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Re: Airbox's??

To: Ronnie Day <ronday@home.com>,
Subject: Re: Airbox's??
From: Dan Neuman <dneuman@stars.sfsu.edu>
Date: Tue, 9 May 2000 23:46:32 -0700
Hi Ron,

>Daniel,
>
>I'd think you could repair the threads with heli-coil inserts. I'm not 
>sure of the size, but hopefully someone else has offered that info by 
>now. There are a couple of sources for Weber and Solex parts out your 
>direction. I'll do some digging and forward what I find, again if someone 
>else doesn't sooner.

        Have not heard anything yet on the thread size.. I am embarrassed
to admit I do not know what helicoils are??

>Regarding your idea of rolling your own cold air box, you might consider 
>the following. Use the stock base to make a pattern so you don't have to 
>cut on the stocker. I plan on doing something similar with the factory SU 
>heat shield for the L-motors in the 510s. I think the OEM heat shield is 
>a fair start, but if it were larger it would be more effective. 

        This is what I am planing on doing.. The stock solex aircleaner
base has little vel stacks built in. I just plan to make  a BIG fiberglass cap 
to 
fit on to it.  I do not plan on cutting up the stock aircleaner at all, to rare 
I 
suppose.
>
>I'd think that if you allowed a clear space above the stacks equal to the 
>carb throat diameter there would be plenty of airflow for virtually all 
>conditions. So..., if you use 20mm stacks on 44mm carbs you'd need 
>approximately 3 inch tall elements in a comparably sized box. I'd also 
>think that you'd need to support a box of this size externally to avoid 
>putting too much stress on the carbs. Something else I've wondered about 
>is if feeding/ramming cold air into a closed box might not generate 
>turbulence that can upset the fuel/air mixture. I suspect having air 
>cleaner elements inside the box would probably dampen any disturbances.

        Yes this is something to be concerned about.  I have two excellent
books that cover this subject pretty well.  They are for motorcycles but hey
same difference. the Books are 'Sportbike Performance Handbook' by 
Kevin Cameron.  Good section on ram air and rejetting carbs and such the 
other is Motorcycle Turbocharging Supercharging and Nitrous Oxide.  Good 
section on ram air also.. Its funny a lot of the draw thru super-turbo charged
bikes suck thru a 44phh Mikuni carb?!?!? Crazy ehh??
        Reducing tubulence has to do with the port size and shape and air
box size and shape.. I think that you have to slowly reduce the air velocity 
so that by the time it hits the airbox it will not cause as much turbulence/
have a higher pressure.  I hope to build in a resonance around 2000 rpm to help 
boost my low end.. though I am not sure if that will really kill my top end.
        Good thing about the Mikuni's is that the float bowls appear to be 
already vented to the airbox so I will not have to worry about a differential 
in pressure sending fuel back into the float bowls.

>
>Please post what you wind up doing, with pictures. Speaking of pictures, 
>you might look at
        Irene is promising to do up a super professional web page for me 
after I graduate..have to look for a grown-up job..Anybody looking for a 
bio-engineer with a masters in physics??  I hope to have a good sized section
on my car then...
>
>< http://zcarmag.com/images/shasta/>   
>
>and select the second picture from the right in the group that I shot 
>last summer at Shasta. It's a shot of Mark Nuenke's turbo L-20 that shows 
>the cold air set up in his 510. This thing has pretty much all the bells 
>and whistles. The rest of the car is just as well finished as the engine, 
>too.
        I remember this car and picture. This is what put the idea in my 
head to begin with!!
        Daniel 69 2000
        SF CA



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