180 Track Car Build

[ZS Phil]

Been collecting parts over the last few months so decided this week to get her in the garage and make a start.

Planned list of changes to make:

- Change coilovers
- Raise ride height slightly to accommodate slicks
- Improve brakes (new pads, hoses, fluid and rear discs)
- Improve gear ratios and fit LSD
- Fit light-weight flywheel and diesel clutch
- Fit manifolds
- Change the belts and possibly cams at same time
- Change broken balance VIS motor
- Remap to avoid running too lean
- Remove more weight

Since the last update I have had it on a weigh bridge. Not doing too bad but could lose more.
1120kg with both seats in and 3/4 tank fuel.

In this department next steps are to further lighten panels, particularly the bonnet, fit plastic windows and a light weight blower unit.


For now though I've started with jobs on the chassis.

Slightly controversially and in some ways against my own principles I have decided to try modified dampers (fronts shortened and valving to suit stiffer springs) as I felt body roll was too much with the previous set-up. On very hard cornering the fronts were sat on the bump stops.
There were a few options-
-Raise it up and keep the springs and dampers the same
-Maintain the ride height and just shorten the front dampers (this would do nothing for the body roll)
-As above with the addition of stiffer ARBs to address body roll
-Maintain standard ARBs and fit stiffer springs/dampers

The last track day I did there were 2 other ZS's out, both running significantly higher spring rates than me and the difference in pace through the corners was marked (one was a respected Cockshoot car the other a keen "hobbyist"). OK, there are lots of other variables to consider however after talking to the owners and taking these into consideration I was suitably convinced to at least give it a try. I had my other set of GAZ coilovers off the TD (now SORN) so off they went with a list of changes:

New specs:
850 lb/in front (Previously 550)
600 lb/in rear (Previously 330)
Front dampers shortened by 10mm
All new rods / oil / seals
Valving to suit new spring rates
Helper springs all round

So this is how they came back (shame they didn't paint them this time)






To show the difference in damper length, standard on left, shortened on right:




I have also raised the ride height slightly too
From center of hub to bottom of wheel arch is now 31.7cm front and rear. This was previously 30cm front and rear so the rake has remained constant. This should create enough space at the front to accommodate the extra width and profile of the slicks I've acquired.
Once I've got them mounted on some rims I'll re-assess this.


I've also made a start on the brakes:

After the last track day the rear discs and pads (blue stuff) were looking pretty sorry for themselves and the front pads (yellow stuff) were just over half worn so figured since I have now SORN the car and it isn't being used on the road, I might as well upgrade to Blue Stuff all round.







Rears- bin:


Fronts (do as spares)


Decided to give some "Wezmoto" lines a try whilst I was at it, heard good things about the motorcycle stuff they do and from pictures look identical to HEL:







Quality seems great although I was concerned by this "double flare" fitting they share with HEL. Check out the standard cone shape on the standard hose compared to the concave fitting of the new hose.
After a bit of research it seems lots of people who have fitted HEL hoses have been in a similar dilemma (various makes and models) however in all cases people have been reassured by HEL that it works with both bubble flare and double flare hard pipes and will seal. Just to be 100% sure I contacted Wezmoto who said exactly the same thing so decided to fit and push like Chris Hoy on the brake pedal to test- they don't leak.








Routing the front hose required some improvisation so I took a few pics for the benefit of anybody else wanting to use these:



Nifty little trick using the old copper sealing washer and cable ties, stops any chafing against the surface that the hose is tied to.



Just to show the clear run:







Other side to do tomorrow

[Mark S]

all that green hurts my eyes.

for road and track I would say your old spring rates were fine, the new rates are mega hard, even for slicks.
I would first look at driving style/technique for you roll issues.

how have you calculated your shortened damper?
How much does it drop with the weight of the car?
Can it provide adequate bump & rebound?

[talkingcars]

Good to see that the brake hoses come complete with the fixings.

[JOHNDQ]

Looks good mate

[ZS Phil]

Lime green is a guilty pleasure haha

Yes, I'm a bit concerned with how stiff the springs are as the previous set-up felt nice and smooth and predictable on track, just the issue of excess body roll and damper length.
Shaun said from the off that the he thought the fronts were too soft and from having seen the difference in cornering pace between mine and Howards and Martins cars at the last track day, both of which run stiffer springs I'm happy to at least give it a try.
If I don't like it I'll just change them back over

I'm aware that it's probably a less than ideal "quick fix" to get the most out of an otherwise stock chassis (apart from the geometry settings- which hopefully camber at least will be held more constant with the stiffer suspension).

How have I calculated damper length: Truth be told it's a guesstimate based on the fact that there was no point removing more than I have done because the tyre would be getting too close to the top of the arch, it only bottomed out previously on the longest hardest corners not all the time, combined with the new stiffer springs and raised height I think I've removed enough to allow the piston to sit more mid-travel without the risk of bumping out.

How much does it drop with the weight of the car? I haven't measured sag. At the minute though, because I've only done one side the helper springs are fully compressed with the wheel off. I figured this is either because they are not required at the new ride height or because the other side is lower and compressed because of the way the car is jacked so the ARB will be compressing the side I was working on.

Can they provide adequate bump and rebound? At this stage I don't know. I have asked for valving to suit the spring rates so only track time will tell. If you mean will the dampers cope with the extra stress of the increased bump and rebound resistance I've no idea. I have taken advice from others who use this set-up and theirs seem to do ok in terms of longevity.

Without the luxury of computer modelling it's all "best guess" factoring in what has worked for others over the years. Whether it will work for me is another matter but at this stage I'm happy to take advice

[ZS Phil]

Originally Posted by talkingcars

Good to see that the brake hoses come complete with the fixings.

The rears bolt straight on but the fronts require some improvisation if you have coilovers without the brackets. My biggest concern was that difference in the mating surface between the pipes.

Originally Posted by JOHNDQ

Looks good mate

Thnaks! Hopefully it will feel better too

[Mark S]

I would be surprised if gaz changed any valving in the dampers.

You will find a one or two 'click' window with the gaz dampers, people talk about wet and dry settings on the gaz with x number of clicks from zero, in my mind they either don't work or don't work unless they accidentally stumbled on that perfect click!
I found 2 extra clicks (even 1 click at times) took you out of the window and into the non working zone, either they were as hard as scaffolding poles or offered no damping whatsoever.

Could it be that the front end feels/felt soft because the dampers weren't damping?

[Mark S]

the pbs pads are well worth a look (and the guy is up your way) when the blue stuff stop working with 50% pad left.

[ZS Phil]

I must admit, I was a bit suspect as to what they actually do so I called them up and spoke to the guy doing the work. He assured me that the valving has been changed, on the minimum setting they certainly put up more of a fight to move the rods by hand than the other set do.
No dyno report or anything like that tough.

That said, he also said that they were out of stock of helper springs so would send tender springs instead. Either he doesn't know the difference or was just trying to fob me off. Made sure they sent helpers once they arrived in stock.

The more I read and learn about these things, the more I realise that GAZ are not the weapon of choice if I was going to take this to the next level.

I'll have to experiment to find this window but as a start point they will all be set to the middle number of clicks and adjusted from there. I know the knob alters both bump and rebound together but how exactly it is altered and by how much is all a bit vague.

Yeh, Shaun mentioned PBS pads or even carbone lorraine, is that what you ran?

[Mark S]

the silver car ran blue then pbs, after 3 hours of racing and a few track days the pbs are still there and working!

you get one or the other (bump or rebound) with gaz, it is a comprimise and they are called dampers in the loosest possible sense.
But they can still be made to work and the car can still be fast, the silver 1800 is evidence of that.