paulbeyer
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| posted on 12/11/02 at 11:15 PM |
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Indy Ride Height
Seems like every Indy builder is using Gaz shocks with 13" centres. Can someone tell me what the ride height is with this setup?
I don't understand suspension geometry too well but I have worked out with 12" centre shocks (Nitrons) the ride height would be about 61/2" at the
rear and 6" on the front. This seems to be a bit on the high side according to some of the book built cars but surely Gaz shocks with 13" centres
would sit the car even higher.
Like I said, I dont understand this suspension voodoo very well so I've probably got it all wrong. If someone can confirm one way or another I'd
appreciate it. After all I dont want to buy Gaz shocks if I end up with a monster truck.
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donut
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| posted on 13/11/02 at 08:05 AM |
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Indy ride hight
I guess the whole reason for using decent coil overs is that they are adjustable so you can get the ride height you want. The Nitrons do not have
adjustable damping so for a few extra quid the Gaz shocks look the better deal.
Andy
Andy
When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
http://www.flickr.com/photos/andywest1/
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interestedparty
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| posted on 13/11/02 at 08:26 AM |
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Adjusatable spring platforms are there primarily to set the cornerweights. In other words, if more of the cars's weight is being presented to one
front (or rear) wheel than the other then the spring platforms can be adjusted to correct this.
On a twin wishbone suspension system the ride height is correct when the normally laden car's lower wishbone is parallel to the road surface. Small
adjustments may be necessary to acheive this. If large adjustments are required then the springs are wrong and should be changed.
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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paulbeyer
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| posted on 13/11/02 at 01:01 PM |
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quote:
On a twin wishbone suspension system the ride height is correct when the normally laden car's lower wishbone is parallel to the road surface
This is what I was thinking. With my lower wishbones parallel to the road surface the distance between upper and lower mounting point for the shocks
is 12" at the front and 11.75" at the back. This incidently is the same as the dims for the Nitron shocks. Putting aside the pro's and con's of
Nitron v Gaz it seems to me that the Gaz shocks are going to be too long at 13" resulting in the lower wishbones pointing down. In the book I have on
sports car suspension it says this is not an ideal set up and one to avoid if at all possible.
I understand that most Indy builders are using Gaz shocks (I dont know of any one using anything else) so I cant see that you are all doing something
wrong and I have spotted the deliberate mistake I just want to get it clear in my own mind before I commit to one of the most expensive parts of my
build. All of my calculations steer me towards Nitron sized shocks not Gaz, can someone help clarify this? 
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interestedparty
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| posted on 13/11/02 at 01:20 PM |
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The shock absorber does not of itself set the ride height. This function is carried out by the spring.
The shock should be chosen to provide full suspension movement. In other words, the varying distances of the mounting points as the suspension moves
through its stroke should be matched by the available movement of the shock.
Shocks are defined by their open and closed lengths, you cannot define a shock by one measurement
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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paulbeyer
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| posted on 13/11/02 at 02:11 PM |
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Cheers John, it looks like I am looking at it from a far too simplistic stand point. I keep reading the book I have but I just end up frying my brain.
I think I'll follow Bob's example and buy a set of Gaz shocks with the same spring rates and hope the spring lengths are correct. After all Bob is
doing the same build as I am, Pinto engine now with a view to upgrade to 16 valve some time in the future. And if it all goes wrong I can blame
him.
Paul
(In sunny west Swindon)
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interestedparty
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| posted on 13/11/02 at 03:35 PM |
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quote:
Originally posted by paulbeyer
. After all Bob is doing the same build as I am, Pinto engine now with a view to upgrade to 16 valve some time in the future. And if it all goes wrong
I can blame him
This is a perfectly viable and traditional approach to car design, and I can recommend it
BTW I am familiar with the smell of smouldering brain tissue
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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Stu16v
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| posted on 13/11/02 at 07:30 PM |
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quote:
This is what I was thinking. With my lower wishbones parallel to the road surface the distance between upper and lower mounting point for the shocks
is 12" at the front and 11.75" at the back. This incidently is the same as the dims for the Nitron shocks. Putting aside the pro's and con's of
Nitron v Gaz it seems to me that the Gaz shocks are going to be too long at 13" resulting in the lower wishbones pointing down. In the book I have on
sports car suspension it says this is not an ideal set up and one to avoid if at all possible.
Remember mate, that the Gaz are 13" long when fully extended. You DO NOT want them fully extended at normal ride height, ideally you want them 1/3
compressed at running height. So with the figures you have quoted so far, it seems like the Gaz would be the ideal shockers to go for.
HTH Stu.
Dont just build it.....make it!
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paulbeyer
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| posted on 13/11/02 at 11:26 PM |
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Stu and John, thanks for your input. I took onboard all you have said and had a look at my book again and all has become clear. I completely missed
the fact that the shock dims I was quoting were fully extended, what a muppet.
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bob
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| posted on 14/11/02 at 12:11 AM |
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And to think if it went pear shaped you were going to blame me.
Paul i keep telling you,dont panic unles i panic
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donut
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| posted on 14/11/02 at 12:10 PM |
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Gaz Shockers!
Ok i have now received my Gaz shocks but i have a few questions.
1, what tool do you use to adjust the spring compressor ring?
2, How far up are you all going with spring comprassion as a starting point?
3, How many clicks from 'soft' are you going with the damper adjuster knob also as a starting point?
Fanx
Andy
Andy
When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
http://www.flickr.com/photos/andywest1/
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paulbeyer
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| posted on 14/11/02 at 12:22 PM |
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I wasn't going to blame ya Bob, but if you do start a panic don't forget to send me a U2U so I can follow yor example. 
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bob
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| posted on 14/11/02 at 05:22 PM |
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Nice one paul,i'll keep you informed of when next panic attack is coming
Hey Andy
You will only know if you want soft or hard damper setting once you are on the road.
By the way how different are the spring rates for zetec engine compared with pinto,i'm just interested
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donut
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| posted on 15/11/02 at 09:55 AM |
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BOB
The springs are the same as pinto i think, 325 front and 175 rear. I asked for the same as you and the guy at Gaz said they should be fine for zetec.
I don't know how much differencr in weight there is between pinto and zetec, probably not alot.
I still need to know which tool to use to adjust the adjuster ring thingy.
Cheers
Andy
Andy
When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
http://www.flickr.com/photos/andywest1/
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interestedparty
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| posted on 15/11/02 at 11:08 AM |
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The tool you need is a 'c'spanner, needs to be the right size for the spring platforms you have. Probably available from the people you bought the
shocks from, or from Demon Tweeks etc definitely a special tool so don't bother looking in Halfords.
For initial adjustment I would suggest winding the spring platform up maybe 10 mm from the bottom.
Don't forget that the rate of the spring is only one factor in deciding the ride height of any given weight of car, the other factor is the unfitted
length!
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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donut
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| posted on 15/11/02 at 11:48 AM |
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Cheers for that John
One thing... I have put the springs on the dampers and tightened up the spring platform as far as it will go by hand with the damper at full length
and there is about an inch and a half between the platform and the bottom of the shock. There are aprox 5 - 7 threads showing between the weld and the
platform bottom. Is this ok?
Cheers
Andy
Andy
When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
http://www.flickr.com/photos/andywest1/
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