schip43

TonyG

That bump in turn 8 is somewhat violent. It actually knocks my glasses slightly off my face everytime I hit it at speed. Now that I think about it.... I bought a new helmet because of how it moved around on my head when I hit the bump in turn 8. I would hit that bump and then have to adjust my helmet and glasses as soon as I hit the straight.

With aero, big rubber, and a lot of speed, the manual steering is just way hard to control and be smooth. But with the power steering... it's a piece of cake.


TonyG

Lemming

Most likely the differences are setup, not just big rubber as both myself and Eric are running 275's in front and both have aero as well. I didn't see what caster Tony is running, I'm right at 3.8 like Eric. Other differences could include spring rates as Tony is running his relatively heavy car (about 265 lbs greater than me) on fairly light springs (350/500; compared to 600/600 for me and IIRC Eric is near 900 on both ends). Track width may also play a role.

For those that are thinking about the mod, I would suggest running back to back sessions on track with PS and without (remove the PS belt). Choose whichever one you like the most based either on lap times or on what is most comfortable. If you go without PS, then you will be even happier going with the true manual rack.

TonyG

Hey,,

I'm running 450lbs/650lbs spring rates... which are on the soft side.

I think I'll pop in my 550/750lbs springs for the POC Triple Crown at WSIR coming up and see how they test out on Friday.

My caster is about 3.5 on each side.


TonyG

Lemming

Guess you need to update your website

333pg333

It is amazing just what different spring rates people are running. I'm putting together a bit of a spreadsheet and the variations are great.

Van

I just checked my caster - it was about 4.5 to 5 degrees. I was able to get each side down to 3 degrees. That's as low as I could get with the fabcar arms.

I'll be at the track on Friday, so I'll see how it compares.

theedge

There IS a pretty big difference between power steering without a belt, a power steering rack with pump etc removed and a crossover hose installed, and a real manual rack. A power system without a belt is a real beast.

333pg333

My understanding is that we have a fairly limited amount we can adjust the Castor.
What are the pro's and con's of a lot of castor?

schip43

Not an expert by any means but caster I know, more caster makes a vehicle more stable in a straight line.
But can make it harder to turn in hence a plus for power steering. I'm sure others can elaborate more. On my 951 I have the caster set at max per factory specs.

gt37vgt

why would you want less castor ?it is the biggest weakness of that front end ..
if you have only 3 deg you will have your static camber wound up to -3 or more .and they guy running 5deg of castor and less camber will always be out braking you ..
take your blinkers off and have a look at the geometry of some race cars out side this forum . 6 or 7 degrees is normal. an E30 M3 has 9 deg of Castor and was a more successful race car than a 944..
And of course it kept the power steer all the way ..

333pg333

Probably not blinkers as such. More an ignorance of this part of the setup equation. Not much talk of it in here.

samluke

I just finished a race weeknd. The power steering was leaking on the Friday and there was no hope of fixing it so I cut the belt.

4 races over two days with no Power steering, one a 40 minute extended sprint. Its obviously manageable and I was still competetive, however I agree with others that Power makes the car much easier to drive and control, especially at the limit. I won one race and was competetive in the others. I would like to think I would have been even quicker if I had power.

I will be fixing the leak and going back to power.

333pg333

I also wonder how much spring rate might have an effect on the 'feel' in the p/s debate?

thirdgenbird

i dont think this is a fair comparison as there is a big difference between a manual rack and broken power steering