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Spi Nitrous Explained Thread

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#1 Guest_Spenc_*

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Posted 21 August 2008 - 11:16 AM

The Straightline Performance Nitrous Kits Use The Patented Holtzman (pat.# 6,938,841) Nitrous Nozzle.

The nitrous pressure control technology automatically adjusts with your bottle pressure. Nitrous pressure is determined solely by bottle temperature, not by the amount of nitrous in the bottle. When using a fixed nitrous jet, as the temperature rises, the pressure increases, and this pressure change causes an undesirable change in nitrous delivery. The Holtzman nitrous nozzle has addressed this problem with the patented nitrous nozzle which changes jet size with bottle pressure, maintaining a relatively consistent nitrous flow over the typical range of nitrous bottle pressures encountered (300psi to 900psi). This nozzle is especially suited for the snowmobile, ATV, and motorcycle applications were nitrous bottle pressures can be as low as 300 PSI but can rise to 900PSI after the vehicle warms up.

Straightline’s nitrous systems work on constant flow rates which makes it easy to determine horsepower calculations. The nitrous nozzle injectors are rated at grams per second. Each one gram/sec of nitrous sprayed into the engine will provide a 2.5-3.0hp increase on a four stroke engine and 2.0-2.5hp increase on a two stroke engine. For example a 10 gram per second nozzle on a 4-stroke engine will increase horsepower about 25-30. The same scenario on a 2-stroke engine will increase 20-25hp.

Straightline Performance has complete kits for most makes and models of snowmobiles, ATV’s, and motorcycles. We offer great HP options from 15hp to whatever your machine requires. Each nozzle will contain the patented control technology, and are extremely easy to change for you application. If you require more power and want to upgrade, a simple change, or addition of another nozzle, and fuel valve settings and you’re done.

Safety Considerations when using Nitrous:
1.) When filling the bottle, be sure to follow the weight on the bottle tags only. Never over fill a bottle.
2.) Always use a nitrous filter on your bottles.
3.) Be sure to test for leaks before running any nitrous system.
4.) Mount the bottle properly. Siphon tube bottles need to have the valve standing up, non siphon tube
bottle need to be mounted upside down.
5.) When testing with nitrous, it is a safe idea to run high octane fuel until your tuning is complete.
Straightline recommends 95-100 octane during your testing stages.
6.) When first testing, only use nitrous for a short duration, 2-3 seconds and check your burn.
7.) If you would like to upgrade to a larger nitrous jet, contact Straightline Performance directly.
8.) In some cases it may be necessary to run a cooler plug then the standard vehicle uses.
9.) Typical nitrous should only be used for less than 5-10 seconds depending on application.
10.)Do not apply nitrous to a significant loaded engine below the operating range, this can result in
extreme explosion or personal injury.
11.) Purging: purging can be done at idle, but limit it to short, less than 1 second blasts. Wait 10 seconds
before purging again. This can help fill the fuel lines and supplemental fuel system.
12.) Tuning is made easy with the use of EGT’s or and O2 sensor. Straightline highly recommends these
items for nitrous set-ups. When using nitrous the engine should rev up 200-300 rpm over the standard
operating rpm. Be sure to only use nitrous when at wide open throttle.

Custom Nitrous Kits for all Applications:

Straightline offers custom kits for the mechanic, custom race, and lake race applications.
Information needed:
1. Carbureted or fuel injected machine?
2. How many cylinders?
3. How much horsepower you want to produce?
4. Air box, filters or direct spray application?

All custom kits will require the installer to mount all products themselves. Custom kits only come with schematics for install and require the owner to make his own bottle brackets and mounting locations.

STRAIGHTLINE PERFORMANCE 15250 Hornsby Rd Forest Lake, MN 55025 Phone 651-466-0212
www.straightlineperformance.com sales@straightlineperformance.com Fax 651-466-0213

Fuel Valve Settings:

When setting your fuel valve setting, first screw the small straight screw in all the way. Lightly seat the fuel screw and open to the appropriate setting, (as seen in the table below). Straightline’s settings are estimates and should be verified by the end user for optimal performance.

1-3psi. Pulse Pump Applications (ATV Applications)
20 HP Nozzle 7.5g per second – 1/2 turn open
25 HP Nozzle 10g per second – 3/4 turn open
30 HP Nozzle 12g per second – 5/8 turn open

3.5-5.5psi. Pulse pump Applications
20 HP Nozzle 7.5g per second – 1.5 turns open
25 HP Nozzle 10g per second – 1.75 turns open
30 HP Nozzle 12g per second – 2 turns open
35 HP Nozzle 15g per second – 2.25 turns open
40 HP Nozzle 20g per second – 2.5 turns open
45 HP Nozzle 25g per second – 2.75 turns open

40-60psi. Fuel Injected Machines
20 HP Nozzle 7.5g per second – 1/8 turn open
25 HP Nozzle 10g per second – 1/4 turn open
30 HP Nozzle 12g per second – 1/2 turn open
35 HP Nozzle 15g per second – 1/2 turn open
40 HP Nozzle 20g per second – 3/4 turn open
45 HP Nozzle 25g per second – 1 turn open

After initial setting; to lean machine down turn in 1/8 to 1/4 turns until desired mixture is achieved. Straightline Performance recommends the use of an O2 Sensor or EGTs for proper settings.

If the machine has 12VDC ignition or a battery, the use of that as your power source will work. If not, the use of the AA battery holder will supply enough power for a typical season. When using the battery pack do not let any of the exposed metal come in contact with any other items. Straightline suggests using a small holder to contain the the batteries and keep out of contact with any other items.

Nitrous Nozzle Information:
DO NOT remove the inlet fitting to the nozzle. The spray is perpendicular to the nozzles axis in a half circle pattern. Minimize nitrous contact with a nearby solid surface.

Nitrous Comparisons:

The main difference between our system and the competitors is the fact that we use a flow regulator to maintain a relatively constant nitrous flow rate over a wide range of nitrous bottle pressure, 300-900 psi. Since we have a constant nitrous delivery, we simply need to deliver a constant level of supplemental fuel, and this combination provides a constant horsepower increase over this bottle pressure range.
Some competitors use a pressure regulator to attempt to provide this constant nitrous flow rate. We have found that pressure regulators do not work as well as a flow regulator because some of the nitrous boils as it passes through the pressure regulator, therefore providing a mixture of liquid nitrous and nitrous vapor. This mixture can affect the nitrous flow rate as a function of nitrous pressure, actually flipping the curve over, actually making the nitrous flow greater at lower bottle pressure than at higher bottle pressure.
Another competitor uses the nitrous pressure as it exits a delivery manifold to pressurize the carburetor float bowls, thereby enrichening the carburetors to supply the needed supplemental fuel. This is a tricky thing to do, as the bottle pressure can be in excess of 1000 psi and the pressure that is applied to the float bowls is in the range of 1/10 of a psi or less. Even if this is accomplished properly, this still does not address that the nitrous delivery rate of this system is not regulated, and therefore the nitrous flow will be a function of bottle pressure, and hence supplemental nitrous horsepower will not be a constant but will decrease as the bottle pressure drops. Another problem is that carburetor compensators cannot be made to work consistently with this system. The fuel system Straightline uses is simple and extremely consumer friendly. A simple needle valve is used to adjust supplemental fuel flow. Most the model specific kits come with initial needle settings, and after the final tune, there should never be any need to re adjust the fuel again. On all the EFI machines the system does not require a costly fuel programmer to run. Savings of 300-400 on these kits is normal.

These kits are are available through SLED-WERX Racing here in Canada for only $669 CAD
please call 613 925 4015 or email sales@2koolperformance.ca for orders

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#2 87gtNOS

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Posted 16 September 2008 - 06:26 PM

Fellas, I am also around here to help out with these systems!


#3 dragon sp 800


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Posted 14 January 2009 - 12:23 AM

QUOTE (87gtNOS @ Sep 16 2008, 07:56 PM) <{POST_SNAPBACK}>
Fellas, I am also around here to help out with these systems!


wondering about a little info on how the nitrious & fuel makes its way to the engine & how does the fuel adjust.will i need to clutch for a diff rpm.i ran a air box nozzle & 2 fuel jets in the carb boots on my old 800 xc but always had trouble with the nos nozzle freezing up after a couple of quick runs ,it was a 30 shot holtzman kit. info greatly appreciated.let r rip.

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