1.5" DIY ISC rear top hat interference
#22
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Here are the measurements I took last night with the three hats in the rear. I measured from the fender to center of axle like I do to measure ride heights.
NB hat:
Droop = 16.5" Compressed = 10.5" (lots of room around tire)
1" top hat:
Droop = 16" Compression= 9.5" (room around tire, doesn't hit a-arm)
1.5" top hat:
Droop = 15.5" Compression = 9.75" (a-arm hits)
I am shooting for close to 13" ride height.
I started looking at adding a spacer under the bump stop or using taller bump stop to keep from metal on metal contact, but I feel safer on the 1" top hat where I know I won't be hitting anything. I will eithen make another set of 3/4" for the fronts or more than likely throw the NB hats back in.
What is the ideal split in travel between droop and compression, 50/50 ? Or do you want more compression travel than droop?
NB hat:
Droop = 16.5" Compressed = 10.5" (lots of room around tire)
1" top hat:
Droop = 16" Compression= 9.5" (room around tire, doesn't hit a-arm)
1.5" top hat:
Droop = 15.5" Compression = 9.75" (a-arm hits)
I am shooting for close to 13" ride height.
I started looking at adding a spacer under the bump stop or using taller bump stop to keep from metal on metal contact, but I feel safer on the 1" top hat where I know I won't be hitting anything. I will eithen make another set of 3/4" for the fronts or more than likely throw the NB hats back in.
What is the ideal split in travel between droop and compression, 50/50 ? Or do you want more compression travel than droop?
#23
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I've read anywhere from 50/50 to 60 comp/40 droop. I'm sure it depends on the car, driver, road surface, etc. I'd planned on just being somewhere between the two ranges and calling it a day.
FWIW, I'll be playing this game shortly, once I finish with all the other junk laying around waiting to be fixed.. grumble grumble grumble.
FWIW, I'll be playing this game shortly, once I finish with all the other junk laying around waiting to be fixed.. grumble grumble grumble.
#24
I've read anywhere from 50/50 to 60 comp/40 droop. I'm sure it depends on the car, driver, road surface, etc. I'd planned on just being somewhere between the two ranges and calling it a day.
FWIW, I'll be playing this game shortly, once I finish with all the other junk laying around waiting to be fixed.. grumble grumble grumble.
FWIW, I'll be playing this game shortly, once I finish with all the other junk laying around waiting to be fixed.. grumble grumble grumble.
#25
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Well yeah of course, but where you're at in the stroke with the car on the ground and settled is otherwise ride height dependent. So assuming a set ride height, you can still target a certain range of comp/droop by adding extension to the top hats, right?
#29
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Hmmm... I think I see what you mean, thank you. You could keep moving the top of the shock higher and higher, but the A-arms still hit the frame at the same point regardless. Cool beans. I'm assuming this is all patently obvious once you're under the car with a tape measure...
So, he just needs a bump stop long enough for the a-arm not to hit, and that's basically as good as it gets, whatever that ratio works out to, as it won't get any better short of custom arms. Agree?
1.5" top hat:
Droop = 15.5" Compression = 9.75" (a-arm hits)
Droop = 15.5" Compression = 9.75" (a-arm hits)
#31
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Right, so probably a progressive rate bumpstop would be preferred. You could jack up the car on that corner sans spring to try compressing the bumpstop to see where it ends up, but thats only 1g on the bumpstop, not the 3-5gs it might see on the road.. although hopefully it's not seeing that high of loading on the track. My home track maybe, haha.
#33
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I ended up adding one 1/8" rubber washer from Lowes on each corner. In the rear I used the BFH to massage the low point arout the upper shock mount where the upper rear a-arm was hitting. With the shim, I can lift the whole back end of the car off the lift and still maintain > 1/8" clearance between the arm and chassis.
I test drove it yesterday and it feels sooooooooo freaking much better on rough roads. No metal to metal contact even on real rough roads with big bumps. It also feels a lot more confidance inspiring when pushing it to the limit. I can't wait to take it on my daily route to work so I can really tell how much the ride quality has improved.
I test drove it yesterday and it feels sooooooooo freaking much better on rough roads. No metal to metal contact even on real rough roads with big bumps. It also feels a lot more confidance inspiring when pushing it to the limit. I can't wait to take it on my daily route to work so I can really tell how much the ride quality has improved.
Last edited by Rallas; 01-11-2015 at 06:07 PM.
#37
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I had a real world test last night when I hit a monster pothole. I though I bottomed out for sure, but checked everything front and rear with no evidence of bottoming out.
The car is handling the rough roads to work much better now, but I'm still getting a lot of chassis movement. It just feels like the shocks are not dampening the springs.
The car is handling the rough roads to work much better now, but I'm still getting a lot of chassis movement. It just feels like the shocks are not dampening the springs.