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  #271  
Old 02-06-2017, 03:46 PM
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Quote:
Originally Posted by 97 SL320 View Post
Is there any room available to shorten the rack housing and rack ?
I don't think the longer rack body/pivot points will be an issue. The stock steering arms bend inward about an inch or so, I will remove this on the new ones to keep the tie rod length very close to stock.

I will have to spend some time to layout the system in order to make the steering arm u joint location meet what is required for turning radius and bump steer.

My real challenge now is trying to keep the rack close to where I have now and have clearance for the hydraulic line connections and get the steering linkage around the exhaust. Everything is so close. I'm trying to keep from adding a third u joint and a support bearing. Every move takes new parts and way too much time!

I ordered up some parts and will so how it goes when they arrive.

Flaming River has a real good racket going on. You have to buy their special u joint to connect to the rack shaft, $130, then their special hose fittings/adapters, $34.

I will say the rack looks well made and moves very, very smooth.
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  #272  
Old 02-06-2017, 07:21 PM
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Tie rod length is only part of the issue. The angle at which the steering arm is in relationship to the spindle dictates Ackerman. Ackerman is where the wheel on the outside of a turn scribes a larger arc than the wheel on inside of the turn. This is also called " Toe out on turns "

On a rear steer car ( steering arms behind the wheel ) , if you push the steering arm outwards towards the wheel, you are reducing Ackerman.
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  #273  
Old 02-07-2017, 05:40 PM
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As he isn't changing the steering arm angles, it's POSSIBLE he isn't changing the Ackerman, but if the drag link had any motion during steering movement other than perpendicular to the vehicle centerline, then the Ackerman is going to be changed by moving to R&P and it's possible that it may not be able to be brought back to factory spec easily. It may involve changes to the steering knuckle, etc.; I think he's just trying to get something that works first, and presumably would move on to getting it precise, if need be, later on. If both steering arms are shortened by the exact amount, but their wheel/knuckle angle(s) aren't being changed, then I'd suspect it'd stay the same.

Very curious to see the results of the steering setup, since it seems to be your main hangup at this point. I assume you're gonna go back to the dyno once that is sorted?
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  #274  
Old 02-07-2017, 07:00 PM
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Originally Posted by Tomguy View Post
As he isn't changing the steering arm angles, it's POSSIBLE he isn't changing the Ackerman,
But he will by moving the outer tie rod end outward so his tie rod end to end length remains the same with a wider rack.

Quote:
The stock steering arms bend inward about an inch or so, I will remove this on the new ones to keep the tie rod length very close to stock.
If he drew a line from the outer tie rod end to the center of the steering pivot axis then moved the outer tie rod along that line, he could use the stock tie rod length, get a tighter turning circle at the same time and retain ackerman.

The whole steering conversion gets messy when things are moved around. Our guy needs to measure bump steer with the current setup to get some sense where he is at the moment. This info could be applied to the new setup. There are computer programs that will calculate suspension / steering action but are only as good as the measurements taken from the car.
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  #275  
Old 02-19-2017, 02:36 PM
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Thanks all for your comments, very helpful to keep me focused.

I have to say this steering thing is killing me! The gift that keeps giving.

Until I could figure out how, or if possible, to use this Flaming River rack and be able to connect the steering shaft, all other work is on hold. For the past couple of weeks I have been ordering and trying out different ideas, rack location, parts, and calling tech support. The whole issue is the height of the steering shaft coming out of the top of the rack. There is 1 1/2" of exposed shaft that you think you could shorten, and then no more problem. BUT, Flaming River uses the internals of this shaft for a torsion bar to aid in fluid moment to control steering feel. Since I set the engine height as low as possible to clear the brake booster and for low center of gravity, the perfect location for the rack hangs below the bottom of the engine/trans. Not perfect.

But now after a third round of part orders I am 90% there! Close enough now that I a high confidence of this working. Due to the closeness of everything I had to cut about 1/4" off of both the Flaming River U joint and a double U joint to have enough room to place a shaft support. This required welding these joints to the shaft as I cut through the allen screw points. I also was able to modify (grind) the top of the shaft on the R&P enough to lower the U joint location by about 3/8" without getting into the torsion bar area. With these mods I was able to make it clear the exhaust, but by only 1/8". After I finish getting everything dialed in I will have to grind a little on the exhaust manifold to get another 1/8" or so of clearance.

Comfortable with the rack installed location I moved onto the tie rod/steering arms. Since the stock steering had 10" of linear travel and the R&P has only 6" I needed to shorten the steering arms by about 3" to retain the stock steering radius. So I cut off the tie rod mount end and 3" of the arm and tacked the tie rod mount back on. The rack has a threaded shaft to mount their tie rods to. But there tie rod end is a much bigger size. So for simplicity I married part of the stock tie rod to the racks and kept the Mercedes tie rod.

Of course lots of details, measurements, lasers, etc to organize, but mission accomplished, the move results in stock turning radius!

Lots more to fine tune before fully welding everything, but I think I'm back on track again.








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  #276  
Old 02-21-2017, 12:32 AM
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Had a free day today so was able to make a little more progress.

Started off by modifying the passenger side steering arm and tie rod.

I have the U joints just about maxed out on angles, but no binding. But I'm getting a little flex on the steering column shaft, so I ordered another support bearing. I also ordered banjo fittings for the hydraulic supply and return as they should fit my limited space better than the Flaming River adapters plus 90*-AN elbows. I guess I have about 6 hours, and these parts, and I should actually be able to drive the car!

Since I'm suck waiting for these parts I started on some punch list items. One, from the dyno day, was adding a fuel pressure gauge to the fuel rail.

Then I started on the gauge cluster. The dash should be ready this week. As I mentioned before, I ordered custom gauges to match as close as possible the stock gauges. After removing all the old gauge parts I was able to install (with adhesives) the new gauges. Turned out pretty well. Matches pretty close, plus the benefit of a tach and GPS speedo. I'm using the stock turn signals and high beam lights. I ordered a Lokar digital display for the gear selector to replace the mechanical stock gear selector.














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  #277  
Old 02-26-2017, 12:43 PM
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Looking good! Love the gauges!
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  #278  
Old 03-07-2017, 02:48 AM
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Quote:
Originally Posted by Tmadia View Post
Looking good! Love the gauges!


Thanks! And thanks for posting.

I shortened the steering arms and had a friend of mine weld them (professional welder), now I have the full turning radius with just the 6" of travel offered by the rack.



So the car is back down on all fours and I drove it out of the garage and gave both the garage and the car a much needed bath.

I know I'm going to have some issues with steering geometry and I'm not happy with the final ground clearance. The oil pan and rack is only 4 1/4" and I want to be between 5"-5 1/2". So some time consuming adjustments ahead. I think I can raise the engine by adding a steel shim under the engine and trans mounts with no other modifications other than a new smaller diameter brake booster. With some other steering parts I think I can get to stock steering geometry too with the added height.

But for now I'm going to spend time on wiring. Finished the harness going to the rear items today and started on the front.






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