Jet size

General Chat About Nitrous Oxide.

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JSF55
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Jet size

Post by JSF55 » Sun Aug 22, 2010 12:13 pm

Oh well, bit the bullet and bought a second hand nitrous kit ! it's a sniper kit, cheap enough at the time and some gas in the bottle :D
the jets are marked
Nitrous/Fuel Jetting Approximate
Power Gain
Approximate N20
Consumption Rate
47 / 53 100 HP 1.00 lbs. / 10 sec.
55 / 61 125 HP 1.25 lbs. / 10 sec.
63 / 71 150 HP 1.50 lbs. / 10 sec.
Now the motor in the car is using a bit of oil :wink: so i don't want to kill it yet, any advice on a smaller jet size to run say 50 hp more and wil it suffice to tap into the origianl fuel line, it is 10mm bore so a short burst shouldn't be a problem ? john


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Post by JSF55 » Tue Aug 24, 2010 9:33 am

No one got a guess ?
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dbv8
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Post by dbv8 » Tue Aug 24, 2010 4:24 pm

I know a little about nitrous but ony the wizards stuff sorry.
Try giving Real Steel or any NOS distributor a ring.
10.612 @ 129.77
176.5 standing mile.

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Post by mgbv8 » Tue Aug 24, 2010 10:21 pm

Jet sizes that I have from my old NOS system are


36 nos 42 fuel = 50hp
42 nos 47 fuel = 75hp
47 nos 53 fuel = 100hp
55 nos 61 fuel = 125hp
63 nos 71 fuel = 135hp
73 nos 82 fuel = 150hp

This is where I gave up and went over to Wizards stuff...

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Post by JSF55 » Tue Aug 24, 2010 10:23 pm

Cheers Perry, i just might give that a try, john
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Post by ian.stewart » Tue Aug 24, 2010 10:47 pm

dbv8 wrote:I know a little about nitrous but ony the wizards stuff sorry.
Try giving Real Steel or any NOS distributor a ring.
Real Steel have stopped selling any nitrous kit,
I used the Holley/NOS website help line
THE SMOKING GNU
12.604 with an old boiler of a RV8 and no gas
WHY are there so many IANS on this site???????

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Post by mgbv8 » Wed Aug 25, 2010 8:32 pm

As Ian says!
Real Steel are now just selling off old stock.

Just make sure that you can deliver 5-6 psi steadily to the carb and nitrous system when spraying at full power.
And make sure your bottle pressure is at least 800 psi when you use it. Otherwise it will feel lame, run rich and waste gas.

Perry

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Post by dbv8 » Thu Aug 26, 2010 8:03 am

A bottle heater with a pressure switch is the best set up to keep the pressure up and consistant.

You can set the switch to turn the heater off at say 950 psi.
Make sure you either do a static test or check the plugs at this level as you may need to richen the fuel.
More likely the fuel ratio will still be fine but your hit from the gas will double! :twisted:
10.612 @ 129.77
176.5 standing mile.

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Post by JSF55 » Thu Aug 26, 2010 6:19 pm

It doesn't seem to be as easy or cheap as i first thought :( i'll have to see how i get on with selling some other bits first !
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Post by mgbv8 » Fri Aug 27, 2010 1:13 pm

Put up a picture of the kit !!
Then we can see what else you might need. There are shortcuts to getting bottle pressure up just before a race ;)

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Post by JSF55 » Fri Aug 27, 2010 7:01 pm

Will take some pics tomorrow :)
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Couple of pics

Post by JSF55 » Sat Aug 28, 2010 9:55 am

Image
Image
It's a sniper kit ?
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Post by mgbv8 » Sat Aug 28, 2010 8:04 pm

That brings back memories. My first kit was a sniper.
You have all you need to get started. I would invest in a wizards fuel pressure switch at least. This will save you a lot of potential headaches.
The 14 foot braided line may well be far too long. Best bet would be to route it the shortest way possible to the n2 solenoid and then cut it to length and fit a nother -4 end. You can get eh -4 connectors from Pirtek or wizards and many other places. So as long as your bottle has enough pressure you can get going.

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Post by JSF55 » Sun Aug 29, 2010 5:24 am

I can easily get the hose done, truck fitters boy works for pirtek, any pointers on the fuel pump side?I've read some here, but it seems to be overly complicated
http://www.centuryperformance.com/fueli ... g-140.html
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Post by sidecar » Sun Aug 29, 2010 8:31 am

JSF55 wrote:Any pointers on the fuel pump side?

I'm in the same boat as you as I'm about to fit a PowerShot system to my Cob replica. I was also wondering what to do about the fuel pump. I tested my pump for litres flowed per minute, my pump pushes out 1.9 litres which is good enough to make 400 BHP.

BHP= (CC of fuel per minute) / 4.7

I've also monitored the fuel pressure at WOT and peak revs, it was around 6-7 psi (From memory).

My lump makes 285 BHP so in theory there is enough 'spare fuel' available for a 75 BHP NOS kit.

Having said all that I chickened out of using the pump, I then decided that a second small Facet cube pump would be good, the pump would be activated as soon as the NOS system was armed, it would be running before the NOS actually fired. The problem with this is setting up another fuel line etc.

I then decided to just change the pump that I have now as this would be easier. I'm going to fit a Carter 72 g/h jobbie, the lower pressure one so as as not to flood the Eddy carb. I feel that this is better because if I run a second fuel line it could remain 'air-locked' until the fuel solenoid opened. (Some sort of small bleed into the other fuel line might get round this).

When I checked out what pump I have now I was surprised to find out that Facet only rate it for 150 BHP engines, they must build in a huge safety margin into their figures!

Other things that I'm doing are fitting a low fuel pressure NOS system cut off switch and an RPM window switch. (I think the the pressure switch may not be needed with the new fuel pump but I've already order it)

Hope that helps!


EDIT...Just read the article that you posted a link up to, it's very interesting and it does show that my simple calculation may not be good enough! The weird thing is that I did measure the fuel pressure at WOT and peak revs (not an easy thing to do!) and the pressure did not drop 1 psi compared to the pressure at tickover. By the way I don't run any form of regulator, just a low pressure pump connected straight to the carb.

Why is nothing simple? :?

Pete
Last edited by sidecar on Sun Aug 29, 2010 1:43 pm, edited 1 time in total.

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