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Old 04-15-2008, 07:19 PM   #1
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Default Restrictor Question

I know restrictors are used for obvious traction reasoning but how much fuel mileage will I be sacrificing switching from a 7.5 to a 9 in my Sportwerks .26?
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Old 04-15-2008, 07:34 PM   #2
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to much if your racing, ther smaller restrictor will allow the air to hit the fuel with more force or valocity, this is where the increase in runtime comes from using a smaller insert.
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Old 04-15-2008, 07:47 PM   #3
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I haven't played with restrictor selections yet, but as stated above, it would be great if someone could explain what's the use of a larger diameter restrictor

And they're called restrictors because the restrict bad fuel economy? Not performance?

Thanks
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Old 04-15-2008, 08:48 PM   #4
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I understand the dynamics of a carb, I guess what I was asking was a rough estimate of runtime I would lose going from a 7.5 to a 9. Would it be close to a minute or would I lose several mins? Also,would dropping down to a 6.5 to gain fuel mileage be a very noticable change in power?
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Old 04-15-2008, 09:01 PM   #5
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Quote:
Originally Posted by razor_clawzz View Post
I haven't played with restrictor selections yet, but as stated above, it would be great if someone could explain what's the use of a larger diameter restrictor

And they're called restrictors because the restrict bad fuel economy? Not performance?

Thanks
No they are called restrictors because they restrict air. Less air requires less fuel for an optimum air/fuel ratio. That is where the increased fuel economy comes from. If you leave your needles the same going from a 9mm carb to a 7.5 mm carb, the motor would be extremely rich, you would lean it down, run similar temps as the 9 mm setup, just have a lil bit less rip.

Just remeber this. It takes fuel to make horsepower, the more air a motor pumps, the more power it makes, of course like i mentioned, the more nitro you will burn.
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Old 04-15-2008, 09:17 PM   #6
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I understand the dynamics of a carb, I guess what I was asking was a rough estimate of runtime I would lose going from a 7.5 to a 9. Would it be close to a minute or would I lose several mins? Also,would dropping down to a 6.5 to gain fuel mileage be a very noticable change in power?
Here ya go, runtimes as follows 7.5 = 7 1/2minutes, 9 = 9 minutes...
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Old 04-15-2008, 09:27 PM   #7
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thats very wrong...
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Old 04-15-2008, 09:34 PM   #8
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heh heh. good one mr. engineer.
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Old 04-15-2008, 10:32 PM   #9
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Here ya go, runtimes as follows 7.5 = 7 1/2minutes, 9 = 9 minutes...
Yeah, I should probably put some air in my tires to huh?
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Old 04-15-2008, 11:13 PM   #10
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Actually u do need air in your tires, and u should try both restrictors and see which u like...
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Old 04-16-2008, 06:33 AM   #11
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Just remeber this. It takes fuel to make horsepower, the more air a motor pumps, the more power it makes, of course like i mentioned, the more nitro you will burn.
This is true but it also depends on how efficient your engine is....

Example: My first nitro engine was a modded Nosram evo 21 and it had good power, but used a tank in around 7 minutes...

My current engine is an OS Speed and it make more power than the Nosram and burns a tank in 11-12 minutes

Therefore, the Speed is using almost half the fuel to make more power!

Just food for thought!
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Old 04-16-2008, 05:55 PM   #12
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Originally Posted by lowey79 View Post
This is true but it also depends on how efficient your engine is....

Example: My first nitro engine was a modded Nosram evo 21 and it had good power, but used a tank in around 7 minutes...

My current engine is an OS Speed and it make more power than the Nosram and burns a tank in 11-12 minutes

Therefore, the Speed is using almost half the fuel to make more power!

Just food for thought!
True, design is a huge part of it. But just saying a high end .28 is more powerfull than a high end .21 is going to burn more fuel. Not only because of the cc increase but also because to the fact power takes fuel.
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