Bryan Loy wrote:
I don't have the ele. od. option on my car, so I'm
running at a pretty high rpm lvl at interstate speeds.(4500@
70mph.)
For starters take the next exit, get off the interstate, slow down and
relax!
My question is, which would be better, an ele. od, or taller rear
end gearing. Price would have to be a factor here as well.
Has anyone on the list had experience here? Thanks in advance,
Bryan C. Loy
Give me a month and I might have a car with both installed. Until then you
can think about the following:
Overdrive - either unit can in theory fit any car but I would stick with
what was normally fitted to avoid installation problems.
If your car has a commission number before CF/CR1 use an A-type. Works in
all forward gears giving you an 8 speed tranny and an 18% reduction in rpm
If your car has a commission number after CF/CR1 use a J-type. Works in 3rd
& 4th gears giving you a 6 speed tranny and a 20% reduction in rpm
When converting from a non OD to a OD tranny you must replace the main shaft
and you might as well rebuild the whole unit once you have it out.
Cost is about $1000 to $2500 depending on the work performed and required
parts (countershaft 1st & reverse gear alone is over $200).
Since all TR6s were imported with a 3.7 rear end the 3.45 differential is
very difficult to find in the US and must be imported or built from new
parts. The differential works in all gears giving you a 4 speed tranny and a
6.75 % reduction in rpm.
3.45 differential cost is about $400 to $600 for used (must be imported) and
$1000 - $1400 with a new ring and pinion.
Neither way is cheap nor a direct bolt in.
If you have any more questions drop me a line.
Later
Lee Janssen
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