Variable rate springs for Harrison

macloft · #1 (**permalink**) 10-13-2012, 08:48 AM

Hola
Looking at the QA1 shocks for the back of my Harrison. Question is springs.
Has anyone had experience with Variable rate springs on a Harrison and if so what strength did u use? the 175/ 350
I find with the AVOs and the 250 spring I have the ride is to harsh for the road
Thanks Bruce

OZVENOM · #2 (**permalink**) 10-13-2012, 03:54 PM

Hi kings springs make 2 types of progressive springs single and double taper.
These work very well you just have to make sure you can get the right length because if you compress the spring to fit it it stops being progressive and acts like a normal spring. a lot depends on how much you compress it.
hope this helps.
oz.

macloft · #3 (**permalink**) 10-13-2012, 04:27 PM

Hi Oz
So if the car currently has 250 rate springs do you know if i use a 175/ 350 would that give me a softer ride for the initial smaller bumps i hit and then stiffen out.
I find right now the back bangs a little to much even if i soften the shocks down.
I am bringing shocks and springs over from the US with me when i go back to Brissy for a couple of days R&R.
Thanks
Bruce

Merv and Sharon · #4 (**permalink**) 10-13-2012, 04:57 PM

Bruce, the longer shocks and springs should do the job, however, I also tried some keeper springs before I went for the 12" shocks and springs at the rear. There was an earlier thread: spring rates

aussiecoupe · #5 (**permalink**) 10-14-2012, 02:33 AM

Hi Bruce
We allways suggest 350 lbs on the front and 300 lbs on the rear . I have just had an engineer do a road test for rego . His 15 kms test run is like a goat track at the back of Lismore NSW . He was quite pleased as with others with the ride and handling . Unsure where you are driving the Cobra . I would suggest you talk to either King spings
or a spring manufature about the progress spings . One of the Cobra racers is trying Penski shocks to see if he can inprove his times with the two adjustment style . Do not forget the AVO is rebuildable and REg can alter the valving . The others , well look into if they can be rebuilt . We had some problems with leaking shafts but those have been fixed under warranty .

Warwick.

Merv and Sharon · #6 (**permalink**) 10-14-2012, 02:54 AM

Hi Warwick. Catch up with you at Twin Waters in November. We need to have celebration when Rog finishes number 100!

macloft · #7 (**permalink**) 10-14-2012, 08:08 AM

Hello Warwick
Thank you for responding
I have tried to call a couple of times but very difficult due to time difference and my Mexican phone.
I will try again today. I am coming over in a week and have arranged a couple of days to work on my car to finish a few things off and take it for a drive.
Cheers
Bruce

macloft · #8 (**permalink**) 10-14-2012, 06:30 PM

Hola
Just to close out this thread. I have spoken to Warwick and decided to go with the QA1s for the extra 1 inch travel (17") over the AVO. I dont want to compromise the ride height of the car by using to short a shock. I am going to use the QA1 single adjustable shock as I am no suspension wizard and it's not a track car. I do believe there will be enough adjustability to suit my needs.
I am also most likely going to use the standard 12" long coil spring at the 300 lb spring over the variable spring.
Does anyone actually have hands on experience between the handling difference between the variable and fixed springs on a road car. My intuition tells me u probably would not be able to feel a difference through ya butt.
Now to talk to my bank manager

Thanks Warwick (and others) for your response and help.
Cheers
Bruce

400TT · #9 (**permalink**) 10-17-2012, 02:43 PM

Bruce, what settings did you have your shocks set to. It's not as obvious as shocks set too hard.

Going to longer shocks is a great idea.

Just a heads up the QA1's are a very stiff/hard shock, so you will only be using the lower part of the adjustment range.

macloft · #10 (**permalink**) 10-17-2012, 03:48 PM

Hello Craig
The AVOs were set in the middle setting
The real problem I have is, to get the car at the right height to pass inspection (4 inches) i had to jack the back up until the rear shock was almost fully extended. So when I am driving the car and the shock rebounds over a bump the shock would fully extend and bang.
Certainly when the car was lowered I could get the setup to work right.
Maybe I got to short an AVO. I do not have an issue with the AVO itself or the spring I believe I have wrong length.
Cheers
Bruce

Merv and Sharon · #11 (**permalink**) 10-18-2012, 09:49 PM

Yes Bruce, Murray is one of the most knowledgeable people I know on these things. Very experienced. I followed his advice with my shock set up at the rear, although his rear mount setup is much better.

muzzza · #12 (**permalink**) 10-19-2012, 04:31 AM

Meant to say.......QA1 do 1" and 2" alloy shock extensions that bolt onto top of shock shaft.........could be an option. I have some 4140 ( steel ) 1" extensions that I turned up a while back, if you decide that may be an option for you.
Will take pics of shock mounts tomorrow.
Muzzza

leroy17 · #13 (**permalink**) 06-04-2013, 04:41 PM

Bringing up an older past thread.

Muzzza, If you ever get a chance I would be interested in pics of the shock mounts that you mentioned above.

Cheers mate.

muzzza · #14 (**permalink**) 06-04-2013, 06:29 PM

Lee, I have a two ( very average ) pics in my gallery. The rear brackets were cut off and a plate was welded in place with threaded holes for a bolt on bracket. At the front ...... I cut back original mounting plates and bolted on new ones with the upper shock eye relocated downwards. If I want to change ride height, I can remove the plates and re-position the holes.

leroy17 · #15 (**permalink**) 06-04-2013, 06:54 PM

Thanks Murray, pics are perfect and confirms what I thought you had made.

Thanks again.

sambo · #16 (**permalink**) 02-12-2015, 07:19 PM

Reviving this thead again. Bruce, how did you go with the spring upgrades?

I have QA1 shocks on the rear with 250lb springs, which I've pre-loaded roughly 20-25mm for ride height. Cruising around on the street it's too jittery in the rear, so I'm considering a beefier spring with less pre-load.

Options from QA1 include 300, 325, 350 and 400lbs.

For Harrison owners with the Nissan rear end and 12" shocks, what springs are you running and how is the ride quality?

leroy17 · #17 (**permalink**) 02-12-2015, 07:36 PM

On my previous Harrison number 40, and hopefully the new owner may comment as well. I used QA1 with 300 (f) and 275 (r) for memory, or maybe 250 (r). There was minimal preload and the adjusters were set at 5 clicks (again for memory).

Either way, it drove very balanced and stable and I would not have changed a thing from this setting for street driving.

Perhaps the adjusters could be backed off a little, just a thought.

I

sambo · #18 (**permalink**) 02-12-2015, 08:18 PM

Hi Leroy, thanks for the info. If I have any less damping it starts to get pretty bouncy - not enough control over the spring. The rear shocks are only on the 2nd or 3rd out of 18 positions.

With 250lb if I lessen the preload the body sits too low at the rear. The front is as low as I dare on the street.

leroy17 · #19 (**permalink**) 02-13-2015, 01:12 AM

I checked and it was 250lb that I had in the rear and 300 front. Both front and rear were single adjustable.

For pics of mine, here is a link to the last photos I had. For memory the ride heights are not dissimilar to yours.

Harrison #40 for sale (Aus)

I am sure a suspension expert may offer better assistance rather than me as a paper shuffler.

sambo · #20 (**permalink**) 02-18-2015, 06:41 PM

I went with Warwick's suggestion on the previous page and ordered a set of 300lb springs. QA1 have just released a "high travel" range, using fewer coils which reduces weight "up to" 28 percent and increases travel "up to" 20 percent. They should arrive next week.

http://www.summitracing.com/dom/parts/hal-12ht300