Power Steering

[Purple AK]

Originally Posted by TonyD

Guys,

Can I just add a word of caution to those who are thinking of using a powered replacement steering column coupled with existing multi-uj'd lower steering columns and existing racks.

Please make sure that the UJ's below the powered column are up to the job of transferring all this extra turning power down to a rack that was built many moons ago and never designed to handle this power or to turn wide wheels supporting a heavy yank boat anchor.........

What I'm really saying is that are your existing column and racks capable of handling the greater forces that will be passed through them once your columns are motorised ? At the very least it may be worthwhile renewing or uprating the steering column UJ's below the column just to make sure.

I'm using an engine driven PS pump and a powered rack in the two current builds so theres no extra stress on the column or its Uj's. All the stress in in the BMW rack thats designed to handle it.

Of course I may be talking a load of BS but better safe than sorry.........

Cheers,

Tony:thumb:

A Very valid point Tony :thumb:

[kdavies3]

I may be wrong but why would the torque being transmitted through the UJs be any higher than before?
The wheels and tyres haven't changed nor the rack.
I agree that the rate the torque can be applied may be increased, but I think all the EPAS is doing is supplying assistance to reduce the load required by the driver at the wheel.

[TonyD]

Years ago when I was learning to drive I was told not to turn the wheel when the car was stationary as it put strain on the UJ's and track rod ends. Hence my concern re component durability when UJ's etc are asked to do something for which they were not designed.

The amount of torque that can be input by the driver in a Cobra with unassisted steering is limited by his/her strength. If the driver then adds power assisted steering it is natural that he will still tend to use the same steering effort used previously which will then be augmented by the powersteering itself, leading to increased loads through components not designed to take those loads.

In fact most power steering systems on production cars input so much additional steering power that they allow the driver to turn the wheels on a two ton car by lightly pushing the steering wheel in the required direction using a flat palm.

To put it another way, if no greater torque is transmitted there would be no improvement in steering at parking speeds, which is the sole reason why Cobras need power steering in the first place.

Again just my 2 eurocents worth.......

Cheers,

Tony:thumb:

[Nobby]

Regarding the use of Sierra stalks and switchgear on the Corsa column. There is a plastic plate at the top of the column which mounts GM switchgear. This has to be cut off and filed to reduce it to the same dimension as the column tube. Then a DAX supplied adapter plate is pushed over the tube. This is designed to take the Sierra switchgear. Seems to work fine. Even the indicator cancel cam functions correctly on mine although you have to cut a notch in the Momo sterring wheel boss to locate it. The adapter also locates and mounts the Sierra column shroud.

[kdavies3]

[quote:026c4f8875="TonyD"]

To put it another way, if no greater torque is transmitted there would be no improvement in steering at parking speeds, which is the sole reason why Cobras need power steering in the first place.

Most traditional PAS system of course are not using extra torque assistance transmitted down the column but use hydraulics to move the rack side to side, so torque at the steering wheel is minimised, they also feel extremely heavy when the engine isn't running or the belt busts due to the fact that you are fighting the hydraulic system as well as wheel grip. :thumb:

I stand by my comment that the torque through the UJs is not increased by an EPAS column but only assists the driver by suplimenting the torque input required buy the driver.

I love these technical debates. :thumb:

Tony, have you got thase Lexus lumps running yet??

[Steve]

I have had both EPAS and Peugeot systems running on cobs, and would make the following observations


The peugeot system felt superior in terms of feel and feedback,than the EPAs system, and If I had a choice I would go that way

The EPAS system is far easier to install

[kdavies3]

Hi Steve, i'm glad you got your engine mods done allOK I trust?

I just haven't had time to think about the PAS mods this year, but I think I'll persevere with the Pug system when I get time. :thumb:

[Happy Jim]

[quote:a97a88213c="kdavies3"]
feel extremely heavy when the engine isn't running or the belt busts due to the fact that you are fighting the hydraulic system as well as wheel grip. :thumb:

Aha, that clears something up for me now as well! I had the pleasure of being towed in my Volvo a while back for a short distance (nadjed fuel pump relay)...and it nearly killed me steering it, heavy doesn't do it justice, it felt like I was pushing the entire weight of the car through the steering wheel - I didn't factor in the fight with the hydraulic system, clear now though!

[neil still building it]

hi
which pug system is used please
neil

[TonyD]

Originally Posted by kdavies3

[quote:ae1847453c="TonyD"]


Tony, have you got thase Lexus lumps running yet??

Got the first one all plumbed into the chassis and ready for the electrical connections to spark the engine up.

I have the complete workshop manual and wiring diagrams applicable for the two engines.

I have enlarged the wiring diagrams onto A2 paper so I dont have to squint when reading colour codings.

Thus armed I went into the garage tonight to commence battle with the recalcitrant wiring loom.

Twenty minutes later I retreat having had my **** kicked by a loom which shares no similar colour codings to the workshop wiring diagrams and which doesn't have the correct plug and pin spacings shown in the workshop manual for the ECU, and both ECU's are subtly different.....

Mind you having said that I did run out of gas for the workshop heater so the garage got cold and I only have to splice into five wires out of 60 going into the ECU's to get the buggars to run.......

Time to get onto the Lextreme site and get some further wiring advice.

Cheers,

Tony