Capri V8 handling

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billyballer
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Capri V8 handling

Post by billyballer » Tue 15 Apr 2014, 05:38

Hey all,

I've got a US spec '74 Capri that I converted to a ford 5.0 HO V8, T5 and 8.8 limited slip rear end setup.
I've built this Capri for a budget endurance road racing series in the the states called the 24 Hours of Lemons.
Basic rules are sub-$500 car and mandatory sense of humor.
While the handling isn't awful, I know it can do better. The basic issues are diving under braking, too much understeer, and a little more body roll than is ideal.

The suspension we have now is stock struts in the front, with cut springs (about 1.5" drop), then a second set of external dampers (Koni orange) on the front. We are also using urethane bushings throughout the front (Inner and outer TCA bushings and sway bar mounts), and we have a 1 inch bar (26mm I believe). The back is stock springs lowered 1" with traction bars and Koni orange adjustable shocks, turned all the way up. I don't know the front spring rates, but they were some type of aftermarket spring that was already on the car when I got it.

I guess for starters I'm curious what is generally thought of as the best setup for a capri V8. For example MGB's like to be run really soft in the back and much stiffer up front and that gives fairly neutral handling.

I've toyed with buying adjustable TCA's fitted with spherical bushings, as well as some proper coilovers, but again we are on a tight budget and have to plan accordingly and ideally make due with junkyard parts. One kit I saw in the UK eliminated the sway bar as a forward link and replaced it with a dedicated suspension link, which seemed like a great idea. http://www.ebay.com/itm/131143385823?ss ... 1423.l2649

Between now and our next event I'll probably only be able to afford one upgrade (either springs/shocks, or TCA's).

I'm open to all suggestions.


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-Billy

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alvin chetty
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Re: Capri V8 handling

Post by alvin chetty » Tue 15 Apr 2014, 09:02

[quote="billyballer"]Hey all,

The back is stock springs lowered 1" with traction bars

are these drag race traction bars or circuit race. If drag race setup, it might be the cause of your understeer
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billyballer
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Joined: Fri 11 Apr 2014, 03:34
Location: Oakland, California USA

Re: Capri V8 handling

Post by billyballer » Tue 15 Apr 2014, 19:08

I built the traction bars myself out of metal scrap I had laying around the shop. We were having really severe spring wind up without them. Basically they are bars with bushings on both ends, one end mounted under the center of the spring and one that mounts under the forward mounting point of the spring. I set them up with the race car at actual ride height so that they are roughly parallel. I know do to the nature of leaf spring movement, there is some potential for bind but I ran the axle through full travel and it was really smooth.
The setup is similar to the Traction masters traction bars used on Shelby mustangs.

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alvin chetty
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Re: Capri V8 handling

Post by alvin chetty » Thu 17 Apr 2014, 10:05

I think you should remove that and replace one of the leaves with a stronger one will help cure the spring wind and help with the understeer. some of our circuit capris run with just one strong leaf and they handle quite well.
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ZA Perana
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Re: Capri V8 handling

Post by ZA Perana » Thu 17 Apr 2014, 18:37

My suggestion is firm front springs, am running 600 pound springs in my car and it has zero dive under braking and sits well through the corners. Also running upgraded shocks all round and the standard leaves at the back with one leaf added to increase firmness.
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billyballer
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Re: Capri V8 handling

Post by billyballer » Fri 18 Apr 2014, 07:49

600 lbs.... yeah what I have in the front is definitely not that stiff. That sounds like a good place to start as well as investigating a stiffer rear leaf. Just have to hunt down a vehicle with the same width leaf springs that might be a bit stiffer now.

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ZA Perana
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Re: Capri V8 handling

Post by ZA Perana » Fri 18 Apr 2014, 14:55

billyballer wrote:600 lbs.... yeah what I have in the front is definitely not that stiff. That sounds like a good place to start as well as investigating a stiffer rear leaf. Just have to hunt down a vehicle with the same width leaf springs that might be a bit stiffer now.
You could also try running shocks with thicker oil at the back, might stiffen things up a bit. I think check the condition of the front lower control arms and anti roll bar bushes because if these are in poor condition the car wont handle too well.
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billyballer
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Re: Capri V8 handling

Post by billyballer » Fri 18 Apr 2014, 20:30

ZA Perana wrote:
billyballer wrote:600 lbs.... yeah what I have in the front is definitely not that stiff. That sounds like a good place to start as well as investigating a stiffer rear leaf. Just have to hunt down a vehicle with the same width leaf springs that might be a bit stiffer now.
You could also try running shocks with thicker oil at the back, might stiffen things up a bit. I think check the condition of the front lower control arms and anti roll bar bushes because if these are in poor condition the car wont handle too well.

All the front suspension bushings are Fresh urethane, and the ball joints are in great shape. I did have a whiteline inner TCA bushing shred to pieces during the last event though, so I'm a little dubious of the quailty.

ZA would you mind telling me roughly what shocks you are using?

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ZA Perana
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Re: Capri V8 handling

Post by ZA Perana » Fri 18 Apr 2014, 21:25

billyballer wrote:
ZA Perana wrote:
billyballer wrote:600 lbs.... yeah what I have in the front is definitely not that stiff. That sounds like a good place to start as well as investigating a stiffer rear leaf. Just have to hunt down a vehicle with the same width leaf springs that might be a bit stiffer now.
You could also try running shocks with thicker oil at the back, might stiffen things up a bit. I think check the condition of the front lower control arms and anti roll bar bushes because if these are in poor condition the car wont handle too well.

All the front suspension bushings are Fresh urethane, and the ball joints are in great shape. I did have a whiteline inner TCA bushing shred to pieces during the last event though, so I'm a little dubious of the quailty.

ZA would you mind telling me roughly what shocks you are using?
Shocks aren't anything special, just locally available ones with slightly thicker oil. In reality my car is set up with the adjustable 600 pound springs at the front, the springs are so hard the shocks hardly do any work at all. This is basically a hybrid of the set up that was used on the racing Capri's here in the 70's i.e. set the front up so hard that the nose doesn't dive at all.
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colin davids
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Re: Capri V8 handling

Post by colin davids » Sun 27 Apr 2014, 14:44

Hey Billy. I'm very interested to see how this turns out because i am also building a mk1 capri perana v8 for track use.My setup consists of stiffer front coils,shortened shocks,double front anti-roll bar,front and rear poly kits,decambered rear springs with an extra blade added and a rear panhard rod.I dont know much about the us spec cars but our v6 and v8 cars came with bushed rear axle tramp rods that run from the top of the differential to the rear chassis rail. If you dont have these you will definitely see severe spring windup.Also,a double front anti-roll bar should improve your turn-in.I do not have much circuit racing experience so im no expert but i got these ideas from other capri racers and it seemed to make sense.Good luck.
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