Very budget track build

[Clarkj93]

Smoothed out the sunroof panel with a Mallet and some tiger seal. It's much better fit now but does look quite rough not for the faint hearted or the garage queen owners.





Interior has all been cleaned up



Been trying to wire a cut off switch in the fuel pump, but this mysterious relay cannot be found ended up wiring in the starter relay instead via some poor technical documentation I followed online. I've just left the cut off switch in place, see no reason to cut off the starter relay but it's more effort to undo then leave so oh well



4 week wait but bucket seat turned up! Great service from GSM, highly recommend.









Actually drove the car this week for the first time in almost 4 months. Feels like it's gone to stage 2 due to how much louder it is in the cabin and how noticeably faster it is. The non res miltek cat back still doesn't drone even when the interiors stripped mind so shows how good of an oem + exhaust that is. It does feel a little stiffer also, centre of gravity will now be lower and with the car being lighter now the spring rate will feel a little stiffer too.

Next job is RUST! The jacking points and the interior side of the sills need doing. Idea is to use brushes and wire wheels, then a rust converter and then some simple black hammerstein stuff. Por-15 is good but it doesn't work well on an area that gets hammered by debris and Jack's coming into contact with it.

 Il be doing the Super pro bushes on the rear too, not sure what I'm going to do with the subframe yet... don't really want to leave the car on axle stands for a week or so while I refurb the subframe on a wonky drive way. Its alright for a day as the Jack's in place just in case but overnight I get a little concerned...

I have an idea too for suspension.... the b14 coiliver set uses progressive springs and fits oem front top mounts. My idea is currently to use a Compbrake adjustable top mount that's meant for non oem fitment as this will allow me to use a linear spring on the front,  and the rear should be a straight swap easily enough. So not only a linear spring but a stiffer one. My research tells me the springs should be 250 front/285 rear, my research also tells me that going up 2kg/mm of spring rate should not be an issue for the valving of the damper, beyond 2kg supposedly is quite safe up until 4kg when things become unpredictable. So I'm thinking of going 375 front/400 rear. It kinda sounds like I should just upgrade the coilovers but think personally I'd rather leave it until I can justify getting something really quality and custom to my application and not just off the shelf with predicted spring rates and valving, plus I can use these top mounts for other coilivers.

I may even get around to finally fitting the TT hubs! Maybe anyway!

[pudding]

I love how generous the Germans are with interior paint 

Yeah you'll need different spring rates now you've stripped it out.  You usually you go softer as there's less sprung mass to hold up.  70/60n/mm is fairly typical for a hot hatch in the coilover market (dunno what that is in lbs/in) so maybe try 50/50?  Nicely balanced out there 

[Clarkj93]

Yeah literally no need to paint the interior, its got enough overspray to count as painted on a well galvanised steel body.

So currently ( I will have to check the spring rate myself when they're off the car) the spring rates are apparantally on the b14:
Front = 250lb/in - 4.5kg/mm - 43.8N/mm
Rear =  285 lb/in - 5.1kg/mm - 49.9N/mm

I'm proposing:
Front = 375lb/in - 6.7kg/mm - 65.7N/mm
Rear =  400lb/in - 7.1kg/mm - 70.1N/mm

So the spring rates will be far closer to what I see the full on expensive race coilovers using (around 80N/mm-120N/mm typically from info I've seen). Yellowspeed race coilovers use around 160N/mm springs on the front though.... which is not far off the stiffest spring rate most manufacturers of race springs even make!

Most setups I see are stiffer up front as the front is quite chunky compared to the rear where as this setup is and will be the other way around but having front and rear adjustable 24mm Arb's I can always get closer to that setup by going full stiff up front and full soft on rear if that is what works best after some trial and error.

[bobby_fodge]

Can you slide the seat backwards and forwards with those side mounts?

[Clarkj93]

Can you slide the seat backwards and forwards with those side mounts?

Mine are solid mounted but sparco make a cheap set of runners that can go in between, it will just mean the seat is ever so slightly higher.

[Clarkj93]

Front SP bushes turned up.



Got the new adjustable Combrake top mounts ready to fit with linear springs I need to order. Compbrake get a mix of reviews on quality but these top mounts do look and feel very nice, time will tell how robust they are.



So next step is to attach a linear spring, the Compbrake top mount will accept a 2 to 2.5 inch ID spring and the Bilstein spring perch is for 2.5 inch ID springs so it is simple enough to just stick a 2.5 inch ID spring in there, the springs are also just over 8 inches long. I tried calculating the spring rate of the progressive spring, its quite tricky to be 100% confident like you could be with a linear spring. Here is the method I used to figure it out:




This article was useful https://shocktherapyst.com/the-truth-about-dual-rate-springs/#:~:text=The%20formula%20for%20a%20dual,125%20lb%20combined%20spring%20rate. it made me realise that these "progressive" springs on the market and really just cheap to produce dual rate springs.

So after realising this I calculated the spring rates as Rate 1 and Rate 2. Rate 1 being the initial softer rate and Rate 2 being the stiffer remaining rate. I split them by the coils that had protective tubing on and the ones that did not, the reason for this is as the article explains that a dual rate spring like this will result in Rate 1 fully binding together and taken out of the equation ad then Rate 2 taking over so I thought it was semi-safe to assume that coils with the tubing are the ones that bind and therefor are part of Rate 1.



So this gave me the results for the front spring:
Rate 1 =  225 lb/inch - 4 kg/mm - 39 N/mm
Rate 2 = 343 lb/inch - 6 kg/mm - 60 N/mm

slightly different to the results I found on this thread a while back https://www.mk5golfgti.co.uk/forum/index.php?topic=31277.0

I'll paste it here:
B16 PSS 10 Golf 5:
215 f, 285 r (both progressive)
Front: E4-FD1-Y704A00 = progressive; initial rate 32.8N/mm (approx 190lbs/in), secondary rate 43.4N/mm (approx 250lbs/in)
Rear: E4-FD1-Y754A00 = progressive; initial rate 33.0N/mm (approx 190lbs/in), secondary rate 50.1N/mm (approx 285lbs/in)
At static height:

>>  39 and 51 N/mm  (R32 B16: 250F and 285R lbs/inch)

So on that basis and my previous understanding that an additional spring rate of 2kg/mm  OR 112 lb/inch OR 20 N/mm should be well within the ideal tolerances of the valving.

So I will most likely opt for Faulkner race spring of the following rate:
450 pounds/inch - 8 kg/mm - 79 N/mm

A little stiffer than my calculations OR a lot stiffer if I have ballsed the calculations up and the previous thread got it right but just going to linear I imagine will have the effect of feeling like a stiffer spring rate anyway as there is not any initial "give" like the dual rate stuff.

[Scheero1312]

I though of a good idea for the intake on your track build.

Take out the bottom fog light have a tube or pipe running from where the fog light used to be and to a cold air intake.

Let me know if you try this and how it goes.

[Clarkj93]

I though of a good idea for the intake on your track build.

Take out the bottom fog light have a tube or pipe running from where the fog light used to be and to a cold air intake.

Let me know if you try this and how it goes.

1 step ahead of you not sure how effective it is mind you, would be better if it was directed to a sealed up alloy air box I think

[Clarkj93]

So a lot of trial and error, wrong springs, drilling, angle grinding and we have a finished setup. In the end I used the b14 damper, with 7 inch 450 pound springs at front, with a Compbrake 2.25 inch top hat and Compbrake adjustable top mount. Anything bigger than 7 inch is like OEM ride height at this stiffness I found.







Also cleaned up the TT arms and fitted with super pro bushes.







The mk5 consoles with TT solid bushes are now in a box after being cleaned up if anyone wants them



Love a suspension shot...





I still need to finish off 1 or 2 little jobs on front end, sort out some more efficient brake ducting and then onto the rear, found a local shop that is happy to sand blast and powder coat the subframe and control arms for 300 quid so may get that done in grey/silver so matches the front control arms and subframe and then fit with SP bushes all around. Will be a little while before I can do a real test drive on the road of how this setup behaves.

 Also got my eyes on a Varley red top 25 battery too which is about 10-12kg further weight saving which I think I will mount behind where the passenger seat would be.

[Clarkj93]

Very frustrating update - having paid for and tried multiple spring lengths along with helper springs I've concluded that its just not possible to use a linear spring with these dampers without causing other issues.

Due to the damper design maybe being too long that it gives the following issues:

- a 450 pound 7 inch spring requires a helper spring to get a good ride height, however this the spring perches are obviously not designed for this in mind as the helper perch and spring perch come into contact as you can see



- Also at the ideal ride height there is only half an inch of bump travel.... which is 1/8th of the dampers travel which is very detrimental and may even be un-driveable. Raising the car to half about 50% of total travel for bump which is the minimum you would want really makes the ride height so high it may as well be an off-roader build instead. You might be able to see from the pics how high it is, although in real life it looks way worse!









So yeah the resulting options are....

- use a very very soft linear spring, that will give a consistent feel, allow for more camber but be way too soft on the track
- use a stiffer linear spring, that will give a consistent feel, allow for more camber but have almost no bump travel
- use a stiffer linear spring, that will give a consistent feel, allow for more camber but very very high ride height and then high CoG
- continue to use bilstein springs, that are overly soft before being loaded up on turn-in and only allow the car to a max of -2.3 deg camber but allow for a ideal ride height and so a much lower CoG

So in my opinion the only option is to continue to run bilsteins, pretty crappy result after all the effort and money I've put into this.

This article sums up the fundamentals well here, although took me some time to really grasp some aspects and do some other research on top https://suspensionsecrets.co.uk/coilovers-installing-and-setting-ride-height-correctly/.

I know a lot more about suspension than I did a month ago but left feeling quite deflated after wasting quite a number of hours of taking the suspension on and off and wasting a good chunk of money over a spring and solid top mount collection....

So I think next I will refit the bilstein springs, sort out some better brake ducting and get the thing booked into retro resus then for a few jobs:
- rear control arms refurbished and bushings changed ( I took some of the arms off the other day, bushings are awful and I cannot be bothered with doing it myself now)
- ditch the aircon and majority of air bags
- corner weight

I was going to switch to a Varley red top battery and get it relocated towards the rear of the car with an internal cut off switch but think I may just look to save some cost for now and maybe stick in a basic toyota aygo battery or something for 40 quid off of ebay as a quick cheap solution for now that still saves 7+kg.

If anyone does want a brand new set of Compbrake top mounts, or even any length of 450/375 pound springs, let me know.

[pudding]

Welcome to the wonderful & annoying world of suspension tuning 

The one thing I loved about the Ohlins was they were just fit and forget.  All the preloads, damper travel, ride height etc was all worked out, and no buggering about with helper springs.  They don't even use them at all, which is another great thing.  It's literally just mounting the spring perch threads at the right position on the strut for the task at hand. 

I'm guessing the Bilsteins are designed to ride a lot lower, so the threads are a lot further down the strut, which is why you're possibly struggling?  Did you experiment with 8" front springs to ditch the helpers?

I would mount the stock battery in the boot personally. It's 20Kg in a better place for weight distribution and has none of the draw backs of a small battery.  Don't forget the PAS eats a LOT of current.

[Clarkj93]

Welcome to the wonderful & annoying world of suspension tuning 

The one thing I loved about the Ohlins was they were just fit and forget.  All the preloads, damper travel, ride height etc was all worked out, and no buggering about with helper springs.  They don't even use them at all, which is another great thing.  It's literally just mounting the spring perch threads at the right position on the strut for the task at hand. 

I'm guessing the Bilsteins are designed to ride a lot lower, so the threads are a lot further down the strut, which is why you're possibly struggling?  Did you experiment with 8" front springs to ditch the helpers?

I would mount the stock battery in the boot personally. It's 20Kg in a better place for weight distribution and has none of the draw backs of a small battery.  Don't forget the PAS eats a LOT of current.

Yeah lesson learnt! Yeah it's definitely made me question more off the shelf stuff that's a bit more on the reasonable price side with no bump tuning available and poor set up guides from the manufacturer whether its actually quite limited setup in reality.

I think after learning what I know now for around the 1k/1.2k mark I'd either go for something custom so I can nag them into getting the right ride height and travel or something with travel adjustment built in so I can get it just right.

But yeah you do know you're in safe hands with the big boy names like Ohlins, AST, Nitron etc.

Yeah I tried 8 inches ones and it was just massively too high, like oem height at absolute best and still not great travel left either.

Battery is buggered I think, takes forever to charge, and lasts no time at all, I found some acid residue under neath it so I'm going to take that as a sign to replace . You are right but I'm just feeling fed up now  so thinking of just replacing with a very cheap citroen c1 battery for now and re think the battery situation in a year or 2. Ahhh did not think about PAS... definitely need to give that some thought actually!

[pudding]

It's all valuable experience you can't buy 

All this faffing about makes you realise why OEMs do the things the way they do with suspension    You wouldn't think simple springs and dampers could be so complicated, not to mention all the geometry and roll centre related stuff on top!

Yeah the more popular coilover kits tend to be a bit too generic and cover a lot of versions of the same car, where as the higher end stuff is model/spec specific.  I thought it was strange when I got my Ohlins that the ride height adjustment was only +/- 15mm.  Then I saw they literally only give you an inch of threads on the front struts    They basically pre-configured it to lower the car 20mm. And sure enough, every corner was dropped exactly that. No helpers and only 2mm of spring preload. It was like fitting fixed strut suspension, it just went on and worked a treat    Shame the cost of entry to such convenience is so high.

I'm just not a fan of helpers, or having to wind in shed loads of spring preload to raise the car up, it just ruins the ride and reduces travel.

Shame the taller springs didn't work out.  You would think that would be an obvious fix, but clearly not!

Custom can work out really well.  I think I mentioned before, but years ago Gaz knocked up a set of Gold coilovers for me, based on gross vehicle and axle weights, desired height range, stiffness preferences, majority use (road or track) etc etc, and that worked out great. It just plopped on and worked like the Ohlins  The only downside was the quality. The piston rods started shedding it's chrome plating after about 12 months    Couldn't fault the ride or handling though, because it was made that specific car 

Unfortunately, that or the big boy kits might be the only way achieve what you want, or just stick a B12 kit on there and be done with it 

Oh well, don't give up. You're on the right track, pun intended 

Did you try longer helpers and shorter mains?

[Clarkj93]

Thanks for making me feel better about it Yeah Gaz have been on radar a while for that custom setup but think if I do take a punt on them need to be ready to get a rebuild at about 300 odd quid every couple of years... hopefully they last longer than 12 months these days! I do now have the top mounts they supply their dampers with so that is a bit of influence.

Yeah you're right in terms of oem design, the TT is an example of that, the amount it would cost to design and engineer a bunch of alloy hubs and wishbones wirh different geometry just to make it a little sportier on top of the various designs they alresdy make for other mk5 era cars, would have thought they'd just stick some tougher dampers on and be done with it.

Yeah think you're right there. May as well just wirh this setup now and only re think it once I either go big boy or custom via Gaz. Some light weight hubs is probably the only near future suspension upgrade I imagine for now!

I tried 5,6,7 and 8 inch springs just to be sure. Told you I did waste a good chunk there

[pudding]

£300 is pretty good  Much better than the UK outfits that want £1000 to rebuild Ohlins coilovers  Needless to say, they are still rotting in my parts cupboard    I might sneak them onto the MK6 TDI when the missus isn't looking    Also got the MK7.5R front brakes to chuck on as well 

Yeah I reckon they've addressed the quality issues by now.  It was circa 2006 I got a set and they hadn't been in operation that long at that point. Yeah I used the Comp brake top mounts on my Corrado many moons ago.  I would recommend switching out the spherical bearings for NMB or Aurora (Merlin Motorsport sell them) as the ones supplied in mine only lasted 1000 miles 

Yeah exactly, those lengths are what it takes merely to run a car low whilst keeping the roll centre where it needs to be    It's a hell of a lot of changes over a Golf! The TT is easily the sportiest setup car of the Golf platform cars 

   Oh well, I guess all that faff is what we pay someone else to figure out