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RE: [FOT] merge colectors

To: "'Jack W. Drews'" <vinttr4@geneseo.net>, fot@autox.team.net
Subject: RE: [FOT] merge colectors
From: Bill Babcock <BillB@bnj.com>
Date: Fri, 2 Jun 2006 11:00:56 -0700
I don't know about everyone else, but I'm busy fixing Peyote's nose after
hitting the wall at Mission last weekend. Total cost so far is $244, and I
pretty completely wiped out the nose and the nose structure subframe. What a
great car. I think I got away for quite a bit less than the Lotus 23 that
got turned back into a kit in the next session, or the McLaren Formula 5000
that I understand did the same thing on Sunday. I wasn't there, I was taking
the "drive of shame" back home. Mission is a bit tricky in the rain,
especially for a high-strung go kart like Peyote. 

I know we all talked about merge collectors some time ago without much
resolution. I don't know if they help but I sure like looking at them. The
manufacturers, and for that matter a lot of racers, swear by them, but
getting them to actually do something is probably tricky. I spent a lot of
time and effort on headers and expansion chambers long ago, and decided that
at that time there were too many factors influencing the compression and
extraction pulse timing for computer simulation to yield anything but an
approximation. Still, the approximations I got from 3,000 lines of FORTRAN
(on hollerith cards!) won races.  

We've come a long way in computing power and modeling since then, but I
suspect the header manufacturers are not using anything all that zooty to
design their collectors and position them on the pipe. 

That's a very long way of saying your mileage will vary and a hacksaw is
your friend, but that's what I figure. You'll need to tune it on a dyno to
see much from it. Incidentally, you can weld a washer on a rod and slide it
up and down inside a straight pipe and change power output dramatically at
specific RPM. Been there, done that, got the burned fingers. Not useful for
most engines, but the 50cc road racer I used to tune in the mid-70's for a
spectacular kid named Karen White profited greatly from tuning it's
expansion chamber that way. She'd hit 9000 RPM and it looked like the
nitrous kicked in--all the way to about 9750. We went through a lot of head
gaskets tearing that bike down to answer protests. With a $100 "gasket fee"
and a $5.00 gasket cost it was the most enjoyable thing about running that
bike. Well, that and looking at Karen after she leaped chest-first into
puberty. 

> -----Original Message-----
> From: owner-fot@autox.team.net 
> [mailto:owner-fot@autox.team.net] On Behalf Of Jack W. Drews
> Sent: Friday, June 02, 2006 9:53 AM
> To: fot@autox.team.net
> Subject: [FOT] merge colectors
> 
> The FOT list has been entirely too quiet lately. It gives me 
> the heebiejeebies when I come in here and see this empty 
> screen. Assuming that everybody is out playing with their 
> cars but might look at their screens occasionally, my latest 
> question is
> 
> Does anybody know for sure if a merge collector is of any 
> benefit on our four cylinder relatively low revving engines?
> 
> I'd test mine with and without on the chassis dyno but that 
> is a really difficult thing to change at the dyno shop.
> 
> The reason I'm asking is that I put on a merge collector from 
> Burns Stainless a couple of years ago and other guys still beat me.
> 
> uncle jack 
> 
> 
> 
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