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Discussion Starter #1
Hi guys..

Im runnig a 705" bbc with a fast efi system, i have a dry shot nitrous mounted..

Is there any way of calculating what the fuel lbs/hr should be on the injector vs the nos jet??

My base fuel curve on the motor is 95-130lbs/hr @4000-7000rpm

The fuel curve i have on the nitrous now is 360-600lbs/hr @4000-7000rpm but not sure if that is way of

Im planning on running 30 jets and my injectors are 160lbs

Anybody got a idear of where i should be at??

thanks
 

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Discussion Starter #3
@ what fuel pressure im running 60 psi, and 110lbs dosent seme like mutch, is that a flat curve on the rpm band?
 

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45psi.
Thats what we add over top of the motor lbs/hr.
Of course we taper it in over 1,000 rpm off the Tbrake.

We started with 120 lbs/hr but it was slightly rich, ended up with 110 lbs/hr.
 

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Hi guys..

Im runnig a 705" bbc with a fast efi system, i have a dry shot nitrous mounted..

Is there any way of calculating what the fuel lbs/hr should be on the injector vs the nos jet??

My base fuel curve on the motor is 95-130lbs/hr @4000-7000rpm

The fuel curve i have on the nitrous now is 360-600lbs/hr @4000-7000rpm but not sure if that is way of

Im planning on running 30 jets and my injectors are 160lbs

Anybody got a idear of where i should be at??

thanks
Something seems way off in the numbers you quoted in the red above. I would think you would have way more than 130lbs/hr at 7000. Unless something is set differently and making you use smaller numbers to. If this is the case the numbers you get from us will not be correct. I don't see how your engine can only use that amount of fuel when I am looking at a fuel map for a SBC and it is at 124lbs/hr @4000 and 313lbs/hr @ 7000. If I was to guess your injector opening time is not correct. But, I can tell you this if you run the car with the Nitrous map you have currently the car will stall as soon as the nitrous comes on best case) OR you will hurt it if it tries to run.

But, to answer your question I add 105lbs/hr for a 30 jet. I also have 160lb/hr injectors. So the difference between ATVracer and me is I add 35lbs/hr per 100hp and he adds 36.6lbs/hr per 100hp and we are both assuming 30 jets are 300hp. At least thats how I see it.
 

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I also run mine at 45psi. The 160lb/hr injectors are allready capable of handling what around 2000-2200hp unless you are going to be above that I don't see a reason to run them at 60psi.
 

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Hi guys..

Im runnig a 705" bbc with a fast efi system, i have a dry shot nitrous mounted..

Is there any way of calculating what the fuel lbs/hr should be on the injector vs the nos jet??

My base fuel curve on the motor is 95-130lbs/hr @4000-7000rpm

The fuel curve i have on the nitrous now is 360-600lbs/hr @4000-7000rpm but not sure if that is way of

Im planning on running 30 jets and my injectors are 160lbs

Anybody got a idear of where i should be at??

thanks
You have those numbers backwards?

I could see the 360+ lbs/hr for the engine itself, but I would really hope that you are running more. If you are actually running 600 lbs/hr with that size engine, I could see that.

Adding 100 lbs/hr on top of the other numbers for the nitrous seems more like it............
 

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Discussion Starter #8
I am new on this efi system, so i have a lot to lern.

But when i look at the fuel calculation parameter setup of the system the injector flow rate is set at 190lbs/hr...Could that be why the flow rate is not correct??

I am running opening time 5.1 - 5.3ms on the injectors

All these parmameters were set in up when i bought the engine, and the afr semes correct and the plugs too....
the fuls curve on the engine running N/A is from my data logging system.
 

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Discussion Starter #9
and also, the fuel curve for the nitrous, will make the original curve for the engine it self disapeer, so when nitrous is activated that is the total fuel curve..

But that still dosnt seeme right, then the n2o should ad 200-470lbs more on the base curve.
 

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We use 312 lbs/hr at peak hp on motor.

Since we only have 2 stages we use the 3rd stage fuel table as our N/A fuel curve.
For the 30 jets we will go into 1st stage power adder and add 110 lbs/hr on top of the N/A curve to get our "exclusive" fueling for that jet.
So at peak HP we are using 422 lbs/hr for the motor and the 30 jet.
Hope that helps some.

200 lbs/hr is enough fuel for 2 sets of 30 jets.
 

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Discussion Starter #11
We use 312 lbs/hr at peak hp on motor.

Since we only have 2 stages we use the 3rd stage fuel table as our N/A fuel curve.
For the 30 jets we will go into 1st stage power adder and add 110 lbs/hr on top of the N/A curve to get our "exclusive" fueling for that jet.
So at peak HP we are using 422 lbs/hr for the motor and the 30 jet.
Hope that helps some.

200 lbs/hr is enough fuel for 2 sets of 30 jets.
If you use the 1 stage as n/a curve u just have that activated from launch or? i mean it cant be run all the time..

And still im not understanding why i only read 130lbs om my engine curve...
On dyno i made 1336hp

are you using the fast wp or xfi sofware ?
 

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We use the 3rd stage as a lbs/hr guide for the motor.
1st stage is the power adder exculsive table .... add N/A lbs/hr + nitrous lbs/hr = 1stage power adder curve.

CCom WP - XFI

Are you sure you logging lbs/ hr ?
Mine only makes about 800hp N/A
 

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Discussion Starter #13
well the data logger i calling the curve fuel #s/hr..

So you dont set the opening time on the injectors know that you use the 3stage for fuling the engine or?

and you are running alpha/n mode right?
 

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It only uses that table if you tell it to use 3 stages, since we only have 2 its never turned on.

We use the power adder exculsive tables for our N20.
Example...

300 lbs/hr for motor = no power adder is being used
1stage = 100 lbs/hr so we have to have 400 lbs/hr in stage 1 power adder curve
2nd stage = another 100 lbs/hr so we have to have 500 lbs/hr in stage2 power adder curve.
 

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If you use the 1 stage as n/a curve u just have that activated from launch or? i mean it cant be run all the time..

And still im not understanding why i only read 130lbs om my engine curve...
On dyno i made 1336hp

are you using the fast wp or xfi sofware ?
In the power adder fuel table you can set the 3rd stage graph using your base fuel table values then add the fuel for the first and second stage on top of it. You will have a purple line on top (2nd stage), green in the middle(1st stage) and red on the bottom (motor). You are using the red line (3rd stage) as a motor fuel reference only. Just be sure your power adder global parameters have only one or two stages.
 

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First key is to make sure your N/A tune is good before adding anything else on top of it. More info is needing on your setup to properly setup a baseline throttle body size, cam shaft, solenoid setup, purge location, ext. Typicaly you will not find a motor taking a set amount of fuel on top of the tune-up for the entire curve. And don't forget this time of year the conditions will affect the amount of fuel you are adding. Also setting up your rpm scale at the bottom of your fuel table is important to give you the best control of your setup. Just some thinks to think about.

KG
 

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Listen to this guy ^^^^^, he knows what he is talking about!

Something seems goofy with the info you are giving. Talk to Kevin (Kgiblin) about your combo, he can help you out.
 

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Discussion Starter #18
First key is to make sure your N/A tune is good before adding anything else on top of it. More info is needing on your setup to properly setup a baseline throttle body size, cam shaft, solenoid setup, purge location, ext. Typicaly you will not find a motor taking a set amount of fuel on top of the tune-up for the entire curve. And don't forget this time of year the conditions will affect the amount of fuel you are adding. Also setting up your rpm scale at the bottom of your fuel table is important to give you the best control of your setup. Just some thinks to think about.

KG

I know not 2 motors run the same, and different setup means different fuel curves.

But if i am reading only 130lbs/hr on my n/a curve, i must have something in the program not programmed right.

I will have to solve that problem before trying the spray, i have no idear were to put the fuel curve when you guys are runnig totaly different numbers...

First i try to adjust the pressure down to 45 psi and chance the fuel calc parameter to the correct 160lbs/hr and se what happens


And last what openenig time on the injectors do yall run on your systems???

I have 5.0-5-3ms at full throttle

thanks
 

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Does the engine run correctly right now without using nitrous? I thought you mentioned the power it made, was this on a dyno? Was it dynoed with your system, fuel pump and all? There is no way you are running your engine with only 130lbs/hr of fuel! No way in the world. Even a lousy 400hp engine will use roughly 200lbs/hr of fuel.

It won't cost you anything to talk to Kgiblin on here. Does anyone in your local area use the same ECM that you have?

At least you understand that you better not touch the nitrous until you figure-out the N/A side of things first.
 
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