On Sun, 25 Nov 2001 Opntop@aol.com wrote:
> Hello listers,
Howdy.
> I am setting up my TR250 with a supercharger, and my gearbox has no OD. Has
> anybody experimented with a differential ratio other than 3.7 ?
I've driven large TR's with 3.70, 4.10, 4.30, 4.55 and 4.88 diffs. If
you're going to more power (assumed due to your blower application), then
you don't need anything lower than 3.70. If you shop around a bit, you can
even find a 3.53 (the TR6 PI gearset, and 2500 saloon if memeory serves).
> is anything
> available to experiment with ?
Well, you are limited due to the TR6 differntial casing...
> What's more power if your engine's RPM's limit
> your top speed ?
Well, this is "all relative". "Gears" (higher numerical ratio) will "get
you there faster", but will limit your top end. The stock gears (3.70)
with stock tires (26.5 inches total height) gets you roughly 110 MPH top
speed at 5500 in top-gear without overdrive. By way of reference, with
4.88 gears this equates to a lot lower number (under 100 for sure, and
under 90 MPH with 23 inch tall tires at "really high" RPMS (6500+).
But if you're making power, you don't really need gears. Unless you're a
racer, in which case logic does not apply - only speed and acceleration.
:-)
The limiting factor in this application is going to be the differential
itself. The stock TR6 differential is good for 200 HP or less, but if you
go higher than that, you should seriously consider other differentials.
The choices available to you are fairly large in number. The closest to a
bolt-in that I'm aware of is the Nissan 300 ZX setup, but some
fabrication/ chassis modification is necessary. Talk to Richard Good of
GoodParts for particulars, as he's done this on his car and will sell you
"stuff" to do it yourself. If you have a large budget, you could consider
a custom application such as Jaguar or possibly a shortened Ford 8.8"
unit.
FWIW, I've seen a couple of V8 powered TR6's that use a Ford 8 or 9 inch
setup _with live axle_ and leaf springs (ala TR4A non-IRS). It works fine
for a boulevard cruiser and you have the advantage of _cheap_ gearsets
(and axles). Compare this to trying to find odd-ball gearsets for your
Triumph differential and suddenly the costs don't seem so bad.
> Thanks
> Sal
> TR250 blower ?
regards,
rml
TR6's - CF14111U "street car" and CR1871UO "race car"
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