Lyndon Galbraith - New Zealand

[Eircamae86]

Fitting an oil cooler to a rally car diff would just be a liability? break a line/fitting or something & its all over.
Tilt the diff casing & overfill it supposed to be an oldskool trick, has a breather ontop so whats the worst that could happen?

[Eircamae86]

Its all about the $$$.
The Irish lads all go Ford type-9 bell adaptor which opens it all up.
Ford sierra box, dog kits, Quaife dogbox, Quaife sequential, Sadev sequential, Saenz sequential, the list goes on
BUT, most of them use an Atlas rear axle/diff with watts or similar, same as the big bhp mk11s
Boys in Finland modify a Volvo axle/diff.

Last weekends Killarney Historic Rally.

http://www.youtube.com/watch?v=vXpDzgmtM...e=g-subs-u

A bit of Toyota action

http://www.youtube.com/watch?v=Mx94djXcWf8

[LyndonAE86 NZ]

Yes the 5:3 ratios do wear alot faster, and they will not take much punnishment in reverse gear as they bind up and chip teeth. If you ever have a spin and need to use reverse it pays to not dump the clutch and just reverse slowly with little revs...losing a few more seconds in a rally is better than replacing $1000 worth of parts and ending your rally.

With my old car I jacked up one side of the car and removed axle to fill diff oil. I have researched what is involved for running a diff cooler with the new car but it just seems like more money, weight and work for something that could potentialy cause problems. I think diff temperatures would be much higher in a track car due to the amount of loading with grip when braking and cornering so a diff cooler may be more useful for them.

Regulations for Classic rallying in NZ make my gearbox/suspension/diff options limited...eg the car must have same amount of gears as original manufacturer, diff housing must be Toyota, suspension cannot be coilovers in the rear unless you use non cannister type.
Brakes are free, but engine has to be 16 valve, four cylinder and to the nearest oversize 1600cc bore...we are however allowed to run injection even though the original Toyota NZ AE86's were running twin carbs.

Question: if the standard bore size of the 16 valve redtop smallport is 81.5mm and that equals 1587cc, what bore size would create 1601cc?
As I understand a 82mm bore makes the engine 1627cc??

[4000GT]

81.8?

based on your calculations.

But I suspect the stock bore is 81?

[Bean]

stock is 81 indeed...

according to TODA and me 81.25 is 1597cc so 81.5 would be 1606.7cc
1601 is ~81.35mm

the formula is

r^2*pi*stroke*4

r = piston diameter / 2 in cm
stroke in cm too
pi = 3.1415926535897932384626433832795

headvolume doesn't change and wont be compressed so is usually not accounted for.

[LyndonAE86 NZ]

Thanks for that...I have been informed that I can legally run in the 1600cc class with 81.5mm pistons so 1607cc.
Now it is just a matter of finding some good forged pistons cheap but near new

[Bean]

I had my pistons made by JE (Custom spec) incl. rings and pins for 700$ through BrianCrower

and the spec sheet (comp height is not stock on mine):


click pictures for bigger versions

[4000GT]

I did the same route and run CP customer pistons, 15:1 compression, and a whole bunch of other stuff

[Eircamae86]

Ford Type-9 adaptor

http://www.rallyforums.com/forum/showthr...post376348

[4000GT]

Are there cheap Ford Type 9 sequential boxes or something?