Errol, According to http://www.grapeaperacing.com/GrapeApeRacing/tech/intaketuned.cfm A 1-1.5 degree taper on the runner is optimal, my taper is over 2.5 degrees so I don't think pushing it anymore would be good.
Dave >>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<< On 27/06/03, 17:51:59, "E Smith" <[EMAIL PROTECTED]> wrote regarding RE: 40mm weber ram tubes: > I meant the taper on the ram tubes and manifold not the plenum. > I can understand the logic you used in the plenum. > Cheers, > Feral Errol > Get Serious tm<http://www.datrats.com.au/> > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of David Andrews > Sent: Friday, June 27, 2003 2:06 PM > To: [EMAIL PROTECTED] > Subject: RE: 40mm weber ram tubes > Well the way I calculated it, that taper on the plenum means that there > should be constant pressure at the opening of each 6 runners. Ie the > cross sectional area at runner 6 is one-sixth of that at runner 1. This > assumes that there will be one-sixth the air at runner 6 as 5 runners > have done their job of sucking it out of the plenum before it gets there. > This is not strictly true i know, but it should be a relatively easy > thing to change once its going. I can then experiment with different > shapes and designs and see what happens. > Dave > >>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<< > On 27/06/03, 7:43:37, "E Smith" wrote regarding RE: > 40mm weber ram tubes: > > Looks good to me. > > A little more taper in the inlet would be good with larger inlet bell > mouths. This would mean you have to spread 1 & 2 and 5 & 6 runners a bit. > > Cheers, > > Feral Errol > > Get Serious tm<http://www.datrats.com.au/> > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] Behalf Of David Andrews > > Sent: Thursday, June 26, 2003 10:20 PM > > To: [EMAIL PROTECTED] > > Subject: RE: 40mm weber ram tubes > > Re your last two thoughts on manifold design, ie tapering in as you go > > from cylinder 1 to cylinder 4/6 and tapering the inlet runner in. Thats > > the way I have designed my manifold: > > http://thehelix.homelinux.net/davidandrews-240/pictures.phtml > > Yet to actually make it but is there anything really obvious from the > > pics that looks wrong? > > Thanks, > > Dave > > >>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<< > > On 26/06/03, 21:25:20, E Smith wrote regarding RE: > > 40mm weber ram tubes: > > > Yes it does build up considerable pressure for a milli sec or two. So > > when the valve opens, this helps overcome the small time interval > available > > for filling. > > > At high engine speeds the effect of the reflected wave is minimal (when > > compared to the column inertia) in the time available for filling. > > > It is important to remember the reflected wave travels at a set velocity, > > the speed of sound (26.8 m/sec) where the air in the inlet tract is > > travelling at 100 m/sec at wide open throttle at 8000 rpm. Designing a > > tapered "venturi style" inlet tract that increases the velocity even > > further as the air/fuel approaches the valve is a key to some large > > performances increases in very high performance engines. Some high > > performance inlet tracts on bikes reduce to 1/3 of the ram tube diameter > > when they reach the valve throat. That is ram tuning!!!!!!!!!!!! > > > Cheers, > > > Feral Errol > > > Get Serious tm<http://www.datrats.com.au/> > > > -----Original Message----- > > > From: [EMAIL PROTECTED] > > > [mailto:[EMAIL PROTECTED] Behalf Of David Andrews > > > Sent: Thursday, June 26, 2003 1:00 PM > > > To: [EMAIL PROTECTED] > > > Subject: RE: 40mm weber ram tubes > > > Errol, > > > Damn good point there. So what you're saying is that it is important to > > > consider that the air is moving down the inlet tract, and thus has > > > inertia because of its movement and mass. I would imagine that when the > > > valve shuts a nice fat (compession?) wave is sent up the tube in response > > > to the air smacking against the valve. And when you get up to high rpm's > > > perhaps the reflection of this wave back down the tract has some > > > influence also. I wonder what would happen when this reflected wave > > > reaches the valve at the same time as the valve opens and an expansion > > > wave is sent up? > > > Dave > > > >>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<< > > > On 25/06/03, 18:51:27, E Smith wrote regarding RE: > > > 40mm weber ram tubes: > > > > In any intake system there are two main conditions you are dealing with, > > > > resonant frequency changes of the inlet tract under a wide range of > > > engine > > > > speeds and the inertia of the gas column in the inlet tract. Air has > > > > weight! > > > > For every positive increase in cylinder pressure from wave motion there > > > will > > > > be a corresponding decrease at some other rpm. Nothing is free in pulse > > > > tuning you will usually encounter two major positive and two negative > > > > pressure harmonics if running up to 8000 rpm depending on camshaft > > > timing. > > > > If you tried for a node at the choke this would be fine on a single speed > > > > engine but as our engines are required to work over a wide range this > > > node > > > > position would be constantly changing. > > > > On the dyno last week, we tried back to back ramp ups of different length > > > > ram tubes and all had noticeably different performance curves. The best > > > > length was a surprise to me and the dyno operator as it worked well at > > > low > > > > engine speeds and also at high engine speeds. In the middle it had enough > > > > inertia to overcome the negative pulse created and increased air fuel > > > ratio, > > > > that was so noticeable with the shortest ram tubes. > > > > To do any meaningful work on ram tube lengths, you need to consider the > > > > cylinder head as a system. Inlet, Camshaft and Exhaust all parts of that > > > > system. During the cam overlap period the negative wave produced by the > > > slug > > > > of exhaust gases has an effect on the tuned desirable tuned length as > > > well. > > > > The majority of benefits from longer ram tubes do not come from pulse > > > > tuning. Rather the main benefit is from the inertia of the column of gas > > > > that is contained in the system. This slug of gas is moving at approx 100 > > > > m/sec at WOT. This column should be at least 1.2 times the volume of the > > > > cylinder being fed by the inlet tract so a complete cylinder fill is > > > always > > > > fully contained in the tract or mixture stand off can occur at WOT and > > > the > > > > mixture gets diluted and dissipated over the inner guard etc and larger > > > jets > > > > have to be used to compensate for the screw up in the pulses. > > > > There is considerable benefit to be had from port shaping to create a > > > vortex > > > > in the throat area just before the valve and by directing the charge into > > > > the cylinder to help cylinder filling > > > > Its worth noting that you have approximately 4 milli-seconds to fill the > > > > cylinder at 8000 rpm > > > > My 20 cents worth of opinion. > > > > Cheers, > > > > Feral Errol > > > > Get Serious tm<http://www.datrats.com.au/> > > > > -----Original Message----- > > > > From: [EMAIL PROTECTED] > > > > [mailto:[EMAIL PROTECTED] Behalf Of Robert Charles > > > > Scealy > > > > Sent: Wednesday, June 25, 2003 4:26 PM > > > > To: [EMAIL PROTECTED] > > > > Subject: Re: 40mm weber ram tubes > > > > Maybe you could get some difference if you made the distance from the > > > > port to the choke equal to the tuned length from the choke to the > > > > bellmouth exit, then you would have some chance of setting up a harmonic > > > > standing wave, with a node at the choke? Like if you pick a guitar > > > > string, and then place your finger over the exact centre of the string, > > > > you still get some of the sound? > > > > On Wed, 25 Jun 2003, David Andrews wrote: > > > > > Guys, what you are talking about is the RAM effect which occurs as > > > > > follows: > > > > > > > > > > When the intake valve opens, an expansion wave travels up the intake > > > > > runner. When it reaches THE FIRST JUNCTION, it is reflected back as a > > > > > compression wave. The RAM effect is using the compression wave to > > > > > compress the air into the cylinder just as the intake valve closes again. > > > > > It is apparently possible to achieve Volumetric Efficiencies above 100% > > > > > (for a specific rev range obviously). > > > > > What Kris said was correct, longer is for low end, shorter is for top > > > > > end: > > > > > > > > > > http://www.grapeaperacing.com/GrapeApeRacing/tech/intaketuned.cfm > > > > > > > > > > But if you actually plus the numbers in, you're not talking 1.5 inches. > > > > > You're talking more like 15 inches. The link above has some formulas for > > > > > working it out. But the important thing to note is that it won't make > > > > > fuck all difference on a car with carbies because the first junction > > > > > (where the reflection happens) is at the `out' side of the carby, not the > > > > > inlet side. > > > > > > > > > > However, using bellmouth shapes does increase the airflow into the carby > > > > > by reducing the turbulence around the opening. But the length of this > > > > > will have a negilible impact on the overall VE of the engine. > > > > > Regards, > > > > > > > > > > Dave > > > > > > > > > > > > > > > >>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<< > > > > > > > > > > On 25/06/03, 14:31:24, Richard Webb wrote > > > > > regarding Re: 40mm weber ram tubes: > > > > > > > > > > > > > > > > I found a pic of some on that race car that someone sent to the list > > > > > > recently.... > > > > > > > > > > > http://www.race-cars.com/carsales/other/1054143781/1054143781ph.jpg > > > > > > > > > > > They are tiny?? and the eggcups wouldnt need any extending.. I guess > > > > > > they are after high end. Isnt there a stainless bowl or cup or > > > > > > something I can modify... :) > > > > > > > > > > > ----- Original Message ----- > > > > > > From: "Kristian Walsham" > > > > > > Date: Wednesday, June 25, 2003 2:09 pm > > > > > > Subject: Re: 40mm weber ram tubes > > > > > > > > > > > > A long one will better suit low to midrange torque and power while > > > > > > > a short > > > > > > > one will produce more mid to top end. > > > > > > > I think most short ones are about 1.5 inches long while longer > > > > > > > ones are > > > > > > > about 2-2.5 inches long. You would have to design it around engine > > > > > > > bay space > > > > > > > and the type of cam you are using. > > > > > > > > > > > > > > Kris. > > > > > > > ----- Original Message ----- > > > > > > > From: "Richard Webb" > > > > > > > To: > > > > > > > Sent: Wednesday, June 25, 2003 1:48 PM > > > > > > > Subject: Re: 40mm weber ram tubes > > > > > > > > > > > > > > > > > > > > > > I know this has been discussed before but how long (idealy) > > > > > > > should the > > > > > > > > ram tubes be? Also how the hell do you join stainless steal? The > > > > > > > > article says use tig welder... or hose clamp? Any ideas, because > > > > > > > I dont > > > > > > > > have a welder... > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > > > > From: David Andrews > > > > > > > > Date: Wednesday, June 25, 2003 1:21 pm > > > > > > > > Subject: Re: 40mm weber ram tubes > > > > > > > > > > > > > > > > > If twas me: i'd be going from 47 (45 by moi) down to the 40 > > > > > > > with a > > > > > > > > > nice > > > > > > > > > cone rolled up by your local stainless shop. I'm doing the same > > > > > > > > > thing, > > > > > > > > > albeit longer, for my custom intake manifold. > > > > > > > > > > > > > > > > > > Dave > > > > > > > > > > > > > > > > > > >>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<< > > > > > > > > > > > > > > > > > > On 25/06/03, 15:36:55, Richard Webb wrote > > > > > > > > > regarding Re: 40mm weber ram tubes: > > > > > > > > > > > > > > > > > > > > > > > > > > > > Yeah just got the article, 47mm diamater isnt going to work too > > > > > > > > > well on > > > > > > > > > 40mm > > > > > > > > > > webbers. I'll have a look with one of them see what I can make. > > > > > > > > > > > > > > > > > > > I dunno how that Jullian Edgar guy comes up with 1/2 that > > > > > > > > > stuff.... hes a > > > > > > > > > > total car nerd :) > > > > > > > > > > ----- Original Message ----- > > > > > > > > > > From: "E Smith" > > > > > > > > > > To: > > > > > > > > > > Sent: Tuesday, June 24, 2003 5:11 AM > > > > > > > > > > Subject: RE: 40mm weber ram tubes > > > > > > > > > > > > > > > > > > > > > > > > > > > > Dave, > > > > > > > > > > Youve been reading Autospeed :-) > > > > > > > > > > > > > > > > > > > Cheers, > > > > > > > > > > Feral Errol > > > > > > > > > > Get Serious tm<" target="l">" > > > > > > > target="l">http://www.datrats.com.au/>> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -----Original Message----- > > > > > > > > > > From: [EMAIL PROTECTED] > > > > > > > > > > [mailto:[EMAIL PROTECTED] Behalf Of David > > > > > > > > > Andrews> Sent: Tuesday, June 24, 2003 2:42 PM > > > > > > > > > > To: [EMAIL PROTECTED] > > > > > > > > > > Subject: Re: 40mm weber ram tubes > > > > > > > > > > > > > > > > > > > > > > > > > > > > You may be able to make your own out of some egg holders from > > > > > > > > > > Safeway/Woolworths. They're $1.85 each here, perfect bellmouth > > > > > > > > > shape. ID > > > > > > > > > > of 44mm. Regards, > > > > > > > > > > > > > > > > > > > Dave > > > > > > > > > > > > > > > > > > > >>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<< > > > > > > > > > > > > > > > > > > > On 24/06/03, 14:01:59, "Kristian Walsham" wrote > > > > > > > > > > regarding Re: 40mm weber ram tubes: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > You could try Four Plus Performance in Brisbane ( i don`t > > > > > > > have the > > > > > > > > > > number) , > > > > > > > > > > > or Autosport in Vermont, Datrally in Cheltenam. > > > > > > > > > > > > > > > > > > > > I know i had a few spare somewhere, i will have to look. > > > > > > > > > > > > > > > > > > > > Kris. > > > > > > > > > > > ----- Original Message ----- > > > > > > > > > > > From: "Richard Webb" > > > > > > > > > > > To: > > > > > > > > > > > Sent: Tuesday, June 24, 2003 1:39 PM > > > > > > > > > > > Subject: 40mm weber ram tubes > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Hi guys, > > > > > > > > > > > > > > > > > > > > > > > > Can anyone tell me where abouts I might be able to get some > > > > > > > > > weber ram > > > > > > > > > > > > tubes/pods/trumpets (whatever you call them). The guy at > > > > > > > > > unifilter> > > thaught he had some but doesnt anymore! Now I've > > > > > > > > > rang up a few places > > > > > > > > > > > > and they are telling me no one makes them anymore??? > > > > > > > > > > > > > > > > > > > > > > > > Im in melbourne and would be interested in any info on > > > > > > > where to > > > > > > > > > > > > purchase them. > > > > > > > > > > > > > > > > > > > > > > > > Thanks in advance, > > > > > > > > > > > > > > > > > > > > > > > > Richard > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > --membersozdat------------------------------------------------- > > > > > > > ---- > > > > > > > > > -- > > > > > > > > > OZDAT Mailing List Please Note:- > > > > > > > > > Send (un)subscribe requests to [EMAIL PROTECTED] > > > > > > > > > Send submissions to [EMAIL PROTECTED] > > > > > > > > > No unauthorised redistribution of this email > > > > > > > > > http://www.ozdat.com/ozdatonline/index.htm > > > > > > > > > http://www.ozdat.com/ozdatonline/listindex.html > > > > > > > > > http://www.mail-archive.com/[EMAIL PROTECTED]/ > > > > > > > > > --------------------------------------------------------------- > > > > > > > ---- > > > > > > > > > -- > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > --membersozdat----------------------------------------------------- > > > > > > > -- > > > > > > > OZDAT Mailing List Please Note:- > > > > > > > Send (un)subscribe requests to [EMAIL PROTECTED] > > > > > > > Send submissions to [EMAIL PROTECTED] > > > > > > > No unauthorised redistribution of this email > > > > > > > http://www.ozdat.com/ozdatonline/index.htm > > > > > > > http://www.ozdat.com/ozdatonline/listindex.html > > > > > > > http://www.mail-archive.com/[EMAIL PROTECTED]/ > > > > > > > ------------------------------------------------------------------- > > > > > > > -- > > > > > > > > > > > > > > > > > > > > > > > > > > > --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[EMAIL PROTECTED]/ ---------------------------------------------------------------------
