Steering response/upgrades - all in
05-02-2017, 06:36 PM
#1
Three Wheelin'
Thread Starter
Steering response/upgrades - all in
This is about all that you can do for the 964 steering, bumpsteer notwithstanding. 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.
2. The 993 rack is slightly quicker than the 964. The 964 rack ratio is 18.5:1. The 993 rack is 16.5:1. I measured the rack travel per steering wheel turn as 44mm/turn for the 964, and 48.6mm/turn on the 993 rack. Sounds significant. In reality, it’s barely perceptible. Despite a Porsche bulletin saying that it won't fit into a 964 C4, it fits perfectly fine. Will obviously fit a C2 also. Completely plug and play. More info in this thread: https://rennlist.com/forums/964-foru...l#post13813785
3. The 964 RS 4-spoke steering wheel is a very nice improvement. Feels great in the hand and fits the car perfectly. With my 4’10 wife right up against the airbag of the stock wheel, it was an easy decision. These wheels pop on ebay often. Few seem to realize that quite a few late 944’s came with this “sport” steering wheel. While you're at it, use the late 944 horn pad with it. The 944 pad is about an inch more narrow than the pads that came on 911’s with this style of wheel. The 964 airbag wheel is 380mm, the 4-spoke RS wheel is 363mm. More here: https://rennlist.com/forums/964-foru...d-install.html
4. FVD monoball inner tie rods <-- you want these. These really sharpen the steering response and bring the car into the modern era. Anyone who has installed the 993evo uprights are noticing the solid tie rods when they steer and not the different upright geometry. I have no idea why Porsche uses these forked inner tie rods with a big chunk of rubber separating the pieces. Most makes/models seem to use solid inners.
The 3.2 models have been using these solid inners (“turbo” tie rods) for ages. Lucky for them the price is peanuts. Unlucky for us, the cheapest 964 option is these FVD parts, which definitely aren’t cheap for a simple inner tie rod. There may be a generic off-the-shelf part out there somewhere, but I wasn’t able to find anything. The thread into the steering rack is a normal M14x1.5. The thread onto the outer tie rod, however, is an M14x1.5 female thread. Good luck finding that combo, let alone in the correct length. FYI- these FVD parts come from Germany, so use your travel credit card and avoid the DM exchange charge!
5. Last, electric steering from an A-class Merc. Don’t expect a performance benefit here. All of the stock parts that get removed: pump, all lines, hardware, add up to almost exactly 10lbs. The Merc pump is 8.4lbs, plus another pound or so for the new lines and brackets. So you’re moving a whopping 10lbs from the front of the engine to the frunk. The lack of drag of the mechanical pump is partly/completely made up for in the increased electromechanical drag from the higher alternator load. My butt dyno can’t perceive any extra hp.
What you do get out of this: greatly simplified ps lines and the removal of all of the very expensive leaky stock lines. Unfortunately, you also get a noticeable “hmmmmmm” from the pump. I’m going to try and baffle the sound. The swap is relatively easy once you accumulate all of the parts:
- 10awg wire for +12v off the battery, a 60amp in-line fuse, and m6 ring terminal for the +battery connection
- an6 straight fittings for high-pressure hose, x2
- high pressure power steering hose (I used aeroquip aqp high pressure ps hose), 3ft is plenty
- an6 to m16x1.5 adapter with o-ring
- an6 to m12 banjo fitting
- Cohline 9.5mm power steering return line hose (pn 2019970382), 16mm od hose clamps, and reuse the barbed banjo from the stock line
- homemade brackets
- grommet where the lines pass into the frunk
Here’s a video of it humming away:
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.
2. The 993 rack is slightly quicker than the 964. The 964 rack ratio is 18.5:1. The 993 rack is 16.5:1. I measured the rack travel per steering wheel turn as 44mm/turn for the 964, and 48.6mm/turn on the 993 rack. Sounds significant. In reality, it’s barely perceptible. Despite a Porsche bulletin saying that it won't fit into a 964 C4, it fits perfectly fine. Will obviously fit a C2 also. Completely plug and play. More info in this thread: https://rennlist.com/forums/964-foru...l#post13813785
3. The 964 RS 4-spoke steering wheel is a very nice improvement. Feels great in the hand and fits the car perfectly. With my 4’10 wife right up against the airbag of the stock wheel, it was an easy decision. These wheels pop on ebay often. Few seem to realize that quite a few late 944’s came with this “sport” steering wheel. While you're at it, use the late 944 horn pad with it. The 944 pad is about an inch more narrow than the pads that came on 911’s with this style of wheel. The 964 airbag wheel is 380mm, the 4-spoke RS wheel is 363mm. More here: https://rennlist.com/forums/964-foru...d-install.html
4. FVD monoball inner tie rods <-- you want these. These really sharpen the steering response and bring the car into the modern era. Anyone who has installed the 993evo uprights are noticing the solid tie rods when they steer and not the different upright geometry. I have no idea why Porsche uses these forked inner tie rods with a big chunk of rubber separating the pieces. Most makes/models seem to use solid inners.
The 3.2 models have been using these solid inners (“turbo” tie rods) for ages. Lucky for them the price is peanuts. Unlucky for us, the cheapest 964 option is these FVD parts, which definitely aren’t cheap for a simple inner tie rod. There may be a generic off-the-shelf part out there somewhere, but I wasn’t able to find anything. The thread into the steering rack is a normal M14x1.5. The thread onto the outer tie rod, however, is an M14x1.5 female thread. Good luck finding that combo, let alone in the correct length. FYI- these FVD parts come from Germany, so use your travel credit card and avoid the DM exchange charge!
5. Last, electric steering from an A-class Merc. Don’t expect a performance benefit here. All of the stock parts that get removed: pump, all lines, hardware, add up to almost exactly 10lbs. The Merc pump is 8.4lbs, plus another pound or so for the new lines and brackets. So you’re moving a whopping 10lbs from the front of the engine to the frunk. The lack of drag of the mechanical pump is partly/completely made up for in the increased electromechanical drag from the higher alternator load. My butt dyno can’t perceive any extra hp.
What you do get out of this: greatly simplified ps lines and the removal of all of the very expensive leaky stock lines. Unfortunately, you also get a noticeable “hmmmmmm” from the pump. I’m going to try and baffle the sound. The swap is relatively easy once you accumulate all of the parts:
- 10awg wire for +12v off the battery, a 60amp in-line fuse, and m6 ring terminal for the +battery connection
- an6 straight fittings for high-pressure hose, x2
- high pressure power steering hose (I used aeroquip aqp high pressure ps hose), 3ft is plenty
- an6 to m16x1.5 adapter with o-ring
- an6 to m12 banjo fitting
- Cohline 9.5mm power steering return line hose (pn 2019970382), 16mm od hose clamps, and reuse the barbed banjo from the stock line
- homemade brackets
- grommet where the lines pass into the frunk
Here’s a video of it humming away:
Last edited by -nick; 05-02-2017 at 07:13 PM.
05-02-2017, 06:54 PM
#2
Three Wheelin'
Thread Starter
Edit: This is how I'm turning the pump on now: https://rennlist.com/forums/964-foru...l#post15145555
Almost forgot- here is a pic of the switched +12v for the ps pump. Not sure if C2's have this same plug, I think that it's in all abs cars as an abs diagnostic/test plug. The red wire is switched 12v and is convenient to use for the ps pump remote on/off. If you suck the solder out of the terminal, there is room for an additional 22awg wire. Then solder both wires into the terminal.
Almost forgot- here is a pic of the switched +12v for the ps pump. Not sure if C2's have this same plug, I think that it's in all abs cars as an abs diagnostic/test plug. The red wire is switched 12v and is convenient to use for the ps pump remote on/off. If you suck the solder out of the terminal, there is room for an additional 22awg wire. Then solder both wires into the terminal.
Last edited by -nick; 07-16-2018 at 05:57 PM.
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kos11-12 (10-13-2019)
05-02-2017, 07:58 PM
#4
Racer
05-02-2017, 09:36 PM
#5
Three Wheelin'
Why would you do the tie rods instead of the uprights?
05-03-2017, 12:22 AM
#7
Nordschleife Master
That's not even what he said. Go back and read, "bumpsteer notwithstanding."
He's saying that when people do the 993 Evo uprights, the mod requires the upgraded inner tie-rod. So when post-mod, they attribute the steering feel to the upright, but it's actually the tie-rod they're feeling.
He's saying that when people do the 993 Evo uprights, the mod requires the upgraded inner tie-rod. So when post-mod, they attribute the steering feel to the upright, but it's actually the tie-rod they're feeling.
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05-03-2017, 02:01 PM
#9
Three Wheelin'
That's not even what he said. Go back and read, "bumpsteer notwithstanding."
He's saying that when people do the 993 Evo uprights, the mod requires the upgraded inner tie-rod. So when post-mod, they attribute the steering feel to the upright, but it's actually the tie-rod they're feeling.
He's saying that when people do the 993 Evo uprights, the mod requires the upgraded inner tie-rod. So when post-mod, they attribute the steering feel to the upright, but it's actually the tie-rod they're feeling.
05-03-2017, 03:38 PM
#11
Rennlist Member
The trick setup with the Evo upright (which is not available right now) is the ERP outer tie rod with the ERP inner tie rods which are a direct copy of the old RS pieces which are NLA. The FVD setup is similar but slightly different in design.
I like what you did with the electric pump. Remove the parasitic drag, the pipes running under the car, etc.
I opted to leave my rack stock as with all of my chassis/suspension work and how direct the car is I'm not sure I want any quicker response :-)
I like what you did with the electric pump. Remove the parasitic drag, the pipes running under the car, etc.
I opted to leave my rack stock as with all of my chassis/suspension work and how direct the car is I'm not sure I want any quicker response :-)
05-03-2017, 05:03 PM
#13
Rennlist Member
When I rebuilt my steering rack last month I used the Tarrett inners and OEM Lemforder outers. They are OE quality and super stout. My alignment guy really liked them as well. The Tarrett's eliminate the double ended internally threaded tube section with the stock 964. Much easier to align the car with only the one threaded section vs the stock two Darin said. I used 993 accordion boots and everything fit well. I kept my stock uprights and the steering is so much more responsibe now. Love it
05-03-2017, 07:38 PM
#14
Three Wheelin'
Thread Starter
Cheers folks!
Achtung, yes I should have mentioned the inner tie rod option from Tarett. With the generous discount from Rhonda at FVD, the price is about the same between the two.
tjb, I'm using stock outer tie rods. I didn't add the steering rack brace but it's on my list to make. It's just a flat bar of aluminum with two holes and two spacers. I can't believe anyone pays money for these... I honestly don't expect it to do much but it can't hurt.
Andrew, good to know that yours runs quieter! I'll post up some more pics of my mounts. Undoubtedly, it could be better isolated. I have some extra oil tank rubber mounts that could work well.
Flyin, no extra holes! The front bracket that is visible in the photo of the wiring uses one of the c4 diff lock controller mounting bolts. The rear bracket uses two other nuts that are already welded in the frunk (used for rhd cars maybe?). The pump sits on a rubber donut (an original steering rack -to- body rubber piece that I had an extra of). The donut is fairly soft, but I could add another softer layer of foam between it and the frunk floor for a little better sound isolation. I'll get some more photos up of the brackets. I made them easily by bending/cutting/drilling some pieces of aluminum.
The original parts are all pretty easy to remove, except the long steel lines. I had replaced the long fuel lines in the past so I knew what to expect. With some contortions, the long lines will come out. The higher you can get the car off of the floor the better. It would be relatively easy if you have a lift.
Spyerx, the 964 RS inners are the same as the C4. Supposedly stiffer rubber in the forks than the C2. The 993 RS inners are similar to the regular 993, but also supposedly use a stiffer rubber. The 993RSR inners are the spherical ones with no rubber.
The electric pump does remove mechanical drag, but it pulls a lot of amps and I'm sure induces quite a bit of drag from the alternator. I don't think that there is much benefit there.
With the stock bits I'm unsure how you're getting too quick a response? Unless you're just running toe out?
mystert, good hear someone else's feedback on these spherical inners! The original tie rod setup with the "turnbuckle" adjuster is like having an m14x3.0 thread since turning it changes the threads at both ends (one is a reverse thread). The spherical setup has just one threaded end to adjust, so it makes sense that you could get a more accurate toe this way.
Achtung, yes I should have mentioned the inner tie rod option from Tarett. With the generous discount from Rhonda at FVD, the price is about the same between the two.
tjb, I'm using stock outer tie rods. I didn't add the steering rack brace but it's on my list to make. It's just a flat bar of aluminum with two holes and two spacers. I can't believe anyone pays money for these... I honestly don't expect it to do much but it can't hurt.
Andrew, good to know that yours runs quieter! I'll post up some more pics of my mounts. Undoubtedly, it could be better isolated. I have some extra oil tank rubber mounts that could work well.
Flyin, no extra holes! The front bracket that is visible in the photo of the wiring uses one of the c4 diff lock controller mounting bolts. The rear bracket uses two other nuts that are already welded in the frunk (used for rhd cars maybe?). The pump sits on a rubber donut (an original steering rack -to- body rubber piece that I had an extra of). The donut is fairly soft, but I could add another softer layer of foam between it and the frunk floor for a little better sound isolation. I'll get some more photos up of the brackets. I made them easily by bending/cutting/drilling some pieces of aluminum.
The original parts are all pretty easy to remove, except the long steel lines. I had replaced the long fuel lines in the past so I knew what to expect. With some contortions, the long lines will come out. The higher you can get the car off of the floor the better. It would be relatively easy if you have a lift.
Spyerx, the 964 RS inners are the same as the C4. Supposedly stiffer rubber in the forks than the C2. The 993 RS inners are similar to the regular 993, but also supposedly use a stiffer rubber. The 993RSR inners are the spherical ones with no rubber.
The electric pump does remove mechanical drag, but it pulls a lot of amps and I'm sure induces quite a bit of drag from the alternator. I don't think that there is much benefit there.
With the stock bits I'm unsure how you're getting too quick a response? Unless you're just running toe out?
mystert, good hear someone else's feedback on these spherical inners! The original tie rod setup with the "turnbuckle" adjuster is like having an m14x3.0 thread since turning it changes the threads at both ends (one is a reverse thread). The spherical setup has just one threaded end to adjust, so it makes sense that you could get a more accurate toe this way.
05-03-2017, 07:53 PM
#15
Rennlist Member
Are the ERP inners the same as what Tarett is selling?
EDIT: http://www.tarett.com/items/993-964-...rtr-detail.htm
EDIT: http://www.tarett.com/items/993-964-...rtr-detail.htm
Spyerx, the 964 RS inners are the same as the C4. Supposedly stiffer rubber in the forks than the C2. The 993 RS inners are similar to the regular 993, but also supposedly use a stiffer rubber. The 993RSR inners are the spherical ones with no rubber.
The electric pump does remove mechanical drag, but it pulls a lot of amps and I'm sure induces quite a bit of drag from the alternator. I don't think that there is much benefit there.
With the stock bits I'm unsure how you're getting too quick a response? Unless you're just running toe out?
The electric pump does remove mechanical drag, but it pulls a lot of amps and I'm sure induces quite a bit of drag from the alternator. I don't think that there is much benefit there.
With the stock bits I'm unsure how you're getting too quick a response? Unless you're just running toe out?
Assuming you've capped off the pump I'll bet you get less drag with the electric setup.
My car is setup very, very agile, all solid everything, no toe out, but with the setup it's very quick to change direction. K
Too bad you're not in SoCal would be interesting to feel yours relative (and vice versa).
