosmo pump. And like I said I am even going to see if I can turn off the big pump when I am not making any boost. This is very easy to accomplish with the EMS.

Next year, I will have an elaborate system in place, most likely unitizing a “surge tank”, to give me proper fuel supply during handling courses.

Leon
RR

 

[1fast97gsx]

Yes, a lot of fuel pump you need. My system controls them just fine (they are actually 1680's). I pull ~1% at idle, 800rpm, 14.7:1 a/f. Some systems can't do that though, so make sure you either a)post what you have or b) call the manufacturer.

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hey man do you have a pic of your car from the outside ... I think I may have seen it before. Thanks.

 

[kpt4321]

The problem is that if your fuel pump can only keep up with 850 cc injectors when the 1600 opens up the system will naturally fall in pressure to increase flow.

Your fuel pump requirements are based on the injectors....it gets really tricky when you have to figure out how many are open at any given time.

It took me a second to clearly understand your line of thinking Peter. However, now that you mention it, it's a VERY interesting point.

For those of you who don't follow yet, think about this. You have 4 1600 cc/min injectors, operating at 50% duty cycle. That's 3200 cc/min of total fuel flow, assuming a 43.5 psi pressure differential across the injector which works fine for this example.

Now, let's say that your fuel pump can supply 3200 cc/min (maximum) of fuel at whatever operating fuel pressure we are talking about here. That's about 190 liters per hour at a high fuel pressure, so it's totally reasonable for a big fuel pump. This means that the pump SHOULD barely be enough.

However, Peter said something about how many injectors are open at any given time. I have not done any critical thinking with regard to injector timing yet, so let's just assume that the following is possible for the sake of clarity.

Let's say that all 4 injectors are open. Now, I think this really will not happen due to the way the ECU fires the injectors, but again, just work with me. At the instantaneous moment that all 4 injectors are open, there is 6400 cc/min of fuel flow through the injector! Now, since this is not a condition that is occuring all the time, the average flow rate over time is less than the instantaneous flow rate at that point. HOWEVER! At that point in time, the fuel pump can't support the flow through the injectors!

What I'm thinking is this: I don't know how likely this is, but I think it could be possible. However, if the effect is big enough to show itself in AFR, than you will definately see it on a fuel pressure gauge.

Very, very interesting. Food for thought at the least.

 

[kpt4321]

hey man do you have a pic of your car from the outside ... I think I may have seen it before. Thanks.

You mean, sort of like the one he ALREADY POSTED IN THIS THREAD?

Look on page 1.

 

[Mirage2LTurbo]

>Sump it and only run an external.

Not really an option, at this point:

1) I do not have enough time (I need to have it running with-in a week or so).
2) I would like to convert to a fuel cell, but I make everything much more complicated than it has to be, so it is not such a quick thing for me .
3) Everything I read suggested that this pump (A-1000) likes to be below the gas tank. That is out of the question if you are going to sump your tank.

So I figure that I will finish off this season running on A-1000 pump being fed by a Cosmo pump. And like I said I am even going to see if I can turn off the big pump when I am not making any boost. This is very easy to accomplish with the EMS.

Next year, I will have an elaborate system in place, most likely unitizing a “surge tank”, to give me proper fuel supply during handling courses.

Leon
RR

You could install a cell and run the lines and everything in one day tops, I had my stock cell out in about 2 hours, cut the floor and sheet metal'd it in another 2 (including a run to Home Depot for rivets), and had the new cell mounted along with the pump in another few hours. I then ordered line and fittings, waited, and installed it.

The a-1000 MUST be below the tank, or atleast gravity fed. That small intank pump is going to get outrun by the aeromotive, I'm not sure I agree with that setup even though several run it. I don't think surge tanks are practical, I think someone with too much time and a lot of theory devised them. Get a big enough pump to power your engine, and be done with it. The stock tank baffles or in my case, foam in my cell, assures me fuel will get to the pump and it wont cavitate.

 

[Mirage2LTurbo]

It took me a second to clearly understand your line of thinking Peter. However, now that you mention it, it's a VERY interesting point.

For those of you who don't follow yet, think about this. You have 4 1600 cc/min injectors, operating at 50% duty cycle. That's 3200 cc/min of total fuel flow, assuming a 43.5 psi pressure differential across the injector which works fine for this example.

Now, let's say that your fuel pump can supply 3200 cc/min (maximum) of fuel at whatever operating fuel pressure we are talking about here. That's about 190 liters per hour at a high fuel pressure, so it's totally reasonable for a big fuel pump. This means that the pump SHOULD barely be enough.

However, Peter said something about how many injectors are open at any given time. I have not done any critical thinking with regard to injector timing yet, so let's just assume that the following is possible for the sake of clarity.

Let's say that all 4 injectors are open. Now, I think this really will not happen due to the way the ECU fires the injectors, but again, just work with me. At the instantaneous moment that all 4 injectors are open, there is 6400 cc/min of fuel flow through the injector! Now, since this is not a condition that is occuring all the time, the average flow rate over time is less than the instantaneous flow rate at that point. HOWEVER! At that point in time, the fuel pump can't support the flow through the injectors!

What I'm thinking is this: I don't know how likely this is, but I think it could be possible. However, if the effect is big enough to show itself in AFR, than you will definately see it on a fuel pressure gauge.

Very, very interesting. Food for thought at the least.

Possibly true, but your point is null. If you fired all 4 injectors at once, you are going to have puddling on the valves, it's going to run PIG rich because for every cylinder, for every firing of the spark plug, you would have 4 firings of the injector, so if you normally ran 12:1 a/f, you would be running 3:1 afr. It's going to kill spoolup times on your turbo - speaking from experience. When Bill first put the Autronic on his MR2, he had the trigger plate spun 180 degress. Thus it was firing on the ignition/firing phase of the combustion cycle, and when he fixed this, he picked up almost 800rpm spool on his FP3065.

The only possible scenario I could see your point applying to is if you are running a decrepit standalone that must use batch firing. Every standalone I know of has 4 injector drivers, but assume you were running a v8, and had to use batch firing. It would STILL only be 2 injectors at a time, and I'd hope you'd be running a larger pump.

Also if you are running (4) 1680cc injectors on a 190LPH fuel pump, you don't deserve to own your car. Thanks.

 

[GRNDSM]

>Let's say that all 4 injectors are open

But they never open all at once!!! So this is a moot point

And now that you brought it up, larger injectors will stay open for less time, allowing the same amount of fuel to escape. That means two things:

a. A portion of your fuel rail will be emptied quicker
b. You have more time to refill the portion of your fuel rail

Which one will prevail will largely depend on the size of your fuel rail, explaining why some people eventually move onto larger fuel rail. But unless you are dealing with extra small rails, I can see “b” being more beneficial for your fuel supply. In ether case, I do not think that going to a larger injector will put more strain the fuel pump.

The more I think about it, the more I like the idea of larger injectors. If you have “maxed out” 800cc injectors (which have gone static) and a pump that is on the verge if being “maxed out”, you will have a hard time supplying injectors which are down the stream. That is when people end up with #1 cylinder lean condition.

Leon

 

[Mirage2LTurbo]

Not to mention when yours injectors are static, you can't tune as well What if you get a colder gust of air.. uh oh

 

[kpt4321]

Guys, I think I clearly stated in my post that I wasn't saying it was possible. To the best of my knowledge, it's not going to happen except under weird circumstances with some ECUs.

I was just clarifying the point Peter was trying to make because it seemed as though people didn't understand it. Nowhere did I say it was a worry.

 

[4SFED4]

Larger injectors will be open for a much shorter time. No more fuel is pulled from the rail than the engine is using, regardless of injector size. If no more fuel is being taken from the rail, why do we need more flow/pressure to backfill it?

True, but there is a such thing as minimum injector pulse width and accelerator "pump" enrichment. This is where the delimma is if you try to retain a fairly stock idle. At a base rail pressure of 35 psi the lowest I could get my idle with out an obscene 10:1 a/f ratio was 1600RPM. Dropping the pressure to 22psi allowed me to get down to 1200RPM.

 

[Kevin Jewer]

The a-1000 MUST be below the tank, or atleast gravity fed. That small intank pump is going to get outrun by the aeromotive, I'm not sure I agree with that setup even though several run it.

Dont forget that the cosmo pump being used essentially as a lift pump will be running at very low pressure. Less than 5 psi most likely, but I dont have a flow chart for the cosmo handy. I ran the numbers on a 255 at 0 psi, and it just about matches the output of the A1000 at 70 psi I'm assuming at 0 psi the cosmo will outflow the A1000 at 70 psi, thereby providing slight pressure at the main pump eliminatin the need for gravity feed. The purpose of a lift pump is to supply slight head pressure at the main high pressure pump, the way diesel setups work.