Which uses less fuel?

[SoulKiss]

Originally Posted by startrek.steve

Whats a sid squid?

This is a Sid Squid

Originally Posted by breakz187

I thought that the engine braking causes the vacumn to build up massively, reducing the amount of pressure within the fuel pressure regulator. I thought this was how it worked on injected petrol engines anyway. Obviously the injectors will have different control logic but i dunno...

Think thats a fair bit old on the early injection engines.
Things have come ona long way since then.

But on a modern engine, rolling + in gear uses no fuel, but taking it out of gear and idling uses quite a bit of fuel.

Tend to agree with Jambo, modern Fuel Injection systems will not inject any fuel into the combustion chamber when at 0% throttle, however in older FI engines this may not be the case. Anything with a carb will use fuel on 0% throttle.

[Sid Squid]

Originally Posted by jambo

Depends on the fuelling system. Top Gear took a V8 diesel Audi to Edinburgh and back on a tank of fuel a couple of years back. With the modern FI in that if you coasted with your foot off the gas the FI put no fuel into the engine at all, as the engine braking was keeping it turning. A similar system was much criticised on Yamaha's FZ1 when it came out as it led to a hesitation as you went from negative to positive throttle while cornering.

Carbs, of course will always add a little fuel as long as the engine is turning, but using smooth, gentle throttle in the correct gear and not building up speed that you then need to scrub off helps fuel economy.

He's right. As for the later comment about the Yamaha, all FI systems go 'dry' on high vacuum/shut throttle.

Originally Posted by jambo

If all else fails, fit a Sid Squid, annoyingly this makes more difference to fuel economy than anything else I've tried.

There's no substitute for being fiscally sensitive, .

[Spikenipple]

Are you sure no fuel is injected (FI bike obviously) when the clutch is out and you're engine braking?
That would effectively be the same as flicking the kill switch, which is completely different than just using engine braking (on my bike anyway, it slows you down a lot faster). I was under the impression that it will inject just the amount of fuel it needs to stay at idle speed.

Originally Posted by Sid Squid

He's right. As for the later comment about the Yamaha, all FI systems go 'dry' on high vacuum/shut throttle.


There's no substitute for being fiscally sensitive, .

So whats the going price in today's climate for Sid Sqid after maket mod? What does the bidding start at?

i read somewhere that with carbed engines it makes a difference to the fuel usage when coasting but with the electronic injected engines they use more fuel when coasting than if you stay in gear as the injectors shut down or something btu i may be talkign out of my bum.....