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Competition Inspired General Fast Road / Trackday Upgrades


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Just make a template from cardboard, then transcribe to 0.8mm soft alloy sheet.

You can seal it with a polyurethane sealant, Dum-Dum, or double-sided body moulding tape, then fix in with neat self-tappers.

It's well worth preventing the original filler cap latch from tripping if nudged.

The early type can either be taped, or drilled & lockwired across the cap to the hinge.

The later type can be drilled through sideways above the latch & an R clip inserted to limit its movement.

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Hi Badfrog,

 

As Jon says above will do nicely for the Firewall, if you'd prefer to buy ready made all the usual suspects should be able to supply

TR Enterprise/Revingtons/Racetorations and many of the others also.

 

Excellent modification, cost effective, easy to do yourself with the undoubted benefit of when you hear the sound Wwwwhhhhuuummmpppfff whilst hanging upside down you at least stand a good chance that it will keep the flaming petrol inside the boot area and give you a chance to get out.

 

Mick Richards

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Deviating slightly, my car doesn't have a lot of castor return to the steering, precious little in fact plus the steering is heavy. I have 1 degree negative camber at the front and otherwise it's to the book with 165/80 tyres. The rack operates smoothly and everything is new (well 5000+ miles since rebuild). Any pointers?

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Measure what the castor is, Your car is a 4a and if so memory says it should be a 3 deg castor, if it's a jigsaw car has it the correct upright ? And not an early TR4 version which is different.

 

Mick Richards

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Given that the components appear to be correct, back to the original suggestion of measuring the castor and confirming that it does indeed show a 3 deg castor at BOTH uprights. Just trying to eliminate chassis damage at the front.

 

Mick Richards

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Try taking 1/2 degree off the Neg on the front and check your rear toe in. Do you have anew rack and how many turns lock to lock is it? If its a quick one then they can do that.

Stuart.

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Trunnions are most likely sticking; 3deg castor is plenty, camber will have no real effect on tall skinny tyres.

Offset will be correct on any TR wheel, not so with 70-spoke centrelace wires, for example; 6" ones are a ghastly drive.

Try a very early TR4 with its fast rack, short steering arms, zero castor & crossplies for a good fright.

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Cheers guys, some food for thought. On the move it's very stable, no bump steer (a nod to the thread), no tramlining and no sawing at the wheel on cornering. Rear toe is to the book, and one degree negative camber there too. I'll see about double checking the castor and rack ratio (it was new with the heap of parts for the car).

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Your car's 1 degree negative camber is the problem. The 3 degree castor makes the front wheels want to turn in whilst the 1 degree castor makes them want to turn out thereby cancelling the self centering effect.

 

My 4A has 0 degree front camber and the self centering is OK.

 

As for heavy steering the wheels should have the standard offset which give the correct scrub radius. Hopefully your car has original undamaged vertical links and not ones that have been bent/ machined to achieve negative camber. The latter will increase the scrub radius and produce heavy steering.

 

Tim

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Your car's 1 degree negative camber is the problem. The 3 degree castor makes the front wheels want to turn in whilst the 1 degree castor makes them want to turn out thereby cancelling the self centering effect.

 

My 4A has 0 degree front camber and the self centering is OK.

 

As for heavy steering the wheels should have the standard offset which give the correct scrub radius. Hopefully your car has original undamaged vertical links and not ones that have been bent/ machined to achieve negative camber. The latter will increase the scrub radius and produce heavy steering.

 

Tim

Oops I got the first bit wrong! The 3 degree castor and the negative camber work together and both tend to make the wheels toe in hence contributing to the heavy steering. With positive camber the steering is lighter.

 

Must try harder.

 

Tim

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Elclem1

Sorry I'm late on this thread.

I note that you are considering a tank in the spare wheel well of your TR6 for track use. Are you staying on Lucas fuel injection or going the Weber route? If stopping on PI then caution required, from personal experience, you will suffer from fuel starvation on low tank levels due to insufficient head of fuel to the pump. Even with my pump fitted under boot floor alongside chassis I can't run less than approx 6 - 7 litres of fuel in the tank which in my case is above the floor level. Problem mainly on left hand corners at low fuel level.

 

Mick

PM sent for your Bump Steer article please.

 

Dave Mcd

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I can vouch for that. OK, Vitesse, but 2.5 and Pi. I used a Facet gold top as the lifter, because I had one, but a cheaper pump, such as their solid-state would do. The idea of having my fuel pump out in the breeze - and stones - doesn't thrill me, so pumps inside the boot. Gets complex as you need at least three returns to the tank - Metering unit, PRV and swirl pot.

John

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  • 1 month later...

Hi Dave McD

I have webers that I am going to use for the very reason that you say. Even on a normal set up on the PI it is possible to get fuel starvation at Low tank levels. It also negates the reason for too many returns to the fuel tank. By the way cheers for all of your advice thus far. Regards andy

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  • 2 weeks later...
  • 7 months later...

Mick, PM also sent for the article.

 

I have the old type stearing rack mounts, so suspect that the method mentioned here with packers will not be possible for me. Lowering the front susp by shortening the alu spring spacers is needed on mine to reduce a very high wheel arch gap. Will careful meurement when doing this help contribute towards triming out any bump steer?

 

Cheers, Richard.

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Hi Richard,

 

I've never measured the older TR4 type steering rack bump steer (I presume you mean what is sometimes referred to as the "rabbits tabs" mounting) where the rack is held by two (and it looks very flexible) separate small u section fabrications, so I'd be interested to see what the measurements were recorded using the system I suggest in my small article.

Because it's easy to measure the changes in bump steer using this system you can easily run 4 or 5 tests, I'd be tempted to "maccle up" a system of resiting the rack possibly by clamping it with mole grips or c clamps onto the rack mounts and see what results are achieved and measurements taken.

The ride height changes you propose making obviously changes the geometry on various items so the first step is to set the car at the ride height you anticipate it will be run at (without springs) then follow the system which I've e mailed to you.Then you could post your findings and we could possibly make suggestions as to how the rack positioning could be changed to reduce or negate the bump steer.

 

Mick Richards

Edited by Motorsport Mickey
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  • 6 months later...

The 3 runs best and is most predictable with an uprated front suspension and leaving the rear basically stock. First I suggest going through the front suspension. Check the trunions and ball joints for wear. Your suspension and steering will never work properly with worn out of spec parts. Replace any part that is worn. Reassemble with Nylatron or equivelent non rubber bushings and the competition spec front springs. Then add a big front anti sway bar to the vehicle. You want to tame the body sway or corners.

 

If you are new to the TR3 suspension I suggest doing one side at a time so you can refer to the other side for where the parts go during reassembly.

 

For the rears I suggest rebuilding the rear shocks using heavy duty valves. Fabricate rear shackles that are about an inch (2.54 cm) longer than stock. This will allow for more axle movement before the axle rests against the frame and starts to lift a rear wheel.

 

A rear sway bar in conjunction with the front bar will make the car more stable on curves but it will be less predictable when you loose rear traction. Most serious racers don't use a rear anti sway bar because the car is less predictable in a hard curve.

 

If you wanted to spend money there is always a limited slip differential with overdrive ring and pinion gears. Of course an overdrive helps as well.

Edited by Teriann
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New bit of technology available, the "Holley mat"

https://www.holley.com/news/articles/holley_debuts_new_hydramat_fuel_reservoir/

 

This could do away with swirl pots, lifter pumps and all that 'Turkish distillery' piping in the boot, which is essential for fuel injection set-ups, to keep air bubbles out of the fuel stream.

 

It's an absorbent mat, covered with permeable membrane.

The membrane works in the way that a goretex jacket keeps rain from getting in, but allows water vapour, sweat, to get out.

It allows the fuel to seep in but not to drip out and will not admit air.

The collector tube is connected to the interior of the mat.

 

Thus, as long as fuel is sloshing about the inside of the tank, it is 'sucked' up by the mat and available to the collector tube without air bubbles.

 

The cheapest version is $150, so very competitive in price with all the distillery kit.

JOhn

Edited by john.r.davies
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And, if you still fancy a "Turkish", those nice people at Toolstation sent me their new catalogue

See item 75473:

http://www.toolstation.com/m/part.html?p=75473

 

Now if that isn't a swirl pot ......

 

 

JOhn

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