My 1303 just got a step closer to a GL

[Supercool]

Originally Posted by evilC

The spring plates are highly desireable since they provide camber (and ride height) adjustment as well as obviously matching the trailing arm bracket. If you use the bug spring plate you will need to re-drill it to fit the Posrche trailing arm. Re-drilling IMO does weaken the plate maybe not enough to worry about but the Porsche bit does resolve that concern. Also, the Porsche spring plate should come with the eccentric adjusters that that suit the elongated holes.
Clive

I will have to return for the spring plates, etc. Should I get the torsion tube and sway bar as well?

Originally Posted by evilC

I never clean up rotors - it isn't worth it. To get even slightly rusty rotors re ground is around £20 each here with the distinct risk of extra run-out and a rotor that is then closer to the wear limit. Compare that with £43 each for brand new rotors and the extra £23 makes a lot of sense. Correcting run out on re-ground rotors puts them even closer to the scrap limit. Also, there is the issue with potential cracks in old rotors from unknown abuse that may not show up until re-ground.

That's ~$32USD to get one rotor cut? ZOWWIE! Over here I can get a rotor cut for around $5USD each. Modern machining equipment with a competent machinist at the controls should be able to improve on factory tolerances on most of these older parts. New parts that may be made with inferior steel are, in my opinion, an option I will reserve until my other options have have run out.

Originally Posted by evilC

If you are running 944N/A brakes front and rear then the 24/19 won't solve the problems with the bias. The plain fact is that the rear brake caliper is too small for the front. You will need to increase the rear piston area up to 2200sqmm/caliper to get correct bias with a 19/19 m/c and 1383sqmm/caliper for the 24/19 m/c (19mm piston to the rear, which is actually the wrong way round for the dual piston layout).

Brake bias will definitely need sorting after installation. It will all come down to keeping the rear from locking in HARD braking. What I learned from using parts from at least 3 different models of GM cars on My Monte Carlo was that the rear only needs to do a relatively small percentage of the total braking. Most “authorities” on these matters say 60% front 40% rear. I have found that as soon as you throw it into a turn or evasive maneuver 40% becomes way too much. Granted the Monte is weight biased considerably lighter in the rear than the Bug but I would rather have the fronts lock than have the rears lock causing me to spin uncontrollably.

Originally Posted by evilC

The 911 m/c is I understand a 20/20 unit so is less desireable than the standard beetle one for best hydraulic advantage

It seems to me that this would be a trade off of a taller pedal for less force and would certainly be a very subjective sort of decision.

[evilC]

Originally Posted by Supercool

I will have to return for the spring plates, etc. Should I get the torsion tube and sway bar as well?



That's ~$32USD to get one rotor cut? ZOWWIE! Over here I can get a rotor cut for around $5USD each. Modern machining equipment with a competent machinist at the controls should be able to improve on factory tolerances on most of these older parts. New parts that may be made with inferior steel are, in my opinion, an option I will reserve until my other options have have run out.



Brake bias will definitely need sorting after installation. It will all come down to keeping the rear from locking in HARD braking. What I learned from using parts from at least 3 different models of GM cars on My Monte Carlo was that the rear only needs to do a relatively small percentage of the total braking. Most “authorities” on these matters say 60% front 40% rear. I have found that as soon as you throw it into a turn or evasive maneuver 40% becomes way too much. Granted the Monte is weight biased considerably lighter in the rear than the Bug but I would rather have the fronts lock than have the rears lock causing me to spin uncontrollably.



It seems to me that this would be a trade off of a taller pedal for less force and would certainly be a very subjective sort of decision.

The standard 944 rear uses 23mm torsion bars that are the best for a road going VW IRS rear. Depending on the 944 model the bars may be 25.5mm thats getting a little stiff but worthwhile if you intend to primarily compete with it. Again, the AR bar is a useful addition and I have fitted the standard 14mm 944 one to our 1303 Super. You may find larger AR bars on the same model depending on spec but the choice of using a rear AR bar is subjective and dependant on what the vehicle is used for.

We all have our different price structures and certainly you wouldn't get the majority of our engineering firms to pick the phone up for equivalent to $5. having usually invested all the time and effort in sourcing good second hand parts I always replace the consumables to give me what I believe is a near to new set up - but to each his own. I always use good quality new parts including rotors that will normally be Brembo or Zimmermann (both are Porsche OEM). The metal quality and machining has been improving over the years. One thing you will have to watch with the single pot calipers at the front is that the pads and the rotors should be changed at the same time since as they both wear the pads end up tapered due to the slight rotation of the caliper (due to the one sided anti-knockback/adjustment spring) therefore new pads will not match ground rotors until they themselves have been ground in and in the interim you will get a long travel pedal and weak braking. Don't use such pads in anger as heat build up will not be even and you could locally burn the pads

The standard and thus the conservative brake bias on the bug is ~50/50 and unless you change the weight distribution completely or have specific requirements for competition that is what it should be. That bias accounts for the 40/60 weight distribution AND the weight shift under hard braking. Increasing the braking at the front will lock the fronts prematurely deminishing the overall brake performance. With a front engined car the weight bias will in any case be to the front and it is not unusual to have a 80/20 front brake bias to account for the weight shift under hard braking.

Porsche on their whole 911 series have always maintained around 50/50 brake bias even for racing so I would take a lead from the experts otherwise you could have little effective brakes at all.