Okay, I have afr 195s and a stealth ram on my 355. It's using svo 30# injectors and is making about 500hp at the flywheel with a 224/224 110 560/560 cam. I have an NX wet nozzle kit that I am wanting to use a 150 shot. Will my stock lines flow the volume needed for this setup? It is very important that I am not running lean under spray, and I didnt want to try it until I got some opinions! Thanks!

 

It is a single nozzle kit and about 150 HP? I think the 3/8" line will perform well I looked to see what you were running for a fuel pump and didn’t find it in the signature but I'm sure you got something good. On a carbed style app I would be worried but I'm sure you understand the significance of the capability of the same line when filled with 40 psi fuel gives it the ability to supply a higher HP engine than carbed pressures would so you got that going for you. What EFI computer are you running? Stock (what year type)? Aftermarket?

 

ECM is 7730 GM, eprom is going to be an Ed Wright Fastchip dyno-tuned, fuel pump is a holley in-tank. Do you still think I'm alright? Thanks!

 

Sorry to get off topic on your post, but did ed wright tune the PROM for your stealth ram? Did you like the results?
thanks

 

no problem, Cobra. The Fastchip appointment is set for October 21st. It's a dyno chip, so I'll post numbers and tell you how it goes.

Perhaps someone reading this could also answer my other in the ecm board about breaking this sucker in on the stock chip?!?
The post is here

If anyone has any further opinions on the fuel lines, I'd really like to hear them! Thanks for taking interest...

 

Yes, NX makes a single nozzle kit! It is very precise, impedes airflow much less than a plate, and makes for a more even distribution of the fuel/n2o mix. ...or so I'm told. I am by no means an expert. I sold my plate and bought this NX nozzle and lots of jets new for~ $200 direct from NX at the recommendation of a local speed shop.

 

you will have to excuse me, the 7730 ecm is the speed density? either way if the chip you have now is a stock 305 chip (19# inj.) then I would say run it with the 19#'ers until dyno day. I'm suggesting you go drive it around too much, but I believe you could safely break in the cam and bearings/seat rings. avoid any high RPM running and I think you will be fine. the reason I say no on the 30#'s, is that is too much of a jump and you are surely to wash down the rings. dodge runs its 360 on 19#'s in the dakotas and I believe ford non-lightning pickups with the 351 ran with 19#'s also.

 

Sorry for not being clear on this... The car is running on it's quasi original 350 chip. Some timing has been backed out of this chip (supercharger was on car), and the fan temp has been reduced. Other than that it should be stock as far as fuel delivery because I was using 24# with the supercharger. Unfortunately I no longer have my 24#s or my 22#s. I do have an afpr on my stealth ram rails so I thought I could get away with the 19#s that I have. I planned on setting my rev limiter to 2700 or so during breakin so no accidents are realized. I just wanted to be sure running it this way would be okay.

 

without the 22-24# I dont know what will happen. with the 22-24# you could probably drive it alot until you got you new chip.

 

Why not just crank up the fuel pressure and use the 19's. 56# will make them flow 22, mid 60's will make them flow 24. I run my stock 22's in my L98 at 54 all the time...

 

Heres the math for you do it yourselfers...
M1/M2 = square root of P1/ P2
M1 = rated mass flow rate of the injector at fuel pressure P1 in lb./hr.
M2 = new mass flow rate of the injector at fuel pressure P2 in lb/hr
P1 = existing fuel pressure setting in PSI
P2 = new fuel pressure setting in psi

So for your setup it is:
M1 = 19lb/hr
P1 = 43.5 psi
Required mass flow rate M2 = 22 lb./hr.
P2 = (M2/M1)(sq) * Pi
P2 = (22/19)(sq) * 43.5
P2 = 58 PSI
So with your 19 LB/Hour injectors your fuel pressure will have to be increased to 58 PSI to get 22Lb./Hr injectors.
Now to get 24 Lb./Hr. Injectors:
P2 = (24/19)(sq) * 43.5
P2 = 69.4 PSI
your fuel pressure will have to be 69.4 PSI to make your 19Lb/Hr. injectors flow like 24 Lb/Hour injectors.

Keep in mind your Fuel injectors should NOT be pushed past 60~ Psi, according to Holley. Holley also says:
"Running pulse widths smaller than 1.8ms the injector may run in "non-linear" portion of it's dynamic range. such a condition can lead to engine "hunting" during idle to hesitation during off idle condiitons" This is important because if you jack up fuel pressure, your idle injector pulse width will have to be smaller to maintain the right air/fuel ratio, and that could lower it below 1.8ms which can lead to the above condition.

 

And now ladies and gentlemen I will perform another math task:
Lets see how big of injectors you need for your engine to get the best performance!
According to Holley:
"Engine output is in direct relation to fuel supplie to the engine, however installing injectors, which are too big, will not make more power. It is therefore very important to math thefuelinjector flow characteristics to specific engine appliucations. matching the fuel floe of fuel injectors is as important as match the jets for a specidic engine application. "

and now the math:
Injector static flow rate [Lb./Hr.] = (Engine HP * BSFC) / (Number of injectors * DC of Inj.)
Engine HP = Realistic HP estimate
BSFC Brake specific Fuel consumption (Lb./Hr.) Good approximation = 0.50
Duty cycle of injector = max. opening time of injector / cycle time.
Max duty cycle = 0.90
Your engine:
horsepower = 500HP
Number of injectors = 8
Injector static flow rate (lb/hr) = (500 * 0.50)/(8*0.90) =>
34.7 Lb/Hr. Injectors require to feed a 500 horsepower engine.
A 400 horsepower engine only needs 27.78 Lb/Hr injectors.
and a 350 horsepowe engine only needs 24 Lb/Hr. injectors.

Dont Flame me! Im just repeating what I learned from Holley! Im just the middle man I swear! Its all holley's fault!

 

Dang, now you're talking! That really helps a bunch!!!! It shows me that my 30# injectors are going to get real close to being on the money. However I'm still left with the notion that the neither the 19# or the 30# are going to idle and part throttle this thing correctly on the stock chip. To remedy this, I'm just not sure what to do.

Do you happen to have any flow equations for the ammount of fuel I'm going to need for this 150 shot and the 30# injectors at full throttle once the chip is properly tuned? Will the stock lines suffice for this? Thanks!

 

<b>Do you happen to have any flow equations for the ammount of fuel I'm going to need for this 150 shot and the 30# injectors at full throttle once the chip is properly tuned? Will the stock lines suffice for this? Thanks!</b>


Ahh are you trying to kill me?? Eh Let me do a little research because now IM curious...
Ill post a reply when i find out for you, IF i find out for you...

 

OK according to HOLLEY, generally they say the fuel system will need an "upgrade", which makes sense, but doesnt specify if your exact lines will suffice. I know people using the stock fuel lines with NOS, And i know people who installed some of that aluminum line and use 2 fuel pumps etc.. it all depends on how safe you want to be. Your fuel pump really determines if your lines will be ok, since its whats pushing the volume... And consider your nitrous will probably have its OWN fuel flow so upgrading your injectors / changing pressure probably wont be necessary, But it seems like dual fuel pumps would be a good idea. I dont know much about this sort of thing, and holley really isnt much help either. maybe somone else who has this sort of thing can chip in some info.

And what kind of fuel economy are you getting with the stealth ram?

 

OK, to start with, I wouldn’t plan on any upgrade to be done so that it barely works for what you’ve already go. Based on that, you really should be shooting for a duty cycle in the 70-80% range. You can run into all sorts of funky tuning problems at over 85, and at anything over 90 you can assume that your injectors are going static.

Based on that, if you’re making 500hp NA
((500 * .5 BSFC) / .75 duty cycle) / 8 = 41.6lb/hour (to be safe).

WRT to what you need the pump to pump you can just get rid of the duty cycle and the # of injectors, giving you 250lb/hour (you have to make sure that the pump can pump that at the pressure that you’re running).

I’m assuming that you’re adding the N2O fuel enrichment through some other means (not the injectors). To figure out how much extra the pump has to pump, figure that N2O systems jet for about 50% more fuel for the HP delivered, so for 150 hp you need to add:
150hp * .75 = 112.5Lb/Hour more
or a total of 362.5Lb/Hour.

Gas weighs about 6.3Lb/gallon, so were taking about:
362.5 / 6.3 = 57.5 gallons/hour.

To convert that to liters/hour multiply by 3.8:
57.5 * 3.8 = 218.7 L/hour

So you’ll need a pump that could pump at least that at whatever the highest pressure is that you’ll see.