early or late how they feel?

[colin944]

I think I may have stumbled across the reason why early cars feel more alive than late cars.I have often been told quite vocally on here that early cars feel more alive to drive than late cars ( remember pixie) The thing is could it be a simple as the set up of the front suspension and steering.Late cars are set up with negative roll radius steering i.e the king pin is inreased to allow the centre of the supension line to fall outside the centre line of the wheel. This makes the car alot more stable but less willing to turn in as sharply as cars without a negative roll radius. Hence the later cars feel a bit more ponderous in the steering and not as twitchy as the early cars .
Any of you track boys who know about suspension sets ups shed any light on my little theory?

 

[Jonny944CS]

I would agree colin.
Positive steering offset does make the steering more responsive to suspension inputs, as the tyre contact patch is operating with a lever-arm onto the steering king pin.

Great for response and turn-in, as you say. However it could be argued as less than ideal, saftey-wise, for a road car. I think this is why Porsche took the opportunity to correct the geometry (caused by the track increase from the 924) when they moved to the ABS compatable '87-on suspension. It also allowed them to change to a diagonal-split braking system, bringing further saftey benifits.

 

[Mike_Pollock]

Completely agree and have said so on several occasions .on here, having owned both at the same time .

 

[DivineE]

Can't picture what you are describing or how it would affect the contact patch against the road but running the Lindsey racing caster mounts which move the wheels forward in the arch seemed to make a massive improvement on WUF's handling compared to any other late turbo I've driven. It still wasn't quite as light on its feet as an early car but it did tip into corners far better and never wanted to push on understeer into bends. My other M030 turbo was terrible, the only way to get it mobile was to break the traction from pure power otherwise it sat in gentile, steady understeer forever.

I find understeer far more unnerving than oversteer as it gives you no options. If you are going too fast and unable to turn you either manage to lose enough speed before you hit something to get it back under control / possibly snap into violent oversteer from braking too hard. Or you crash.
With over steer you can maintain your line on the bend and counter steer to avoid an accident. If it gets wildly sideways you'll probably lose most of your speed/possibly even spin 180* in the road but it's far safer/more manageable.

 

[Mike_Pollock]

I have a diagram in a book at home which shows the difference. Will try and find if later.

 

[Jonny944CS]

Can't picture what you are describing

I have a diagram in a book at home which shows the difference. Will try and find if later.

I'll save you the trouble Mike []

running the Lindsey racing caster mounts which move the wheels forward in the arch seemed to make a massive improvement on WUF's handling compared to any other late turbo I've driven

Caster is measured in the longditudinal direction, (as opposed to transverse for steering offset) and has many characteristics all of its own...

I'm not familiar with the Lindsey caster mounts. Do they allow more caster than the factory adjusters?

 

[Neil Haughey]

Correct, its a safety issue when you have a blow out as the drivers reaction ends up being to put the incorrect steering input in, in reaction and hence causing a crash.

Early non-ABS cars also have lighter hubs I believe and are generally lighter cars anyway.

 

[Suffolk944]

My early non-abs turbo certainly felt very different on the road to my later one not just in the responsiveness of the turbo but in its agility too.

 

[Mike_Pollock]

Yes - just like that![]

 

[colin944]

The 924 always had negative foll radius fron the start. They nust have ended up with possitive in an attemt to fill the arches on the front.

 

[simdel1]

ORIGINAL: colin944

I have often been told quite vocally on here that early cars feel more alive to drive than late cars ( remember pixie)

Very little chance of me forgetting to be honest...




It's interesting to understand the reason for the difference though. This has been a very enlightening thread []

 

[944Turbo]

Was the first oval dash model with the old offsets similar in geometry to the early cars?

 

[Mike_Pollock]

Tony , Yes they were similar.
Seems strange to me that 1 year they changed to alloy arms and then the following year all the dimensions!

 

[944 man]

ORIGINAL: simdel1

ORIGINAL: colin944

...remember pixie?

Very little chance of me forgetting to be honest...

Im trying to forget.

 

[colin944]

LOL [][][][][]