Steve 90

The system im looking at has a built in pressure releif for this very reason. Steve.

Any chance you could let me know where you got the spreadsheet or did you work out your own formulas to do it? Think I have got my head around the maths of the job now, Just waiting for some ram dimensions and I can get going on the sums but a spreadsheet would make things a little quicker im sure. Cheers. Steve

Pretty much exactly as I was thinking. Which is kind of what im looking at doing. How are you setting yours up? What is the rrelationship between king pin, rack, steer arm etc? Steve.

So Daan, Your saying that Ackerman is not that important. Quite interested in that and If its correct will make the fitting process/my life easier. My main concern was that when turning at tighter angles (When the ackerman is at its greatest) on a low grip surface the last thing I wanted was the tyres fighting against each other and destroying the small amount of traction we do have, causing the front end to push on where it may have turned. The fact that the outer wheel can turn through a greater angle with parralel steering before the inner wheel hits the radius arm is something I hadn't thought of. Would the wheel fighting against each other cancel out any advantage gained or has it proved to not be an issue. Any experience anyone? Very interested to hear more about the possibility of parralel steering and if you think it will cause issues when turning tight angles on poor surfaces. Scrub steer, You are correct. The scrub steer on my truck is terrible. More so running Boggers, less so on the Simex (which we ran in Croatia) but still quite bad. I completely agree that the increase in load through the steering box due to this is massive and steering box failure would probably be almost a thing of the past if we ran center point steering. But, I dont know of a strong axle set up that will correct this without going down the line of custom Spider trak or similar. So, a steering solution is probably the most cost effective/straight forward fix at the moment. As far as driving style is concerned. These events are getting faster and tougher (Which is exactly what I like, which is why I want to do them). We have broken boxs with very hard hits, sometimes driver error, Sometimes bad luck. We have also had broken box's that have never had any shock loading that I wouldn't expect it to have to take through normal driving on this style of event. Probably all comes back to the scrub steer issue, but it is what it is so we'll deal with it. If everyone ran a defender box then driving to the strength of a defender box and staying on pace would be an option. But, we are traveling at speed on tracks we have never seen before. Even the most careful driver is going to take a hit if they want to run at the front. As soon as people build trucks with stronger steering systems they are going to get away with pushing a little harder. You either have to let them go, Risk a DNF and keep up or build the truck to survive. A few years ago people were having the same discussion about standard half shafts and driving in a style that will not risk breakage, Things move on, so do the trucks. If someones truck is stronger you cant sit back at a safer pace waiting for them to break something..............and most of all, whay would you want too whan you could have strong steering and drive fast :D So, the threads not about driving within a defender steering box's capability, Its about making the truck stand up to the inevitable hits it will take on these events and mainly the geometry when fitting Hydraulic steering. I think the question is now, Will Parallel steering be ok???? I hope so! Steve.

Other way round! Steve

Afternoon guys. Just in the process of modifying the steering on my land rover. Really fed up of broken steering box’s and giving serious thought to a full hydro set up. That way I can have a strong setup that can easily be tuned for speed/force etc. Does anyone have any experience in using a double ended (not the type Simon keeps under his bed) ram in front of the axle and its affect on the Ackerman effect? My limited knowledge is that I need to have the steering arms as straight as possible and keep the rack (or ram in this case) behind the line of the track rod ends, This gives an angle between the steering arms and track rods of less than 90 degrees. The resulting increasing/decreasing angles when locking the steering around will give the difference in steering angles needed. I have googled it quite a lot but had very few useful results, maybe I need to tweak the search terms. Does anyone know of a calculator or can give me any pointers in calculating some dimensions to fit the ram and maintain (roughly) the correct Ackerman effect. On my axles (Ashcroft force 9’s) with the existing (8” ctr to ctr) steering arms I can just about get the ram behind the line of the track rod ends and use an 8” stroke ram. I would like to check if this will give roughly the correct geometry. If not I will need to make some longer arms which of course will require a longer ram, different orbital etc etc. Any help/pointers from anyone who understands the sytem or has any experience would be great. Cheers. Steve.

VAS (the VAG dealership tool) will not allow the system to regenerate at anything above 90% ash mass. I have done them for people that have been told by VAG that they need an expensive replacment many times. After checking everything is OK with the system, I have forced regeneration at 150% ash mass, but would only do that on the road as the heat would be scary when stationary. If that fails we soak and wash them through and re try. As said above, We do a lot of stuff for other garages including sort stuff that the dealer has failed to fix. Steve.

They will reach a limit yes. Assuming the system has been operating correctly (a lot will not re generate if there are any fault codes stored, DPF related or not) , some PSA stuff (peugeot and Citroen) was about 80,000 miles. VAG seem to go a little longer. We do now have a gel from Germany that we soak through the filter overnight and steam clean out the following day. That does extend the life a little. But, they will eventually get to the point where they need replacment. Steve.

On most systems you can not fool the ECU with a resistor. The differential pressure sensor will be looking for a different back pressure (or difference across the filter) for different air flow/engine load and time conditions. For example, If you have driven at 75% engine load and 80% throttle for 2500ms it knows what the differential pressure should be and that it will be different for any variation in engine condition. It has a MAP in the ECU that will cross reference all the engine load sensor readings against feedback from the differential pressure sensor and flag a fault if it’s outside of tolerance. So a constant value will flag a fault code for an implausible signal from differential sensor and the ECU will default to limited operational strategy. If you remove the filter without writing it out of the software it will see too low a differential pressure and again flag a code and default to LOS. Basically the system is pretty clever and will know if you remove the filter the same as it knows when it’s over loaded. Most systems can have it written out. Never failed yet with a Bosch, most the others are removable about 90% of the time but would need to read the software before being certain. Some of the Jap stuff (Mazda 6 etc) can be tricky but I think we’ve probably cracked that now. A lot of performance tunes have to be limited when a DPF is present so a lot get removed for that reason. Trouble is, very few have decent diagnostic equipment and even less have a clue what they are doing or how the system works. We do Diagnostic work for pretty much every garage and a few dealerships in our area, The level of skill and understanding in 80% of the trade is (I am ashamed to say) very poor. HTH Steve.

Sorry Nige, Hadn't seen this until now. Yes its a full locker. Can be seen here http://www.ashcroft-transmissions.co.uk/index.php?act=viewCat&catId=89 An excellent piece of kit. Steve.

FIXED!!! I was sure all the external bits (wiring/sensor) were OK. So, I ordered a new ECU (I wanted a spare ECU before we go to the Croatia trophy) . Nige got it to me in double quick time, Plugged it in and the MAT is correct. Just got a TIG-a-thon tonight to get the last of the rear rad pipes welded up and I can get it running again. Hopefully everything will be well, but I have a sneaky suspicion there'll be some more logging and Tuning needed yet. Nothing ever runs smoothly! Cheers guys. Steve. P.S. Old ECU will be going for repair and kept as spare, I'll post up what was wrong when its done.

Have a look at the new offering from Ashcroft. Works in a similar way to an ARB but they have built it in a way that does away with the problem areas. Air leaks are a thing of the past and it engages and disengages quicker (IMHO). An excellent unit thats competitively priced. We've been using one for a while and its brilliant. Cheers. Steve. BTW, We are what would be called a heavy user, We took 1st place at Manby/90 degree challenge first time out with it. Ive 100% confidence in the unit.

Yea, Thanks for that!

Nope, Scrap that post, The sensors are around the 6K ohm so they are OK Steve.

Errrr what Fridge said! To be honest I don't know, Ive just used it as set up by Fridge and Nige. Its started and run without the slightest hiccup or issue until now so Ive never paid too much attention to it. I'll have to rely on the knowledge of others to make a call on weather the sender im using is compatable "as is" or if it needs to mave some correction. Cheers. Steve.