jackal2513

Hiya guys, greetings from the UK. I hope you're all well.


I was just wondering what the standard rake setting is for a 993 (in cm or mm)

obviously you can't work this out by simply subtracting one ride height from another because the points at which front and rear axle ride height is measured are different heights themselves

another way of asking the question is when you put a spirit level on the door frame (on a nice flat floor) the car obviously needs to be nose down slightly but by how much ? Where exactly should the bubble in the spirit level be ? Should the right hand side of the bubble just be touching the left hand marker ?

thanks in advance

chris walrod

One degree nose down seems to be a typical target for rake.

jdistefa

+1

The degree of rake desired will also depend on f/r spring rates, amount of rubber (deflection) in the rear suspension and subframe, and driver preference.

....But 1 deg is a pretty standard setup .

AOW162435

Not very accurate, but my '95 is set up with 25.25" at the front fender and 25.5" at the rear - measured through the centerline of the wheel and sighted level to the underside of the lip.

I agree with Master Walrod's comment.


Andreas

matt777

The manual gives the measurement points for setting ride height but there is a fairly wide tolerance. It seems to me that if you set the rake you may not get the desired corner balancing. This might not be of concern to you.

rsr91128

One advantage of being a tool junkie.

Paul902

So if the Porsche shop manual ride height settings are used as a starting point, is preserving rake or corner balancing more important? Let's assume that speed limited to 200km/hr in practice, and car used 25% of time for DE.

rsr91128

My answer would be to corner balance.

I'm no expert, but I split the difference between ROW sport and RS and then corner balanced. Ended up not quite 1 dg. down on sill plate (not shown in above pic) and 41% front 59% rear with a full tank and drivers ballast. It really wasn't too far off setting it by ride height, difference was in the left front because of ballast.

From what I have read and learned, ride height first then corner balance, should be close to 1 dg. down no matter your height.

I went conservative on alignment and the car does have a little understeer when driven hard, probably smart, but I plan to get rid of that

NC TRACKRAT

It's been a long time since I used trig., but, if we take the wheelbase of 2272mm (or 89.4 inches) using 1 degree of rake, the sine of that angle would be approximately 40mm or about 1.56 inches. Granted, it's a calculated figure but isn't that a bit much?

Paul902

Thanks, Erik. I'm asking because I am going to have my car lowered a bit more and more aggressively aligned.

NC TRACKRAT...your trig is good!

matt777

Sounds right (tan 1 degree). I think much of that is built in to the car. I don't know if the door sill is a reference point. I would just go with the factory ride height points / differentials. IIRC the rake/differential front and back ride heights is not the same between all of the ride height settings (RS/ROW/ROW Sport)

jackal2513

thanks all

jackal2513

the radial or front to back Sill angle can only change w.r.t. front and rear ride height (or unless you have severe panel damage !)

a spirit level is a good guide I would have thought

I know that it works for Chris at COG and he's widely held as the best setup man in the UK

Raptor

It doesn't seem like 0.25" and 1 degree are compatible. 0.25" is about 63.5mm. The Tan(63.5/2272) is .028 radians, which is about 1.6 degrees.

NC TRACKRAT

Uhhhh, Raptor, .25"x25.4mm/in.=6.35mm