Suspension again

[GrayKnight]

Thanks OJ.

The Lovells springs - are they readily available? I couldn't find them on their website.

Also, is the increase in EBH of about 40mm (with the Lovells) ok with the drive line etc?

Cheers
Richard

[old Jack]

Hi Richard,

I seem to recall another forum member was able to do a special order of the CRR-69EHDVR coils direct from Lovells.

I do not believe these are the best spring for your application unless you are changing the front coils.

If you are keeping the front coils I would looking at using the OME 2838 with the Peddars 5899 rubber cone springs.

Zig you have an auto trans you need to be aware of the ni peddle


You really should aboir use the Lovells CRR-69EHDVR unless you have changed the front coils. keeping the rake angle to about 30-40mm difference in front and rear ride heights on an "empty" Challenger is about right.

Upgrading front coils, I ran Lovells front coils for about 90,000kms, they were standard height but an increase in spring rate by about 10%. I found the spring rate on these coils too high, great for on road handling but not so good on substandard roads, ack roads and off road. These where fitted to Bilstein struts, I had 3 strut failures within the 90,000km duration and I finally worked out why! The Lovells coils are not ground flat on the top face where they mate with the upper mount, this means the coil is not setting 100% square in relation to the strut, so a side load is applied to the strut shaft Nresulting in the top seal failing and the scoring the strut piston rod. So this is why I do not recommend fitting a King/Bilstein combination.

[GrayKnight]

Thanks for all your advice OJ.

Sorry to be a nuisance, but nobody near where I live (Gosford) stocks Oztec and freight from Brisbane could be expensive. You're not keen on Bilsteins, in my case, so what would be your suggestion as second choice after Oztec? Thanks.

I'm going to keep the front springs and fit OME 2838 springs at the rear plus the Peddar cones.

Cheers
Richard

PS. Have checked cost including freight and it's not too bad (see post below), so will order Oztecs.

[littleriver]

Thanks for all your advice OJ.

Sorry to be a nuisance, but nobody near where I live (Gosford) stocks Oztec and freight from Brisbane could be expensive. You're not keen on Bilsteins, in my case, so what would be your suggestion as second choice after Oztec? Thanks.

I'm going to keep the front springs and fit OME 2838 springs at the rear plus the Peddar cones.

Cheers
Richard

Ring

https://www.gcsuspension.com.au/

For the oztec shocks will do you a good price and freight....




...

[GrayKnight]

Ring

https://www.gcsuspension.com.au/

For the oztec shocks will do you a good price and freight....


...

Thanks, I did ring them and Oztec as well. GCS were slightly cheaper than Oztec, and the price looks reasonable, just under $800 for four shocks plus the freight.

I'll go with GCS.

Cheers
Richard

[old Jack]

Hi Richard,

Looks like you are all sorted out.
Please let us know what you think of the upgrades once they are done.

OJ.

[GrayKnight]

Hi Richard,

Looks like you are all sorted out.
Please let us know what you think of the upgrades once they are done.

OJ.

Yes, all sorted now. I will let you know how the car is after the upgrades, but it will be a while as I'm having knee surgery in a few weeks which will keep me out of the bush for some time.

Thanks again Jack, you've been extremely helpful.

Cheers
Richard

[GrayKnight]

Hi OJ,

I had the suspension upgraded last week. As you recommended, I kept the factory front springs with new top seats, fitted OME 2838 springs at the rear with Peddar bump stops and put Oztec shocks all round. I've only done about 200km on bitumen so far, dirt will have to wait. The ride is a lot firmer as you would expect.

The EBH measurements before/after are
With permanent load RF 550/550, LF 550/550, RR 515/610, LR 515/610.
With load plus camper RF 550/560, LF 550/560, RR 490/580, LR 490/580.

A huge difference. I presume the rear springs will settle a bit, but the increase in clearance means I no longer have to worry about the long- range fuel tank bottoming out.

All good.

Cheers
Richard

[old Jack]

Hi Richad,

Are the rear ride heights at 610mm correct, this sounds high.
What is the rear axle weight?
What is the gap between the bottom of the Peddar 5899 cones and the lower spring pad where they contact?
Auto or Manual trans?

OJ.

[GrayKnight]

Hi Jack,

The 610 is correct, the distance between the bottom of the bump stop and the seat is 70mm, and the rear axle weight was 1,120kg when weighed a few weeks ago.
Auto transmission.

Cheers
Richard

[old Jack]

Hi Jack,

The 610 is correct, the distance between the bottom of the bump stop and the seat is 70mm, and the rear axle weight was 1,120kg when weighed a few weeks ago.
Auto transmission.

Cheers
Richard

Hi Richard,

610mm rear ride height and 70mm clearance on 5899 cones lines up with my records I have on file.

OME 2838 that you have fitted are riding 20mm higher than I calculated for a load of 1120kg, my theoretical ride height was 590mm. I would expect coils to only settle about 5mm - 10mm but this may not happen until the coils have been really loaded up and cycled through multiple compression, like you would experience during a long trip when fully loaded.
When fully loaded with wife, kids, gear in cargo area and camper hooked up you will mostly likely be sitting at about 550mm - 560mm so this is a great ride height for touring.

I am a little worried that 610mm is a bit on the high side for everyday use.
Are you getting any driveline vibration/harmonics between 35-45kph?
This is common for auto Challengers once you have a rear ride height of 590mm or more.
If you are noticing driveline vibrations/harmonics and these are annoying you then you have 4 options.

1. Keep the OME 2838 and see how it settles down or the next month or so.
2. For the next few months add and extra 100 -150kg in the rear cargo area and keep your LR tank full most of the time, this will assist in the settling down of the OME 2838.
3. Swap coils over for OME2938, these are identical to KCRR-23HD, they both have the same spring rate as the 2838 but are 20mm lower in free height. These would be better for normal suburban duties but you would be losing about 20mm ride height when fully loaded with the camper hitched up.
4. Remove the rear coils and cut about an 1/8 to a 1/4 of a turn off the lower coil so the free height is reduced. 20mm free height reduction will make them similar to OME2938/KCRR-23HD. A 10mm free height reduction will give you 10mm ride height reduction and may actually be the best sweet spot in the long run.

As always there are compromises that must be made, you need to decide which ones you are wiling to make.

OJ.

[GrayKnight]

I am a little worried that 610mm is a bit on the high side for everyday use.
Are you getting any driveline vibration/harmonics between 35-45kph?
This is common for auto Challengers once you have a rear ride height of 590mm or more.

OJ.

Hi Jack,

I've run the car through that speed range a number of times in the last two days. Idling down a hill (I live on a hill), cruising on the flat at various speeds within that range, gentle and hard acceleration on the flat and hard acceleration going up hill. I couldn't detect any vibrations or odd noises.

Is there a particular RPM that induces the vibrations/ harmonics?

Cheers
Richard

[old Jack]

Hi Jack,

I've run the car through that speed range a number of times in the last two days. Idling down a hill (I live on a hill), cruising on the flat at various speeds within that range, gentle and hard acceleration on the flat and hard acceleration going up hill. I couldn't detect any vibrations or odd noises.

Is there a particular RPM that induces the vibrations/ harmonics?

Cheers
Richard

Hi Richard,

Not everyone with an auto trans and a lifted suspension reports vibrations/harmonics.
If you have it, it is most noticeable when gently accelerating up to 60kph on a flat road, and you can feel/hear a minor driveline harshness between 35kph and 45kph.

OJ.

[picard]

Dobinsons mrr failure

Well it’s time to either replace or rebuild my dobinsons mrr as the left strut seal has failed and it seems to of originated from the floating piston within the remote res’ failing releasing gas into the system.
So do I rebuild and hope they last another three years or replace with a seemingly more reliable twin tube although not so sublime dampening characteristics.
So Has anyone Had a similar experience?
And if so what path did you take?
Cheers

[old Jack]

Well it’s time to either replace or rebuild my dobinsons mrr as the left strut seal has failed and it seems to of originated from the floating piston within the remote res’ failing releasing gas into the system.
So do I rebuild and hope they last another three years or replace with a seemingly more reliable twin tube although not so sublime dampening characteristics.
So Has anyone Had a similar experience?
And if so what path did you take?
Cheers

Have you looked at the Dobinson IMS which is the replacement for the MT. I have had MT's for 43,000 kms and the much prefer these to the Bilstein B6 in ride comfort and rebound control.

OJ.