Sorry if this have been covered before (If so please quote the thread) or i am opening a large can of worms.
Im very unsure of what to use.

Whats the pro's and con's?

Any BHP figures of either setup?

I need to know which is best before i go splashing out on new stuff.

Many thanks Locosters.


Matt

[Edited on 17/10/07 by matt.c]

What about an option for standard airbox and re-jetted?

There is very little advantage (if any) in using a foam filter over the standard airbox, unless you have clearance issues or can't get an airbox. Personally, I'd go for the airbox everytime but re-jetted to optimise the performance of the engine in a kit car.

Phil

[Edited on 17-10-07 by Hellfire]

Standard every time unless it's an out and out race motor, I don't think the japanese would have spent all that money designing and building these air boxes if a 50p foam filter worked better. waiting to be shot down
tony

Air box - it will run a lot quieter and will work just as well as a sausage.

Only main benefit for a foam filter (in my opinion) is if you like the look of one sticking out of your bonnet and induction roar.

Pat...

depends on the year of the bike engine, new engines there is little difference, older engines there can be power gains as the airboxes were restrictive. For a ZX9R 140bhp for standard set up, approx 150bhp with aftermarket air filter and re-jet.

Cheers

Ian

My engine is the ZX9R "C" so i could make a big amount of difference then?

Tonight i tried fitting the standard filter but its going to need alot of hacking about to make it fit, so the airbox idea is out the window!

I have heard a few things about sucking in hot air and turbulence. Whats peoples opinions on this?

If you reverse the airbox 180 degrees and remove a couple of inch of the top corner (will need blanking off), it will fit under the Indy with a bonnet bulge and possibly save yourself £200 in the process

Andy

Neither, you need a third option

3) Standard airbox and rejet

See my answer in the "ZX9 Vacuum Valve" thread

- Paul

How about new airbox but same jets

I made my own airbox because the ST1100 airbox is huge!!! Thought it needed a rejet because of this but TTS said it was actually pretty spot-on. They put a very thin shim washer under the needles on one bank to correct the AFR but in retrospect I suspect that was actually more related to a slight airleak upstream of the Lambda sensor... Never mind.

It may be possible to get away with standard jets but in most cases it won't be running optimally. A trip to the rolling road (as you did) is the best way to find out one way or another. Usually running on standard jets mean you have not got the best out of your intake/exhaust combo as its quite common to get a good 5-10hp gain if you get these right - hence more fuel needed.

Just to show how sensitive the carbs are to exhaust changes, I had to change jet sizes when swapping from an R1 can to a custom made race can. When you consider the variations in manifold design a rejet/needle height tweak is almost certain.

Cheers

Paul

quote:

---

Originally posted by progers
Neither, you need a third option

3) Standard airbox and rejet

See my answer in the "ZX9 Vacuum Valve" thread

- Paul

---

That'll teach me to read properly

Great minds think alike....

Homemade Airbox and larger mainjets worked for me on my carbed 5JJ
Set up by TTS on rolling road gave me around 122 at wheels.

Works very well.
Rescued attachment airbox2.JPG