Very heavy steering when counter-steering

[WP0ZZZ]

The non-assisted steering in my MY80 SC is very light in normal conditions. So light that I could normally steer with two fingers. However, when I lose the rear and counter-steer at high sideslip angles, the steering wheel becomes very hard to move. Interestingly, applying little counter-steer corrections mid-corner is easy. It's only when I really lose the rear and need to counter-steer a lot that the steering wheel becomes very hard to move.

I'm just wondering, is this something common to old 911s? Or maybe it's something particular to my setup...

For context, this is the current setup:


Front

22 mm torsion bars
20 mm anti-roll bar (stock SC)
Bilstein Sport dampers
ER ball joints everywhere and turbo tie-rods
Toyo R888R 205/50-15 @ 2.0 bar hot
6Jx15 ET36 cookie cutters
615 mm height to the wing
1.7 deg camber
0 toe
Close to max caster


Rear

29 mm torsion bars
18 mm antiroll bar (stock SC)
Bilstein Sport dampers
ER polybronze main bearing and stock inboard bushing
Toyo R888R 225/50-15 @ 2.1 bar hot
7Jx15 ET23 cookie cutters
610 mm height to the wing
2.5 deg camber
0 toe

[WP0ZZZ]

Has anyone had the same problem of heavy steering when applying opposite-lock (i.e. counter-steering)?

[Sailkane]

If you think about the situation...rear has no traction and the only thing gripping the road is the front tires they will feel heavy. This is normal , we see this all the time in Autocross.
The opposite is true when you have oversteer ,the front tires are light and easy to correct back until they gain traction.

[panzerfaust]

your settings ? close to max caster will load up the steering efforts noticeably. live with it, since the front bites much better than dialing back the caster. it gives you more camber gain on the outboard and dives inboard side for quicker turn end. more weight jack for rotation and better stable at high speeds too. all good stuff with caster........ but , the steering effort goes up.

your situation sounds odd. if you run lots a camber its should self center more easily? "Mr. Porsche" 70's 911 racing driver Nick Faure known to be blindingly quick with ludicrous drift angles in the UK says its the easiest car to slide since its self correcting simply by "LETTING GO" of the steering wheel when crossing up! Ive tried this and sure enough it does work well almost like magic if you keep your foot in it and centers itself arrow straight. i wasnt comfortable doing in 3rd gear yet. Mr Faure caught the eye of porsche and later became a factory driver since he was beating people in 3.0 RSRs in his street spec 3.0 RS in uk races as i recall.

coupled with quick ratios racks (todays mini vans have faster steering) high weight and CASTER, nearly every single in a modern car outside of a flyweight elise can not do without power steering.

my 2cents

[WP0ZZZ]

Originally Posted by panzerfaust

the easiest car to slide since its self correcting simply by "LETTING GO" of the steering wheel when crossing up!

This is very interesting! It's exactly how I have ended up controlling the car when I really lose it and I find myself with lots of sideslip angle.

When I need to correct a bit of oversteer I counter-steer normally but when things start to go really sideways, the steering becomes very heavy and letting it go stabilises the car. Then I quickly catch the steering wheel again to orient the car in the right direction. This leads to awkward trajectories. I would prefer to have a suspension setup that allows me to control the car in a more conventional way, even if this results in the loss of some mid-corner performance...

[panzerfaust]

yes its really weird compared to other cars... like its on autopilot self correcting isnt it? as long as you dont let off.... in fact the more you keep your foot in it the quicker it straighten itself out.

fun car to drive.... 993 guys are probably missing out? those cars feel different to me.

[Bill Verburg]

Originally Posted by panzerfaust

yes its really weird compared to other cars... like its on autopilot self correcting isnt it? as long as you dont let off.... in fact the more you keep your foot in it the quicker it straighten itself out.

fun car to drive.... 993 guys are probably missing out? those cars feel different to me.

No modern car will ever feel like an older air cooled 911, it's simple Physics. The 2 main factors affecting steering feel are caster and scrub radius. The more of each the more feedback and self centering there will be and while caster is respectable s.r is out of the ball park.

A '69-89 911 n/b w/ ET23.3 wheels will have a s/r of 52.4mm, 6ET37 it is still a hefty 39.7mm, for comparison a 964 w/ 7ET50 has a s/r of 0 a 993 w/ 8ET52 has -12. The modern cars need to have 0 to negative s/r for ABS to function effectively and large neg s/r would intrude into the trunk too much. To compensate modern cars run larger caster angles 911 spec is ~6°5', 964 is 4°25'+15'-30', 993 is 5°20'+15'-30' . The factory listened t complaints about the dead steering in 9654 when designing 993 and so sported the specs up a tad)

996 & 997 have non adjustable caster of ~8°00'+/-30 to 8°20'+15'-/-30' on sportier models, I don't have the s/r specs for these cars but it is certainly small neg.

W/ any 9111 driven at speed the gas is as important as the steering wheel, on the gas moves weight t the back giving you tons of rear grip at the cost of unweighting the front and losing some steering, on the brakes does the opposite, just hope brake bias is nominal and lsd is functioning well.

[panzerfaust]

hi bill yes hard not to agree with you, although the lotus mk1 elise or opel/speedster (which has different suspension with each other) come pretty darn close in feel. it has a near race quick ratio and a tiny steering wheel in which you can opposite lock it through the whole sweeper with flick of the wrist in handcuffs. like the 911 its odd and unique in its own way. the 911 has this old school appeal sitting upright a sawing at that big steering wheel with flailing elbows out. :-) some feel the kickback and bump steer is unrefined while others love it.


on the geometry the elise/opel surprisingly has only moderate caster 0f approx 4 degrees but it has something else up its sleeves to load up the tires progressively. it runs anti-ackerman steering geometry for induced scrub. the early opel only had only tiny 175mm section tires, very little static camber since the it makes up for in jounce with a classic double A arm camber gain.


im surprise the 964 has 0... ive notice they always try to add a on way or the other scooch to eliminate wander on a performance car. i dont have enough seat time to fully understand suspension geometry merits between the 964 and 993 . all know is i prefer the way a 964 feels with my brief street drives. i think the 993 might be too competent with the multi link rear perhaps? soaks up huge loads with ease in the back with comfort too.

yes most moderns do have near zero or neg SR but i would stop short of saying is a necessity for ABS. road cars just behave better this way? my first car was a 70's mk1 scirocco. they were first of a new breed econoboxes imported with high offset, neg scrub geo. It would take another 10-15yrs before ABS was widely available yet they had this type of geometry. the neg SR gives is less steering kickback and more importantly in a high speed tire blowout, the car will be less likely to throw you off the road as an important safety measure. other advantages are well know which, less moment stress on spindle/wheel bearing enables a lightweight design. reduced sweep area from lock to lock for smaller wheel houses. less areo drag shrouded from the wheel and tire itself....etc...

[Bill Verburg]

Originally Posted by panzerfaust

…….
yes most moderns do have near zero or neg SR but i would stop short of saying is a necessity for ABS. road cars just behave better this way? my first car was a 70's mk1 scirocco. they were first of a new breed econoboxes imported with high offset, neg scrub geo. It would take another 10-15yrs before ABS was widely available yet they had this type of geometry. the neg SR gives is less steering kickback and more importantly in a high speed tire blowout, the car will be less likely to throw you off the road as an important safety measure. other advantages are well know which, less moment stress on spindle/wheel bearing enables a lightweight design. reduced sweep area from lock to lock for smaller wheel houses. less areo drag shrouded from the wheel and tire itself....etc...

0 or negative scrub is an absolute necessity for ABS, that is what provides the corrective force to keep the car going straight if s/r is positive the force will shunt the car to the side. I had a '75 Sirocco too, first year for ABS and cat. The ABS worked fine, the cat burned itself up one cold morning when leaving Boston, the cops stopped me when they saw flames shooting out the end of the exhaust, exciting morning.

the magnitude of the s/r is what gives the kickback to the steering wheel it's leverage, greater magnitude = greater kickback at the steering wheel, the sign determines the direction of the kickback, again this is why 0 or negative is an engineering necessity and why cars lost the deep dish wheel look in front when they acquired ABS

[panzerfaust]

bill are you sure your 75 scirocco had abs? that sounds way early to me. i had a 78 and you counldnt even get it as an option not that i wanted these crude early systems. I recall one of the first cars in america with ABS was the top of the line Mercedes Benz B S class in 78-79ish. my folks had one. MB a big stink of ABS with double page advertising in car & driver, road & track etc... im guessing it was the mid to late 80's before they became available across the board.

any how i think we are arguing about the same thing? near zero or neg SR has many attributes whether you have abs or not. the vast majority of the cars in the 70's in america did not have ABS as of yet as i recall?

its not just kick back from the leverage also a way to tune suspensions. racing karts have no suspension they have a massive SR that are adjustable for tuning front end bite. at times the SR is greater than the diameter of the short tires. couple with caster and kingpin inclination they rely on weight jacking to get around tight corners without a rear differential. this is how they tailor the chassis dynamics with a fixed wheels for different courses. you can do this to passenger cars to a lessor extent. america's chassis guru Carrol Smith had no idea if this phenomenon as a senior judge he said our car wouldnt work. our car ended up winning the Formulas SAE outstanding performance award. :-)

honesty i cant remember too much of my scirocco but I too had exhaust issues. i had installed set headers. it was a funky champagne edition 78 and you can only get a 4 speed. i recall gearing was so high, I red lined it for about 15-20mins straight running flat out at near the century mark. its blew out chunks of the header at the bend near the cylinder head ports... scirocco were such wonderful underrated cars. sad that they arent coveted with the enthusiast more? i think my car weighed under 1800-1900lbs stock which is pretty amazing when you think about it.

all the best.

ps us old guys love deep the dished wheels! the 964 3.8 RSR had ABS and ran with deep dished wheels in the back on narrow body banana arms?

[Bill Verburg]

Originally Posted by panzerfaust

bill are you sure your 75 scirocco had abs? that sounds way early to me. i had a 78 and you counldnt even get it as an option not that i wanted these crude early systems. I recall one of the first cars in america with ABS was the top of the line Mercedes Benz B S class in 78-79ish. my folks had one. MB a big stink of ABS with double page advertising in car & driver, road & track etc... im guessing it was the mid to late 80's before they became available across the board.

any how i think we are arguing about the same thing? near zero or neg SR has many attributes whether you have abs or not. the vast majority of the cars in the 70's in america did not have ABS as of yet as i recall?

its not just kick back from the leverage also a way to tune suspensions. racing karts have no suspension they have a massive SR that are adjustable for tuning front end bite. at times the SR is greater than the diameter of the short tires. couple with caster and kingpin inclination they rely on weight jacking to get around tight corners without a rear differential. this is how they tailor the chassis dynamics with a fixed wheels for different courses. you can do this to passenger cars to a lessor extent. america's chassis guru Carrol Smith had no idea if this phenomenon as a senior judge he said our car wouldnt work. our car ended up winning the Formulas SAE outstanding performance award. :-)

honesty i cant remember too much of my scirocco but I too had exhaust issues. i had installed set headers. it was a funky champagne edition 78 and you can only get a 4 speed. i recall gearing was so high, I red lined it for about 15-20mins straight running flat out at near the century mark. its blew out chunks of the header at the bend near the cylinder head ports... scirocco were such wonderful underrated cars. sad that they arent coveted with the enthusiast more? i think my car weighed under 1800-1900lbs stock which is pretty amazing when you think about it.

all the best.

ps us old guys love deep the dished wheels! the 964 3.8 RSR had ABS and ran with deep dished wheels in the back on narrow body banana arms?

I've gotta admit that my memory of the '70s is questionable at best, yes, they were fun light and very direct cars