Terry, This is for kph in any gear. (((60/diff ratio) x tire circumference)/gear ratio) Divide 60 by the diff ratio, then multiply that answer by the circumference of the tyre in metres. Divide that answer by the gear ratio for the gear being used = kph in that gear. Eg. 60/3.7(diff ratio) =16.216. 16.216 X 1.83 metres circumference (205/60x13 tyre) = 29.675 this is kph for 1:1 gear (4th) For other gears divide by the gear ratio eg for 0.864 5th box 29.675/0.864= 34.346 kph For 1st gear 29.675/3.362=8.821kph etc
Cheers Feral Errol -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Terry Rudd Sent: Friday, 15 February 2002 10:48 PM To: [EMAIL PROTECTED] Subject: RE: Boot Release OK Errol, I'm havin' a bit of trouble with that formula, I'm doing something wrong with it and it gives me a funny number that doesn't mean anything to me. This is the way that I do it, and I'll explain to process along the way. The answer is expressed as: MPH/1000 rpm and you can either work it out using klm's direct or convert the mph number at the end. I'm going to do it in mph as that's what I'm used to, and I'll recognise a stuff up on my part. What you need to know. Constant - This is 60000 which is the number of times the prop shaft rotates in 1 hour in the direct gearbox ratio i.e. 1:1 at 1000 engine rpm (i.e. 1000 * minutes in 1 hour) Diff ratio - you need to know how many times the rear axle and therefore the wheels rotate in 1 hour at the constant rate. Tyre size - You need to know how many times your tyres rotate in a mile. You can get the number of rpm direct from good tyre sites for most popular sizes - Bridgestone USA is my favourite and I usually use RE92 Potenza or if you measure the circumference of the tyre in inches you can work out how many times they rotate in a mile. Now you can work out how far the tyres have gone in 1 hour at the constant rate i.e. engine speed of 1000 rpm. The formula: (((constant/diff ratio)/tyre rpm)/gearbox ratio)*(engine speed rpm/1000) = mph Let's plug in the data for the question that Dave asked for his Stanza At 1000 rpm (((60000/3.7/894)/0.854) = 21.2 mph so at 6500rpm the road speed is 21.2 * 6.5 = 137.8 mph or 221.8 kmh OK, for those of you still reading you can now check the accuracy of your speedo and also work out what speedo drive you need for a particular diff ratio. It's pretty easy to do but you have to understand a few things to get it done accurately. A speedo also has a built in constant. Not all of them use the same method but most Datto speedos use 1024 speedo cable rpm to indicate 60 mph. The constant figure is usually written somewhere on the speedo face so have a look for it next time you've got a speedo out. The constant usually is a number of cable rpm for 1/2 the total speed range, hence the 1024 @ 60 mph for the 120 mph 1600 speedo (Niles). Kmh speedos are the same but they will have a number of cable rpm to indicate 100 kph. A tip with Datto speedos is that they have a small amount of adjustment built in to the hair spring so that the rate that the magnet spins the disc at 1024 cable rpm can be varied slightly in relation to the cable rpm. The range is in the order of +-6% which is very handy if you change your diff ratio from standard by < 6% eg from a stock 3.7 diff, you can adjust the speedo to be acceptably accurate with either a 3.54 or 3.9 diff without changing the speedo drive in the extension housing. The small problem with an old speedo that's done 100k miles at a constant hair spring tension is that they don't adjust to well if you need to reduce the hair spring tension as is the case for when you go for a taller diff eg (3.54), it works damn well the other way though for a 3.9. As the odometer is also run off the disc in a Datto speedo it is also adjusted in relation to the indicated speed. This is why those distance markers on the side of the freeways are sort off useful to check your speedo accuracy up to a point as there is a direct link between the odometer and speedo accuracy but don't bank on this before you go speeding though and also they are always in klicks (for the record 5k's is 3.1 miles.) A speedo drive is driven by a worm gear on the gearbox output shaft. There are two ratios used in Datto boxes and you have to know which one you've got in your gearbox. The steel type drive holder has a 5x worm and the alloy type longer drive is 6x. We'll use Dave's stanza box again, it's doggy and they have the steel 5x drive. In 4th gear the Stanza is doing 3308 rpm @ 60mph. To work out how many teeth are required to indicate 60 mph on the speedo we need to do some more math. The formula: ((output shaft rpm at 60 mph * worm gear ratio)/speedo cable rpm to indicate 60 mph) = speed drive gear (i.e. number of teeth) ((3308 * 5)/1024) = 16 Say Dave changes his diff ratio to a 4.111 (like we do) His engine rpm at 60 mph in 4th gear will increase to 3675 Let's work out what speedo drive he needs to fit to get his speedo accurate again. ((3675 * 5)/1024) = 18 Easy eh? regards Terry -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of E Smith Sent: Thursday, 14 February 2002 7:19 AM To: [EMAIL PROTECTED] Subject: RE: Boot Release (((60/diff ratio) x tire circumference)/gear ratio) Cheers Feral Errol -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of FJ510 Sent: Thursday, 14 February 2002 12:42 AM To: [EMAIL PROTECTED] Subject: Re: Boot Release what's your calc for this? ----- Original Message ----- From: "Terry Rudd" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, February 13, 2002 8:38 PM Subject: RE: Boot Release > With 195/60x14 tyres, 3.7 diff, 0.854 5th @ 6500rpm? ~222 kph (138 mph) on > new tyres, a bit slower if they're worn. > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of David Costello > Sent: Wednesday, 13 February 2002 9:22 PM > To: [EMAIL PROTECTED] > Subject: Re: Boot Release > > > what's the equation to work out speed from gear ratio, diff ratio, tyre size > and revs?? > > I was sitting on 6500rpm in 5th gear (Dogleg SSS 5spd) with a 3.7 rear end, > and 60 series tyres on 14" rims the other night and I wanna work out how > fast that is cause the speedo only goes up to 180 on the dash. > > Dave > ----- Original Message ----- > From: "E Smith" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Wednesday, February 13, 2002 6:15 PM > Subject: RE: Boot Release > > > > 3.382 > > 2.013 > > 1.312 > > 1 > > 0.854 > > > > > > Cheers > > Feral Errol > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED]]On Behalf Of David Costello > > Sent: Wednesday, 13 February 2002 4:50 PM > > To: [EMAIL PROTECTED] > > Subject: Re: Boot Release > > > > yeah I was after those ratio's too was about to start a new thread and ask > > I want them to try and work out what speed I've had the stanza upto, the > > speedo only goes upto 180 so I don't know haha > > ----- Original Message ----- > > From: "Richardson, Thomas Morgwn - RICTM002" > > <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Wednesday, February 13, 2002 3:08 PM > > Subject: RE: Boot Release > > > > > > > Hey Nick, you're pretty cluey about all things Stanza, do you know what > > the > > > ratios in the 5 speed SSS box are? > > > > > > Cheers, > > > > > > - Tom > > > > > > -----Original Message----- > > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] > > > Sent: Wednesday, 13 February 2002 2:26 PM > > > To: [EMAIL PROTECTED] > > > Subject: Re: Boot Release > > > > > > > > > Hey, you are freaking me out! > > > > > > I have a remote boot/fuel filler release from a SSS Stanza at home I got > > it > > > from a U-Pull wrecker along with the Gearbox. I also saw but did not > take > > a GL > > > Stanza Boot only release. > > > Both square headlight models. > > > > > > Perhaps it was an aftermarket job, but it fits like it was designed for > > that > > > installation.. > > > > > > I also have a Bluebird TRX one. > > > > > > My car is about as classy as a $2 Hooker so I haven't installed these > > niceties > > > yet. > > > Nick > > > > > > > > > > > From: "David Costello" <[EMAIL PROTECTED]> > > > > Subject: Re: Boot Release > > > > Date: 13/02/2002 12:55:42 > > > > To: <[EMAIL PROTECTED]> > > > > > > > > I've owned 4 stanza's all of which were SSS and later square headlight > > models > > > and never seen one with mechanical boot or fuel filler release ?? > > > > > > > > Dave > > > > ----- Original Message ----- > > > > From: [EMAIL PROTECTED] > > > > To: [EMAIL PROTECTED] > > > > Sent: Wednesday, February 13, 2002 12:22 PM > > > > Subject: Re: Boot Release > > > > > > > > > > > > SSS and other late model Stanzas have mechanical release boot AND > fuel > > > filler flap. Bolts straight in. > > > > Bluebird also has remote mechanical release, cheaper and easier to > > get. > > > Harder to hook up though. > > > > > > > > What do you do if the solenoid, or linkage, fails and you have no > boot > > > lock? > > > > > > > > Nick > > > > > > > > > > From: "David Costello" <[EMAIL PROTECTED]> > > > > > Subject: Boot Release > > > > > Date: 13/02/2002 12:01:40 > > > > > To: "Ozdat Mailing List" <[EMAIL PROTECTED]> > > > > > > > > > > I wanna hook up either an electrical or mechanical in cabin boot > > release > > > in my Stanza, via either a switch/button on the dash or a lever down > > beside the > > > seat, and remove the external bootlock all together, what model car > should > > I be > > > grabbing the parts from? > > > > > > > > > > Dave > > > > > > > > > > > > > > > > > > This message was sent through MyMail http://www.mymail.com.au > > > > > > > > > > > > > > > > > > > > > > > > -------------------------------------------------------------------------- > > ---- > > > > > > > > > > > > I wanna hook up either an electrical or mechanical in cabin boot > > release in > > > my Stanza, via either a switch/button on the dash or a lever down beside > > the > > > seat, and remove the external bootlock all together, what model car > should > > I be > > > grabbing the parts from? > > > > > > > > Dave > > > > > > > > > > > > > > This message was sent through MyMail http://www.mymail.com.au > > > > > > > > > > > > > > > > > > > > --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]/ ---------------------------------------------------------------------
