Steering response/upgrades - all in
05-09-2017, 04:43 PM
#31
Instructor
The fvd inners aren't meant to, nor advertised, as affecting bump steer. Inner tie rods have no effect here. I'm not sure who is suggesting this?
Spyerx has the procedure. I still don't know if it's setup, or you folks are running below rs height but at rs height any bump steer is honestly imperceptible on mine. No difference whether I set my shocks to 85% max for event days, or full soft for the street; if one front wheel dips into a pothole the car doesn't change direction. I have 50mm of compression travel before touching the front bump stops, so it's not as if the travel is limited.
964tit, I think some changes are getting confused. Camber plates absolutely will not effect how light or heavy the steering feels. However, toe out will definitely lighten it up as will less caster. I'm with Spyerx and am not a fan of any toe out. Slight toe in also gives the best tire wear, anything else will accelerate wear.
I should mention here that the 993 rack does lighten the steering feel weight. I drove a student's C2 yesterday at our autocross school and confirmed that it wasn't just my old, dead, rack that felt heavier than the 993 rack. This is with the same alignment settings on both racks. I've since added another degree of caster to get 5.2 and the 993 rack is still slightly lighter than my old rack. This could explain why Porsche increased the caster on the 993.
Spyerx has the procedure. I still don't know if it's setup, or you folks are running below rs height but at rs height any bump steer is honestly imperceptible on mine. No difference whether I set my shocks to 85% max for event days, or full soft for the street; if one front wheel dips into a pothole the car doesn't change direction. I have 50mm of compression travel before touching the front bump stops, so it's not as if the travel is limited.
964tit, I think some changes are getting confused. Camber plates absolutely will not effect how light or heavy the steering feels. However, toe out will definitely lighten it up as will less caster. I'm with Spyerx and am not a fan of any toe out. Slight toe in also gives the best tire wear, anything else will accelerate wear.
I should mention here that the 993 rack does lighten the steering feel weight. I drove a student's C2 yesterday at our autocross school and confirmed that it wasn't just my old, dead, rack that felt heavier than the 993 rack. This is with the same alignment settings on both racks. I've since added another degree of caster to get 5.2 and the 993 rack is still slightly lighter than my old rack. This could explain why Porsche increased the caster on the 993.
I don't track my car and am still 'learning' what's best for alignment.
05-09-2017, 06:11 PM
#32
Three Wheelin'
Thread Starter
I can only relate how the Merc pump works, which is very simple and you probably gathered it all from listening to the short video clip. Wiring consists of the big 10awg +12v, ground, and a switched +12v which must flip an internal relay to complete the 10awg to ground circuit through the motor to turn it on. The motor adjusts feed pressure based on demand. The amps certainly go up when you turn the wheel. No speed sensor necessary. The feel is exactly the same as it was with the mechanical pump.
964tit, gotcha! Unless your old mounts had truly dead bearings, the monoballs won't give change the steering weight. Certainly no more than new factory mounts would. It sounds like had an alignment done at the same time? That's what would have changed your steering. The performance benefit of monoball top mounts is to control camber change on the loaded outside wheel in a turn. The flex in rubber mounts will push the camber toward positive with enough force. At least that's the theory. Not very useful on the street and they all alter the strut travel, which has to be measured when you use them. Not to mention keeping the bearings sealed from dirt.
964tit, gotcha! Unless your old mounts had truly dead bearings, the monoballs won't give change the steering weight. Certainly no more than new factory mounts would. It sounds like had an alignment done at the same time? That's what would have changed your steering. The performance benefit of monoball top mounts is to control camber change on the loaded outside wheel in a turn. The flex in rubber mounts will push the camber toward positive with enough force. At least that's the theory. Not very useful on the street and they all alter the strut travel, which has to be measured when you use them. Not to mention keeping the bearings sealed from dirt.
Last edited by -nick; 05-09-2017 at 06:32 PM.
05-10-2017, 09:08 PM
#33
Instructor
I can only relate how the Merc pump works, which is very simple and you probably gathered it all from listening to the short video clip. Wiring consists of the big 10awg +12v, ground, and a switched +12v which must flip an internal relay to complete the 10awg to ground circuit through the motor to turn it on. The motor adjusts feed pressure based on demand. The amps certainly go up when you turn the wheel. No speed sensor necessary. The feel is exactly the same as it was with the mechanical pump.
964tit, gotcha! Unless your old mounts had truly dead bearings, the monoballs won't give change the steering weight. Certainly no more than new factory mounts would. It sounds like had an alignment done at the same time? That's what would have changed your steering. The performance benefit of monoball top mounts is to control camber change on the loaded outside wheel in a turn. The flex in rubber mounts will push the camber toward positive with enough force. At least that's the theory. Not very useful on the street and they all alter the strut travel, which has to be measured when you use them. Not to mention keeping the bearings sealed from dirt.
964tit, gotcha! Unless your old mounts had truly dead bearings, the monoballs won't give change the steering weight. Certainly no more than new factory mounts would. It sounds like had an alignment done at the same time? That's what would have changed your steering. The performance benefit of monoball top mounts is to control camber change on the loaded outside wheel in a turn. The flex in rubber mounts will push the camber toward positive with enough force. At least that's the theory. Not very useful on the street and they all alter the strut travel, which has to be measured when you use them. Not to mention keeping the bearings sealed from dirt.
The KWs I put in came with monoballs on the rear. I wanted camber adjustment on the front so monoballs came with the rennline parts I picked for the front. Quite happy with the outcome. Just did a 4000km round trip lapping Tasmania and I thought handling was vastly improved.
06-01-2017, 06:10 PM
#36
Instructor
I was thinking of going down the No power steering route. As per the the 3.2 Carrera etc.
Only as I think there will be more feel and its just a less complex set up. What do you think? Do these cars need power steering?
Only as I think there will be more feel and its just a less complex set up. What do you think? Do these cars need power steering?
06-01-2017, 08:33 PM
#37
Rennlist Member
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When stopped or moving slow it helps, at speed not really necessary. If you have power steering but have pump issues you may want to look at electrical pump options. It is an easy conversion, and not bad on wallet.
06-02-2017, 01:00 PM
#38
Rennlist Member
..Cliff notes version, the solid inner tie rods are the biggest upgrade, followed by a smaller diameter steering wheel. The other changes are subtle.
1. Poly steering rack bushings
2. 993 steering rack
3. 363mm RS steering wheel
4. FVD inner tie rods
5. Electric power steering
1. The poly steering rack bushings are a very minor improvement to steering response. They are, however, very cheap and not too difficult to replace. The stock bushings are very soft rubber and will allow the rack to shift left/right by a small amount as you steer. No added NVH with the poly. I would recommend them for everyone. Buy them on ebay and avoid some of the Porsche tax.
1. Poly steering rack bushings
2. 993 steering rack
3. 363mm RS steering wheel
4. FVD inner tie rods
5. Electric power steering
1. The poly steering rack bushings are a very minor improvement to steering response. They are, however, very cheap and not too difficult to replace. The stock bushings are very soft rubber and will allow the rack to shift left/right by a small amount as you steer. No added NVH with the poly. I would recommend them for everyone. Buy them on ebay and avoid some of the Porsche tax.
Limited mileage post install, but the immediate impression is that something feels just slightly heavier (like taking air out of the front tires) but more solid over bumps. I also installed the rack brace.
Very subtle mod ($100 parts), but nice to know every thing is a notch more solid, with no negative affects (added NVH).
Last edited by 911Jetta; 06-02-2017 at 02:15 PM.
06-04-2017, 07:32 PM
#39
Three Wheelin'
I have the 993 inner tie rods with ERP outer , the steering is so precise and quick it's fantastic !!
I had the uprights modified ,.
And also have the urethane ruber and the brace from Rothsport ,
I bought the Merc A class pump , will fit it soon , I like this mod as it shifts weight to the front
I had the uprights modified ,.
And also have the urethane ruber and the brace from Rothsport ,
I bought the Merc A class pump , will fit it soon , I like this mod as it shifts weight to the front
06-24-2017, 04:20 AM
#40
I am looking to decrease my turn to lock to about 2.4.
Quaife is making this till the G model,was thinking asking them if the could produce this for the 964 rack.
For sure they will not make one,could there be more intrest?
Maybe do a group buy?
https://shop.quaife.co.uk/porsche-91...pinion-kit-2-5
Quaife is making this till the G model,was thinking asking them if the could produce this for the 964 rack.
For sure they will not make one,could there be more intrest?
Maybe do a group buy?
https://shop.quaife.co.uk/porsche-91...pinion-kit-2-5
06-25-2017, 01:07 AM
#42
Originally Posted by 964Andrew
Great writeup! I noticed your pump sound much louder compared to mine. Maybe, try to isolate any metal on metal mounting point with rubber grommet?
Thanks!
Andrew
Thanks!
Andrew
07-16-2018, 05:56 PM
#43
Three Wheelin'
Thread Starter
The Benz pump has been trouble-free after stress testing it for 5,000 miles, including about 20 autocross days, and outside temperatures from 0-98F. I thought some additional wiring info would be useful to update this thread. Inspired after seeing s4magman's new thread using the 997 cup electric steering pump-
https://rennlist.com/forums/964-foru...ring-pump.html
For the remote pump turn on, I picked up one of these simple programmable relay/timers:
http://timers.shop/Multi-Functional-...-amp_p_12.html
The timer is wired: switched +12v input, ground, and an output to the pump signal wire. Then I tapped the oil pressure signal wire* for a trigger input into the timer. Anything above ~1bar of oil pressure is enough voltage for the timer trigger input. There are lots of programming options, I set it up as: once triggered by the oil pressure, there's a 2sec delay, the +12v switched input is bridged to the timer output wire (the steering pump signal wire). The pump only turns off when the switched +12v is removed (ignition off). This way, the pump turns on 2 seconds after the engine has started. No reason to tax another ~15amps to pressurize the steering pump while the starter is cranking the engine over.
*Fun fact: Porsche used the oil pressure signal to disable the power cabriolet top operation with the engine running. So there is precedent for using this input!
Regarding the pump volume, keep in mind that the phone was recording from the floor of the frunk and very close to the pump. In real life, the volume is pretty similar to what I've heard on other electric pumps. And yes, I had fluid in it for the video
https://rennlist.com/forums/964-foru...ring-pump.html
For the remote pump turn on, I picked up one of these simple programmable relay/timers:
http://timers.shop/Multi-Functional-...-amp_p_12.html
The timer is wired: switched +12v input, ground, and an output to the pump signal wire. Then I tapped the oil pressure signal wire* for a trigger input into the timer. Anything above ~1bar of oil pressure is enough voltage for the timer trigger input. There are lots of programming options, I set it up as: once triggered by the oil pressure, there's a 2sec delay, the +12v switched input is bridged to the timer output wire (the steering pump signal wire). The pump only turns off when the switched +12v is removed (ignition off). This way, the pump turns on 2 seconds after the engine has started. No reason to tax another ~15amps to pressurize the steering pump while the starter is cranking the engine over.
*Fun fact: Porsche used the oil pressure signal to disable the power cabriolet top operation with the engine running. So there is precedent for using this input!
Regarding the pump volume, keep in mind that the phone was recording from the floor of the frunk and very close to the pump. In real life, the volume is pretty similar to what I've heard on other electric pumps. And yes, I had fluid in it for the video
07-16-2018, 09:30 PM
#45
Loving all this electric power steering info- definitely going this direction. Also looking for an electric compressor for the a/c. If only there was an option for a rear mounted oil cooler I’d be able to eliminate all the front to rear lines.....
Thanks-
pete
Thanks-
pete