Technical Articles & Reviews http://www.sideways-technologies.co.uk/forum/Blah.pl? http://www.eblah.com en Rotoflex Rear Suspension TUNING, The LO-TEC Way! http://www.sideways-technologies.co.uk/forum/Blah.pl?m-1209505353/ http://www.sideways-technologies.co.uk/forum/Blah.pl?m-1209505353/#num1 REAR SUSPENSION TUNING, THE LO-TEC WAY
By John R Davies (Cheers)


     The worst feature of the Triumph swing axle and variants is the astounding amount of positive camber that can occur. Positive camber means that the top of the wheel is further from the car's centre line than the bottom. When you are going round corners, positive camber is BAD!
  
     In a corner, the only thing that stops you flying sideways off the road is the grip of the tyres. For maximum grip, as much as possible of the tread should be in contact with the road, and in an ideal world the wheel would be always vertical on the road. However, because a tyre must deform even slightly, some negative camber is desirable. That is, the wheel top should be slightly nearer the car centre line than the bottom. Then, as the tyre deforms, all the tread    contacts the road.

     But in most cars, the suspension allows the wheels to move up and down and no one has been able yet to design a suspension that do so and does not allow some camber change. By having springs so stiff that the suspension hardly moves at all, Formula One racing cars come closest to this ideal, but at the expense of an impossibly rough ride. In our real world, with roads less than smooth and a general dislike of being shaken to death, we need softer springs and a suspension that moves up and down a bit.

     The standard Triumph swing axle suspension is particularly bad at camber angle change in movement. Can this be improved? There are many ways of doing so, but how can you decide what might be best, without a series of expensive experiments on your car?

     How can you decide between a spacer under the spring, different wishbone mountings, or drive shaft lengths? Which to use, alone or in combination? You need a lot of time, money or a degree in mechanical engineering. But here is a way to evaluate any possible modification of your suspension and assess the likely effects with some graph paper and cardboard on the kitchen table.

    You need the paper and cardboard to make a model of your rear suspension. Not a real model, but full size and in only two dimensions, which is quite enough for measuring camber. The graph paper needs to be about 600 x 460mm (2 x 1 .5ft), much bigger than the usual A4 pad, but tape some sheets together, or buy it by the roll at a stationer�s.

     You will also need to know the precise dimensions of your suspension, and the modifications you want to make. Many of these numbers are available from your workshop manual, or from club magazines (Ref: 1), but unless you are certain that your car�s parts are original, it will be best to get under and get measuring.

Measure or know for certain:


1/ HALF the length of the spring (eye centre to eye centre) (520mm/20.5")

2/ EITHER (Non-Rotaflex)
          Length of drive shaft, U/J centre to tyre centre.
And: Height of vertical link, from drive shaft centre to spring eye.
OR (Rotaflex)
        Height of Vertical link, wishbone eye centre to spring eye centre (232mm/9.1")
And: Wishbone length, chassis bracket eye to vertical link eye centres. (235mm/9.25")
(The dimensions given are for my own Rotaflex Vitesse, for you to try out this method.)



Making the model.

     This is how to make a Rotaflex model. Other variants can be made in the same way. Cut two strips of cardboard, and join them together at one end with string, a paper clip or other means of allowing them to pivot on each other, like the hands of a clock. Mark them so that the distance, from the pivot point to the marks is the same as the actual lengths of the wishbone and vertical link.

     On your graph paper, draw a vertical line, parallel to the right hand side of the paper. This is the centreline of the car. Draw another line at right angle to this, about a third of the way down the paper, and measure along it HALF the spring length. This marks the NEUTRAL position of the spring.

     Using a piece of string as a compass, draw an arc to show how the spring moves from bump (up) to droop (down). Remember that the spring is bolted to the top of the differential, which is four inches wide, so that this centre part of the spring hardly moves. Centre your "compass" two inches along the spring line away from the centre line.

     Mark the limits of spring movement. Unless you have fitted wider tyres or other modifications, in which case me e these as well, use 50mm of bump and 66mm droop.

     Now draw a vertical line 285mm(11.2") to the left of the centre line and a point on it 158mm(6.2") below the spring neutral line, to mark the normal position of the wishbone bracket.  Look at the diagram if this is not clear.   Please note: these dimensions are correct, I think, for the Rotaflex Vitesse. GT6s may be different, though I doubt it. Your model is now complete!

Using the model.

     To operate the model, place the cardboard vertical link/wishbone assembly on the paper, and fix the inboard end of the wishbone to the wishbone bracket point with a drawing pin. Set the top of the vertical link on the spring movement arc, and move it from bump to droop. As you do so, you will see that the vertical link is not always in a vertical position. In fact, it will change, from slightly negative camber (top of wheel in. bottom out) in bump, to wildly positive (top out, bottom in) in droop. The wheel is always parallel to the link, so this camber is the same as wheel camber.

     Use a protractor, that semicircular piece of plastic that you measured degrees with in school geometry to measure the camber angle. Line up the straight edge of the protractor with the edge of the "vertical link", and read off the angle from the vertical lines on the graph paper. You may have to slide the protractor up and down the "link" a bit to find a good place to measure, especially when the angle is near zero. Remember that negative camber (good) has the top of the wheel, or "link" nearest the centre line.
     
       The instability of the swing axle is due to the amount of positive camber that it produces, and the change in camber across the range of movement. Remember, when cornering hard the car leans outwards and the outer wheel is in bump (up) while the inner wheel is in droop (down). Very confusing for the poor car! The Rotaflex version is little better.
     
       Now that we have a model, we can experiment and find the best modification, at no cost and without dirty hands! You will find that changes in the suspension are easily simulated. Remember that raising the spring and lowering the wishbone bracket are the same in terms of this model, although the first will do more to lower the centre of gravity of the car. Measure either change along the vertical line for the wishbone bracket.


By manipulating the model, some very interesting figures result:

Table 1. Wheel camber from bump to droop.

Different spacers under spring.

                                         Bump     Neutral      Droop
Normal position                    -1           +2            +8
25mm spacer (1")                   -1         +1              +5
50mm spacer (2")                  -0.5        +0.5            +2
               
(All figures are in degrees.   "+" = positive camber.  "-"  = negative camber)
     
      Table 1. shows that a two-inch spacer gives the least camber change from bump to droop. However, a spacer this tall is too big to fit without modifying the floor of the rear body tub to accommodate the higher spring. Let�s look at the effect of changing the wishbone bracket:

Table 2. Wheel camber from bump to droop.

Different wishbone brackets.

                                  Bump     Neutral          Droop
Standard bracket              -1            +2             +8    (as above table)
"Racing" bracket                -2           -0.5           +3.5
Eickoff 'A' bracket                0             +1            +3.5
Eickoff  'B' bracket              +1            +1            +1.5

Differences from standard bracket

"Racing"           =25mm    (1") down. 5mm (0.2") out
Eickoff "A"          = 44mm   (1.7") down
Eickoff "B"          = 66mm   (2.6") down



     These three designs of wishbone bracket all lower the eye below the standard position. The �Racing� design also pushes the eye out by 5mm. The Swedish engineer, C.H.Eikhoff described the other two designs in an article in the TSSC publication "Turning Circle" (Ref: 2). He predicted, from theory and detailed engineering drawings, both the bracket position for the least strain (plunge) on the Rotaflex doughnut (Eikhoff A), and for minimum change in camber (Eikhoff B).

     Without boring you further with tables, it is sufficient to point out that Eickoff was right, at least about camber change. His "B" bracket does produce the minimum of camber change, but the camber always remains positive. The "Racing" bracket on the other hand imposes more change, but mostly stays in negative camber.

     Further experiments show that the combination of a 25mm spacer to lift the spring and the "Racing" bracket produce the optimum position:

Table 3. Wheel camber from bump to droop.

                                                                                      Bump    Neutral     Droop
25mm spacer under spring PLUS "Racing" bracket         -1             -2            +1

Observation with a jack under the car, and testing on the track confirm that this does happen.

Further experiments.


     As you can see, it would be easy to make and modify a similar model for cars with the swing axle, by making a cardboard drive shaft and changing the length. Different spring lengths can be modelled. I am sure that even swing spring cars may be modelled, but I have not done so. Would anyone with such a car like to give it a try?



Above image shows how to accurately place the rotoflex bracket to factory specs.

References
1 / John Thomason "Suspensions sussed". Courier August 1993, p31,
2/ C.H.Eickoff "Rear Suspension Talk", p9. Turning Circle Feb.1989
(Both published by the Triumph Sports Six Club of the UK.
       Back copies or reprints may be available)

*side note by Dave*... I may or not agree with what is described as optimum! I'd personally like -2 deg of camber static, growing to -3.5 over the first 1 inch of bump....which the racing bracket is most likely to give. (DISCUSS?)

Please ignore wonky tables, you can make sense of it I am sure? I will learn how to use the table command setup (oneday)]]> Tue, 29 Apr 2008 22:42:33 Apeman Race Car Wiring for Beginners http://www.sideways-technologies.co.uk/forum/Blah.pl?m-1202573084/ http://www.sideways-technologies.co.uk/forum/Blah.pl?m-1202573084/#num1

Energy is defined as the work done when a force acts on any system. A force of one Newton acting over a distance one Metre produces one Newton-Metre of work, or one Joule of energy.

Power is defined as the rate of change of energy with time. One Watt = One Joule per second.

The Coulomb is a measure of electric charge and is approximately 6 ×1018 electrons.

Current is a measure of the displacement of electric charge. One Ampere represents the rate of one Coulomb of charge per second.

Voltage is defined as the potential difference across a conductor. One Volt occurs when a current of one Ampere dissipates one Joule of energy per Coulomb of charge.

Resistance is a measure of the degree to which an object opposes an electric current passing through it. Assuming a uniform current density, an object's electrical resistance is a function of both its physical geometry and the resistivity of the material from which it is made.

R = (L x P) / A

Where: L is length, A is cross-sectional area, P is the resistivity of the material.



It therefore follows that if one Amp is a Coulomb per second and one Volt occurs when one Joule of energy is dissipated per Coulomb, then the power generated is one Watt. Therefore:

P = I x V

Where P is Power, I is current, V is voltage (the easy way to remember this is Watts = Amps x Volts).



Ohm's Law states that, in any electrical circuit, the current passing between two points through a conductor is directly proportional to the potential difference (voltage) across the two points, and inversely proportional to the resistance between them. The mathematical equation that describes this relationship is:

V = I x R

Where V is voltage, I is current, R is resistance.




Using these 2 equations we can always work out the current requirement(s) for any given electrical component in a car. If we know the current requirement we can use the appropriate grade wiring, fuses, and/or relays.

This way, we can wire the car in such a fashion that we don’t:

1. Use over graded wiring (which is a weight penalty.
2. Use under graded wiring (which will lead to excessive current flow, overheating and, eventually an electrical fire.
     

]]> Sat, 9 Feb 2008 16:04:44 Debs Wiring Lightweight Nippon-Denso Alternator Triumph http://www.sideways-technologies.co.uk/forum/Blah.pl?m-1202093666/ http://www.sideways-technologies.co.uk/forum/Blah.pl?m-1202093666/#num1 This is how to WIRE Nippon-Denso alternators; like this shown below.

Fitting to: Spitfires and GT6 Triumphs. Maybe applicable to ANY Triumph with some commonsense poured on, even MG and any LUCAS equipped classic.






This is NOT a procedure for retro fitting Triumph Lucas alternators.

This covers the Nippon-Denso, Kubota, Brise Alternators.

I LOVE these alternators. 40AMP BULLITPROOF total Japanese reliability.

If the Alternator looked those shown above, it should be good to go, BAR if it's a 1 wire model (covered at the very end of this article).

I will cover fitting them later, from the info here, you should be able to rewire an ALTERNATOR equipped 1500 or GT6 Mk3 or any British car with some thought.
----------------------------------------------------------------------
This is the procedure for wiring it to a dynamo equipped Triumph Spitfire Mk1-2-3 or GT6 Mk1-2
----------------------------------------------------------------------
First technique is using existing wiring, advise taking the time to REWIRE and not following this section.

You will need to remove the control box for GOOD.

At the control box you will see as shown below 6 terminals



1, connected = 2x BROWN (1 to ignition switch, 1 to Starter Solenoid
2, connected = 1x BROWN (to LIGHT SWITCH)
3, connected = 1x Thin Brown/Green (to small connection on Dynamo)
4, connected = 1x Thin Brown Yellow (to ignition warning lamp on Speedo)
5, connected = LARGE Brown/Yellow (main power feed from Dynamo)
6, connected = Black (Earth to body)

Firstly remove the black wire (6) and remove it from the car completely. It's no longer needed.

Remove all the wires, label them as above, 1-2-3 etc and remove the control box, save it!

Maybe give it to a friend?

We now have a bunch of wires.

Strip off the connectors and insulations from ALL of them.

Get the Large Brown/Yellow wire (was connected to 5) and the 3x Large Brown wires (were connected to 1-2). These must be joined together; solder and heat shrink them to link them all together.

This now means the Alternator is driving the power into these brown wires, as needed and they are connected and the battery is charged from brown wire going to the solenoid.

-------------------------------------------------------------------------------------------------------------

That's stage 1 of the not rewiring technique, done.

-------------------------------------------------------------------------------------------------------------

The Denso alternator needs a different method from some others from here on.
On the Alternator (if 3 wire) you will see a small connector box with two spade terminals and a stud.  The main powering wire/charging wire, the Thick Brown/Yellow must be connected to this via a ring terminal.



Above shows a Thick White Wire, think of this as the Thick Brown/Yellow Main charging feed.

You need to add two other cables now, some really thin 11amp will be MORE than adequate.

Ref 11. 16/0.20mm, 0.5mm2, 11amp.
http://www.vehicle-wiring-products.eu/VWP-onlinestore/cable/thinwall.php

The thin green in the image above MUST go to the ignition switch, to a switched feed, so only powered with the IGN on. So find some cable and join the (IG) terminal on the Alternator to a SWITCHED ignition source (green wire in my picture), this must ONLY be powered when the ignition is on. This energises the alternator, turns it on ready for use.

The black wire shown above is an EARTH SWITCH.

To get the charging light working properly. Follow these steps.

Gain access to the back of the speedo, find the ignition warning light unit/holder which push fits into the speedo. You will need to discard this as the modern alternator system doesn't work in the same way. On the IGN warning light holder you will see a white wire (which goes to the ignition switch (+) and a thin brown/yellow (which did go to (4) on the control box).

Snip the connections from the rear of the IGN warning lamp holder, discard the lamp holder. If you wish remove the entire length of the brown/yellow wire going to the control box, leave the loom open and rewrap it later, after going through all steps in this article, especially if going for the total rewire method). Or just leave it there; cover the end with shrink wrap.

To get the IGN warning light working.

Buy one these lamp units.
CWL12
http://www.vehicle-wiring-products.eu/VWP-onlinestore/switches/warninglights.php

Images below show the unit will fit in the old lamp holder boss on the instrument.




Just CAREFULLY chop the end off (by my finger) and insert it the opposite way around to my demonstration. Chamfer the end and thin down the plastic a little.

Connect the white wiring you chopped off the old unit onto one side of this new lamp (its got two spades on) and from the other side run a NEW black wire to the alternator spade marked L (as seen above in images of the connections on my alternator, with the black wire connected to it). This will now switch OFF the earth connection when the alternator starts making voltage, so putting this light OUT when the alternator is working.

You now have a working alternator with a working IGN lamp.

--------------------------------------------------------------------------------------------------------

If you wish to REWIRE the system, follow the instructions below.

--------------------------------------------------------------------------------------------------------

2, Total Rewire of Mk1-2-3 Spitfire and GT6 Mk1-2.

Read above and get a handle on what goes where.

Repeat the procedure for wiring the two small connectors from the alternator, including the IGN warning light mod.

You now have 4 wires to deal with. The main brown/yellow wire that goes to the Alternator (main charging feed).

You have 3 browns.

I suggest buying 5metres of new brown wire (33AMP) and 2metres of new Brown/Yellow (39AMP), cause I hate spliced up spaghetti, its bad for resistance.

Buy:
http://www.vehicle-wiring-products.eu/VWP-onlinestore/cable/thinwall.php
Ref 33 . 44/0.30mm, 3mm2, 33amp brown 5metres
Ref 39. 56/0.30mm, 4mm2, 39amp brown/yellow 2metres

You will also need 4x 8mm ring connectors
http://www.vehicle-wiring-products.eu/VWP-onlinestore/terminalsnonins/noninsrings.php
RD8 x4

You will need 2x normal female spade connectors and two rubber boots.
http://www.vehicle-wiring-products.eu/VWP-onlinestore/terminalsnonins/noninsblades.php
FB66 x2 (you can only buy 10 min)
FBI66 x2 (10min quanity)

Now we are ready to do some wiring.

--------------------------------------------------

As I said I hate joined up cables, you can do that if you want, I mean splice in extra lengths inplace of this rewire? If so read on. You can do this a number of ways....Read this article and do what you like.

--------------------------------------------------

The brown wire that was on (1) on the control box can be discarded completely (it went to the solenoid)

You are now left with two browns,one was on (1) and one that was on (2).

(1)     Goes to the ignition switch.
(2)     Goes to the light switch.

You want to strip out these wires completely from the control box to the light and ignition switch, chuck them. I never liked the way these super high powered wires had NO fuse on them.
You can now add a small fuse box where the control box was or anywhere between the solenoid where these wires will terminate and the switches, so fusing these connections, I�ll leave that to you.

Use the new brown wire and run it through the car, 1 wire to the ignition switch and one to the light switch where the old wires were on the correct terminals.

(1 TERMINAL on IGN) and (4 TERMINAL on the light switch)

Solder on the spade connections to the switch ends, not forgetting to fit the rubber boot FIRST. Fit these two wires to the switches (IGN/LIGHT) run them neatly back along the wiring loom and out of the bulkhead into the engine bay.

You want these wires to terminate/join onto the starter solenoid the same side as the main battery wire using two of the Ring Connectors. Neaten it all up and route it well, then fix these wires on the solenoid.

So you have removed 1 of the 3 control box browns completely and re-routed the other two.

You now have just 1 wire left the original dynamo wire. Discard this.

Get your new length of brown / yellow and solder on a ring connector to the one end, fix this to the alternator, (as the white wire on the image of my setup). I suggest attaching this wire directly to the battery (+) terminal.

You can manage that, if the main terminal on the battery is REALLY OLD it will be a lead job moulded onto a cable or it maybe some other type. Basically just affix the cable to the terminal.

This charging wire can go on the solenoid where the other two brown wires are, its just my preference to run it to the battery

That's it your done, attach the battery.

I suggest just tapping the terminal on the battery lug a few times, quickly and just check you have done nothing wrong. If it sparks you may wish to seek professional advise!

----------------------------------------------------------------------------------------------------------

I offer no warrenty on this information.

----------------------------------------------------------------------------------------------------------

I do advise breaking the two brown wires that enter the cabin and go the IGN switch and Light Switch with a fuse box and run 40AMP fuses in there, you can hide the fuse box in the bulkhead etc.

To me the lack of fuses here is DANGEROUS. If you have a light switch failure or are fiddling with something and one of those browns gets an earth your ENTIRE LOOM IS SMOKED IN UNDER 10seconds.

I know cause???

If you have a 1 wire only alternator, simply connect it straight to battery. Do all of the rewiring section, but do not add an IGN feed to the alternator, or mess with the IGN warning light, cause neither will work or be needed, it's a 1 wire! Your ignition warning light will be unworkable. So disconnect its power and let it rest.

So, Just take the two browns I talked about above that retained, that were going to the IGN and Light switch and affix them to the solenoid as covered above. Removing the original Brown wire than was going to the solenoid, completely, as above. Your good to go, just ignore the sections covering the two other wires from the alternator.

---------------------------------------------------------------------------------------------------------

Chances are the Denso alternator will do 200,000miles before it wears out, ALOT more than you will!

---------------------------------------------------------------------------------------------------------



I am sure you can work it out its all there.

]]> Mon, 4 Feb 2008 02:54:26 Apeman Exhaust Tuning Theory and System Design http://www.sideways-technologies.co.uk/forum/Blah.pl?m-1201221799/ http://www.sideways-technologies.co.uk/forum/Blah.pl?m-1201221799/#num1
Exhaust Tuning Theory and System Design



We've all heard the magazines talk about 'back pressure' (and most of what they say is utter cac) so how do we ensure we have a good, efficient, exhaust system (bearing in mind that 'back pressure, any back pressure, is a bad thing)?

Well, some history:

Back in WW2 the RAF Spitfires ran, what were essentially, open headers (they called them 'ejector stacks'). After the Battle of Britain, when they were looking to use Night-fighters, in order to cut down the exhaust glare, they ran aircraft with extended exhausts and found that engine power was increased.

Nothing then really happened until the late 50's / early 60's when the Japanese started producing 2-stroke M/C engines. - These rely upon exhaust efficiency to work.

Shortly after this people like Colin Chapman and the men at Coventry Climax started producing the 'bunch of bananas' exhausts.


So what was / is going on?



Aside from restrictions in the Silencer (which cause back pressure! and which we don't want in an efficient system!), the lengths of the Primaries / Secondaries / Collector affect the 'pulse tuning' of any exhaust.

Consider a church organ - different pipe lengths and bores make different notes. The sound you hear is due to the resonance or 'standing wave' that is set up as the air passes through the pipe. This standing wave has both a negative pressure component and a positive pressure component, the wavelength being directly related to the sound you hear because wavelength is directly proportional to the inverse of the frequency.

Now it's the same with an exhaust since it is effectively a pipe flowing gasses. Firstly we want the gas pressure in the exhaust to be lower than that at the cylinder head to assist scavenging through gas inertia. Secondly we don't want the exhaust gas of one cylinder to pressurise another cylinder.

Here comes the interesting bit. By altering the length and bore of the primaries and secondaries we can ensure that the negative pressure component of each exhaust pulse reaches the cylinder head when the exhaust valve is open, thereby further assisting cylinder scavenging. This will depend upon engine rpm and the valve opening time, ie exhaust valve duration. So, for example, on a 4-cylinder engine, we can use the negative pressure pulse from no 1 cylinder to assist the exhaust scavenging of no 4 cylinder.

What we are doing is pairing cylinders that are 180 degrees apart. This is why the stock GT6 manifold is so useless, and, more importantly, why the so called ToiletTune (Terrytune) manifold (sold by Moss) is an absolute waste of money (since it links 1,2,3 cylinders together, and 4, 5 and 6 cylinders).

Where it gets really 'trick' is if we use a wide valve overlap, ie both exhaust and inlet valves are open at the same time (hence they 'overlap'), we can use (in the example above) the negative pulse from no 1 cylinder not only to assist the scavenging of no 4 cylinder, but, because of the negative pressure and the fact that no 4 cylinder's exhaust and inlet valves are both open, this negative pulse will actually assist in sucking the new inlet charge into the cylinder. Hence gains in power and torque.

The downside is that this will only work perfectly at a given rpm. If you tune for max power you will inevitably reduce the torque lower down and 'close up' the engine's 'power band'. This is why race engines idle badly with associated popping and farting and lumpy idle rpm.

Similarly engines with a wide torque spread produce less peak bhp.


As with everything there is a series of compromises being made.



Exhaust tuning theory is actually fairly simple; it�s all about getting the negative (and, hence, scavenging) pressure pulse to arrive at the exhaust valve as it is opening. To do this we have to set the pipe lengths and diameters correctly.

The formula for Primary pipe length is:

P = [(850 x ED) / RPM] - 3

Where:
RPM is the engine speed to which the exhaust is being tuned.
ED = 180� plus the number of degrees the exhaust valve opens before BDC.
P = Primary pipe length (on a 4-1 manifold), or Primary pipe length plus Secondary pipe length (on a 4-2-1 manifold), in inches.

Generally road engines will require the manifold to be tuned to the max torque rpm whereas race engines will be tuned to work either at max bhp rpm or a speed midway between the max bhp rpm and max torque rpm.

4 -1 manifolds restrict the power band, whereas 4-2-1 manifolds give better mid-range power but reduce top end power by as much as 5-7%.

Generally speaking with a 4-2-1 manifold the starting point for Primary pipe length is 15 inches, thus Secondary pipe length is P - 15 inches. Changing the length of the Primary pipe tends to rock the power curve around the point of max torque. Shorter Primaries gives more top end power but less mid-range, and vice-versa. There is, however, little change in the peak torque or the rpm where this occurs.

Ideally the Primaries should come off the cylinder head in a straight line for around 4 inches before any turns occur.

Inside diameter of the pipe can be gained from:

ID = sq root [cc / {25 x (P + 3)}] x 2.1

Where:
cc = cylinder volume in cc.
P = Primary length in inches.

In some engines it can be useful to have a 'step' between the exhaust port and the Primary (ie the Primary bore is greater than that of the exhaust port). This tends to be the case in engines with rectilinear exhaust ports.

For a 4-2-1 system then, Primary pipe diameter is calculated as above. Secondary pipe diameter is given by:

IDS = sq root (ID x ID x 2) x 0.93

Where:
ID = calculated inside diameter of the primary pipes.

The pipe diameter can be used to change the peak torque rpm � a reduction in diameter of 0.125 inches will drop the peak torque rpm by 500-600 rpm in engines over 2 litres and by 650-800 rpm in smaller engines. Increasing the pipe diameter by 0.125 rpm has approximately the opposite effect.

The total length of the Collector and Tailpipe (to the front of the silencer) should be equal to P + 3 inches (or any full multiple of P + 3 for a road car).

Tailpipe internal diameter is given by:
IDT = sq root [(cc x 2) / (P + 3) x 25] x 2

Where P is calculated as above.

Collector length is given by:

CL = [(ID2 � ID3) / 2] x CotA

Where:
ID2 = diameter of Collector inlet
ID3 = diameter of Collector outlet.
CotA = Cotangent of angle of Collector taper (which ideally should be around 7-8� (certainly less than 10�).

The design of the collector should be such that the inlet pipes terminate abruptly otherwise the tuned exhaust pressure wave will carry on into the tailpipe and the calculations done to get the negative scavenging wave back to the exhaust valve on time will all be wrong.
]]> Fri, 25 Jan 2008 00:43:19 Debs Making effective use of braided hose and fittings http://www.sideways-technologies.co.uk/forum/Blah.pl?m-1200891060/ http://www.sideways-technologies.co.uk/forum/Blah.pl?m-1200891060/#num1 Hope this is useful.

I get asked about this subject alot! This is here to save me being parrot'like! I will add bit on "making" them up some other time.

Firstly I do not advise braiding the whole car, but it can be done, its every bit as good as metal pipe, bar it cannot be
readily inspected. Best to use it for clutch lines, master cylinder to brake union block, brake lines, pressure gauges etc.

People seem to get confused about what fits, what fitting to use, how the various parts go together.

It's very easy actually.

The braided hose comes in many sizes, dash numbers, the -3 hose for example will fit the usual suspects, JIC, AN or the relevant -(Dash) fittings.

You want to make braided lines for a Triumph, you need -3, JIC3 or 3AN fittings.

Why? Cause the threads on the parts are 3/8th.

JIC3 is a 3/8th threading, same as any -3 hose fittings labelled as 3/8, JIC3, 3AN, these have 3/8th threads!

If the fitting is 1/8BSP, M10 it will also take -3 hose, but obviously won't fit. JIC3 is ALWAYS 3/8th. If an adaptor etc is not JIC3 both ends it will say so where its being sold.

Basically any fitting in the following 4 terms / families are the same thing refered to as 3/8, -3, JIC3 or 3AN, but different suppliers call them different names which is confusing.

Basically.



The Society of Automotive Engineers (SAE) specifies a 37deg angle flare or seat be used with high pressure hydraulic tubing. These are commonly called JIC couplings.

The JIC 37deg flare male will mate with a JIC female only. The JIC male has straight threads and a convex 37deg flare seat. The JIC female fittings have straight threads and a concave 37deg flare set. The seal is made on the 37deg flare seat.

-----------------------------------------

Hose, proper stuff with a dash number is always used with JIC/AN fittings.

Comes in various sizes as do the fittings. -2,-3,-4 up to dash -32! Bar dash -3 and very rare -5 they are all even numbers jumping in steps of two (4-6-8-10) up -16, then a 4 step to -20, then 6 to -26, then 8 to -32.

This hose is an industry standard and -3 is the type used for braking and clutch lines, gauge lines and small oil feeds, like the external rocker shaft feed on the Triumph engine (not to self : there is another technical article, how to make that work).

Provided you stick with the relevant hose size fittings and hose (goodridge, mocal, think, aeroquip) its all good.

I will only discuss one or two sizes here, as this will cover all sizes, alteast once you understand the system!

---------------------------------------------------------------

All fitting on Triumph master cylinders, clutch slaves, rear brake cylinders, brake block unions and also female connectors on the end of copper brake pipes are 3/8th thread.

JIC 3 or 3AN is also a 3/8th thread. So you can use -3 braided hose with JIC adaptors, banjo bolts, 3AN fittings, Bulkhead adaptors and anything listed at Goodridge or Mocal that's JIC or -3.  Which opens up all sorts of possibilities, cause there are hundreds of fittings.

So you can fit -3 JIC adaptors and fittings into master cylinders, brake block unions etc as well as the normal pipe stuff.

ALWAYS get your FEMALES as SWIVEL CONNECTIONS, ie the pipe doesn't turn when you do up!

Thats why I use a MALES in the master cylinders and in BOTH objects at either end, pipe is then connecting via female swivel joints at both ends, no pipe twist.

A combination of using a concave seat and a convex seat making a pair (as above)

The normal copper brake pipes on a Triumph end with a brass female connector with the pipe flange inside. You can fit a male -3/JIC3/3AN fitting with a convex seat into this too. (as per braided brake lines)

Aftermarket oil gauges, fuel pressure, have a 1/8BSP thread on the gauge with a FLAT seat, you can even make your own lines for the gauge, just use this connector on the gauge. It's a special fitting from Merlin.

http://www.merlinmotorsport.co.uk/p2877/1/8BSP-FEMALE-SWIVEL-GAUGE-END/product_info.html



Shown above this special gauge adaptor has a 1/8BSP thread, it has a flat seat to join onto gauges with flatseat 1/8BSP male stub.

Use a small O-ring between seats.

It says -3 or 3 in the sales blurp, so it can be used in combinations with any other -3 hose fittings where thats 3/8th/JIC3/M10/BSP etc. The hose size never changes, only the thread. It'll state the thread.



Above shows my fuel gauge line coming off the fuel union on the carb via an AN815 MALE/MALE (see below), onto the AN815 goes a Female 3/8th/JIC3/3AN 90deg adaptor, it then goes to the bulkhead and meets "straight 3/8th/JIC3/3AN female".

I will explain the blue connectors on the bulkhead lower down.

To run the new pressure gauge line off an existing oil pressure light hole on the block, or from a T piece, you will find the T or oil hole is always 1/8th NPT thread (National Petrol Taper I think). So, you need a "JIC3 to 1/8th NPT adaptor". Easy!

AN816 male/male. AN816 is a "taper thread to JIC" Family of adaptors. You need JIC3 and 1/8NPT...So look through the AN816 list.

http://www.merlinmotorsport.co.....8_171_172/index.html

Till you find it.



These as with all the "adaptors" can usually be had in alloy, plated or some in stainless (££).

To get the braided line onto the AN816 you obviously need a "3/8th/JIC3/3AN female"....Could be straight, 90, 120, 180, Forged etc.

Usual suspect is a staight female.

http://www.merlinmotorsport.co.....EL/product_info.html



Just an example of what can be done easily.

-----------------------------------------------------------

To make braided brake lines from the master cylinders. I always use "-3 to -3 Male/Male" connectors with a brass washer on Steel Adaptors, and an Alloy Washer on Alloy adaptors.

Technically all the JIC/AN/Goodridge adaptors are familied as I hinted at above. "AN815 MALE/MALE" is the technical name for the right adaptor (-3 to -3, male/male). This remains as AN815 whether its -3,-4 up to -32.



With the above adaptor screwed into the master cylinder and seated on a washer, we can fit any female 3/8/JIC3/3AN fitting we like.

We can also forget this adaptor and run a banjo bolt 3/8th and run a "3/8th/JIC3/3AN banjo", as seen below on my rear brakes.



This is the same in any other "type" of adaptor, the family name remains the same through the sizes. So there are about 30 families, with every size option in each family and different materials.

Each JIC(No) and (dash)hose size relate to eachother. JIC3 is -3, JIC6 is -6...etc

Back to master cylinders.



Above we see the AN815 -3 to -3 male/male adaptor in the master cylinder.

Now we can run any 3/8/3AN/JIC3 or -3 named fitting.

http://www.merlinmotorsport.co.....8_244_352/index.html

Any of these females labelled as -3, JIC3 or 3/8th will fit any male JIC3 end.

If the females are special or convex seat, not concave it will say convex, cause convex is not a normal female fitting. If it says 3/8, JIC3 or 3AN it'll be good to go, provided its female.



I like 90s coming from the AN815 in the master cylinders. Same on my fuel pressure gauge line shown below.



ALWAYS BUY THE FEMALES AS SWIVEL CONNECTIONS!

So that kind of covers it.

Some other examples.



My oil pressure gauge and fuel pressure gauge lines run in sections.

To get the lines through a panel without a grommet and allow undoing of either side you need a bulkhead fitting, above on my car it shows a blue fitting in the bulkhead, this is "AN832 Male/Male" a bulkhead fitting, family is AN832.

AN832 comes in JIC3 through to JIC12.



To order STEEL ask for AN832 STEEL.

For Stainless ask or look for "SS", sit down before then ask! $$$

For Alloy quote Alloy.

Same for any family. Quote Family number, - size, and material.

So to order these parts you quote AN832 (3) for -3 or JIC3, 3AN fittings. AN832 (6-6) for -6 or JIC6, 6AN.

http://www.merlinmotorsport.co.uk/GOODRIDGE-Goodridge-Adaptors/c108_171/index.html

Useful to become familiar with the families and types of adaptor, cause using JIC adaptors opens up infinite possibilities.

Below is another example of using a 90 deg bulkhead to make a nice neat housed join between two sections that will need to come apart.



JIC3 thread is 3/8th
JIC4 is   7/16th
JIC6 is   9/16th
JIC8 is   3/4th
JIC10 is 7/8th

Ciao.]]> Mon, 21 Jan 2008 04:51:00 Apeman