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Fuel Return Line
Pdlewis - 11/4/08 at 07:17 PM

This sounds like a silly question to me bu going to ask it any way.

Is it ok to run say a 10mm fuel line to feed the engine and have a 6mm return? Its a 02/03 R1 engine

NeilP - 11/4/08 at 08:25 PM

Probably not but they are usually the same size - Most people use 8mm so the 6mm return might be a little small?...

What BHP are you expecting and what are you on - injection or carbs?

MikeRJ - 11/4/08 at 10:21 PM

Not a good idea, the return should be at least as large or preferably larger than the feed since it is a low pressure line. Any restriction here will increase the fuel rail pressure.

matt_claydon - 12/4/08 at 03:00 AM

quote:
Originally posted by MikeRJ
Not a good idea, the return should be at least as large or preferably larger than the feed since it is a low pressure line. Any restriction here will increase the fuel rail pressure.


Agreed, a restrictive return will have the same effect as turning up the fuel pressure regulator. May be negligible effect but hard to say - not worth the risk in my opinion. Any particular reason not to just use 8mm like most people do?

Bluemoon - 12/4/08 at 07:14 AM

On a carbed sierra the return is smaller than the feed! I would stick with the same size for simplisity anyway (and one real of 8mm copper will do both)..

Dan

MikeRJ - 12/4/08 at 12:28 PM

quote:
Originally posted by Bluemoon
On a carbed sierra the return is smaller than the feed!


Then again a carb is not sensitive to fuel pressure, as long as it's low enough for the needle valve to operate correctly.