Montyjohn

Montyjohn

Well-Known Member
My P38 came with Arnott Gen 3 bags, but no other suspension mods.
I want to keep the car fairly standard looking so I want standard ride height, motorway and access heights to be as standard as possible.
Since I have a spare 2" on my bags, I was wondering if I could raise the off road height by say 1" with minimal other mods.
I was thinking if I fitted something like terra-firma +2" shocks, this would allow the 1" lift, plus and extra 1" of articulation without stretching the bags.
I would assume I still need to extend the brake lines, but can I make this change using something like a nanocom?
Would +2" shocks be short enough to work at standard ride heights?
Would the sensor rods need adjusting to not be over stretched.

If it can be done with just shocks and brake lines, I will probably go for it.
If it means mucking up my standard ride height, extending bump stops etc then I may leave it standard.
 
brianp38dse said:
You will still have the same ground clearance because if the axle.
Click to expand...

But that's only really true if driving in ruts.
For everything else, wading, approach/departure, breakover etc then there still would be a benefit.
Also helps keeping the side steps higher so there's a bit less likely to hit something and crumble up like tinfoil.
 
The EAS ECU will not let you go beyond set limits at any height selection, you may get away with a few millimeters at extended height. To get any more you would need to mod the sensor links but you would end up with all heights increased.
 
Datatek said:
The EAS ECU will not let you go beyond set limits at any height selection, you may get away with a few millimeters at extended height. To get any more you would need to mod the sensor links but you would end up with all heights increased.
Click to expand...

A bummer.
I might have to get my maths teacher wife involved and see if we can come up with the best compromise for the sensor arms. There must be a ratio where perhaps the motorway setting is unaffected, and all higher settings are increased by a an increasing amount until my highest setting is 1" higher.
I think I'd be happy with that. Should just be a matter of fiddling with the ratios between the two arms. How hard can it be? :p

I know I said earlier that I didn't want to get into chopping and changing such things, but the rabbit hole continues.
 
Montyjohn said:
A bummer.
I might have to get my maths teacher wife involved and see if we can come up with the best compromise for the sensor arms. There must be a ratio where perhaps the motorway setting is unaffected, and all higher settings are increased by a an increasing amount until my highest setting is 1" higher.
I think I'd be happy with that. Should just be a matter of fiddling with the ratios between the two arms. How hard can it be? :p

I know I said earlier that I didn't want to get into chopping and changing such things, but the rabbit hole continues.
Click to expand...
Change the sensor links and ALL height settings will change. You might get to having access height equalling motorway height ad the rest higher by the the same amount. There is a narrow range of valid settings for each height, attempt to go beyond the valid settings range for any height and the ECU will revert to default settings. You cannot pick one height out of 5 that you do not want to change unless you can reprogram the ECU.
 
Datatek said:
Change the sensor links and ALL height settings will change.
Click to expand...

That is definitely true if you only extended the one arm that links to the radius arm, but I was talking about change the ratio between the two arms.
Diagram below is the radius arm, sensor and sensor arms in Motorway position for example.
Notice how I have drawn three different sensor arm lengths, and they all achieve the same angle on the sensor.

But they will all result in different heights at other positions, with the orange being the most sensitive to change.

sensorArm.jpg


What's annoying is the more sensitive setup (i.e. the one I want) can accommodate the least travel because it uses shorter arms overall.
So maybe there's a way to move the point that attaches to the radius arm to achieve what I want.
I'm going to need some lollipop stick for this however.

I'm sure plenty of people have already thought about this and come to your conclusion, but I need to check it for myself. I need some measurements from the car, but it's getting dark and it's raining.
 
I agree with Keith, but before you start planning sensor arm changes, check the actual values in EAS ECU for extended height. You might have enough bits left to raise it a little, but beware if it's close to the limit the ECU will fault if the suspension extends any corner too far beyond max limit while driving. If your current calibrated values are at the low end for the mode, then you could have room to play.

High range on ECU is 120-180 Front and 105.150 Rear, but the ECU does have a non-selectable extended mode in case it detects grounded chassis or body. Theoretically the high mode bit-count could be beyond the default ranges, but will probably fail to save values outside the range for each height. Also the ECI will error if beyond lower limit of 40 bit counts or the upper limit of 225 bit counts.

From EAS SID:

AUTOMATIC HEIGHT SELECTION
The system will default to extended ride height if the system is unable to lower a sensor’s bit
count for any ten-second period, indicating the vehicle is “high centered”. A flashing high
profile lamp will indicate extended ride height. The system will stay in this mode for ten
minutes or until the operator manually requests a lower ride height. The system could also
drop to standard if the vehicle speed exceeds 35 mph.

The system will automatically drop to low profile when the vehicle speed exceeds 50 mph for
more than thirty seconds. The lower lamp will be illuminated. This automatic feature should
be cancelled while towing by depressing the standard height button. This feature can be
selected at any speed on Range Rover by pressing the inhibit switch and the down rocker
switch.

ANY HEIGHT SENSOR ABOVE OR BELOW LIMIT
This is set when a specific sensor is detected operating outside of its allowable operating
range. Select Dynamic Tests/Heights and Valves to view sensor readings. Also refer to TIBs
60/04/95/US and 60/05/95/US to help locate the defective component.
Verify sensor readings over the entire range of suspension travel. The lower limit is 40 bit
counts and the upper limit is 225 bit counts.
 
Montyjohn said:
That is definitely true if you only extended the one arm that links to the radius arm, but I was talking about change the ratio between the two arms.
Diagram below is the radius arm, sensor and sensor arms in Motorway position for example.
Notice how I have drawn three different sensor arm lengths, and they all achieve the same angle on the sensor.

But they will all result in different heights at other positions, with the orange being the most sensitive to change.

View attachment 273847

What's annoying is the more sensitive setup (i.e. the one I want) can accommodate the least travel because it uses shorter arms overall.
So maybe there's a way to move the point that attaches to the radius arm to achieve what I want.
I'm going to need some lollipop stick for this however.

I'm sure plenty of people have already thought about this and come to your conclusion, but I need to check it for myself. I need some measurements from the car, but it's getting dark and it's raining.
Click to expand...

You're going to have to extend them (along with ABS sensor wires etc) so why not slip an extra cam-like link in?
 
Grrrrrr said:
You're going to have to extend them (along with ABS sensor wires etc) so why not slip an extra cam-like link in?
Click to expand...

What do you mean by cam-like link? Do you mean something to progressively change to sensor angle with a cam setup? Do you know of an example. Sounds tricky.
 
Montyjohn said:
What do you mean by cam-like link? Do you mean something to progressively change to sensor angle with a cam setup? Do you know of an example. Sounds tricky.
Click to expand...

Yes, something offset but I would have to have a play with something like drinking straws first.
 
Montyjohn said:
But that's only really true if driving in ruts.
For everything else, wading, approach/departure, breakover etc then there still would be a benefit.
Also helps keeping the side steps higher so there's a bit less likely to hit something and crumble up like tinfoil.
Click to expand...

I’m loving this thread, but, I have to pull you back to this very good point made by @brianp38dse. You will rapidly find when green laning that ruts are exactly what you need the extra height for, and unless you can raise your diff’s by an inch or two you will always be left wallowing in the ruts while other LR’s seem unaffected. This is because if you discount hairdressers cars like the Freelander then the ones you really play with are the Series, the defender’s and the Disco’s - plus the Mitsubishi’s and the Toyota’s. They all have more ground clearance than the p38 so they make the deeper ruts and we, the enlightened purist p38 owners are the ones left stranded in a muddy puddle because the diff’ is grounded.

If you want to play around in the mud, on the rocky ground, with the tanks on Salisbury Plain or the logging lorry’s on the tracks, then you have to raise your diff’s. So, you need more wheel clearance, hence a body or full Sus’ lift, then fit f*** off big tyres on 16” rims - and try and get another 1” or so on your ground clearance.
 
I have used the free EAS Ulock software to change my off heights. Front set at 165 and rear at 140. This sets the bottom lip of the front and rear fenders/wings at 36.5 inches. The frame at the driver's door is 16 inches above ground. Top of the front bumper is 30.5 inches above ground. I ha.ve not changed anything else on the car and have done quite a bit of off road driving. I believe the height I get is similar to the supper extended mode that the car automatically goes into if it thinks it is high centered.
PS: normal ride height is normal
 
Salisbury Nick said:
I’m loving this thread, but, I have to pull you back to this very good point made by @brianp38dse. You will rapidly find when green laning that ruts are exactly what you need the extra height for, and unless you can raise your diff’s by an inch or two you will always be left wallowing in the ruts while other LR’s seem unaffected. This is because if you discount hairdressers cars like the Freelander then the ones you really play with are the Series, the defender’s and the Disco’s - plus the Mitsubishi’s and the Toyota’s. They all have more ground clearance than the p38 so they make the deeper ruts and we, the enlightened purist p38 owners are the ones left stranded in a muddy puddle because the diff’ is grounded.

If you want to play around in the mud, on the rocky ground, with the tanks on Salisbury Plain or the logging lorry’s on the tracks, then you have to raise your diff’s. So, you need more wheel clearance, hence a body or full Sus’ lift, then fit f*** off big tyres on 16” rims - and try and get another 1” or so on your ground clearance.
Click to expand...
Fit Unimog axles with reduction hubs, that would give another 6 inches ground clearance at least:rolleyes::eek::eek:
 
brianp38dse said:
You will still have the same ground clearance because if the axle.
Click to expand...
No you don't.

There is also ground clearance between the ground and the chassis or bumpers. All of this will be increased with a lift. And you are far far more likely to get beached on the chassis rails or hit the bumpers on the ground than you are to be sat on the diffs.
 
Salisbury Nick said:
I’m loving this thread, but, I have to pull you back to this very good point made by @brianp38dse. You will rapidly find when green laning that ruts are exactly what you need the extra height for, and unless you can raise your diff’s by an inch or two you will always be left wallowing in the ruts while other LR’s seem unaffected..
Click to expand...

This is why it would be great if I could just raise the offroad height.
I could then have a set of bigger off-road tyres for such times, and normal roads ones for 90% of the cars life.
The tricky bit would be the bump stops. How to make these rapidly adjustable depending on what wheels you're wearing.
 
Montyjohn said:
This is why it would be great if I could just raise the offroad height.
I could then have a set of bigger off-road tyres for such times, and normal roads ones for 90% of the cars life.
The tricky bit would be the bump stops. How to make these rapidly adjustable depending on what wheels you're wearing.
Click to expand...

That's easy enough. The centre is hollow and it is circular so with a lathe you could easily knock up an insert that fits over the top of the existing bump-stop with a peg down the centre that is gripped by the rubber and rests on the bolt-top. Just stick it on wading height to pop them in when you're changing the wheels over.
 
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