How to calculate fuel your motor will need with n20

[Joel]

HP divided by 2=lb/hr
lb/hr divided by 6=gallons per hour required (min)
Multiply GPH by 1.15 for safety factor.

Example:600hp divided by 2=300
300 divided by 6=50
50 multiplied by 1.15=57.5 (minimum gallons per hour)

This was obtained from http://www.nosnitrous.com/HiOctn/ProdLine/Products/NOS/index.html


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1998 Camaro Z28 M6 (http://joel98z.mbaskett.com)
T1 Cam, 4.10's, Juice!

[mbaskett]

more info can be found here:
http://www.mbaskett.com/z28/N2O/Default.htm

[mbaskett]

BTW, great stuff Joel!!!!!! keep it coming!

[Joel]

So lets see here:

My Car:
340 RWHP NA + 75 Shot = 415 on Juice

415 / 2 = 207.5
207.5 / 6 = 34.58
Saftey Factor:
34.58 * 1.15 = 39.77

So it looks like my Fuel system needs to flow 39.77 GPH for a 75 shot.

I know the '98's have 28# an hour injectors, what does that equate to in GPH???

[mbaskett]

Joel, not to throw you off or anything, but are you s'posed to use RWHP in those calcs? or flywheel/crank HP? I would think if you're using calcs involving the fuel system, you would want to use the crank HP ratings.....

M6 tranny sucks ~12% off your crank rating.

Also, the 28# rating. It's 28 lbs/time I believe. if we can get that unit... I think we can figure out if you need to upgrade or not. Also the rating of the stock fuel pump will play into effect here as well, so we may need to find that, too....

[mbaskett]

Originally posted by Juiced Joel:
HP divided by 2=lb/hr
lb/hr divided by 6=gallons per hour required (min)
Multiply GPH by 1.15 for safety factor.

Example:600hp divided by 2=300
300 divided by 6=50
50 multiplied by 1.15=57.5 (minimum gallons per hour)


It seems that by using this calculation and making some assumptions....

15% drivetrain loss
and using 75 HP added @ the rear wheels.

(340+75)/.85= 488.2

488.2/2 = 244.1lb/hr

lb/hr is (assumed) the rating used on the injectors. so.....

244.1/8 = 30.5lb/hr per injector.

Sounds like the 30# injectors won't work.... BUT... they are SVO 30# injectors.... rated @ 30lb/hr @ the Ford fuel pressure level of about 42psi. Our fuel pressure = ~50psi. No calcs on this, but I've been told the SVO 30# injectors flow 36.4lb/hr on our cars.

you want to run your injectors at no more than an 85% duty cycle, so to flow 30.5lb/hr with the leftover room for safety, you have to have

30.5/.85 = 35.9 or 36lb/hr flow through your fuel injectors.

Correct me if I am wrong anywhere, but I think I just found somebody who's going to be upgrading their fuel injectors VERY soon http://www.torquecentral.com/z28/ubb/biggrin.gif (not me, I've already done that)


[This message has been edited by mbaskett (edited January 18, 2001).]

[00WS6]

Shit, you guys really get into the calculations and everything. That's cool though ... since I've got a strong math and science background it really helps me to understand what the hell is going on! It will help prevent me from doing anything stupid too ... maybe I won't blow up something. Thanks and keep the info coming!

mbaskett: Please don't ever turn this into one of those sissy boards! http://www.torquecentral.com/z28/ubb/wink.gif

[mbaskett]

Don't worry, I won't!!!

These calcs are still not 100% verified, but I think they are getting there.....

It's nice to know what mods you need to do BEFORE you blow up your car! http://www.torquecentral.com/z28/ubb/smile.gif

[Jay Johnson]

LS1's run about 58psi.

I prefer to use the normal calcs with a horse
power rating and its fuel injector
requirement.
The wet kits don't really come into this
equation except for lowering the effective
fuel pressure and unless you running a HUGE
shot, the fuel psi does not deviate
significantly.

With a wet kit, you can basically run an
injector that adequately supplies the motor
with fuel on a NA peak pull.
Then just ensure that the fuel psi is
maintained on the wet shot, since the wet
kit commonly pulls the fuel straight off of
the rail.

The dry kits send the injectors above the
80% duty rating to add fuel to the mixture.
I don't really like the idea of this, but
it does work to a point. Enough of this
max'ing out the duty rating *could* make
and injector fail, and possibly at the
wrong time.

I guess that's why I prefer the wet kit in
general, but I'm interested in any trick
Nitrous setups.


Jay Johnson