Prawn and BigAls A3 Track Car

[Golfyste]

Bouncy bouncy!!
..... or actually not so bouncy bouncy with the new rates haha

 

[Prawn]

Looks like Ste guessed it

Out with the KW V3 that have served me so well for the last 5 years.

In with these!





Gaz Golds - Custom built to my specified spring rates, and valved accordingly







2 sets of springs, to allow a bit of experiementation and some mixing and matching front and rear:

a set at 550lb all round:



And a set at 650lb all round:



Rates were decided upon after lots of deliberation and input from various people tracking and racing the same chassis in various places on various tyres.
From some hardcore VW racers telling me I wanted 800 minimum on the rear and 700 on the front if using slicks, to Tony and Rich in Combe Saloons running 450/450 in a lighter car on road tyres. I decided I liked the idea of square rates front and rear. This should give a reasonably tail happy car, which suits my driving style and dials out all the understeer. I'm hoping it'll compliment the plate diff nicely too.

I've got the option of running 650lb front and 550lb rear if I find square rates too tail happy, and I've got the option of 550 fronts and 650 rears if I find the square rates understeer. replacement springs are very cheap if I decide to go softer all round, or further at just one end.

I have of course also got the option of going stiffer / softer, or completely removing an ARB at either end too in my quest to tailor it to my needs. With such stiffer rates the springs themselves should largely take care of body roll now. There is a school of thought that does away with the front arb all together to 'decouple' the front axle and allow the inside tyre to drop and get more grip.

There are those who will shun the purchase and say my KWs were better, and in terms of outright quality, I'm sure that's true, but regardless of quality, my V3's have become unsuitable for my needs running aero and slicks, and KW were absolutely not interested in revalving, only in selling me a complete motorsport kit for 3x what the Gaz cost.

What I've got here is a kit that's custom built and valved / sprung to my exact requirements, and also easily and cheaply rebuild or revalved in the UK.

It's potentially a slight dip in quality, and I'll be taking measures to protect them to keep them in top condition for as long as possible, but I'm really excited to be trying a new setup with some more suitable rates, after tracking the car for so long on the stock rates KW supply for a sporty road car setup.

Now, if only I had an engine to be able to go and test them

 

[badger5]

"plate diff" ? sneaky... when did it get one of those then?

 

[Rainbird]

Coming soon to a crustacean near you

 

[Prawn]

"plate diff" ? sneaky... when did it get one of those then?

Coming soon to a crustacean near you

A mutually beneficial arrangement has been entered into between myself and the above mentioned R'Bird

Said deal results in 'Bird recieving an 02M box with a peloquin diff, and Prawn recieving some monies towards a shiney new NXG Plate diff

 

[Rainbird]

It does mean I need to dig out the spare box from the depths of my overflowing garage, stick it in the boot with the AGU head and pay you a visit at some point though, which on current work schedule is tricky but on current PrawnTime needs to be done sooner rather than later. Will sort something out via WA (Y)

 

[Alex C]

lbs per inch?

 

[antwan64og]

Ooooooh, large port head from Rainbird!

You know you need a race spec subframe and tubular control arms from USRT.

You can always practice those welding skills and brace the rear arm with rose jointed supports while you're at it

 

[Prawn]

yes Alex, lb per inch.

650 are just shy of 12kg/mm

550 are just shy of 10kg/mm

 

[Prawn]

Ooooooh, large port head from Rainbird!

You know you need a race spec subframe and tubular control arms from USRT.

You can always practice those welding skills and brace the rear arm with rose jointed supports while you're at it

Large port from R'Bird yup All wangled into a deal involving a spare gearbox and some money in exchange for my Diff'd box

I've actually got a spare rear beam from George Seamons old LCR. When this current round of work is done, and I've had half a chance to help Erik out too later in the year, I'll get the spare beam shot blasted and look at adding triangulation over the winter hopefully. that all ties in with a plan to delete the spare wheel well though, and move the exhaust to the centre, which in turns lead to a plan for a diffuser. but seeing as I've currently got no engine I think I'm getting a little carried away here

 

[Rainbird]

On the subject of tubular subframes/wishbones, I've often thought about taking a load of measurements from the spare setup in the garage with a view to building my own down the line. To be honest, it's a long way off for my own car, but when the time comes I'll likely use the standard kit to knock up a jig and look at churning out a couple of sets (a couple of friends locally have also expressed a future interest so economies of scale win on that front). Sod paying the best part of a grand for some tube fashioned into a subframe and arms, mini-projects are fun!

 

[sparrow]

I've actually got a spare rear beam from George Seamons old LCR. When this current round of work is done, and I've had half a chance to help Erik out too later in the year, I'll get the spare beam shot blasted and look at adding triangulation over the winter hopefully. that all ties in with a plan to delete the spare wheel well though, and move the exhaust to the centre, which in turns lead to a plan for a diffuser. but seeing as I've currently got no engine I think I'm getting a little carried away here

Nothing wrong with planning ahead. You should see the list for the Golf...

 

[desertstorm]

Looking forward to what you think of the Gaz Golds Nick, I have been looking around for suspension for the TT and they seem to get a good write up, the fact that they are customised by GAZ is a definite plus point and the price seems quite reasonable. They looked a bit more blingy when they used to be gold but I suspect black is cheaper and who needs bling on a track car.

 

[Lavis89]

On the subject of tubular subframes/wishbones, I've often thought about taking a load of measurements from the spare setup in the garage with a view to building my own down the line. To be honest, it's a long way off for my own car, but when the time comes I'll likely use the standard kit to knock up a jig and look at churning out a couple of sets (a couple of friends locally have also expressed a future interest so economies of scale win on that front). Sod paying the best part of a grand for some tube fashioned into a subframe and arms, mini-projects are fun!

Am i right in thinking you're still around the SW kinda area? If so then let me know once you've got the jig all sorted, i'm sure i can lend some of my time to pop over and assist with the welding if need be. TIG welder qualified up to nuclear standards

 

[Rainbird]

Shall do! I'm actually working in Wales for a couple of months, having left the RN just before Christmas (nuclear isn't so fun when you're spending months underwater with it - quite monotonous and dull!) but still living in Ivybridge and will be permanently based at home again from July. I'm sure we could figure something out and get some nice parts sorted all round. As I said, I won't be doing it for a while yet (if at all) but it's certainly an option when I start looking to shed weight from the car down the line

Sadly welding is something I'm entirely useless at - I've only had a very quick go and never had to do it in anger. Would love to learn to do it properly, perhaps when things are a little more steady (living at home again, wedding out the way etc) I'll book onto an evening course/similar.

Edit; Sorry Nick, got distracted. You can have your thread back now (provided you fill it with lots of pictures of things)

 

[Nigep]

Thought I`d sign up so I can see what`s happening

 

[sparrow]

Thought I`d sign up so I can see what`s happening

Hi Nige!

 

[Prawn]

To continue the trend of posting pictures of boxes, this arrived this week:

 

[Prawn]

I don't think it takes a genius to guess that one!

To compliment the new suspension, we have a brand new set of Silver Project adjustable top mounts too





After 4 1/2 years there was absolutely nothing wrong with mine, but I contacted SP and asked them for new bearings as a precaution for when new suspension went on, and they volunteered a full brand new set so that everything on the suspension is completely fresh

What awesome service! Thanks guys

 

[badger5]

same size/spec bearings in these? or something which lasts now?

 

[Prawn]

Same size Bill, but I'm told the bearings are higher quality from a different supplier.

Oddly, mine were the first pair in the UK, and in 4 1/2 years I only had one bearing failure, despite around 20k road miles and lots of kerb bashing in trackdays all this time!

 

[Prawn]

What i do plan to do is measure up these, and find a very high quality version from skf or similar, and press these into the spare lower sections I'll now have.

They will come with me as spares to trackdays like I've done previously

 

[Sam_]

Interesting re:spring rates going square. I run the H&R RSS which are ~900lb front and ~1100lb rear. I guess the higher rear rates is related to extra weight in the rear? It's obviously very firm but I don't mind it. That said I've still not tracked it yet. How much variance does the valving on the Gaz allow for? Usually around 100lb isn't it?

 

[Prawn]

The Quattro has a very different motion ratio at the back than the fwd car Sam.

I forget what the fwd chassis is exactly, but the Quattro is 0.63 MR at the back, meaning your 1100lb spring gives you a wheel rate of around 700lb.

On the fwd chassis the MR at the back is much closer to 1. From memory my 550lb spring will give around a 500lb wheel rate.

As you say, typically. You can go 2kg either side of what a shock is valved for (~100lb)

I asked Gaz to valve these with. Both rates in mind, so they should be valved for around a 600lb rate, giving me scope to go both stiffer and softer than the 2 options I've currently got.

Another real plus point to Gaz was the ease of sending it back to them to be revalved at really low cost and a quick turn around. Once you're onboard as a customer they seem keen to make sure you're 100%, which I really like.

 

[Sam_]

Do they cost a bomb? More than the V3?

 

[Prawn]

Considerably less at retail price, with some negotiation room too.

I'm sure kW are higher quality in the long term, but they had no interest in revalving my v3's, and would only offer a standard valving rebuild at upwards of £400, or sell me a Motorsport kit for many thousands. Neither of which were suitable options!

 

[SHUk]

Would you have considered BC RACING suspension...?

 

[RobinJI]

...
They looked a bit more blingy when they used to be gold but I suspect black is cheaper and who needs bling on a track car.

I'm sure nick could confirm, but I believe the new black finish is still and electroplate rather than paint, so probably isn't any cheaper. I think it's a revision they've made to try and improve the corrosion resistance.

...
I forget what the fwd chassis is exactly, but the Quattro is 0.63 MR at the back, meaning your 1100lb spring gives you a wheel rate of around 700lb.
···

Just as a point of interest, it would actually be around 440 as the motion ratio is squared when calculating wheel rate.

As I've said, I'll be really interested to see how you get on with the golds as they're almost certainly what I'll be putting on 924 when it's done. It's interesting to see parallel rear springs in your kit, I wouldn't have expected there to be enough space for them not to go coil-bound. I guess it may be something to be careful of if you change springs, although I'm sure gaz will more than look after you from that perspective.

Oh, also, the engine plans sound good!

 

[Prawn]

Would you have considered BC RACING suspension...?

Whilst BC are good, I wouldn’t have considered them no. We fitted them to Ashs LCR a few years ago, and he’s been very happy with them, but I don’t think they would have worked for me.


I’d say BC are towards the top end of the ‘off the shelf’ generic coilover units.


They’re good in that they come in a range of spring rate options to suit different applications, but they’re still a mass produced product from afar. Not easily built and revaled, and I’m not sure that the different rates as sold actually come with different valving, or if it’s a ‘one fits all’ damper with different springs thrown on at the time of dispatch.


Whilst they’re not a million miles apart price wise, BC are towards the top of the generic stuff, whilst Gaz are at the lower end of the truly custom customer specified products.


Of course, Time will tell if they’re any good, but I’m quietly hopeful, or I wouldn’t have bought them

I'm sure nick could confirm, but I believe the new black finish is still and electroplate rather than paint, so probably isn't any cheaper. I think it's a revision they've made to try and improve the corrosion resistance.




Just as a point of interest, it would actually be around 440 as the motion ratio is squared when calculating wheel rate.


As I've said, I'll be really interested to see how you get on with the golds as they're almost certainly what I'll be putting on 924 when it's done. It's interesting to see parallel rear springs in your kit, I wouldn't have expected there to be enough space for them not to go coil-bound. I guess it may be something to be careful of if you change springs, although I'm sure gaz will more than look after you from that perspective.


Oh, also, the engine plans sound good!

The black is still electroplating yes. They don’t appear to be painted. In the interests of extending lifespan I’ll be protecting these before they go on to keep them looking brand new for as long as possible.


Interesting that the wheel rate uses the MR², I didn’t realise that. From our discussions this is because both the lever length AND distance travelled are changed by the MR.


So for an S3 (take Sams as an example):


900lb front springs would give a wheel rate of 900x0.97² = 846lb/in


1100lb rears would give 1100 x 0.63² = 436lb/in


Quite an interesting shift when you look at it like that!


I really need to get under the A3 and measure the MR of the FWD chassis, just for my own interest!

 

[Stuart B]

Hi Prawn,

Did your autopsy show what went wrong with the engine?

Thanks

 

[finney]

Hi prawn, just read the whole 220 pages over the past few weeks! Awesome build, so similar to my situation it's unbelievable, I'm just starting with the car but I'm 3/4 through building my garage and I also ride trials, dunno if you still have time for that with little prawn!! Anyway, I was wondering if you ever got rid of the beep and brake buld warning light, I got rid of the beep permanently off mine just now!!! And best bit of all it was a free fix! Keep up the amazing work

Finney.

 

[Prawn]

Hi Prawn,

Did your autopsy show what went wrong with the engine?

Thanks

I still havn't found time to strip it yet Stuart! I've stripped my old AGU that blew last year, to extract the rods which I've sold:





And my new favourite paper weight:

Hi prawn, just read the whole 220 pages over the past few weeks! Awesome build, so similar to my situation it's unbelievable, I'm just starting with the car but I'm 3/4 through building my garage and I also ride trials, dunno if you still have time for that with little prawn!! Anyway, I was wondering if you ever got rid of the beep and brake buld warning light, I got rid of the beep permanently off mine just now!!! And best bit of all it was a free fix! Keep up the amazing work

Finney.

Cheers Finney! Sounds like a fun position to be in! Building your own garage is awesome, you get to have it exactly how you want it. Or at least that's the plan, unless you're like me, when you get some walls up and a roof and move in far too soon and ruin it all

I'd love to still ride trials, and won't ever sell my bike, but since getting glasses I've not been able to ride well at all. I can ride with contacts in, but Im not so great at getting contacts in, so I've not really bothered. I'm hoping to get out on the bke again this summer though, but time is not on my side!

I never did solve he brake light warning no. I got a new relay module that apparently can solve it, but never got it fitted before the engine died.

how did you solve it? Once I've installed my oil temp and pressure gauges I'll happily just desolder the buzzer, but without the gauges I don't dare lose the audible warnings.

Thanks again for the kind words make sure you start a thread for you own car when you've got some progress to share! Always good to see new stuff being done

 

[Stuart B]

lol #hulksmash cylinder 2.

I am loving your clam approach to all this. I suppose it doesn't matter, if all going to be rebuilt anyway.

how's the little one doing? babies change you - do you find yourself defending him just in case of danger, even when there's not one there.

 

[finney]

I just removed the buzzer from the back of the clocks so still get the warning just without the noise! Once I've made some progress I'll post up a build thread, mostly getting the garage sorted and a wish list of parts first!

 

[badger5]

I am loving your clam approach

lols at the typo... clams, prawns, seafood everywhere

sorry, I'll get my coat

 

[tcg]

I am loving your clam approach to all this

I guess he's just trawling for an answer

sorry, I'll get my coat

I'd better have that coat after you @badger5

 

[Erikn89nl]

He's been through some troubled waters recently, and I bet he feels gutted.
Right now, he needs these jokes like a fish needs a bicycle.
All I'm herring is a couple of big fish in a small pond.

sorry, I'll get my coat

I'd better have that coat after you @badger5

I'll leave with these two

 

[Stuart B]

I'll get my boat

 

[bigal 1]

I'll get my boat

Lets going fishing. Sea you down at the quay. We could put the lines out all night and drop anchor in the bay in the prawning and then get some sleep.

 

[badger5]

lol, what have we started - sorry nick