Babalouie

Are your lap times broadly comparable to your friends?

If so, it might just be a difference in driving style or line, and what you lose at the apex, you might be gaining in corner entry or exit?

Jimjacqmx5

My lap times are off the pace by 2-3 secs a lap and I know people will point to driving. For those who watch Moto GP, Phillip Island is a classic example. I am doing 53-55's depending on track conditions. My car has adequate power and speed and if anything is making up ground under brakes. I should be doing 50's..
For relativity, I used to do 59's in a fairly stock early model MX5 (Miata) and hype the standard Miata record at this track for nigh on 10 years.

boxsey911

Hi Shamus, I've never measured them from those points before so have just nipped out with the tape measure. The come out at an average of 32.5 cm at the front and 33.2 cm at the rear. I was a bit lower when they were first fitted but wasn't happy with the bump steer. The current ride height spec when measured from the chassis points is RS + 5 mm.

p.s. Love the ducktail

NineMeister

Can't agree Thomas, taking out compliance is no guarantee of "improving" your suspension, in fact the very opposite is probably true. Controlled compliance helps to keep the tyre in contact with the track surface and working in its optimum slip state whilst at the same time providing the driver with feedback on what is happening. Take out compliance & whilst momentary peak G increases it comes at the expense of nervous handling, resulting in reduced average G around a bend - i.e. slower entry & exit.

Way too many people make the expensive mistake of fitting their car with rock hard & low suspension and think they can go faster, simply because the car feels nervous and edgy and is making them work harder at the wheel to keep it on track. Suspension compliance (springs/dampers/roll) allows a driver to control weight transfer and use it to his advantage, linkage compliance controls the movement of the forces within the chassis/suspension/tyre assembly and when used correctly gives the driver useable feedback on what is happening to the grip from the tyre.

NineMeister

In my opinion 60,000km on Konis = knackered, so from your description of use & expectations Jim I recommend that you upgrade your car to RS specification or fit a set of KW Clubsports. RS top mounts & RS or poly bushes all round would be next on my shopping list.

NineMeister

Sounds like you have the same road gangs as the UK.

KaiB

Yep. Another to consider, given the cost of entry and dual purpose use, would be PSS10s should you find a set used with low mileage (like the ones I just sold).

These are actually tremendously capable...I'm within 1.5 to 1.90 seconds of class best times at my home track on the PSS10s, said records done with a full on race suspension.

Jimjacqmx5

I agree 60k on shocks probably equals knackered!
I also agree re the compliance. I am definately a believer that suspension requires travel and enough compliance to keep the rubber on the road. I've driven many an over stiff car with no grip as a result. This is particularily true on Oz tracks which can be quite rough and undulating.
So I'm leaning to KW Clubsports, I believe these come with top mounts etc so I gather a set of bushes for trailing arms etc is the way to go?

NineMeister

As far as I know the KW Clubsports do not come with top mounts on the 964 variant sets. Don't dismiss the V3 as an option, as Steve said, it offers a reasonable blend between road and track, however if your priority is on lap times why bother worrying about road performance?

Once you have the sping & damper kit, I would consider front wishbone and rear trailing arm bushes as priority one, top mounts next.


Final thought, late in the day: a heavy car will corner slower than competitors even if it is fitted with the same chassis and tyres simply because the resulting tyre normal forces are resisting the greater mass of the heavier car at lower acceleration.....

Gus

Colin -
Just read your notes on tire temp readings -

"1. Tyre temperature spread. Using surface temperature gun, measure outer/centre/inner temp of each tyre after a hot lap. You are looking for an even gradient or ideally even temperature across the thread.
Hot outer = too much camber; Hot centre = too high pressure; cold centre = too low pressure."

The Hot outer would mean to much postive camber (?) - Would hot inner mean too much negative camber ? How does caster and toe in, toe out affect the reading on tire temp across the tire.
Ideally, yo ar looking for a even temp across the face of the tire for best set-up and tire contact - Correct?

NineMeister

You got it.

For example: let's say you measure a rear tire from outside to inside at 55-45-45C. First job is to increase pressure until it reads 55-50-45. Next job is to increase negative camber to reduce outer to inner temperature slope. Ok, at the front end you may have 40-50-50. In this case the pressure is too high and you have too much negative camber. I would say that a 4-6 degree spread is close to ideal but would not be unduly worried about 10C.

Now obviously you have to add a bit of common sense to this because you cannot have optimal temperatures on all tyres unless you are running on a track with the same number and duration of right and left bends, but nevertheless you can definitely get a few big clues as to how well the suspension is performing in its job of presenting the tire to the road at the optimal angle.

Toe will affect the scrub angle of the tire in all circumstances but will generally affect the inner tire on a corner more than the outer (which will be carrying the most load), but if the geo is that far out that it is hitting the temperature spreads significantly the car will be driving like a donkey and will be letting you know in other ways.

So, whilst more empiric than scientific, tire temps are one of the trackside tricks available to get us into the ballgame quickly.

Gus

Colin -
Thanks for the time and info - great help - interesting that you point out that the toe will effect the inner temp reading more than the outer. I had to do a track side toe adjustment with tape measures and plates ( in a hurry). After a few runs I checked the temps and the inside was about 18 - 22 degrees hotter than the rest on the front - Interesting that the next day at the shop we found that my track side settings were way off -

Shamus964

thanks for doing that, and for the compliment - I'm really liking the duck too!

I'll check my ride height measurements this evening - I like that measuring point because it removes the wheel/tire combination from the equation, although the body panels on a hand-built car do vary a little.

Metal Guru

Body panels on a 964 are not hand formed like the aluminum body of an old Ferrari. The body panels are stamped with diesets and the panel/unit body interface is tightly controlled. This makes for a minimum of alterations at the factory (making the cars cheaper to build) and for cheaper, better looking repairs in the field.
The issue is that the panels are slightly different from each other left to right due to small differences in the diesets that form them. So if you try to use the wheel arches to find the height, you could be substantially off from true ride height.

Shamus964

Yeah, I didn't mean to imply that the panels themselves are hand-built, just that the positioning of the panels varies as the cars are screwed together. It's something that was mentioned to me during corner balancing that I was unaware of until then.