Front-end drifting at speed

[defcon65]

I'm planning to do some work to the front-end to eliminate the lateral drifting my car experiences at higher speeds and in cross-winds. The car is 20 years old and has 54K miles on it. I have not yet jacked it up to inspect the bushings and tie-rods, which are original and probably suspect due to age. What's the best bang for the buck for tightening up the suspension and making it track better? It's not a real extreme drift, but becomes much more apparent above 100 and especially in cross-winds I find myself fighting it to stay centered in the lane.

Thanks, Joe

[real550A]

Sounds like it's due for tie rods anyway. Then, a front end alignment.
Make sure you switch tires around a time or two to see if that affects it. If so, maybe new tires before the alignment.

[Jeff]

Joe, do you have a front lip spoiler? This will probably cut down on front end drift if your suspension is in order.

Also you should never run a rear wing without a front lip spoiler.

[tonythetarga]

You might be due for shocks as well. Check your rear sway bar mounts for cracks or a broken mount.

[defcon65]

Tires are almost brand-new Toyo Proxes, maybe 1500 miles on them. I will certainly get a balance and alignment after any repairs are made, which brings up a related question: Should I go ahead and get the four-wheel and thrust alignment or just the front-end done? Should I trust generic tire and alignment shops to do this correctly or do I need to take it to the (gasp) Porsche dealer to have it done right? Some of these Car-X/Midas/Goodyear grease monkeys don't really look like they would know or care about the technical requirements and specifications for aligning this car correctly. Any recommendations? What type of equipment should they be using to do it right?

[defcon65]

No spoiler, no wing. Plain stock 85 Carrera. No bounce in shocks all around, checked that out when I bought it.

[Jeff]

I would recommend taking it to a shop that does alignments for race cars. They would probably be more apt to do it correctly.

If you post where you are located and the intended use of the car (street, track, both), I'm sure someone can recommend a shop and alignment specs.

[Jeff]

Also, When I replaced my front struts there was no bounce but the shocks were toast. Definetly gave the front more bite.

[tonythetarga]

These cars do react a bit differently then most when testing the shocks. Due to the torsion bars, when you push down on the car you are flexing them and the shocks making it very hard to know if the shocks are worn. If they are original they could be due. If you want to continue to drive at very high speed, I would put in the Bilstein sports. (in fact, I did on my car right off the bat!)

[stlrj]

What's the best bang for the buck for tightening up the suspension and making it track better?

That's easy...an alignment.

Joe G

[ZOA NOM]

Originally posted by defcon65
No spoiler, no wing. Plain stock 85 Carrera. No bounce in shocks all around, checked that out when I bought it.

Chin spoiler will significantly reduce front end "wander". Also, there is no point in doing a front end only alignment. These cars need all four corners aligned and balanced.

[450knotOffice]

True. Find a reputable independent Porsche repair facility that does alignments and have them do it right. These cars need a proper four wheel alignment and need to be corner balanced. If alignment and/or corner balance is out of tolerances then the car will exhibit strange handling characteristics. FWIW, my '84 can be driven with two fingers on the wheel at 110 mph, so you should not be drifting all over the road at that speed.

[Thrasher]

Originally posted by defcon65
Should I go ahead and get the four-wheel and thrust alignment or just the front-end done? Should I trust generic tire and alignment shops to do this correctly or do I need to take it to the (gasp) Porsche dealer to have it done right? Some of these Car-X/Midas/Goodyear grease monkeys don't really look like they would know or care about the technical requirements and specifications for aligning this car correctly. Any recommendations? What type of equipment should they be using to do it right?

Yes, Definitely 4 wheel alignment. A "front end" alignment was back in the day of non-adjustable rear-ends (think frame-based cars). It still applies to some vehicles, but not a Porsche. Basically, they measured the "thrust line" of the rear axle and aligned the front wheels to that vector. That's why you'd sometimes see cars/trucks going down the road on an angle - it's called Dog Tracking.

Some of the national/regional chains hire and train some decent mechanics, and they'll do a great job on your Honda or Toyota - because they've seen/done a million of them. But, if you ask them how many 20 year old 911's they've done, I'm guessing it'll be none or just a few.

Look for a good independent shop in your area that has relatively new (laser) alignment equipment - preferably Hunter. Ask them if they have a dedicated (and hopefully level) alignment rack and how often they calibrate their equipment. Jigs are provided for doing this. Depending on where you live, you may even have an independent shop specializing in Porsche - that's who I'd use. They should also (as a part of every alignment) check for play in bearings, tie rods, ball joints, etc.

I used to work at Hunter. They hold a massive market share in wheel aligners and build the equipment used in almost all the auto factories, including BMW and Ferrari. I don't recall if they supplied aligners to Porsche. I do see that Porsche is using their GSP9700 Wheel balancer that applies simulated road forces to the wheel while balancing. Don't underestimate wheel balance as a source of suspension issues, either.

They have a pretty decent tech section on their website: http://www.hunter.com/pub/undercar/index.htm

Craig

[Emission]

Did you replace all four tires at once?

Several months back, I replaced just my rears with a different design - and the car became a nightmare! After an alignment, and two new fronts (identical brand/pattern as the rear), she's rock-stable again.

[ZOA NOM]

Originally posted by 450knotOffice
FWIW, my '84 can be driven with two fingers on the wheel at 110 mph, so you should not be drifting all over the road at that speed.

And this is when you know you are nearing Nirvana. When you blast down a straight, mash down on the binders and lightly flick your wheel, then back on the mean pedal for a sweet, smooth drift through the twisty!!! ...I gotta go guys, I have the day off. Good luck!

[jluetjen]

What are your ride heights like?

[buster73]

Quite normal for the early cars without adequate spoilers. Driving a car without spoilers on the German autobahn at speed in a crosswind situation, will push your body's adrenaline production to the limit. That's why Porsche introduced more and bigger spoilers, the faster the cars became. Of course a proper alignment and new shocks will help. Lowering the front and keeping some weight in the trunk will also improve the stability.

[defcon65]

The car has stock ride heights as far as I know. It came with the new tires when I bought it. I've been looking for a local independent Porsche specialist with little luck here in Eastern Iowa. There are probably dozens in the Chicago area, a road trip may be in order.

[masraum]

Yes, as stated, you can't test the shocks with a bounce. The suspension's too stiff and the front end too light. My car passed the bounce test, but when I changed my shocks they were really bad. When I unbolted them they compressed under their own weight and they were gas shocks.

Too, at speed with no aero aids you'll get some float. You should replace the shocks and bushings (elephant parts would be good), get a good alignment (the whole thing), and add a front lip spoiler and tail. You will probably notice a huge difference after the new parts and alignment. The lip and tail are not necessary, but for max stability... With a front lip and rear spoiler you reduce the lift on the car at 150mph by 90%. From what I've read this makes a difference as low as 60mph, but probably most noticeable from 80-90 up.

[masraum]

One more thing, make sure that when you get the alignment done you don't get a stock alignment and you get an alignment from a Porsche specialist.