Power Steering

[paustin]

Hi all, interested in improving stering performance on my Series 3 - I've seen the sports rack offered by SNGB but understand gearing is standard
Is anyone ' doing ' a higher geared unit? Alternatively anyone got experience with SNGB unit?

Cheers, Phil

[D COUPE]

Read the upgrade thread its very informative on this subject http://etypeuk.com/forum/viewtopic.php?t=1496

[Richard2293]

I have the CMC (Bridgnorth) uprated steering rack on my Series 3. Improves the steering characteristics greatly. Less steering wheel activity when negotiating bends on twisty roads. See if you can find a car to compare original and the higher geared unit, you won't be disappointed

[MarekH]

Dear Phil,

There are a number of strategies you can employ to reduce/alter the power steering on the s3:-

1/ Fit a smaller steering wheel. A 14" wheel will mean that you will have to exert 15/14 of the energy yourself as there is less leverage at the steering wheel end.

2/ If you look into the internet for GM Saginaw pumps (which is the generic type of pump that this is), you'll find that different manufacturers using this pump have a different pop-off setting for the hydraulic pressure anywhere between about 800-1300 psi. This is achieved by washers which shim the relief valve and Jaguar covered this in a Technical Service Bulletin. Details on many US sites and elsewhere on this site.

3/ The rpm related assistance can be leveraged down because the XJS and etype have the same pump but different sized crank and power steering pulleys. If you are happy to weld up a new power steering pump bracket, you can fit an XJS pump (it's the same pump but the pulley shaft mounting and pulley size differ) which has a larger diameter pump pulley, but keep the etype crank pulley size. The pump will spin more slowly. You need a new bracket because the forward/rear offset of the XJS pulley doesn't line up with the etype belt and it has to sit nestled in between the power steering hoses, main water pipe and picture frame and engine frame.

4/ The option which I believe is the same as the 3rd parties mentioned above is to fit an electrically assisted steering column from an MGF. This will set you back about ?50 plus some machining and lathe work. This has been documented for earlier XK Jaguars and is likely the basis of the commercially avaible kit. You can pay CMC or SNGB a lot for not doing your own homework. Ask the XK150 guys - they'll know.

5/ The "correct" way to do this, keeping all of the other features constant is to use a thicker torsion bar inside the pinion housing. One from an XJS-Sport would be suitable, but unfortunately,. steering racks from these cars are as rare as XJS-Sport cars... so it is mostly unobtainable.


Take as look at some of my photo albums on the jag-lovers.org site and you will spot some of these on my car. It won't go back on the road until I am satisfied with the paintwork so I can't report further on what will work best for you.

kind regards
Marek

[paustin]

Hi Richard, thanks for that .... you mentioned CMC unit to be higher geared, do you happen to know by how much?

Cheers, Phil

[paustin]

Hi Marek, lots of good information there, thank you. Will digest further before embarking down chosen route.
Cheers, Phil

[Richard2293]

Phil, Been out in the sunshine today. Steering is 2 and half turns, lock to lock. Hope this helps

[paustin]

Hi Richard, just back from holidays - now you've really enthused me with the thought of 2.5 turns lock to lock. Cheers, Phil

[fareaster]

Sorry about the late reply, only just registered and seen this thread
MarekH
1/ Agree, I?ve done this on my S3
2/ Adjusting the blow off valve setting will only impact the steering weight during static parking manoeuvres when full system pressure is achieved. There would be no impact once the car is rolling.
3/ All reducing the rpm would do is to reduce the pump flow up to the point that the flow control valve starts limiting the flow, usually in the region of 800 - 1200 rpm. If you regularly drive at these engine rpm?s you might notice a difference.
A popular way to reduce the flow is by adjusting the flow control valve or effecting the same by installing some sort of bypass and this does increase the weighting accross the operating range. This must be done carefully, however, as manufacturers go to great lengths to achieve the correct flow rate. The industry standard is often 1 steering steering rev. per sec., pump flow is sized to achieve this value. What this means in practice is that if the flow is reduced too much and, for example, a high speed emergency lane change manoeuvre is required of the vehicle the steering wheel will feel as if it is "locking". In actuallity it is not, it is reverting to manual as the pump flow is the insuffucient to maintain the required pressure. Not good and if you do get home you will probably need to change your underpants....
4/ To do this I assume the hydraulics of the steering gear are disconnected and pump removed/rendered inoperable, the gear power source now being the column. Again a word of caution, the pinion is sized assuming only a manual input (the hydraulics bear only on the rack), this method puts a lot more load through it and could lead to premature failure.
5/ Agree, making a new torsion bar is, perhaps, easier than you think, the difficulty would be in rebalancing the valve.
You could play around with the control edges too but that would be beyond the abilities of all but the most specialist of tool rooms.
6/ A method I would favour would be to replace the entire steering gear with one of a more modern manufacturer. Not easy as one has to match mountings, cross over angle, inner ball joint centres etc. etc. but I believe it has been done.

[paustin]

Hi Marek, thanks for your further input - have decided to go for new rack ( Ford I believe ) as seems simplest way forward. As you will know, kit comes complete with all pipework and mountings. Cheers, Phil

[Woolfi]

A friend has a different steering in his EV12 and I think it is from Ford. It is less directly and has more turns from the left to the right. Therefore the car feels less "sporty", more "trucky". I didn't like it.
Another friend has mounted a modern electric steering from a BMW. Soon I will drive the car, check the steering-feeling und will report in the forum. The motor without the pump has has few hp more.
Regards Wolfgang Gatza

[paustin]

Thanks Wolfgang ..... look forward to hearing more from you. Cheers, Phil