[ Trackday Prep ] Prism7guy's 306 Gti6 track car.

[Prism7guy 5]

No problem and thanks for the comlpiment.

As for my formula, I didn't really work out how much boost i'd be seeing as there seemed to be a few variables in what it could be from memory.

I basically looked at belt information and found the maximum speed the belt should run at, and used that to calculate the crank pulley diameter ensuring that with the drive ratio i wanted to achieve (14,000rpm for the smallest pulley) was faesible, theres a limit to how small you can go with the s/c pulley with it having a bearing pressed inside it.

As for s/c pullies, i wanted one which would run the s/c at the higest safe rpm which is 14,000 (I know others run theirs faster, which is supposed to be safe-ish for short periods, but i also know how i like to spend 30-40 minutes out on track sometimes where the engine revs sometimes don't drop below 4,500rpm during that time, so i wanted to try and keep some safety margin in there). The next pulley i basically dimensioned so it was 10% under driven compared to the small one, and the third one i just opted to have the s/c at 12,000rpm and that's the one i've been running since completing the setup.

 

I'm hopefully getting a plate diff this winter, once that's in i'll stick the smallest pulley on and get the ecu remapped to suit.

 

http://www.ebay.co.uk/itm/Performance-Tuning-Pulley-Set-for-Mercedes-Eaton-M62-Supercharger-A1110900380-/272401172566?hash=item3f6c600856:g:Fy0AAOSwoudW3LZ8

I found these guys on ebay, might be worth a shot if you're struggling with getting a pulley sorted, the price isnt too bad considering the work that goes into one.

 

If you have access to a lathe then with a lot of time and patience you could make your own, i bought a tool which uses these inserts to do mine, it would be possible with a manual lathe but i cheated and did mine on my CNC lathe at work, much easier

http://www.ebay.co.uk/itm/SVVBN-Turning-Lathe-Tool-16-x-16-With-VBMT-Insert-/282227090560?hash=item41b60ba480:g:MmgAAOSwnDZT1ynh

[Prism7guy 5]

I did a trackday at Brands Hatch on Saturday. The car made it there, took a day of abuse and got me home without a single issue.

The day started off wet and icy, the track was gritted during the briefing and was insanely slippy to start with. By dinner time a few dry lines were starting to appear in certain sections. The afternoon was pretty decent up until around 3pm when it started raining again, so i just messed around with oversteer for the last session since there was no point trying to be fast.

 

Few clips from the day:

 

 

 

 

 

[Prism7guy 5]

Quick update on this, plenty of work has been going on behind the scenes.

 

I did the PSCUK sprint day at Curborough earlier in the year, had a couple of issues. One was one of the bolts holding the satchshift gear lever to the rose joint in the exhaust tunnel came out, so i replaced that there then used a nord-lock washer and a bit of loctite when i got home to make sure it never happened again. (You can see me struggling to get gears in session 5 below)

The second issue was a mis-fire towards the end of the day. When i got home cylinder 4's spark plug was different to all the others, so i swapped out the plugs for all new (BCR8ES) and repaired the header tank which i had previously damaged the sealing face on causing it to overflow.

A compression test showed relatively normal cylinder pressures, all ranging from 200-220psi. You can hear the mis-fire slightly from session 2 onwards below.

 

IMG_8058 by Steve Count, on Flickr

 

IMG_8044 by Steve Count, on Flickr

 

IMG_8057 by Steve Count, on Flickr

 

IMG_8059 by Steve Count, on Flickr

 

 

 

 

 

 

 

Edited November 21, 2017 by Prism7guy

[Prism7guy 5]

After curborough it was clear i needed to get a proper diff. In went the 3J, running 40/90 ramp angles at around 75lbft preload. Minimal fettling was needed to get it to fit in the gearbox housing.

 

IMG_8078 by Steve Count, on Flickr

 

IMG_8127 by Steve Count, on Flickr

 

Once that was fitted i took it out for a test drive, which is when it became apparent that the head gasket had gone. Off came the head.

 

IMG_8169 by Steve Count, on Flickr

 

IMG_8174 by Steve Count, on Flickr

 

IMG_8175 by Steve Count, on Flickr

 

IMG_8176 by Steve Count, on Flickr

 

I sent the head off to be skimmed, asking for the minimum skim possible, new valve guides, 3 angle valve seats and valves cutting and an ultrasonic clean.

Unfortunately for me minimum was somehow misinterpreted as maximum so 0.75mm was skimmed off. I wasn't too happy to say the least as it was a virgin head at 137mm when i took it in.

 

IMG_8214 by Steve Count, on Flickr

Edited November 21, 2017 by Prism7guy

[Prism7guy 5]

The panic was now on as i had booked a trip to the nurburgring and due to go there at the end of the week. After weighing up my options the machinist offered to do a one day turnaround if i could source a spare head and do all the same work. A couple of phone calls later and Steve Heath whipped a head off a spare engine and met me half way between us. Top man!

Once i got home i stripped that down ready to drop off at the machinists and had a quick measure, unfortunately that measured 136.4mm which is once again in dangerous territory for valve-piston clearance, the minimum recommended being 136.8mm from memory.

It was pretty late at night at this point, and in my predicament i realised there was only one real alternative, so off came the sump, oil pump, windage tray and big end caps, and up went the pistons and con rods.

It was about 3:30am at this point, so i wrapped them up and dropped them off at my dads house as he would be driving past the machinists in the morning, raced home and managed a couple of hours sleep before work the next day.

I called the machinists and told them to pocket the valve cut outs 1mm deeper and move them outwards 0.5mm to compensate for the valves now being closer to the edge of the pistons with such a heavy skim.

That evening i picked up the freshly machined pistons, which were done free of charge and they also sourced me new piston rings, big end bearings and a bottle of running in oil, all free of charge. They also lent me their flexi-hone and piston fitting tool.

 

Before

IMG_8217 by Steve Count, on Flickr

 

After

IMG_8223 by Steve Count, on Flickr

 

When the head went away for machining a couple of weeks previously I'd made the most of having the head stripped down by cleaning everything in my make shift parts cleaning setup: a £5 plastic tub from wilkinsons and a £10 bottle of parts cleaning fluid from machine mart

 

IMG_8179 by Steve Count, on Flickr

 

IMG_8180 by Steve Count, on Flickr

 

I also stripped each hydraulic lifter, cleaned them down by soaking them in neat parts cleaner for several days then cleaning with a cotton bud and rebuilt with a couple of drops of fresh oil as one had been sticking slightly since Curborough. I found that filling the piston with oil upon reassembly would cause a hydraulic lock which from my measurements could have caused the valves to crash into the pistons if the engine was to be turned over in that state upon reassembly. Therefore i opted to only add a drop of two of oil in each piston before putting it back into the bucket and making sure it was free to move in and out under moderate finger/thumb pressure.

 

IMG_8183 by Steve Count, on Flickr

 

IMG_8194 by Steve Count, on Flickr

 

Meticulously making sure each one went back together with the same parts it came out with.

 

IMG_8185 by Steve Count, on Flickr

 

IMG_8207 by Steve Count, on Flickr

Edited November 21, 2017 by Prism7guy

[Prism7guy 5]

Time for the rebuild came and Tom Fenton offered his help for rebuilding the engine. Massive thanks to Tom for this as it was the night before i was due to leave for the 'ring and i'm pretty sure i wouldnt have got it all done in time if it wasnt for him!

 

We worked into the early hours of the morning honing the bores, fitting the new piston rings, dropping the pistons into the block, fitting the new big end bearings etc. I was under the car putting the windage tray back on then the oil pump and sump whilst tom was above me fitting the head with the new gaskets etc. We called it a day around 1am once the bottom end was back together and the head was back on with the manifolds fitted and the new cambelt and waterpump sorted.

 

The next morning i was up at 7 and finished off plumbing all the pipework etc back in, quickly went inside and packed the clothes for the trip and went back out to take it out for a test run. It fired first time and off out i went, I had some errands to run so filled up with fuel and called in at work. I got home and made a start packing tools and spares when i noticed there was a severe oil leak from one of the camshaft oil seals that i'd fitted but it was not seated 100% square.

I was now pretty late for my desired set-off time to get to the eurotunnel in good time, but i found time to get the cambelt off, get the pullies off and replace the leaking seal with a new one then refitted the cambelt, and dropped the running in oil for some cheap mineral oil. Once that was done all the spares etc went in the car and i set off for Germany.

I ran the engine in on the way there, constantly up and down the revs, never letting it idle and giving it light loads to start with then more towards the end of the journey. The car made it there without a single issue.

 

When i got to Germany the next day I dropped the mineral oil and filled it with the Fuchs pro-s that I usually run. The cam timing was slightly out as it was very sluggish so I re-set the timing and it was back to its former glory.

Due to the now higher compression ratio and the fact that it's running boost i opted to only put 102 octane in whilst at the nurburgring, in the hope to avoid any detonation. All seemed well on that front. No photo's of the rebuild as there was 3 of us working non-stop getting everything back together as fast as we could.

 

IMG_8264 by Steve Count, on Flickr

 

Another tale of mis-fortune unfolded whilst over there but nothing major. We re-used the custom PTFE gasket that sits between the inlet manifold and cylinder head. Upon sorting the cam timing out i noticed i was down on boost, after spraying brake cleaner at said gasket with the engine running it was clear there was a leak around cylinders 1-2. Careful nipping up of the nuts and capscrews then lead to a chunk of the manifold cracking away creating a worse issue. I'd heard that Dan Clarke was heading over during my stop out there so I asked him if he could bring some RTV or similar with him, which he did and i attempted to bodge it back together to somewhat seal the manifold for the duration. Thanks for that Dan!

p.s. Shut up Dan.

 

IMG_8277 by Steve Count, on Flickr

 

The weather was high 20's to low 30's whilst over there, the coolant was getting a bit hot so i took the bumper off and butchered it, it seemed to greatly help keep the coolant at a sensible level.

 

IMG_8327 by Steve Count, on Flickr

 

I even managed a new PB which i'm pretty chuffed with. I know you shouldn't chase times but I like to record the laps then see where improvements can be made for the next trip.

 

 

Edited November 21, 2017 by Prism7guy

[calvinhorse 870]

You're off you fekking head Stevo, well done mate, epic amount of effort!

 

Fenton's one of the handiest people I've ever known too!

[cybernck 402 1 Cars]

I'm very sad to announce that none of the photos work anymore .

[Prism7guy 5]

Yeah, bloody photobucket! I'll start to sort out the photos when i get a few spare hours one evening, half of the photo's are now uploaded to my flickr account ready.

[Prism7guy 5]

After a great week at the 'ring a few of our group headed over to Le Mans for the 24hr race.

In typical fashion i got around 30 mins away then strange noises started coming from the engine bay.

We pulled into a service station and off came the bonnet, we were looking to see what was causing the noise when a friendly French chap started walking over offering his help as he was a mechanic, he took one look in the engine bay then dismissed that idea and wandered back to his car. This still tickles me to this day!

 

Anyway, the issue was that the steel bracket that i'd made that holds the alternators tensioner link to the engine block had sheared, losing belt tension as the alternator could move slightly, and where the bracket had snapped it went into the idler pulley chewing it to bits.

Here it is next to its freshly machined replacement.

IMG_8395 by Steve Count, on Flickr

 

To solve the constant snapping of these brackets that ive been making I decided to make a new bracket which holds the engine mount plate to the supercharger plate, this is essentially just an extended piece of aluminium compared to the old one. I put multiple mounting holes in it to give some flexibility for how i want to mount the tie bar.

 

IMG_8403 by Steve Count, on Flickr

 

IMG_8405 by Steve Count, on Flickr

 

Next job was the pesky inlet manifold. I TIGged the broken part back on. I hadn't realised how much welding the manifold had warped and pulled everything until i strapped it down to the table and ran a clock across it. After a few light passes the manifold mating face was all cleaned up and shouldnt allow any more leaks. Upon refitting i've opted for just a standard paper gasket.

 

IMG_8401 by Steve Count, on Flickr

 

IMG_8402 by Steve Count, on Flickr

 

IMG_8408 by Steve Count, on Flickr

 

IMG_8409 by Steve Count, on Flickr

 

IMG_8411 by Steve Count, on Flickr

 

I found a video on YouTube the other day where this car makes a sneaky appearance at 3:08

 

 

Edited November 21, 2017 by Prism7guy

[Prism7guy 5]

Another thing i'd forgotten about on the return drive from the Nurburgring and Le Mans was the fuelling was all over the place. It seemed to be quite random but it would shoot up to 17 on the wideband, even if i gave it a quick blip of the throttle which would normally drop it back down to around 12, then sometimes it will just sit at 10 and refuse to get any leaner.

 

I couldn't figure out the cause so had to limp most of the way home where it would keep the fuelling in sensible parameters. I assumed it could be the throttle position sensor which is the best part of 20 years old now, so maybe some of the slider has crumbled away causing it to mis-read the position. I've sat in the car for five minutes with the laptop plugged into the ecu and constantly moved the throttle pedal and all the readings matched what my foot was doing.

I had wondered whether it could be an issue to do with the fuel supply, so i fitted a new fuel rail, with a brand new pressure regulator and also bought a fuel pressure sender and gauge.

Since fitting these new parts the car hasn't done the random fuelling so I assumed I had solved it, until the end of the day at Cadwell a few weeks ago. The fuel pressure looked to be what i'd expect, sitting at 3 Bar under normal throttle conditions then rising up to around 4 when under boost. This now leads me to think the throttle position sensor is the next component to replace and hope that it fixes it for good.

 

As mentioned, I managed to squeeze one last trackday in before winter arrived. Great day out and a couple of familiar faces from this forum joined in the fun too.

 

IMG_0119 by Steve Count, on Flickr

 

IMG_0121 by Steve Count, on Flickr

 

 

 

 

 

 

 

 

And that's the car fully up to date as of November 2017. Hopefully there's more to come in the following years but this car is going to take the back seat for a while whilst I make a start on sorting out a 205 I purchased last year.

 

 

 

 

[cybernck 402 1 Cars]

What an amazing read (and skills)!

 

I'm no stranger to pulling an all-nighter and setting off to an event but running the engine in on the way there is simply... epic!

[mmt 15]

Great work. Did the plastic undertray work? Is it ridgid enough? 

 

Thanks

[Prism7guy 5]

Thanks guys. Yeah I was pretty knackered by the time i eventually got to Germany!

 

As for the undertray, it's not given me any issues since i fitted it several years ago, and it's done 140+mph on several occasions now. Don't ask how effective it is as i can't comment on that, but it certainly helps keep the battery, boot floor and now the fuel pumps and swirl pot cleaner than if it wasn't there. I've found a couple more pictures of it being made incase you wanted any more, the red stuff is some fibreglass and epoxy that i used to hold/strengthen the vertical strengtheners. I epoxied the aluminium flat to the plastic too to help spread load and the tubes down the holes so the mounting screws wouldn't crush it.

 

IMG_1683 by Steve Count, on Flickr

 

IMG_1685 by Steve Count, on Flickr

 

IMG_1686 by Steve Count, on Flickr

 

IMG_1687 by Steve Count, on Flickr

[mmt 15]

Great. Thanks for the pictures mate very helpful. 

[Prism7guy 5]

Small update time.

 

Replaced the TPS and green coolant temperature sensor. Had the injectors cleaned and flow tested.

 

IMG_0432 by Steve Count, on Flickr

 

IMG_0433 by Steve Count, on Flickr

 

IMG_0434 by Steve Count, on Flickr

 

Next up i wanted to improve the boost pipework between the intercooler and throttle body. The old run was as follows:

 

IMG_0422 by Steve Count, on Flickr

 

A few purchases later on ebay and i had some new silicon and ally bends. In order to get them to fit as i wanted i needed to cut down the ally bend as it was too long as it arrived, but i didn't want to end up with no rolled beads as the silicon hoses would be constantly slipping off. The solution was to make my own bead roller, after raiding the scrap bins at work and a few extra hours at work i ended up with this:

 

IMG_0488 by Steve Count, on Flickr

 

IMG_0461 by Steve Count, on Flickr

 

IMG_0570 by Steve Count, on Flickr

 

IMG_0572 by Steve Count, on Flickr

 

IMG_0435 by Steve Count, on Flickr

 

IMG_0575 by Steve Count, on Flickr

 

Much better. Final job for today was to swap over the supercharger pulley, i've now fitted a 15% smaller one, should get a bit more boost, and the s/c would hit the max recommended rpm limit of 14,000rpm when the engine hits 7,500rpm, even though i've set the limiter to the standard 7,250rpm.

 

IMG_0576 by Steve Count, on Flickr

 

All back together, just needs fresh engine oil now which will happen if opie oils has a decent offer on in the near future. It's booked in for a remap on the 29th of March.

I've also booked a trackday on the Nordschleife which was the motivation i needed to crack on with this work, i want the car to be ready in plenty of time instead of the mad rush i had to deal with last year.

 

IMG_0579 by Steve Count, on Flickr

[Tom Fenton 1,542]

Bead roller looks well mate 

[Prism7guy 5]

Cheers Tom.

 

Just had the car mapped, i'll let the pictures do the talking.

 

IMG_0749 by Steve Count, on Flickr

 

IMG_0759 by Steve Count, on Flickr

 

IMG_0761 by Steve Count, on Flickr

 

The green lines show the boost and power curve from the first time i had the car mapped, the red ones were the new setup. Quite pleased with the results. Power is at the wheels.

 

 

[Prism7guy 5]

Small update time:

Broke the alternator again. Seems that trying to run the epas and everything else off this little one was too much for it as it's not the first time it's happened, so i've decided to revert back to the original one.

IMG_0850 by Steve Count, on Flickr

IMG_0849 by Steve Count, on Flickr

Of course nothing is ever straight forward so i needed to machine some new brackets up to mount the alternator to the sump, made trickier by needing it low enough so the belt doesn't rub on the auto tensioner but not too low that it hits the front cross member.
After a bit of messing about i'd figured out what was needed and made a template out of some scrap mdf, once i was happy with that i drew it up in cad with the amendments then went in to work and milled up the profiles and made the relevant spacers and top hat bushes to suit the lugs on the sump.

IMG_1034 by Steve Count, on Flickr

IMG_0915 by Steve Count, on Flickr

IMG_1036 by Steve Count, on Flickr

IMG_1038 by Steve Count, on Flickr

IMG_1054 by Steve Count, on Flickr

Seems to be running alright again now.

[dcc 855]

Steve that great work, the ew12 has a monster alternator (140amp iirc) if you wanted to consider something bigger. Could send you one to mock up of you wanted