Front Wishbone angle / Adverse Roll Centre changes on lowered cars
- Thread starter 924Srr27l
- Start date
Given you have early offset (assuming you only changed the arms) - You could go for a set of steel arms with easily replaceable ball joints and do something similar to this
http://rennlist.com/forums/944-turbo-and-turbo-s-forum/849644-my-front-roll-center-bump-steer-solution.html
I think the wishbone is similar to the golf so you may be able to get a longer balljoint that fits the wishbone and the spindle removing the need for welding.
Or fit the longer ball joint pins to the alloy arms and ream the stub axle, as detailed previously.
There used to be a 17mm longer balljoint kit but there were a few failures (possibly by not inserting far enough) http://rennlist.com/forums/racing-and-drivers-education-forum/409508-rennbay-19mm-pins.html
It looks like the charley arms also use a 19mm balljoint in reamed stub axles
http://forums.pelicanpart...-replacement-arms.html
Tony
http://rennlist.com/forums/944-turbo-and-turbo-s-forum/849644-my-front-roll-center-bump-steer-solution.html
I think the wishbone is similar to the golf so you may be able to get a longer balljoint that fits the wishbone and the spindle removing the need for welding.
Or fit the longer ball joint pins to the alloy arms and ream the stub axle, as detailed previously.
There used to be a 17mm longer balljoint kit but there were a few failures (possibly by not inserting far enough) http://rennlist.com/forums/racing-and-drivers-education-forum/409508-rennbay-19mm-pins.html
It looks like the charley arms also use a 19mm balljoint in reamed stub axles
http://forums.pelicanpart...-replacement-arms.html
Tony
924Srr27l
New member
944Turbo said:
Yes the Orig Steel 924S bones are the same Dims as the Mk1 Golf and also use a 17mm Ball pin
I could as you suggest use a steel wishbone and then fit an Uprated 3 bolt Pin which is what the Picture is on page one,
Somebody makes longer pins for Golf's that have been Slammed.........
But I want to retain Aluminium arms, so I'm looking at either still using the 3 bolted golf Pin, or I could also use a high
quality Male Rod End and have an Aluminium Bosses welded onto a set of Aluminium wishbones. Both ideas will be easy
to replace from wear and tear, I'm just not sure which one would be strongest..
I can get the Charlie's with a 17mm pin version but the Dollar is much stronger now and 3 years ago they would of been £600 and now they are £1000 a pair, so that's not happening!
R
So with aluminium arms you could retain the standard fixing method and use the 19mm pins I linked to earlier designed to fit them, or risk a mod with 17mm pins that might fail - Extended 17mm pins have failed, extended 19 with reamed stub axles do not seem too (as far as I can tell from a detailed search on rennlist where this mod was popular a few years back).
Be interested in the results either way!
Tony
Be interested in the results either way!
Tony
924Srr27l
New member
944Turbo said:
I can get a bigger Pin made to suit a 19mm bore Male rod end or a Spherical bearing and housing, I thought it was the circuit racers
that had issues with 17mm pins? I can understand the loads are a lot more and also the reason Porsche went to a bigger Pin as the 44 got heavier..
I've got a pair of (early speedo cable) stub axles which can be made bigger, although the Golf pins are designed to be welded to the stubs and used with a Sperical bearing which is secured by a circlip in the 3 bolt housing.
I've already got a pair of late wishbones, now with no balljoint as I've cut them off. So I can either weld on a boss for a Male rod end
or have a bracket welded on to accept the 3 bolt flange..
R
944Turbo said:
Yup I can confirm that [
].And don't forget Peter's Brands hatch incident. Lowered suspension and high cornering forces around a tight corner took the original ball joint beyond its operating range causing failure.
Steve Kevlin, (Porsche Club Motorsport head and former 944 racing champion) is dead against lowering the suspension as Porsche did an extremely good job in designing the geometry in the first place and lowering just mucks it all up (as noted in the OP).
924Srr27l
New member
John Sims said:944Turbo said:
Yup I can confirm that [
And don't forget Peter's Brands hatch incident. Lowered suspension and high cornering forces around a tight corner took the original ball joint beyond its operating range causing failure.
Steve Kevlin, (Porsche Club Motorsport head and former 944 racing champion) is dead against lowering the suspension as Porsche did an extremely good job in designing the geometry in the first place and lowering just mucks it all up (as noted in the OP).
Yes, it all makes sense when you think the original pin @ 17mm came from the VW golf and was also deemed strong enough for Road use on the lighter 2.0 924 which started life on 70 series? profile tyres etc..
Porsche's decision to go bigger @ 19MM with the 86' onwards Suspension revamp was overdue as not only did the car's sprung mass go higher but also the Unsprung with heavier brakes / wheels & tyres on the Turbo then S2
No wonder then that the 17mm Pin for competition was prone to break, even the 19mm balljointed wishbone later car's will have a lot more grief even as road car doing a Track day not to mention a full time Race use.
High quality Race Rod ends is the way to go like on these Lindsey arms
R
924Srr27l
New member
944Turbo said:
Ah I must of been thinking about the Golf Mk1 / Mk2 then which went 17mm / 19mm...
That's even more of an explanation then why the later heavier loaded models and harder use (Trackdays)
have reared the issues if all the models used 17mm pins, the 968 wishbone used a better different ball
joint design.
http://www.944turbo.org.uk/balljoints.htm
R
968 wishbones are interchangeable with post 86 cars so I think they have a similar balljoint - however the 968 wishbones do have a hole for mounting the brake duct 'scoop'.
Cutting the ends of your wishbones means you cant rebuild with the longer 19mm pins as others have done and you have more of a challange!
Cutting the ends of your wishbones means you cant rebuild with the longer 19mm pins as others have done and you have more of a challange!
924Srr27l
New member
944Turbo said:
According to that 944Turb
rg Link on the Balljoints "The 968 incorporated 60% improvements over the older 944's and Porsche (in their wisdom) decided also to drop the spring and go for a fixed clearance"Yes I want an Overkill (Strongest Solution) and hence either the 3 bolted housing / spherical bearing or a Rose joint like the Racers use and not a Production based or modified Balljoint.
This will allow me to measure in situ what Pin length is required to get the correct wishbone angle, and also when it wear ours
I can simple replace with a new rod end or bearing..
R
924Srr27l
New member
944Turbo said:
Yes, this one's quite easy to sort.
I've been lent a Wishbone and Stub assembly from a 944 Race car, this is what they did to correct the Geometry
and make sure the solution was strong enough for the loads.
Fitted an M20 rod End with a thick Boss and boxed the wishbone for additional strength.
The Steering Track Rod End was also lowered with a pin, but then this and the wishbone pin were
also boxed and welded up to form one piece.
This is very strong and over the top for a road car, but I will fit an M20 Rod end, but I'll not do the steering arm
as heavy duty.
R
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