944 turbo track car, abs and power steering??

[nicksonmsport]

do people do away with abs and p/s on race/track dedicated cars??
im told p/s can be removed just by disconnecting the belt, so this is easy to try, but to remove the abs pump will require a lot more work to join up the lines correctly etc, so has anyone got experience of running without the abs ?

many thanks
nick

 

[964RS]

Nick. Certainly remove the power steering pump and associated parts for racing. I wouldn't remove the ABS unless you like seeing canvas through your tyres and driving on tyres with flat spots! []

 

[MarkK]

I needed ABS ion my ex-turbo racecar and being honest sometimes leaned on it a bit,I tried it without power steering just the once,went straight back,it just feels better to me like I could put inputs in quicker.

 

[nicksonmsport]

ok good to know mixed responses, but seems the abs is good to stay. i will just try removing the ps belt and see how it feels.
cheers

 

[Mike_Pollock]

The manual rack is a lower ratio I believe. PAS was standard from the '86 model year.

Lots of people feel the early cars feel more sporty when PAS was only an option, but that is down to their different front geometry, not the PAS/manual thing!

So if you really want to save that weight I'd look for an old manual rack.

 

[944 man]

Before you do something thats hard to put right, Id suggest back to back laps with the power steering belt removed. If theyre quicker then dont put it back and remove the pump, and get the hoses made up. If, however, you find that youre consistently one second a lap slower, then put the belt back on and leave it alone. []

Id expect the speed advantage to be worth 10x the weight penalty.


Simon

 

[Neil Haughey]

IMHE its a mixed bag not having PAS. On the positive side the steering feel is just so so much better. On the negative side I have really struggled sometimes on long corners. Our cars are pretty physical to drive as it is but without the PAS you can end up hanging on to the wheel some times in those long corners and that can get very very tiring.

At first I used to find my arms gave up after about 10 to 15 minutes but this seemed to be caused by tension and posture/seating position. I didn't really have much of a problem last year but did get neck ache at Combe probably because all the high g turns are RHers. If it causes me problems this year I will just have to man up as we can't really go back to PAS now. Something I learned from Gary Marsh is to ungrip my hands from wheel on the straights and give the fingers a little shake out. Makes a big difference.

I really don't think PAS delete makes any difference at all to how fast one can turn the wheel despite several ppl I know claiming this, well at least not in a way that is meaningfully useful.

Have a look my vid on youtube (channel is my name NeilHaughey), no PAS on that car.

 

[Hilux]

I drove Fen's (remember him) without PAS, great feel but seriously heavy - so heavy in fact that when parking you had to get the car moving to turn the wheel - at a standstill it was as if the wheel was welded to the column [&:]!

I`d be inclined to leave it on as there are many cars with worse PAS feedback but 944 man`s idea is a good 'un.

 

[Cater_Racer]

We run without ABS mainly because the electronics have packed up, the unit is still in place. So it is quite easy to lock a wheel especially in the wet. First time out Tom stuffed it into the gravel during qualifiying, after putting a stonking quick lap. we've got used to it now, but I would suggest if it does work leave it alone. Power Steering still works and at my age I need it. []

Gerry

 

[u63af]

I have a 944 t track car. I have bought a early 944 manual rack to convert away from PAS. This decision is partly down to existing steering fluid leak, free up space and also cause I liked the way my old 924t drove with manual steering.

The steering will be really heavy if you just disconnect the pump/belt.

Anyone got experience running a proper manual rack on the car? I am slightly concerned about the ratio change and having more "turn to turn" on the steering wheel.

 

[944Turbo]

I have only triggered the ABS 3 or 4 times in over 100,000 miles of 944 driving all except once I backed off the brakes before the second pulse unlocking them manually (the pumps not that fast compared to modern units), the other time I had overcooked it at Donnington and the ABS helped me back onto line as panicked!

 

[Neil Haughey]

ORIGINAL: Hilux

I drove Fen's (remember him) without PAS, great feel but seriously heavy - so heavy in fact that when parking you had to get the car moving to turn the wheel - at a standstill it was as if the wheel was welded to the column [&:]!

T'is true, but as soon as the car is moving its fine. I did 4.5K miles in mine last year as well albeit a lot of that on the road so I am well used to it though. Thing is though the race car is only 1120 Kg or so and runs a lot of camber. On a 1300+ Kg car with more normal camber I imagine it could be a bit much.

Tony if you watch my vid clip the bit where I overtake Ross Morris the wheel is shaking about as the ABS is triggering in and out. Right on the limit that move and ultimately it was that 20 seconds or so of action that made my mind up to do this season. Was well chuffed to pull off a move planned from 2 corners back and executed cleanly.

Gerry I am amazed you guys are managing OK without the ABS. I found it almost impossible as the wheels lock up so easily with not a lot of pressure on the pedal. I have driven an 85 turbo (pre ABS) and the brakes have a very different feel, much more linear.

 

[os951]

You also need to remove fluid off from the steering rack, just removing belt does not give the result you are looking for. If you want to have less aid just install different ratio belt wheel or replace original 110 bar pump with BMW E30 90 bar pump.

ABS is good to be there. Over 20 years old system is out of this day, just too slow. You can easily install newer Boxster pump, when all other ABS parts can be used with it.

 

[333pg333]

I'd opt for both had I the chance. Even though the stock ABS is antiquated, it's better than not having it on there at all. That is if you're going to stick with all the other OEM system. With a booster and no ABS it's too easy to lock a wheel and flat spot expensive rubber. Ask me how. []
We've now removed all the stock brake system and having only experienced the car for a few laps recently, it felt fine and seemed to allow much better modulation than with the old non ABS/Boosted setup.

As for the p/s vs manual, there is a fair bit of evidence out there that p/s is the better way to go. Obviously it depends on the car, tyres, suspension, track, driver, etc....but overall most racecars run with p/s nowdays.

 

[Neil Haughey]

That is high end race cars with slicks, some down force and often LSDs set for maximum traction with high power. You're car in particular is much closer to that than any of ours. Personally I wouldn't go back as the stock system has so little useable feel on track, the extra feel from a manualised rack makes it worthwhile for me even with the g loading.

ABS though I would certainly not want to be without but as I demonstrated several years back with Trefs g-tech performance meter the stock ABS system is holding back the cars potential massively. From memory the best I got from the S2 on list 1b tyres was 60-0 in 127 feet, bog standard Saab 9-5 on 205x55-16s did it in 121 feet. With the tyres we are using such as cups on 1100kg of car on race suspension we are stopping nowhere near as good as should be possible. Watching in car vids from something like the Lotus championship for example it is really noticeable how much later they can brake than us from the same speeds. Maybe the newer models are better so it will be interesting to see how the boxsters and 996 go in this years championship.

 

[Hilux]

Watching in car vids from something like the Lotus championship for example it is really noticeable how much later they can brake than us from the same speeds.

Less weight and less inertia?

The big boys come in with their brake pads smokin`but my Golf doesnt need a mahoosive dab on the pedals but more a firm caress as I have increased the efficiency and mechanical advantage and reduced the weight but I suppose your championship limits any alterations.

 

[Neil Haughey]

On the regs your right, brakes have to be standard which to me means that to follow the spirit of the regs this means performance. Thus if one was to fit say a boxster pump and ABS computer one could argue its legality but it certainly wouldn't be within the spirit of the regs. To my mind it would be a cheat as I am fairly sure a more modern pump would likely allow one to brake much later.

 

[Hilux]

I must admit that when I tracked the 944T the primitive ABS allowed/mimiced trail braking so was an advantage

 

[Neil Haughey]

Well that is just a case of controlling your right foot. It is true though that the modern ABS makes for a less stable car when really hard on the brakes (depending on the car). I can remember doing that 121 ft stop in the Saab and the thing was all over the road, definitely not the way to have the car when about to turn into a corner.

Its a side point but in other championships such as the MX-5's they disable the ABS for their regs. I can understand this as to some its part of the skill of racing is to threshold brake without locking a wheel. However there is a safety issue in there which I feel reduces some of the contact as we don't tend to see cars sliding right through and off the corner in Porsche racing.

I am also fairly sure the shorter side wall tyres on modern cars help as the tyre can twist much less on the rim.

On the subject of flat spotting tyres I have a rear 245 wide cup that needs replacing for this reason. Flat spotted it badly at Silverstone but another problem with that is the heat generation blued the outer 2" on the tread which has now gone rock hard. Thus even if one could run through a flat bit that sort of cooking is not good at all for the tyre.

 

[Hilux]

Removing the servo and going to twin m/c's with a bias bar will increase feel unbelievably. You will feel all thats going on at the wheels a lot quicker and if ratios are carefully chosen the amount of finesse in the pedal movement is massive compared to the deadening of a servo.