Exactly. Sounds almost exactly like the description of handling that
Jack used to describe his old TR-3 with a locked diff that he race in
SCCA in the 70's. He would give it a little extra wiggle on the way
into the corner to get the rear a little broken loose so the car
would turn in, then ride the gas pedal through the corner. He found
that the "bad habits" he picked up making the TR-3 go well were a bit
hard to unlearn when he switched to formula Vee.
It might be interesting to go to an open diff for a weekend to see
how that changes the corner entry.
Tony Drews
At 11:51 AM 1/24/2012, riverside@southslope.net wrote:
>The trail braking with welded diff is probably the cause of most of
>the corner entry push. Try getting all the braking done before entry.
>Use a lot of throttle with entry and a slightly late apex at first,
>adjust apex as dictated by oversteer/ understeer balance.
>
>Going to solid front suspension bushings (or almost solid with a VERY thin
>layer of teflon) might help some too. On a rough track, try
>loosening up the
>front sway bar a little.
>
>art de armond
>
>-----Original Message----- From: Scott Janzen
>Sent: Tuesday, January 24, 2012 9:11 AM
>To: Bobby Whitehead
>Cc: 'Friends of Triumph' Triumph
>Subject: [Fot] GT6 Alignment and suspension set-up
>
>Bobby, I'll share how my suspension is set up, describe the
>handling, and pose a question of the group - what would optimize the
>handling/reduce understeer on corner entry?
>
>Car weight roughly 2100 lb w/ fuel, 200 lb driver/gear, corner
>weighted to optimize, but LF is still heaviest
>Tires 205/60-13 on 6" wheels, R888 Toyo Proxes, 21 psi front, 19 rear
>Front Susp 550 lb springs, 1.5 degrees negative camber. Tried 2.5
>negative on last outing, and got more even tire wear (less wear on
>outer 25%) but more twitchy steering and no reduction in
>understeer. Front bar 1" OD, solid, with about 13.5" lever arm.
>1/16-1/8" toe out. All plastic bushings.
>Rear Susp: stock spring(I think), with spacer on diff to lower about
>3/4", 1 degree negative camber, 1/16" toe-in, 5/8" OD anti-roll bar
>with 9" lever arm. Welded diff. Every connection on "stock" rear
>susp elements is a rod end except for the lower a-arm connections to
>the upright, full IRS w/ rotoflex replaced by ujoints.
>
>The car understeers on corner entry, more as I go faster, and more
>on tighter turns (welded diff). Jason tells me it's my driving
>style - I carry a lot of speed into the corners, trail braking, and
>the car pushes going in, can hear the front tires protesting. At the
>apex, when I get on the gas, the balance shifts rearward, the front
>tires get quiet, the backs start making noise and the car points
>where I want it to go.
>I'd like to reduce the understeer on turn-in. Have increased the
>rear bar stiffness, which did not reduce understeer but made the
>transition to oversteer more dramatic! Adjusting tire pressures up
>and down has not made a material difference.
>So, anything else I should try adjusting? Or, just acknowledge the
>nose heavy nature of the car and get my braking done in a straight
>line, go slow on entry and get on the gas early?
>_______________________________________________
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