The Vacuum

So looking at the GRiSO from the front, you notice those two nice holes that where the hooter / horn or whatever you want to call in your countries flavourful language hide. I was thinking, actually more like farting with my brain out, any case remember the old Kawasaki ZXR750..
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Now my mind tease started to scheme, what if you move / remove those two horns and run some sort of vacuum pipe to the airbox and create your own ram air  or at least create a source of clean air for the airbox?

If there is any warrant it would probably mean a bit twiddling with the fuelling.

Crap idea or maybe some merit?

Completely crap idea. Sorry. Apart from anything else such pressurisation mods for the airbox only begin to become even marginally effective at speeds well in excess of those at which one usually travels. Add in the convoluted routing required and the size of the airbox and you'll end up creating problems rather than making gains. We won't even start to talk about the effects on charge transition with the cams if you were to force induction.

Pete

Please return brain to head and say 'pardon me' for farting.
O

Quote :

We won't even start to talk about the effects on charge transition with the cams if you were to force induction.

I don't think the injection pulse-widths could be increased enough to cope.






I will give you some cred for posting a pic of a bike I lusted after when I was far younger and thought I could ride faster than I actually could.

Carb 1100 Sports were horrors for running the Ram Air system with a pair of dirty great DellOrtos. Lots of people rimmed out the airbox and added pods and the wretched things ran infinitely worse because with a pressurised box you have to pressurise the float bowls too and if you don't it completely screws up the carburetion. Dunno what happened with the Sport Injected but the cam timing on those was still quite pedestrian and conventional. The 8V is Weird Harold Central in the cam department.

Pete

All jokes aside, there is merit in ram air system with fuel injection. Generally speaking, you don't end up with a pressurized airbox, but usually a static pressure during cruise due to the ram-air equalizing the vacuum. This has advantages when you crack the throttle open, as there's a more air to suck in because the usual massive increase in vacuum is offset by the static pressure. The air being at ambient temperature helps, as you get a cooler (and therefore more dense) charge.

So you might get a better throttle response at speed. But, realistically, you might be looking at 1-2% power increase. Hardly worth it IMO.

As Roper-San says, the special needs 8V head with its charge transition issues would be a irksome to get right. Think plummeting mileage.

Once again this is another example of why when thinking about any modifications it's important to look at the whole engine holistically. There are so many factors from the size and shape of the airbox and inlet tracts through the head and combustion chamber design, piston crown shape, bore and stroke dimensions, cam lift, duration and overlap, exhaust shape and length, the list goes on....!

Quite simply this idea so widely believed that all modern engines are somehow strangled and all you have to do to release some incredible 'Inner Demon' is to 'Open it up and add more fuel' is not only wrong but is actively counter productive as it encourages simplistic solutions to very complex issues.

Do I have the answers? Hell no! But I do know what won't work and realise that quite often you need to look at and approach things obliquely to achieve the desired results.

Pete

Would it work "easier" on an 1100?. I spose that's the down side to havin a bike with valves that breed like rabbits...

No, not really.

Ok then back to plan a, mount pair .30 brownings in those holes

Put little propellers in them and tell people lies about what they do

Ahdammit wrote:

Put little propellers in them and tell people lies about what they do

Take some off a Benelli.

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