MK1 Racer (ALL BROKEN PHOTOBUCKET PICS FIXED) - Painted and out of the bodyshop....

At work, carpentry, we use a flat headed hex head bolt M6. Could these be used to bolt the floor up, all they need would be a 3mm counter bore (or slightly deeper to allow for a spring washer) that could be done with a spade bit bigger than the 15mm diameter head that have.

 

I use the same idea, but with an 020 g/box setup, although I do have a nylon mount one end, but its pretty hard!. I also run solid mounts either side and a rose jointed head steady (no front mount) and its fine. when you think about Bike all have solid engine mounts.

Lets you run a fixed exhaust system then, so no dropping off rubbers etc.

It is a little harsh, but no more so than poly inserts in std mounts IMO.

Never had an issue.

 

Sounds encouraging Ali, I've never run on the hills/sprints with toe out at the rear. The car came with toe out, but I found it tricky as you only get 4 runs, on cold tyres for around on minute, and you don't get time to get a proper feel for the car, so took it back to parallel. Better to have a compliant and predictable car when limited time to get a feel for it. However, I'm taking a slightly different tack when I rebuild the Tatty Golf, bigger wheels, proper A15 Avons etc, so you'll have so much grip its not a real issue Lol. Just need to add plenty of power and away....

Where are you measuring the 4mm from? I hear figures of 2mm toe out are best, on hills and sprints anyway.

I think dampers are so important, more so than springs really. These Konis I have should be good, I'm told they have a large range of adjustment, and separate bump and rebound, rose jointed etc.....more to mess up!! I'm using Inverted Bilsteins on the MK2 rally/sprint car, fixed damping, but they work really well....and so simple

I'm still unsure on spring rates but the top guys seem to run really soft springs, with lots of movement, but then again other quick guys run really hard set ups. I'm running 60/40 these days, harder at the front, the car is more compliant this way, but its so difficult to tell with hill climbs. I've won with all types of set ups, so difficult to tell what's best!! I do think I'll try a more aggressive set up next time, with rear toe, but I'm intending running a custom rear beam like a S1600 set up. Those things were super quick, on tarmac much like a UK hillclimb, so I need to get hold of a spec sheet for one of these and see how they were set.

Yeah, with tyre that wide traction will be an issue in a straight line (with big power) if you run too much camber, but you look at the big V8 Aussie touring cars and they run loads!! Of course they are not FWD, and that is the compromise, but the FWD super touring cars used to run quite a bit as well, its a balance I suppose.

The wheels look tidy, strong enough? Good price? I'm sure you mentioned it somewhere earlier, just being lazy and asking here Lol.

 

I've just ordered 90 shore rubber bushes for my c-mount. I'm blaming you and Ali if it goes wrong lol

 

Ali, if you can get in from above, which it looks like you can, simply replace the cap heads with T nuts. These are hammered in to the timber from underneath and the nuts are tightened from the top.


That's what I do


Plywood Aero? It'll never catch on lol

 

Thanks guys, good ideas and will give it some thought.

Yeah, you can run tight clearances on things like the exhaust. Also for example, my gearbox to lower strut bar is only a few mm.

I am not sure but I think you might even be responsible for some of this... I found a pic with sketches of engine mounts on CGTI and then I studied that and looked at how I could best apply it to my car. These sketches...











Thanks if so, got me thinking after seeing them and I could visualise what I needed to do.

The 4mm rear toe is extreme although it did generate good heat in the rears. I setup the car using string and axle stands around the car, so when I say 4mm toe out, the front edge of the rear rims sits 4mm further out of the car than the rear edge of the rims.

The camber is a bit of trial and error and good point on the Aussie V8's - won't know until I give it a go!

The wheels seem strong although tbh, wont know unless I bend one, but they have taken some big hits already. Called Jongbloed and are Chinese made, usually for MX-5's.

Will be fine!! My thinking was lots of single seaters literally have the engine bolted direct to chassis, so I thought why not lol

 

Next on the list was yet another job involving grinders and welders, but as it was going on at a similar stage, (and just to mix it up a little as well), the next part of the winter upgrades to document was the gearing.


As mentioned earlier, the main aim of all of the updates was to improve traction as much as possible, and the most obvious change after the wider wheels and tyres was the final drive ratio. When the 20vt was first installed it was done using a MK3 16v CDA code box, and it was built up with the Gemini semi helical 3-6 speed semi helical gear set (Sprint kit) and the original CDA 3.684 final drive ratio was retained. I was aware that a lot of people tend to fit a longer ratio from a diesel box or possibly even VR6, but as I was hopeful that there would be enough traction so that it could make use of the better acceleration available from the 3.684. well, unsurprisingly that didn't happen.


The turbo torque coupled with the skinny 200mm section slicks was simply too much with the 3.684 and it would spin up each gear all the way and including 5th gear. In the dry.
While I was doing the engine mounts and splitter I had been thinking about this and looking at the options for ratios. At this stage all I thought I could do was fit the 3.389 from a VR6, but I was a little worried that this could blunt the acceleration of the car, especially considering that it would have more grip to play with.


As luck would have it, at this point I happened to see HPR (Hugo) advertise a Gemini crown wheel and pinion (CWP / Final Drive) which was 3.53 bingo. This was pretty much half way between the MK3 16V (3.684) and the VR6 (3.389) and as an added bonus it was a semi-helical cut crown wheel which would be much stronger than the OEM helical cut gear. As a further bonus it was Gemini manufactured and nice that it keeps it in line with the 3-6 kit already installed. Also, both myself and Craig thought it should sound pretty cool!! (It does)


While checking the ratios I based my calcs on the speeds I could achieve with changing at 6750 rpm, as the original dyno plot showed that torque drops off after 7000 rpm, and I didnt want to be revving it out in 6th at bigger tracks with long straights (e.g Spa & the Ring). The calcs showed that the CDA 3.684 final drive would do 147 mph in 6th @ 6750 rpm, and although I suppose that sounds quite fast, I quickly realised its not. I had looked at the speed trap data for other competitors at Knockhill, and to do the lap times I was aiming for, I could see that the car would have to be not far off the limiter in 6th when in reverse direction. Considering that this is at a short circuit track like Knockhill and that the intention of some day doing Spa or Nurburgring in it, I knew it was too short.
The VR6 (3.389) would do 160mph at 6750 rpm which I thought was a bit too long. However, the Gemini 3.53 would do 153 mph @ 6750 rpm which seemed just right, and seeing as I can run to 7200 rpm if I needed to, the Gemini should do well over 160 mph if necessary for the longer tracks.


So I contacted Hugo and after he confirmed it would fit, we did the deal and he quickly sent it out. Very nicely made piece of kit...













I discussed it with Craig beforehand and went over the install, so we knew that it would not be a straight forward bolt on item, as unfortunately being a completely new output shaft to match the crown wheel, it meant almost completely stripping down the gear box to install the new CWP. Martin Emments (Hotgolf) had previously built up the box (and also did an excellent job, highly recommended), but as time was so short to the start of the season and both myself and Craig decided we wanted to tackle the job, we went ahead and stripped it down. The other reason for doing it ourselves was that I was a little paranoid about couriers, as losing something like the box at this point in time had the potential to end the season before it had even started.

Anyway, after researching as much as I could online, we started to strip it down and lay out all of the components in order of removal. I got some big pieces of cardboard to lay everything out and write down the description of what the part was, as this would make re-assembly so much easier.

At the strip down stage we were pretty nervous, as Martin had warned that unless pullers were in the perfect position, there was a real danger of chipping a tooth or breaking a syncro. Even getting 5th & 6th off had us scratching our heads a little, but after some logical thinking and some technical support from Martin, we were well on the way. Once 5th & 6th were off it was easy to build up some momentum and remove each gear from the output shaft before laying out on the cardboard.


Box off and quick check of the clutch pressure plate, all was fine and it has been working perfect so left it alone...





6th gear end case off. Fiddly getting some of the Gemini fittings out...





Starting with the puller...





Laying it all out...















Output shaft with 1st, 2nd and 3rd...





Side by side of stock CDA 3.684 Vs the Gemini 3.53

































After speaking to Martin and also reading workshop manuals, we knew at this stage that we had to remove the old shim from the casing, then fit the test shim, output shaft and then measure for the preload or float. We ordered the new shims from VW, removed the old one using some tiny flat heads whilst being careful not to damage anything, and then Craig installed the test shim. Once he had checked and double checked the measurments it was then clear to see which size of final shim we would need (cant remember what this was).


At this stage I got pretty busy with work and so Craig took on the job of re-assembly of the box. Having laid it all out methodically, this was fairly straight forward and before we knew it the box was back together, filled with new oil, and then back in the car. We didn't take any pics after this but you know what the box looks like anyway.

This change has been very effective and contributed to the increase in pace, as now the car will now take full throttle in 4th gear and above, and a good bit in 3rd, although I still need to feather throttle in 3rd to avoid wheelspin.


A new challenge but probably one of the more enjoyable bits to work on.

 

I don't know why these thumbnails are getting attached to the end of posts, but it seems to be uploaded pics that I have later deleted as I don't want them there, but once I delete them from within the post edit they still appear as thumbnails??

 

With that amount of power and wheel spin, have you considered traction control?

 

I`m certain you`ll be going over 153 down Dottinger Hohe ! Your car is lighter and more powerful than mine and I`m a whisker under 160 already. With a slipstream from something fast enough, I`ll easily get over 160.

Really liking these updates.

 

Yeah, they are my sketches Lol. I like to draw parts and modifications to see how they will work, often from a few different angles etc. to see if they clash or foul things - comes form my training in three dimensional illustration!!

I've just found I can post pics on here direct (after the Photobucket fiasco), that's a bit easier... and has got me interested again!! So going back to Nige's tee nuts idea, here is a fixing method I developed for fixing all sorts of things - but probably not for your ply under tray as I think tee nuts are ideal for that...anyhow...here it is for reference.



Use a hole cutter, say 50mm, to cut out an alloy disc from a sheet of alloy. Get a flange nut, say M6 or M8 and drill the centre of the alloy disc out so its about the same dia of the flats of the nut.



Get a tube the that's slightly larger than the outer dia of the nut points, then use it to hammer the disc over the flange nut, forcing the nut points in to the alloy disc, thus joining the two together.



Then apply a polyurethane adhesive to the disc and bond it to whatever you want to attach the nut to. Useful for bonding a fixed nut to alloy, GRP, steel etc without welding, or special fixings etc. and very cheap The surface area of the disc is large, so very strong, the alloy is light so not heavy. I find them useful.

 

Just as a matter of interest, all other things being equal a helical cut gear is actually stronger than straight (or Semi, as here)
All things being equal includes the material and tooth tooth shape, these are areas where aftermarket is often superior to OEM where they must produce mant units quickly and cheaply.
Straighter cuts do have less power loss
Often if a helical fails it is due to the lateral load and the case being forced apart, it can be extreme enough that the teeth no longer engage right and, hey presto, broken box. Hence why a main shaft bearing support works so well, it ties in the box so that you don't get that growth., of course helical will be slower to shift as well as it can only move the speed of the tooth angle allows, but when you are comparing dog boxes this is a minsule amout of time (although a significant percentage)

 

I have already added in ABS reluctor rings all round and the uprights/stub axles are ready to accept hall sensors, I just couldn't get a big enough gap in the calendar to send the ECU back for the TC upgrade, but this should be happening over winter. Even though TC has been very much in the long term plan, I still wanted to do everything else possible to maximise traction rather than relying on TC as a quick fix.

Cheers. Yeah, DH would be pushing it with the old CWP.

With the new 3.53 I could increase the limiter slightly, as even a 300 rpm increase to 7,500rpm should see 170mph - aero permitting... Not sure how power a brick shaped golf needs to overcome the air pressure at that speed, although as you say, with a tow it would be possible.

Thanks Tony - good to have for info

Also, know what you mean on the photos. So much easier now and gets the interest back.

Yes, that sounds about right as helical gears have a greater load bearing surface area due to having more teeth engaging. Hopefully the semi-helical gears in this box help to reduce any axial/thrust loads, and the gearbox casing and gears stay intact!!

One of the winter upgrades planned is a pinion brace to be fitted inside the bellhousing - annoyed I did not fit this at the same time as the above work!




The next stage is back to messy work and it was a job that I had been putting off for some time. I had actually started and almost finished this before we did the gearbox, so the work was started mid February. The problem was that when the cage had been modified by a Custom Cages 'specialist', they obviously didn't see the need to meet MSA blue book regs, as the rear stays had been welded direct to the shell and had not had any spreader plates installed.

See here....







... whereas, what it really needed was for proper spreader plates that met the MSA regs to be welded in. These are specified as a certain minimum surface area (I forget the exact size outlined in section K) and must be installed by welding to the shell before the tube is. The problem was that doing this back to front, i.e. putting the plates in after the cage is already into the car, was a major pain in the ass!!!!

This is what the plates should look like...







After trying to work out how to do it for ages, I decided I could minimise the disruption by first removing the bar in-between the turrets, and then I could try and cut the welds between the rear bars welded to the shell. Luckily I had recently bought a small compressor and a cheap air hacksaw - this was essential. Unfortunately it was still a long way from easy, but at least it made it possible.


So, cage surgery started with first cuts....











After a few hours of careful cutting I then had the rear bar out...











After inspecting the welds and checking for access with cutting tools, it was clear I would have to remove the top mount cups, so I drilled out the spot welds. These pics also show some additional cutting to create the gap for the new plates.











So I just kept on going at both sides until I had enough clearance for the plates...

















This was the working environment - not nice while upside down and trying to avoid sparks, grindings etc. Unfortunately I didn't dodge them well enough, as even though wearing full eye protection I managed to get a metal particle in my eye. After a day or so my eye got pretty bad and I ended up in A&E! The worst bit was going home and then having to get straight back into it, as with most of the work being lying upside down with a dremel, it was very difficult to not get cuttings flying everywhere and under glasses (full face protection too bulky around the bars).









At this stage I could cut the 3mm thick plates...





















Then I tacked them in before starting the full welding. For this I managed to use a big screwdriver and some wood to shift the cage enough to fully weld behind.






































Later on I cleaned up some of the weld splatter and sprayed some weld through primer before re-welding on the strut top cups...










I was very glad to not only have finished that, but also that I was able to sort it out at all, as at one stage I was pretty dubious I could work out a fix for it. It was important as living in the North of Scotland, I couldn't risk driving for 8 hours to an event down South and then have the car fail scrutineering

 

Bloody Nora, that was an awful job to do.

 

... for patience Ali !

 

What a pain that was, as I was reading I was thinking how annoying the job was!

Get yourself some motocross/skiing goggles these are close to your face and seal around your face and don't fall off either

I recently had a similar misfortune and ended up at the eye hospital first trip they thought it was all out but had to go back as some was left in my eye and going rusty!! Bloody painful

 

Don`t you just hate modifying roll cages whilst trying to retain the old tubes !

Nice job

 

Wow, what a ass of a job! Well done for completing it and it actually looks pretty neat and tidy! Good work!

 

Thanks for all the comments and on-going enthusiasm for the build

It was the full face style ones you mention similar to skiing goggles, they have proper safety glass as well, but I think I must have got the particle when removing them and something has fallen from them or even my hair! The particle going rusty is the problem and they had to scrape off the rust spot - not cool lol

Absolutely!!



After the gearbox and the cage was a nice change as it was new things arriving. Over last winter I had already collected most of the parts required, but the brakes and the tyres were still required and so were ordered up.

The work required with the brakes was really just limited to new caliper brackets as the bolt hole spacing from MK1 to MK2 hubs is different, and iirc the bells could pretty much stay the same. However, I wanted to change the bells from a solid bolted set to a fully floating setup, so I ordered new bells as well as brackets. I called BG Developments and was told that due to the anodizing process it was best to go with new bells, and so I kept the old ones as spares.

I sent a wheel down to them complete with disc and hub upright assembly, so they were able to get the brackets spot on. This now gives me a 305mm fully floating setup and I already had the AP Racing pro 4 pot calipers from the previous stage. I also changed the old pads out for Pagid RST's to go to a more aggressive compound from previous.


Will let the pics do the talking, but they look good and work pretty good too...

 

NSFW! Haha. Awesome.