Tom Tweed wrote:
> I'm just wondering if maybe the reaction you feel upon sudden
> deceleration isn't just normal for a Roadster (front engine,
> rear drive, `normal' diff) car lay-out.
Well, I've never noticed it in my car, but I don't recall
ever looking for it to happen, either. Thus, seeing as
how today is the first 70+F day in NH this year, I figure
I'll use this excuse to go out to the parking lot, start
'er up, and take a 30 minute break from work to test this
one out... (Be back in a few minutes...)
OK, I'm back. Wow! It is nice out there! What a perfect
ride -- I even got to wave to a maroon Triumph Spitfire!
Anyway, the experiment: I tried accelerating hard in 3rd gear
up to about 4000 RPM, to induce some mild rear end "squat"
and then suddenly let off the gas. The weight rapidly
shifted from the rear suspension onto the front, as
expected, but I didn't notice a tendency of the car to
"dive right" (or left, for that matter.) I then repeated
the test with my hands off the steering wheel, and the
TR did want to go very slightly to the right. It certainly
did nothing that would be considered a "dive right."
I would account for the slight tendency to go right off to
the fact that the front suspension on that car is in sore
need of new bushings, and my front left ball joint has some
play in it.
Then again, maybe my worn suspension is masking
the behavior you are seeing. The reason I say this
is that under very hard acceleration, or under very
strong engine braking, a behavior like the above
may be happening as a result of "torque steer". I
don't know if this is the cause of the symptoms
you're seeing. Essentially, the rotational torque
of the engine causes the car to be "heavier" on one
side than the other under hard acceleration or hard
engine braking. Since I can't recall which way the
driveshaft (and engine) spin, I can't figure out in
which direction the torque steer would tend to point
the car.
With any luck, the Triumph engineers designed it so
that the torque steer is cancelled out by the driver's
weight when no passenger is in the car -- but then,
the question is whether they designed it for the
US or UK? :-) :-)
--ken
'70/'74 TR6 Daily Drivers
PS: Thanks for the excuse to get out and drive!
--
Kenneth B. Streeter | EMAIL: streeter@sanders.com
Sanders, PTP2-A001 |
PO Box 868 | Voice: (603) 885-9604
Nashua, NH 03061 | Fax: (603) 885-0631
|