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Author: Subject: Trackday geometry set up for Fury
T0MMY

posted on 1/5/19 at 10:01 AM Reply With Quote
Trackday geometry set up for Fury

I've just bought a newly built IRS Fury with a 2 litre Zetec and looking for some advice on geometry and spring rates please. I will use it on the road but want it mostly optimised for trackdays as that'll be the primary use.

It's going to Northampton Motorsport next week for mapping and geometry work so just wondering what figures I should ask them to aim for on the wheel alignment? Also the rear springs feel far too soft to me, not sure if they're the standard 180 front/130 rear Fisher recommend but should I aim for 225/180 as I've read a few times? And does that apply to both IRS cars and live axle? According to the SVA docs the car is quite heavy at 590kg if that makes a difference.

Final thing...where should the ride height be measured to front and rear? The last chassis cross member at each end?

Any help much appreciated

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se7ensport

posted on 1/5/19 at 01:06 PM Reply With Quote
Mine is a Stylus, but the set up should be pretty similar:

Front ride height 90mm from chassis rail connecting to suspension, rear ride height 95mm from last chassis tube behind drivers seat (assuming its level with the rest of the car and not lowered to accommodate drivers seat). These heights are with driver in car. Your shocks length might not allow this ride height, but the 5mm rake is a good starting point.

Front spring rater for inboard shocks 275lb, rear shocks are 240 or 250 (can't remember), mines circa 600kg.

Front toe out 2mm
Caster 4-5 degrees
Camber -2.5-3 degrees

Rear toe in on a de-dion is 1mm
Camber -1/2 a degree

[Edited on 1/5/19 by se7ensport]

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G13BLocost

posted on 1/5/19 at 04:53 PM Reply With Quote
quote:
Originally posted by se7ensport
Mine is a Stylus, but the set up should be pretty similar:

Front ride height 90mm from chassis rail connecting to suspension, rear ride height 95mm from last chassis tube behind drivers seat (assuming its level with the rest of the car and not lowered to accommodate drivers seat). These heights are with driver in car. Your shocks length might not allow this ride height, but the 5mm rake is a good starting point.

Front spring rater for inboard shocks 275lb, rear shocks are 240 or 250 (can't remember), mines circa 600kg.

Front toe out 2mm
Caster 4-5 degrees
Camber -2.5-3 degrees

Rear toe in on a de-dion is 1mm
Camber -1/2 a degree

[Edited on 1/5/19 by se7ensport]


Seems more than reasonable





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adithorp

posted on 1/5/19 at 08:48 PM Reply With Quote
I'll look mine up in the morning.





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T0MMY

posted on 2/5/19 at 08:48 PM Reply With Quote
Thanks for the replies chaps.

Se7ensport, that's a lot more front camber and a fair bit less rake than the standard Fury set up I believe. Was yours set up for the track? Is the Stylus definitely going to be similar to the Fury? I don't know much about them other than they look quite similar!

[Edited on 2/5/19 by T0MMY]

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jeffw

posted on 2/5/19 at 09:04 PM Reply With Quote
I'd venture you are way off on the Rake for the Fury with those settings. More like 20-25mm rake
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adithorp

posted on 3/5/19 at 11:09 AM Reply With Quote
Mine is set to...

Front. Toe-out 20', Castor 6deg, Camber -2deg

Rear. Toe-in 20'. Camber -1deg

Ride heights. Front 115mm. Rear 140mm (rake 25mm).

That's an IRS Fury with R1 motor. I'm running front 180lbs and rear 160lbs springs with shaped polymer bumpstops both ends. Originally had 210/160 then 210/180 but came to the current mix after a lot of experiment. I've also checked and corrected the bump steer (meant spacing the rack forward+up) which made a big improvement (before I had front toe at 1deg in but as much as 2deg out under bump).

[Edited on 3/5/19 by adithorp]





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se7ensport

posted on 3/5/19 at 11:56 AM Reply With Quote
Question to the Fury guys with 25mm rake, is that with or without driver?
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se7ensport

posted on 3/5/19 at 11:57 AM Reply With Quote
quote:
Originally posted by T0MMY
Thanks for the replies chaps.

Se7ensport, that's a lot more front camber and a fair bit less rake than the standard Fury set up I believe. Was yours set up for the track? Is the Stylus definitely going to be similar to the Fury? I don't know much about them other than they look quite similar!

[Edited on 2/5/19 by T0MMY]


Set only for the track, I sprint it.

They used to share a chassis in the very early days, I believe they changed a little, but fundamentally would be very similar.

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T0MMY

posted on 3/5/19 at 03:52 PM Reply With Quote
Another quick question...the brackets that the upper rocker arms connect to have two holes, inner and outer. Why is that? The build manual says to use the inners but can you use the outer ones to get more trackwidth (and if not why are they there?)? This is assuming you can wind out the lower balljoint far enough to still get negative camber but even then the wishbones would then be different relative lengths. I only ask as I've seen photos of other Furys where they are using the outer holes!
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adithorp

posted on 3/5/19 at 04:27 PM Reply With Quote
quote:
Originally posted by se7ensport
Question to the Fury guys with 25mm rake, is that with or without driver?


Thats with driver. Don't think they shared a chassis as far as I know but all JP chassis share similar features. I've run more and less of everything and think thats the sweet spot. I have run a bit more camber (+1deg f+r), for (dry) track but thats what I find it is the best compromise for all conditions (fast road/dry+wet track).


quote:
Originally posted by T0MMY
Another quick question...the brackets that the upper rocker arms connect to have two holes, inner and outer. Why is that?...


I think it's for different uprights. Outer ones for Escort, inner for Sierra (I could be worng).





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JekRankin

posted on 3/5/19 at 07:27 PM Reply With Quote
Adi,

Approximately how much did you need to space out the rack to eliminate the bump steer? 3deg toe change Iím bump seems quite a lot of bump steer in the chassis?Iíve got an order going out to the laser cutters soon, and I may just get a bunch of rack shims cut at the same time.

Jek

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T0MMY

posted on 3/5/19 at 07:29 PM Reply With Quote
quote:
Originally posted by adithorp
I think it's for different uprights. Outer ones for Escort, inner for Sierra (I could be worng).


Ah ok, that makes sense then. It would have been nice to have a bit more track width though as I'm a bit concerned about the lack of steering lock compared to my MNR. Pretty sure I've had a few moments in that which wouldn't have been recoverable with the steering angle the Fury can get to.

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pigeondave

posted on 4/5/19 at 06:47 PM Reply With Quote
quote:
Originally posted by JekRankin
Adi,

Approximately how much did you need to space out the rack to eliminate the bump steer? 3deg toe change Iím bump seems quite a lot of bump steer in the chassis?Iíve got an order going out to the laser cutters soon, and I may just get a bunch of rack shims cut at the same time.

Jek


The pic I got off him looked like 20mm box section

I have the photo but the link wont share off google
if you want i can email the link to the email i got for you 10 years ago when you sorted the willwood group buy.

[Edited on 4/5/19 by pigeondave]

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AdamR20

posted on 4/5/19 at 08:24 PM Reply With Quote
Yeah, you need shed loads of shims, the bump steer as standard is horrendous! 20mm ish rings a bell for me too.
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JekRankin

posted on 5/5/19 at 08:41 AM Reply With Quote
quote:
Originally posted by pigeondave
quote:
Originally posted by JekRankin
Adi,

Approximately how much did you need to space out the rack to eliminate the bump steer? 3deg toe change Iím bump seems quite a lot of bump steer in the chassis?Iíve got an order going out to the laser cutters soon, and I may just get a bunch of rack shims cut at the same time.

Jek


The pic I got off him looked like 20mm box section

I have the photo but the link wont share off google
if you want i can email the link to the email i got for you 10 years ago when you sorted the willwood group buy.

[Edited on 4/5/19 by pigeondave]


Dave, that would me much appreciated, same email address. Thanks, Jek

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pigeondave

posted on 5/5/19 at 09:27 AM Reply With Quote
@Jek sent
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MadMaxx

posted on 22/5/19 at 03:16 AM Reply With Quote
Toe in/out is refered to both wheels.

Caster angle is refered to the single wheel.

Camber angle is refered to the single wheel and a vertical line or between both wheels as value of 3 degree for the single wheel seems to me quite a lot looking from the front of the car? So my doubt.





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adithorp

posted on 22/5/19 at 06:42 AM Reply With Quote
Yes toe I quoted is total across both wheels and Camber is per-wheel.





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adithorp

posted on 24/5/19 at 04:04 PM Reply With Quote
Pictures of the spacers I ended up with to correct my bump steer...

tota phone 104 by Adrian Thorp, on Flickr



[Edited on 24/5/19 by adithorp]





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