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Author Topic: LS Swap Power Steering - The Everything Thread  (Read 10922 times)

Offline frijolee

LS Swap Power Steering - The Everything Thread
« on: November 30, 2016, 04:52:32 PM »
Power Steering for V8 RX7s:

I’ve spent a great deal of effort on steering systems since I’ve first swapped an LS1 in my FC RX7 back in 2005.  I hope the title “Everything Thread” isn’t presumptuous, but I’ve never seen anyone put all this down in one place and I wanted to try.

There are effectively four straightforward power steering setups you can run on an LS swapped car and I’ve now tried three of the four.  With my most recent setup, I finally have a version I’m truly happy with so I wanted to share the details.  This was written from a perspective of an FC but 99% applies to FD as well.




The basic options are as follows:

1) Run a stock GM power steering pump with a cut spring to reduce the bypass pressure.  This is the only version I haven’t run and I’ve never particularly wanted to. The problem is that it doesn’t change flow and doesn’t change pressure at flow levels other than bypass.  I’ve driven a few cars that have this done and it’s OK but not wonderful.  The upside is that it’s free.  Downside is that cutting down a spring is a pretty unreliable method and how much you cut varies the feel a great deal.  I’m told approximately two coils on an F-body pump is about right, but there are some downsides to cutting the spring: https://www.turnone-steering.com/blogs/tech-101/why-the-flow-control-spring-shouldnt-be-cut

1b) On the off chance you’re starting with a 04-06 GTO power steering pump you don’t need to do anything as it’s already correct for pressure and flow rate.  However the GTO’s reservoir is huge and it fades to a dirty yellow which means the pump is functional but not pretty.  I almost ran this as I had a ‘04 GTO engine at one point, but all stock pumps have limitations (more on that in a second) so I sold it for something better.  You can change out the terrible looking reservoir if you can find the version PWR Radiators used to make or install an SS cover from several eBay vendors, but it’s quite a bit of money just for some bling. Synister MotorSports used to make an awesome billet pulley for the GTO but the company folded.  Shame, because it was rad and no one else makes a nice pulley for the GTO pump.  There’s a great deal more info on stock pumps for the LS family of engines here:  http://ls1tech.com/forums/conversions-hybrids/1262185-power-steering-pump-outputs-gto-f-body-corvette-cts-v-truck-etc.html

2) Change pressure via altering the output orifice.   I found a local shop power steering shop which made me a custom orifice for the C5 corvette setup I ran when I first swapped my car.  A change of orifice works great for most street cars and you can now get an off-the-shelf orifice at the correct flow from Turn One Power Steering.  https://www.turnone-steering.com/collections/power-steering-fittings/products/an-6-flow-restrictor




Turn One already offers orifice this sized for Rx7 racks and it makes the high pressure line hookup easy since if you choose the -6 AN version.  The only downside here is that if you’re running hard the GM pumps can fail.  Even before you get to that, the pumps can run hot enough boil the fluid.  When it starts to boil the assist goes away in an instant when the air bubble hits and suddenly your steering is alarmingly heavy.  That’s no good if you ever plan to play on a race track.  If the assist quit mid-corner you could be in trouble.  A bigger cooler would certainly help.   I had the Mazda factory loop cooler when I ran this way and it wasn’t quite enough. 

3) Ignore power steering entirely and go with a manual rack.  There was a 20:1 ratio manual rack option on FC’s.  Some FD folks swear by the Atomic Rex rack, but bring money.  When I ran a manual rack, I did so by depowered my last 17:1 rack (more info on that is here: http://www.norotors.com/index.php?topic=1274.msg14170#msg14170) pulling all the seals, and welding the quill.  The road feel is great but, to be blunt, not having power steering simply makes the car less fun to drive.  You just can’t chuck it into a corner the same way you can with power steering.  Once I went widebody, not having power steering became a significant annoyance.  With 295 section front tires I technically could turn the wheel with one hand at rest, but only if I braced myself and really got into it.  It got annoying enough that I’d avoid parallel parking if I could avoid it and when I was climbing into the car after a long day of work I’d find myself thinking, “I need to do something about this”.

4) Buy an upgraded PS pump design for the swap and meant to take some abuse.  This is where I ended up after trying effectively all the lesser versions thereof.  There are two common options I’m aware of here:  KRC (http://www.krcpower.com/) and Turn One (http://www.turnone-steering.com/). They’re both high quality units, but there were a couple distinct factors helped make up my mind.  The KRC pumps are super sexy with the all metal reservoir, but they’re damn expensive…  If you go that way you want to get their aluminum pump which is rated for higher RPM than the steel version.  By the time you’ve added the correct brackets and pulley (which you’ll have to buy separately since at least at the time of this writing there’s no LS1 kit available) you’ll be out the door for about $900.  Turn One is still a chunk of change but it’s less than half of the KRC even if you spring for their billet pulley. 

Function was the most important factor for me.  In doing several search on LS1tech and Corvetteforum.com for reviews I found a great many success stories with Turn One, and not many reviews on KRC.  The later might be related to cost of entry, but it made me nervous.  I also ran across many horror stories involving failures of the factory pumps.  One guy who was regularly tracking his Corvette claimed he burned out 4 factory pumps in a season then switched to Turn One and hasn’t had a problem since.

Per the folks at Turn One the secret is that the pump has been fully rebuilt internally to flow LESS.  That means full assist comes in at 1500 rpms instead of 900 rpm like a stock pump.  After that either pump is bypassing internally.  By flowing less the pump also generates significantly less waste heat and regains a couple hp would be lost otherwise (bonus upside!).   This also means your PS fluid runs dramatically cooler (~20 degrees on average) and it all adds up to a pump living a long happy life.

I went with the Turn One pump https://www.turnone-steering.com/collections/power-steering-pumps/products/98-02-ls1-f-body-conversion-pump and thus far, I couldn’t be happier.  Jeff at Turn One was great to deal with.

Specifics of the install and driving impressions follow.
-Joel Payne

PS One final bonus approach) A few folks have managed to retrofit the Mazda PS pumps onto the GM block.  That approach is beyond the scope of this write up since it involves custom machining and bracketry, but it’s interesting none-the-less.  Examples: http://www.norotors.com/index.php?topic=16737.0  http://www.norotors.com/index.php?topic=20551.0
« Last Edit: November 30, 2016, 10:40:42 PM by frijolee »
LS2 stroker FC, Mandeville big brakes, widebody, etc
Build thread:  http://www.norotors.com/index.php?topic=1274.0
www.roninspeedworks.com

LargeOrangeFont says: "Joel is right, and I love Joel. But his car sounds like the wrath of God."   ;)

Offline frijolee

Re: LS Swap Power Steering - The Everything Thread
« Reply #1 on: November 30, 2016, 04:54:53 PM »
Since the accessories I had were from a 2004 Pontiac GTO (for which the PS pump bolts directly to the head), I needed to find an F-body power steering pump bracket.  They crop up from time to time on ebay but it was slim pickings when I was looking so I threw down for a billet bracket from CBM (p/n 10750)




Turn One offers a nice billet PS pulley, but I already had my eye on one from Wazees for which the spoke design almost matched my wheels.  http://wazees.com/products/fbodyps.html  Itís a nice piece.




Hereís Turn Oneís version of the pulley in case youíre curious:




I do like the fact the Turn One Pulley is bolted and safety wired to the pump.  Thatís a nice touch.  The Wazee pulley is just a press fit like stock.  Note, thereís nothing stopping you from using a factory pulley as well, but the downside is that a stock F-body pulley is a smooth blank.  Choosing a pulley design with holes or spokes means you can run a socket through the pulley which in turn makes install and removal significantly easier.  If you go with the Turn One pulley at the same time the pulley comes installed for you.  If you run something else like I did, youíll need to track down a special tool.  More on that later.

The only part of this install thatís challenging is building the lines to convert from the GM style pump to the Mazda rack.   You need two lines: a high pressure rack feed line and a low pressure return to the reservoir.  They may look similar externally but theyíre quite different on the inside, as typically the high pressure lines are rated with a working pressure of minimum 2000 psi while the return is only rated for a couple hundred.

Note: same OD, very different wall thickness.




My hoses and fittings were bought from a local hydraulic hose shop: Orme Brothers (www.ormebrothers.com) in Northridge, CA.  However you can get these easily via Summit or Jegís as well.

High Pressure Feed Hose
Earlís 130606 http://www.summitracing.com/parts/ear-130606erl/overview/
You can also get the above by the foot under p/n 130006 but not through summit.

Low Pressure Return Hose Options
3/8" ID line Ė various options on Summit and elsewhere...

The low pressure return hose is easy.  It just interfaces with a barb at the reservoir and another at the end of the Mazda power steering cooling loop.  Theyíre even the same diameter.   Cut to length and add hose clamps (fuel hose type if youíre using worm gear clamps) and youíre done.

Note, I havenít found the limit with this setup yet, but the guys at Turn One say you want to keep the fluid below 275 degrees F.  If youíre really pushing hard and find this limit then you need to add a finned cooler into the return loop and get that cooler into some fresh air (likely at a bumper opening).  I found the loop cooler was marginal with a stock pump so now that the pump itself runs cooler and Iím a firm believer that simple is good.  If you leave it as the factory intended that interface to the rack easy.

There are two ways to make the ends for the high pressure hose.  I personally like keeping things as factory as possible, so I used the respective ends that came with each car and had them braised to high pressure the matching high pressure fittings (the GM flared hardline at the pump and the Mazda banjo at the rack).   Unfortunately I didnít get part numbers for the exact fittings Iím using from Orme Bros, but Iíve done some research into what I think

Note, it looks possible to use entirely off-the-shelf fittings made for self assembly (rather than braising).  If want to try this you want to be sure you have Turn One include the AN-6 pump output adaptor.  To my eye youíd want to run a 90 degree fitting off the pump and another 90 to connect to a AN-6 banjo connection at the rack.  I HAVE NOT TRIED THIS, but hereís some notes on what I think it takes.  Iíll be glad to edit if others can prove this.

Lines:
Same as already referenced

High pressure 90 degree fitting (youíll need 2), several company sell versions thereof so Iím including a few to give you options : 

Earlís 139106 http://www.summitracing.com/int/parts/ear-139106erl
Fragola 259006 http://www.summitracing.com/int/parts/fra-259006
Russell 620421 http://www.summitracing.com/int/parts/rus-620421

Banjo to -6 AN:
Unisteer Power Steering Adapter Fittings 8021550 http://www.summitracing.com/int/parts/uis-8021550

The risk with going fully off-the-shelf is that you have to rely on the face of the rackís aluminum quill housing to be sufficiently flat and flush to seal against copper crush washers typical of a universal banjo. 

It also looks like youíll need to re-use the Mazda banjo bolt either way as that comes in a thread pattern of m12-1.25 which can be a little challenging to find.  I canít guarantee this would work with the Unisteer banjo above.  Please post up if you try and it works.  Braising is a bit of a brute force solution, but itís straight forward and I have capable shops of doing that for me close by.  Everything that follows is specific to the way I did this install.
« Last Edit: November 30, 2016, 10:21:31 PM by frijolee »
LS2 stroker FC, Mandeville big brakes, widebody, etc
Build thread:  http://www.norotors.com/index.php?topic=1274.0
www.roninspeedworks.com

LargeOrangeFont says: "Joel is right, and I love Joel. But his car sounds like the wrath of God."   ;)

Offline frijolee

Re: LS Swap Power Steering - The Everything Thread
« Reply #2 on: November 30, 2016, 04:59:57 PM »
Install

As mentioned, this is my second time running power steering and Iíd already done the braising step to convert to a Vette pump when I first swapped my car.  The output fitting of the F-body pump (upon which the Turn One pump is made) is different so I needed to procure an F-body power steering line.  I bought that line from a local parts store.  Hereís where I started component wise.




Factory fitment F-body hose on top, former PS hose on the bottom, Vette output fitting braised to the mating hose fitting on the left.

Hereís what is left of the F-body hose, now braised to the high pressure fitting end needed.




I pulled the exterior fitting shell of my hose since this hose was going to be a slightly different length and I wanted to show how these fitting go together anyways.  (Note, all of the normal high pressure fittings Iím aware of are steel.  Standard ĖAN aluminum fitting like you might use for an oil cooler are not appropriate as youíd like the devices to be rated well above the working pressures: ~1600 psi is the upper limit of most GM pumps we care about.)




The threads on the exterior part of my fitting (those threads which engage the OD of the hose) were left hand threaded aka opposite from normal tightening direction so you may want to check for that. 




You first screw the exterior fitting onto the outside of the hose.  This takes some gusto because the high pressure hose is a stiff mother with steel braids that donít really want to be compressed into a smallish hole.  Once itís on, you then screw in the internal fitting piece.  Thereís a second set of thread in the tip of the exterior fitting which will pull this down into position.  The hose will be wedged into the taper between exterior and interior sections of fitting.




Before you actually install the fittings you need to verify length of the line via a test fitment on the car.  Here was my assembly for trial:




Hardware was only hand tightened at this point, but this was enough to prove that this bolts up nice, aims the hose in a generally happy direction.  As mentioned a 90 deg AN -6 fitting would be a good starting point as well.




You want to verify this yourself on your car as fitting selection and engine mounting kit used both mater.  Power steering works great with both Ronin Speedworks and Samberg mounts.    :wave:  Moving onÖ

Now itís time to cut hoses to length.  When cutting any kind of braided hose, I wrap the outside in electrical tape to keep it from fraying and use a cut off wheel (the kind made for cutting metal) on an angle grinder.  Youíll want to cut right through the middle of the tape so you leave some tape on both sides.  Take your time to keep it neat and square and be careful because the hose may want to snag and pull.  Use of a vice and two hands on the grinder is recommended.  Note this type of cut will result in rubber dust getting inside the hose, but weíre going to flush before final install so itís ok.

Now that hoses cut to length you can install the fittings.  The below shot is just about fully installed (Note they tell me a 1/16Ē gap between housing and wrench hex on the core is about right). 




The internal fitting will be damn hard to turn at this point.  Thereís a lot of friction going on.   You can see the braising at this end as well.   Before you take the fitting all the way tight you need to do one more fit check.  This time, we need to check the ďclockingĒ of the ends.   The high pressure hose is so stiff that itís unforgiving in twist.    You need to hit the right angle and hit it right on so the banjo can lay flat against the quill housing. 




This is a good time to talk about variations in Mazda racks.  In the above shot, youíll notice that my Mazda rack has two holes at the quill housing.  This was the standard 17:1 ratio steering rack which is also the more common of power steering racks available for FC RX7s.  However, see the suspicious looking blank at the bottom of the quill?  That was for a variation of FC which used a three hole rack, came with speed sensitive steering and had additional valving to hook up a third hydraulic interface to the rack.  There was a dedicated controller to run that.  GM doesnít have any of those options, so if you do have a three hole you need to plug that front most hole with a bolt and thread tape to have this function. 

That said, the assist for the 15:1 ratio was intended to be disabled at speed; thatís how the speed sensitive part worked.  Since we canít, you end up with a car that can be twitchy at speed.  Iíve never run it that way, but Iíve heard very strong opinions from folks who have, Charlie Shatzen of Mazcare being one such voice of experience.  To paraphrase CharlieÖ  on the off chance you have a ďthree hole rackĒ (which is what the 15:1s are usually referred to as), do yourself a favor and sell it.  You really want the 17:1 ratio.

Since weíre talking about racks and details thereof, if you removed or need to replace the hardlines which run from the steering shaft quill to each the two inputs on the rack itself, theyíre oriented as follows.

FC






FD is the same idea




None of the three pics above are mine, but the 17:1 rack I bought had its hardlines cut during junkyard removal by the gent I bought it from, so figured this info might be helpful.  In both FC or FD the port on the rack closer to middle of rack connects to the port closer to the splined steering column input at the quill.

Note, if the hardlines on your rack are reversed itíll set up a crazy feedback loop where your steering wheel jumps side to side.   
« Last Edit: November 30, 2016, 05:09:01 PM by frijolee »
LS2 stroker FC, Mandeville big brakes, widebody, etc
Build thread:  http://www.norotors.com/index.php?topic=1274.0
www.roninspeedworks.com

LargeOrangeFont says: "Joel is right, and I love Joel. But his car sounds like the wrath of God."   ;)

Offline frijolee

Re: LS Swap Power Steering - The Everything Thread
« Reply #3 on: November 30, 2016, 05:01:57 PM »
Now that the lines are built itís time to turn attention back to the pump and install the new pulley.  I picked up Napaís GM power steering tool at the same time that I bought the F-body line.






The pulley has a little step inside the tip so you just need to pull it down until that bottoms.




The tool comes with two different drive mandrels.  You want the one on the left.  The one on the right has a different thread pattern at the tip. 




The problem is that the threads in the pump are a little deeper than the tip on the right and thatís what the drive comes installed on out of the box.  That meant the mandrel on the right WILL start to thread into the pump normally, but only engage 3 threads or so (the first threads at full diameter about 1Ē up the tip of the mandrel).  If I hadnít noticed and had tried to install the pulley, odds are high I would have blown out the threads on the inside of my new fancy pump.

Lube is good for the threads on the drive mandrel (no need to fight friction too).  I added a little anti-seize to the nose of the pump to help prevent galvanic corrosions (sometimes called dissimilar metal corrosion).

Once the tool is assembled, you just drive the pulley home with wrenches.




Here it is bottomed against that step I mentioned.  Wazeeís claims this pulley is intended for one time use so buyer beware on that score.




Now itís time to install everything for real.  Bolt up the pump and torque to factory specs.

GM Bracket to head is 37 ft-lbs for the m10s
GM Pump to bracket is 18 ft-lbs for the m8s

Install the serpentine belt.  Install the high pressure hose, but only connect the end to the pump leave the end at the rack dangling.  There will be an o-ring included with the F-body donor line (or with Turn Oneís output adaptor if youíre using that).  Be sure you donít leave the O-ring off since most of your test assembling may have been done without.

Now weíre ready to flush the lines and bleed the system.
« Last Edit: November 30, 2016, 05:09:24 PM by frijolee »
LS2 stroker FC, Mandeville big brakes, widebody, etc
Build thread:  http://www.norotors.com/index.php?topic=1274.0
www.roninspeedworks.com

LargeOrangeFont says: "Joel is right, and I love Joel. But his car sounds like the wrath of God."   ;)

Offline frijolee

Re: LS Swap Power Steering - The Everything Thread
« Reply #4 on: November 30, 2016, 05:04:18 PM »
Flushing and Bleeding




Turn One recommends using a good quality synthetic power steering fluid.  I went with Royal Purple as thatís what I found at my local parts store and they generally have a good reputation.  That said, I also knew I would be flushing both lines and the rack so I was likely to be wasting a bunch of fluid so I bought some basic fluid as well.  Both types shown.




Weíre going to flush the system in three stages 1) pressure line, 2) rack & return loop, 3) fully system with the good fluid.  Debris from cutting the lines can be a cause of pump failure so we need to do more than just hit flush lines with a Turkey baster.   

Start by plugging the reservoir return nipple with the factory cap Turn One sends with the pump.   




Disconnect the coil packs so you can crank the motor without it firing up (the starter cranks at ~250 rpm which tends to be more controllable than letting it fire off and idle).

Fill the reservoir with your cheap PS fluid and stick the end of the high pressure line in a jar or catch can (at least pint size, quart might be better).  Crank the engine.  That will drive fluid through the line and into the jar.  Itís a short hose so it wonít take much but youíll likely see some significant black rubber dust come through and we also donít want to risk flushing that into the rack.  Itís best to do this a couple times and empty the jar between each to be sure youíre getting nothing but clear fluid.  You may want to find a friend to help so you can hold the jar and watch fluid while they crank it over.  Getting your significant other to help on the car project in meaningful (yet easy) ways is always good.

When thatís clean and clear, we can now hook up both the high and low pressure lines to the rack.  Both lines use o-rings.   Assuming youíre using the Mazda banjo these rings are on both top and bottom.  If you decided to try the universal banjo mentioned above, now is the time to add copper crush washers.

Mazda banjo is torqued to 15 ft-lbs (both FC and FD manuals say 12-17 ft-lbs technically)
Mazda low pressure fitting isnít listed so I assume a healthy snug is fine.   






Set up your catch can on the output of the low pressure line.  Low pressure should not be hooked to the reservoir yet.   Double check fluid in the reservoir (no where in this process should it be allowed to run dry.)   Crank as before, but this time have the person inside the car run the steering wheel back and forth all the way from lock to lock.   To avoid working the starter too hard I generally do 10 seconds on, 30 seconds off.

BTW I we really glad I did this because I pushed a ton of NASTY fluid out of the rack I bought used.  I definitely didnít want that getting back into the internals of the pump. 

When this runs clear, you can now swap over to the good fluid for our 3rd flush.  Using Royal Purple is pretty cool in this regard, because now instead of running clear I could instead look for it to run steady purple, and I didnít waste a lot of the good stuff.  Same deal for running the steering wheel back and forth while flushing.

When itís fully flushed, all thatís left is to hook up the low pressure line to reservoir.  The moment you pull that red cap youíre like to make a mess so jam towels or whatever under there and be ready to push the line on as soon as the cap is off.  Thatís it.  Get the car back on the ground.  Align it if needed and go for a drive.
« Last Edit: November 30, 2016, 05:09:45 PM by frijolee »
LS2 stroker FC, Mandeville big brakes, widebody, etc
Build thread:  http://www.norotors.com/index.php?topic=1274.0
www.roninspeedworks.com

LargeOrangeFont says: "Joel is right, and I love Joel. But his car sounds like the wrath of God."   ;)

Offline frijolee

Re: LS Swap Power Steering - The Everything Thread
« Reply #5 on: November 30, 2016, 05:05:50 PM »
So how does it drive?




Answer:  like factory. The assist is pretty much perfectÖ  Turn One nailed that.  Itís not too heavy not too light.  Itís stable every speed Iíve tried (well into three digits).  If itís actually heavier due to not quite as much assist below 1500 rpm itís hard for me to tell, I think itís a perfect level of assist but I probably prefer a bit heavy vs. overboostedÖ  These are lighter cars than F-bodies as well, however a disclaimer might be in order because I was pretty damn tired of fighting my car at every three point turn in the past.  As such, having steering assist when not moving feels WONDERFUL.   That said, even in a three point turn or parallel parking youíre likely going to be over 1500 rpm so itís really not an issue. 

Suddenly the car is "flickable" instead of it feeling like you were pulling it through corners.  The road feel is really good so if you plan to drive your car hard and want power steering this is a great setup to have.

Good success on your projects!  See you out there.
-Joel


« Last Edit: November 30, 2016, 10:16:30 PM by frijolee »
LS2 stroker FC, Mandeville big brakes, widebody, etc
Build thread:  http://www.norotors.com/index.php?topic=1274.0
www.roninspeedworks.com

LargeOrangeFont says: "Joel is right, and I love Joel. But his car sounds like the wrath of God."   ;)

Offline scuter83

Re: LS Swap Power Steering - The Everything Thread
« Reply #6 on: November 30, 2016, 05:31:06 PM »
I need to just do the Turn One pump.  I have their reducer, and it still feels a little light to me ( I do have a 3 hole rack though), plus I am on my second stock pump and it just sounds awful.  Keeps squealing even after checking alignment and a new belt....

Offline su_maverick

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Re: LS Swap Power Steering - The Everything Thread
« Reply #7 on: November 30, 2016, 05:58:39 PM »
Thank you for this!

Offline wickedrx7

Re: LS Swap Power Steering - The Everything Thread
« Reply #8 on: November 30, 2016, 07:51:41 PM »
Great post! Sticky this for sure. I get a decent amount on pm's about my stock Rx7 pump mounting. I am very happy with it but does take some fabrication and $$$. This was my other option.  Also, as an FYI- the f-body pump does get very hot and noisy after hard laps, that is another reason for ditching it.

1993 Touring, 2012 L99, T-56, Ronnin 8.8, Ohlins, Speedhut, Samberg and lots of custom parts
Build Thread - http://www.norotors.com/index.php?topic=19354.0
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Offline Cobranut

Re: LS Swap Power Steering - The Everything Thread
« Reply #9 on: November 30, 2016, 09:06:11 PM »
Nice write-up, and great pics Joel.   8)
I'd like to reinstall P/S on my FD, but finding a power rack at a reasonable price has been difficult.  :banghead:
1995 FD, 7.0 Liter stroked LS3, T56, 8.8, Samberg kit.

Offline Bowtie7

Re: LS Swap Power Steering - The Everything Thread
« Reply #10 on: November 30, 2016, 09:40:02 PM »
Well written Joel and covers all the bases but one I just experienced. After Russ's car was driven in testing by  my good friend and former F1 driver Tommy Byrne, we wanted more feedback and less numbness to the steering. We are running the preferred 2 hole rack with Turn One pump and Turn One adjustable flow valve. The feeling has always been good but just not enough feel/feedback for our taste and Tommy confirmed what we felt. I spoke with Jeff at Turn One and sent him a spare rack to dyno. After some conversation we came up with a plan and Jeff tore down the rack to make some internal changes. He had targeted a 50% initial torque increase and was able to get to a 35% increase. This is based on calculations but is actually somewhat trial and error and each trial = 1 rack as it cannot be changed after modification. Bottom line, we tested 2 weeks ago at Road Atlanta and the results were very good. We are back to Road Atlanta this weekend for the NASA season end so looking forward to a successful race.

Jeff at Turn One was great to deal with and is brilliant on steering components in a street or race environment. Joel, great job on this article!
Mazcare build #10 1988 FC LS2 power now with Ronin Exploder diff setup

Offline fastfalcon94

Re: LS Swap Power Steering - The Everything Thread
« Reply #11 on: November 30, 2016, 09:53:53 PM »
I've been talking to Turn One for a few months now waiting to try out their 05-06 gto pump, but it's been on backorder. From my understanding the ls2 gto pump is the same pressure but flows too much (like 1.7-1.8gpm). Turn One said 1.3 gpm is what the rx7 rack likes. I pre-ordered it on Cyber Monday to save 15%. The stock ls2  pump seems like it's overpowering the stock rack. Feels like I'm turning while parked on ice at higher speeds. Looks like I have an alternative if it doesn't work.

Offline largeorangefont

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Re: LS Swap Power Steering - The Everything Thread
« Reply #12 on: November 30, 2016, 09:56:08 PM »
Nice write up Joel!

I'm manual rack for life in my car.
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Offline frijolee

Re: LS Swap Power Steering - The Everything Thread
« Reply #13 on: November 30, 2016, 10:11:56 PM »
Good stuff gents. 

Wicked, any feedback how the stock Mazda pumps are holding up running hard?  I'd be curious what the rotary track day hounds have to say so I had to at least mention the Mazda pump approach.

Charlie, I'm glad to hear the envelope can still be pushed further (because it already feels pretty good to me!).  If we call up Turn One and ask Jeff for the "Russ/Mazcare" rack mod is that enough?  If you decide you need to refine further I bet you'd find plenty of stock racks as donors to take your upgraded (but not absolutely PERFECT versions). 

Falcon, Turn One was really great to deal with, glad they're helping you as well.

Ash, my manual setup had two leverage disadvantages vs what you're running.  Bigger contact patch (wider tires with less static camber) and it was also a 17:1 ratio instead of the true manual rack's 20:1.  Road feel was awesome, I still liked it a lot at speed, and you certainly can't beat the weight reduction and simplicity.  I finally decided the upsides weren't worth it as a street car though...   :( 
« Last Edit: November 30, 2016, 10:46:37 PM by frijolee »
LS2 stroker FC, Mandeville big brakes, widebody, etc
Build thread:  http://www.norotors.com/index.php?topic=1274.0
www.roninspeedworks.com

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Offline largeorangefont

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Re: LS Swap Power Steering - The Everything Thread
« Reply #14 on: November 30, 2016, 10:44:35 PM »
Correct Joel. I think the ratio difference is really the largest differentiator.

While I do have more camber, my tires are stickier, and my 275 race tires run very wide (they are barely stretched on 10.5 in wheels).

That said, I personally don't mind the extra effort in parking lots or the pits, and at speed it does not bother me at all. You'll have to let me give your  setup a try, maybe you'll convert me :)
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