vbares Vittorio Bares Mega Moderator Location: Londonderry, NH Join Date: 04/10/2007 Age: Ancient Posts: 413 Rally Car: Audi 4k (3b conversion) |
Hi all - I've installed a 2:1 quickener in the Audi 4k - just took it out for the first time today - and holy cow, its really "HEAVY" - is this normal??
I'm thinking of backing down to the 1.5:1 - i'm sure that will help or am I generally screwed due to the characteristics of the Audi rack? What about a smaller pulley? More PSI on the pump (there are heavier Audi's with about 130psi pumps), however would be concerned about blowing seals... Start working out and stop being such a pussy? Any ideas are appreciated - oh and have good fucking New Years, alright? ![]() |
Pete Pete Remner Senior Moderator Location: Cleveland, Ohio Join Date: 01/11/2006 Age: Midlife Crisis Posts: 2,022 |
My Quantum has the same rack/pump system your 4000 does, and I can easily overpower the pump by turning the steering wheel too fast.
On the bright side, turning the steering wheel more than about 1/4 turn just seems to make the car go straight, so in a way the car doesn't need a quickener! Just diffs that do more than give a choice of "open" or "locked solid" ![]() The later racks are (supposed to be) a direct fit. The main difference seems to be that the seals were upgraded for a higher operating pressure. I personally think that there is a VOLUME issue and not pressure. The first thing I'd want to do would be to eliminate the banjo fittings on the pump somehow. Three more things - 034 Motorsport (you've heard of them?) sells a quick rack, sometimes these come up for sale on eBay for a lot less than $1000. Could you post pics of your quickener installation? I'm curious to see how you did it. I'm not going to have shitty diffs forever. What the hell am I doing here? There's a bottle of Maker's Mark with my name on it a few miles from here. Happy f'ing new year too! Edited 2 time(s). Last edit at 12/31/2010 06:44PM by Pete. |
john vanlandingham John Vanlandingham Super Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
Doooooooood, (or should i say Muuuchachitito miiiiio!) In PS systems the assist is a function of the VOLUME thru the relief valve. They all make 1150-1290 or more Peee Esssey Eyes, mang, they use different diameter holes, ya kNose? And I din't knoes you was a pussy, I mean it's not like you drive some blue fawkin Sub-a-rat!! |
vbares Vittorio Bares Mega Moderator Location: Londonderry, NH Join Date: 04/10/2007 Age: Ancient Posts: 413 Rally Car: Audi 4k (3b conversion) |
Well, grasias amigos...
so, this pressure relief valve - I would assume that it's located in the pump? Attached is a schematic of the Audi setup...is this something that can be modified? From the description we are trying to increase flow (without affecting PSI?) - would that mean a bigger valve and a smaller pulley? |
vbares Vittorio Bares Mega Moderator Location: Londonderry, NH Join Date: 04/10/2007 Age: Ancient Posts: 413 Rally Car: Audi 4k (3b conversion) |
Did some research on this powersteering system:
Power Steering explained Would it be fair to say that if a stiffer spring was added to the pump, then higher pressure would be maintained throughout the speed range... From the description here - my understanding is that pressure adds assist, and flow is increased as pulley speed increases to reduce pressure (i.e assist).... Did I miss something? |
Pete Pete Remner Senior Moderator Location: Cleveland, Ohio Join Date: 01/11/2006 Age: Midlife Crisis Posts: 2,022 |
Here's a good primer in a very long thread - http://www.corner-carvers.com/forums/showpost.php?p=183980&postcount=19
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heymagic Banned Godlike Moderator Location: La la land Join Date: 01/25/2006 Age: Fossilized Posts: 3,740 Rally Car: Not a Volvo |
In the late 70s, early 80's we had to drill out the relief valves on a buttload of GM steering pumps to stop the intermittant sttering loss issues.
Also many Jap cars (maybe Euro??) have a built in screen in the PS reservoir that can actually clog and cause pressure loss. |
vbares Vittorio Bares Mega Moderator Location: Londonderry, NH Join Date: 04/10/2007 Age: Ancient Posts: 413 Rally Car: Audi 4k (3b conversion) |
Ok - I think I'm starting to get it...this was also helpful Power Assit Explanation.
To Johns point, if there isn't enough flow - the rack will cavitate, creating a loss of pressure and therefore loss of assist. Pulley size is not a game changer, although can be used to get to full boost at lower/higher RPMs - but this will not change the amount of assist. Since my issues are consistent and not intermittent, either: 1. I have blockage somewhere in the system (lack of flow) 2. The amount of pressure generated is not sufficient 3. both I've got a spare rack that I'll take apart after making sure that I have some flow through the system. |
john vanlandingham John Vanlandingham Super Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
Muchachchito, pressure is probably enough, those pumps pump. The relief valve in the pump is probably behind the big hex---in the piccie--and the flow valve is 99% surely part of the same assembly. You don't have to fawk wif the rack. yet. I've got a spare rack that I'll take apart after making sure that I have some flow through the system. |
1fastben Ben Hetland Ultra Moderator Location: Utah Join Date: 09/12/2007 Age: Settling Down Posts: 297 Rally Car: None, right now |
Soooo... I think I could use a steering quickener on the Datsun. It currently is 3.1 turns lock to lock, (NO power steering) on a Tercel rack. It becomes a bit much to handle in rallyX, and a slightly better ration would be nice on stage.
From what you guys have said, having a quickener on a at least a FWD or AWD car, it's very necessary to have PS. How about RWD? I only ask because there's no axles on those, obviously, and maybe that makes a difference? My steering is already a bit of a workout. The other option I thought of is to put a 200 or 240sx PS rack in there (2.6 turns lock to lock). With PS racks, am I right in that you can just plug off the PS inlet/outlets, and use it as a manual rack? |
Pete Pete Remner Senior Moderator Location: Cleveland, Ohio Join Date: 01/11/2006 Age: Midlife Crisis Posts: 2,022 |
You don't plug them off unless you take the rack apart and remove the internal piston. (Look online for "depower Miata rack", it will give you the general idea)
If you're too lazy to do that, like I am, you spin the rack back and forth a few times to pump the fluid out and then loop the two lines together. |
Tim Taylor Tim Taylor Godlike Moderator Location: Oakland, CA Join Date: 02/02/2007 Age: Possibly Wise Posts: 622 Rally Car: Mazda 323 GTX |
Rack depowering guide that we did on the Miatabusa Project...well, Dave wrote it and I did the machining and welding.
http://www.motoiq.com/magazine_articles/articletype/articleview/articleid/1709/project-miatabusa-part-5--de-powering-the-steering-rack.aspx |
1fastben Ben Hetland Ultra Moderator Location: Utah Join Date: 09/12/2007 Age: Settling Down Posts: 297 Rally Car: None, right now |
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Question: Is the feel heavy only when you turn the wheel quickly or is it also heavy when you turn the wheel slowly? If this only feels heavy when turned fast, then look into the pressure and flow things. If it always feels heavy, even when turned very slowly, then at least part of the problem is that you have lost half of of the steering wheel leverage on the steering system. Regardless of the assist, some wheel torque is always needed (except in the old GM 'no-feel' power steering), and you doubled the required arm-force needed with the 2:1 quickener. Mark B. |
I'm curious to discuss this post; what type of Datsun do you have? 510? 240/260Z? Just for info, our lighter RWD rally cars were just fine without PS. These were Opel Manta and Ascona with R&P steering, and Plymouth Arrow with a box. Now the Starion is another matter; it has PS with a box, and I am glad it does, although it does work almost too easily. I think the real difference between RWD types is the overall car weight and weight on the front, and perhaps tire size and width. I have always guessed that is part of the reason why FWD cars can use PS on the steering: simply more weight on the front wheels. I would also guess that with the wheels pulling with traction, there is a tendency for the engine power to pull the wheels back towards straight-ahead, and that you have to fight this in FWD. That's none existent in RWD. Mark B. |