90 TR Question on handling

Hi, the TR is what's known as a "touring car." It's more of an autobahn cruiser in a straight line. The car has an awful weight distribution and not that great for the turns, track, etc. Nonetheless, I drive my TR everywhere, it becomes a job after a while and sometimes not too much fun. I love it on the open road

 

I understand exactly where you are coming from. I've had mine for eight years and I'm still not entirely comfortable with changing direction. I have found that increasing tyre pressures, particularly in the rear, reduces sway and gives a more neutral balance front to rear as understeer was a problem until the point where it feels like oversteer wants to take over with the pendulum effect. I then had my Koni shocks overhauled which made a significant improvement to stability. I have since changed to 18 inch rims which have increased stability further and worry less about the front and rear letting go. Not to mention the Pirelli p-zero rosso tyres which vastly improve lateral grip. P.S. have also upgraded discs, calipers and pads. I recommend spending a day trying varying tyre pressures to see what works for you best. On 16 inch wheels I think I settled on cold pressures of 28psi front and 40psi rear. On 18 inch I'm currently preferring 34psi front and 38psi rear.

 

just my .02, but I noticed that the front end does not turn as I would like and someone mentioned that with a mid engine car, the front end is much lighter and thus, it may not turn as you expect as with a front engine car. Granted, tires will make a difference and so will brakes because the stock material is not that great. I do not fly into the turns, but I do get on it in the turns and have not had a problem with the backend sliding, yet. When driving on twisty roads, I find the torque is to much and the car is just not that much fun drive in those conditions. Just remember it is a touring car so you should enjoy the high speed performance so choose your drives wisely.

 

if you REALLT want to improve the handling I would suggest some Penske adjustable shocks. They are about $750 @ x 6 but nothing short of slicks will make as big a difference in handling

The older TRs have issues w too much chassis flex, so anything you can do to make the car stiffer would be good too

Here are the Penskes installed on my 512TR race car, they are simply amazing
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18 inch wheels with pirelli's is the best thing i've ever done. I went for the 512tr type which also make the car look just right, a lot more modern. Wheel/tyre diameter is the same at the rear and a little greater at the front so I get the added benefit of extra ground clearance. My prime reason for changing was there were no high performance tyres available here in Australia. My calipers are off a 355 so they are great to look at.
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I find my car has major understeer coming out of a corner under acceleration. Stiffer shocks in the rear my help this. A good track car is all about weight transfer, and this is not the TR's best asset. Also the center of gravity is too high on the TR mainly because of the high mounted engine. This would be interesting to hear what else guys are doing to improve the tracking ability of this car.
The funny thing is, everyone that doesn't know these cars think they handle like an F1 car!

 

Actually, another thought. Has anyone tried a stiffer sway bar in the rear and giving more camber in the front tires?

 

I haven't varied front camber greatly although mine was initially wrong and when fixed it did help (one front actually had positive camber when I got it!). I tried looking into a stiffer rear bar but had trouble finding someone to make one up. I think standard is only 16mm. As a substitute I increased the rear tyre pressure while dropping the front with resulting benefits sending more load going to the rear with a more neutral feel.

 

Hows this ?

F50 brakes, Penske shocks, full cage, fuel cell, 2800 #, 500hp +, Motech ingnition, straight pipes, Bob Wallace Trans, Koenig body

about the only things left are custom adjustable A arms and sway bars, new engine will make around 600hp, then maybe some new carbon fiber body work and drop 100 # more

She keeps up w 360 Challenge cars and sounds glorious
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I would think that these pressures would make her squeeeeelllll in protest like the proverbial farm animal. Seriously - doesn't it push big time?
Rgds,
Vince

 

Robbie,

I have had several current and former TR owners in different parts of the country say the very same thing to me in regards to the handling of the TR and spirited driving:

NEVER lift. The TR is very prone to snap oversteer.

A fellow TR owner in FL tells of such an oversteer moment on an on-ramp (the only real turns in FL) that luckily he was able to save. Maybe he will jump in here soon.

Like Bill (RedTRman) I take it pretty easy going into turns due to brakes, current tires (16" stock wheels and Dunlops) and the stern advice above, I try to enjoy the exits of the corners more. The following straightaways usually allow me to catch up to the more nimble cars.

Curtis

 

Do you have the tire dimension for the front? I tried larger tires and had some rubbing against wheel well...

 

Wouldn't bigger fronts make this car even more tail-happy? I will be honest with you on this - the Testarossa in the rain on a good road surface feels to me a lot like a much heavier early Porsche 911 but with decent tires.

However, that does not bother me - having done years upon years in those cars.

What bothers me is the sense that the front tires are trying to follow every low spot or imperfection in the road on uneven or poor surfaces. That, combined with moderate to heavy rain, makes it feel like a much heavier early Porsche 911 with well worn rear tires.

 

Never lift the throttle - engine braking causes weight transfer to the front and the car will swap ends quickly. Remember she has a big arse and a high CG.

The 2nd bit of council that I have been given is to "learn to left foot brake - gingerly".

I would rather try and avoid the whole mess and enjoy acceleration forces after the apex as I am unwinding the wheel...

 

I know exactly what you are saying. I thought/think the same thing.

I have a little Miata for tearing up the twisties - fun beyond belief. Such a great car for such activities. The TR is for cruising and enjoying the ride. I would hate to think about "twangin" her being stupid...

 

It might also be worth saying once again that this car is very willing to spin both rear tires under acceleration if there is low traction, rain or ice/snow. This can make for a pretty exciting piece of opposite lock steering as well.

 

I think tyre says 235 wide (16 inch says 225 but the 18 inch appeared visually narrower from memory when I had them both off the vehicle) I will need to check dimensions. On day one I noticed some minor rubbing at full lock on the left wheel only but has not been a problem since. I understand it is a common finding to have some rubbing.

 

Actually the most enjoyable settings I have experienced with this car (until switching to 18 inch wheels).....and least terrifying! It eliminated a lot of understeer and also provided a great deal more high-speed stability. Previously on a straight road I used to get rear-end wobbles if I had to go around any obstacles on the road, just waiting to swap ends. Correct me if I'm wrong but from memory a little rear camber and toe-in may have helped also but pretty much factory settings.