where to start

General Nitrous Discussion

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Moparich
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where to start

#1 Post by Moparich » Sat Sep 27, 2008 12:30 am

i hear the term square jetting alot. is that where i should start?

i know from my data logger my car run a tad rich.

NOS gave these combo's
n47/f53
55/61
63/71

these are also all the jets that came with the kit. so knowing i run a hair rich should i start with
i set the NOS fuel at 5.5psi
n53/f55?

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John_Heard
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Re: where to start

#2 Post by John_Heard » Sat Sep 27, 2008 7:13 am

Moparich wrote:i hear the term square jetting alot. is that where i should start?

i know from my data logger my car run a tad rich.

NOS gave these combo's
n47/f53
55/61
63/71

these are also all the jets that came with the kit. so knowing i run a hair rich should i start with
i set the NOS fuel at 5.5psi
n53/f55?
What regulator do you have for the fuel side of your nitrous system? How high can you set it and have it repeat? In this situation using the jets you have I'd use the 55 N / 53 F at about 6.0 psi, make a run check the plugs and see where you're at. It'll likely be a bit fat, start pulling fuel out in 1/2 lb increments, you'll probably end up around 5.5 to 5 psi. That's about a 120 shot. Put about 3 to 4 degrees retard in it. Hard to hurt anything at that shot level. 1 step colder plug would be a good idea as well.

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Moparich
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Location: Suisun Calif
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Re: where to start

#3 Post by Moparich » Sat Sep 27, 2008 10:04 am

http://store.summitracing.com/partdetai ... toview=sku

this one is adjustable from 4.5-9psi
where do i find info on a colder plug? i am currently running autolite app3924

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John_Heard
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Re: where to start

#4 Post by John_Heard » Sat Sep 27, 2008 10:54 am

That regulator is a good one for nitrous, it's a holley 803 just sold under the summit name. That plug your using is a platinum tip plug, I don't have heat info on it. You should probably not run those on nitrous, instead switch to a Autolite racing plug or NGK.

According to my notes, the APP3924 plug is 14mm thread, .750 reach, with a 5/8 hex, non-projected tip. If that is correct, you can use what many people use for nitrous at low power levels, the NGK R5671A-8, stock number 2660. Or the equiv. Autolite, AR3934.

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