GTE valver fast road/track car project

[Harvey]

Re: GTE valver fast road/track car project

GTE flew straight through the MOT today with no issues at all, I should hope not as well as it's done less than 900 miles since the last one

[DarrenH]

Re: GTE valver fast road/track car project

ear plugs or ear defenders cure that tiredness. or go one more "motorsport" and get an intercom system!!

as for the MOT congrats, but as we all know even if you did zero miles its still enough to get "play in offside rear wheel bearing"

[Dannyc]

Re: GTE valver fast road/track car project

Lol at Darren's response which is so true!

Nice one Harvey. The car is an absolute cedit to you.

[Harvey]

Re: GTE valver fast road/track car project

Not done anything to the GTE apart from clean it a couple of times, god dam brake dust and flies. However I did pop to a local show on Sunday 22nd March and to my surprise I won a rather nice trophy for my hard work. I’m well chuffed as you can imagine.

[DarrenH]

Re: GTE valver fast road/track car project

pics or it didnt happen !!!! lol

[BenH]

Re: GTE valver fast road/track car project

Great car! Just a question about your brakes do you find you use the bias valve at all? As I have both a pedal box and a bias valve and I cant remember if I used both at the same not or if I just used the bias valve on it's own before I got the box. It's been a long time since I had them on car and just starting to put this one together thanks.

[Harvey]

Re: GTE valver fast road/track car project

Ben I only installed the rear in-line bias as I was finding I had to wind the pedal box bias all the way to the front. I've now realised that I had the front and rear master cylinders the incorrect way round as the smaller bore should be used on the fronts as it offers more pressure.

[Harvey]

Re: GTE valver fast road/track car project

To keep this diary up to date I've copied a forum post from the General section dated 2nd October 2011.

After a post on the forum by Paul (RallyMarshal) on Tuesday regarding a late scheduled trackday at Blyton Park organised by www.javelintrackdays.co.uk I thought sod it I’ll do it. Main reason was after doing service crew for Paul last weekend and not getting the GTE on track so far this year I thought it was about time that I pulled my finger out as the motorsport bug was there.

I spoke with Paul on Wednesday and he basically said if I booked he would, so I did and he did. Paul had just enough life left in his brakes and tyres after the Woodbridge stages to manage a single track day. My GTE was fresh as a daisy as it’s only covered 332 road miles this year so it was about time it had a good drive on track. The track in question was at Blyton Park a new tarmac 1.6 mile track laid on the old airfield. This is the track BazW had a session at a couple of weeks ago and loved it, more about him later!

Blyton Park 1.6 mile circuit.



The day started at 06:30 leaving the house with car, wife, tools, fuel etc. We then met with Paul, Wife and neighbour called Paul (I'm easily confused) on route at 07:15. Arrived at venue near Gainsborough at 08:15. Unloaded cars, signed in and had a drivers briefing and then the wife drove with me as passenger for three sighting laps. I then jumped in the GTE and went and had a very enjoyable 6 or so laps as did Paul in his wobbly rally beast.

After I came in Amanda (the wife) and Ali (Paul’s wife) jumped in and Amanda headed out for a drive. A minute or so later we all noticed a yellow flag being frantically waved at the pit line entry. After glancing over I spotted the GTE stopped just off track to the right. It was quickly recovered and brought back to the pits. Amanda had managed a whole 100m on track but when going for 2nd gear the gear linkage pivot ball had broken so the car was stuck in neutral. On closer inspection it had obviously started to go before she jumped into the car but just ‘happened’ to break when she was driving, lol. The real kick in the balls is that it had crossed my mind to change this quick shift pivot linkage for a stock item a couple of weeks ago as I had been struggling to select all gears effectively for some time and especially 3rd as I kept missing it on hard driving.

Pic of the offending broken item.



After a couple of minutes of head scratching and the sinking feeling that the day would be over for the GTE I made a call to BazW as I thought he might have a spare stock linkage I could borrow and it was closer to get to him than to pop home. After a quick chat with Baz on the phone and a 2 hour return drive it was fixed and the GTE made the afternoon session. Huge thanks go to Baz and his poorly mk3 GSi that donated it’s linkage for the day. If it wasn’t for Baz I would of lost even more track time so thanks again dude.

Some more pics and vids from the afternoon.

Checking the car and setting up the linkage.



Paul felt the rear end of his would be better with a lower stiffer rear spring so I lent him Amanda’s Eibach’s which are destined for her Astra mk3.



The springs helped a lot and tightened the backend up no end.



My GTE felt fantastic and with the stock pivot linkage fitted changing gear was much better.





Both on track at the same time. Paul was flying in his ikle 1400cc and my god did it handle well. I had a drive of the rally motor and loved it to bits, I was so impressed with the engine performance it’s a credit to the engine builder.







Couple of vids, poor quality but you get the idea of the fun we both had. Click the picture to play.

Click for vid1

Click for vid2

It was all over at 16:30 so we loaded up.







Paul’s fleet of Skodas rock, VRS ‘R’ US and our trusty bus.

[Harvey]

Re: GTE valver fast road/track car project

As it was Christmas Eve and all the festive preparations were complete I thought I’d give the GTE some Harvey time.
After it hadn’t been ran for three months I warmed it up so I could drop the oil and replace with some fresh as well at a nice new oil filter.





I then removed all four wheels so I could spanner check everything.









Then it was time sort the brakes as my master cylinders required swapping over. I had initially thought that the larger bore .700 was for the front and the .625 was for the rear. However this is incorrect as the smaller bore offers more pressure so needs going to the front and the larger bore moved more fluid but offers less pressure so goes to the rear. I had always wondered why I had the balance bar wound all the way to the front d’oh!



The fluid was drained using my Eezibleed and had lost a little of its strange purple colour. I guess it’s just a dye added to the fully synthetic fluid, more on that later.



Using my trusty brake pipe spanner the unions at the master cylinders came out without fuss.



The cylinders then just unbolted and the push rods unscrewed from the balance bar once the lock nuts were loosened.









In traditional Haynes manual style, refitting was the reversal or removal. Note to self, swap over the Front and Rear master cylinder labels.



It was then time for some fresh Automec fully synthetic fluid, it’s awesome stuff and comes highly recommended. If you have a car that doesn’t get used much I recommend you stick this stuff in for your brakes and clutch fluid as it doesn’t attract moisture and never requires changing. I added the stuff I removed back into my top up bottle after filtering it through some tights. I then gave it a mix with the new stuff and bled the brakes. The fresh stuff is an awesome colour as you can see. I guess the colour is just a dye so you can spot any leaks but I might be wrong.

[Roger]

Re: GTE valver fast road/track car project

nice technical review... love it..

[DarrenH]

Re: GTE valver fast road/track car project

nice work again harvey. i guess the master sizing also scales with the slave or pistons in the calipers themselves. if you had giant 6 pots (extreme example) youd need a bigger master to shift more fluid

[BenH]

Re: GTE valver fast road/track car project

nice work again harvey. i guess the master sizing also scales with the slave or pistons in the calipers themselves. if you had giant 6 pots (extreme example) youd need a bigger master to shift more fluid

Thats why my box and 4 pots came off and got thrown in a box many years ago. Hopfully this time I can get them to work! (my caliper pistons had too much area!)

[Harvey]

Re: GTE valver fast road/track car project

Darren/Ben it was my original thought that my larger m/c needed to go on the front due to the 4 pots but I have since been advised that I'm wrong, that's why I have swapped them round. This does tally up as I had the balance bar wound all the way to the front due to the rears locking up. I'll work out the surface area of my 4 pots and the original ATE calipers and post up my findings.

Update:
I've found out that my Hi Spec Billet 4 use a 24mm piston (4 pistons per caliper) so each caliper has a total piston surface area of 1810mm meaning the pair are 3620mm.
The standard ATE caliper uses a single 52mm diameter piston which has a surface area of 2124mm meaning the pair are 4248mm.

As you can see above the Hi Spec Billet 4 caliper are just less than the surface area of the standard ATE calipers.

This is just my brain dump so feel free to comment; Now for the bit I still struggle with in my head. If I needed to move more fluid I would think I need a larger bore m/c, correct for hydraulic clutches where you want a m/c to move the slave cylinder as far as possible to release a clutch fork but not for brakes. I believe it's the other way round for brakes so if you running a larger bore m/c you are moving more fluid so you get a harder pedal, less travel and require more force on the pedal where a smaller m/c offers softer pedal, more travel and less force pressing the pedal. I'm sure there are much better technical explanations for this but I can't be bothered searching round for them.

[BenH]

Re: GTE valver fast road/track car project

You have to double the the area for sliding calipers, as it's counted as a 'twin pot' so to speak. So you can call that 8496mm2. Trouble I had among other was my 4 pots were far to big, in comparison to the rears. To get the correct pressure, I ran out of travel.

Bottom right of top page. If your 4 pots were double what you have as standard, I know from experince you'd of had no front brakes to speak of. Mine were somthing like a 3rd to a half bigger

http://www.rallydesign.co.uk/pdf/designing_4_pot_brakes.pdf

Edit. Are the gte pisiton's not 50mm diameter, looking at my notes? or is there a difference with 8v (late type) and 16v ones. My 4 pots were 43mm pistons!

[easytrans]

Re: GTE valver fast road/track car project

This is just my brain dump so feel free to comment; Now for the bit I still struggle with in my head. If I needed to move more fluid I would think I need a larger bore m/c, correct for hydraulic clutches where you want a m/c to move the slave cylinder as far as possible to release a clutch fork but not for brakes. I believe it's the other way round for brakes so if you running a larger bore m/c you are moving more fluid so you get a harder pedal, less travel and require more force on the pedal where a smaller m/c offers softer pedal, more travel and less force pressing the pedal. I'm sure there are much better technical explanations for this but I can't be bothered searching round for them.

Just thinking (not in anyway detailed technically), With a calliper in normal use the piston pots (calliper chambers) are fully charged with fluid and all the way back to the m/c so the extra "fluid" required to move the piston[s] (that usually sit a few thou from the disk) is minimal ....... Assuming the pistons are not driven back away from the disk (which I suspect could be the case in extreme rally surface driving) then the diameter of the master cylinder (m/c) would be less important for delivering the quantity of fluid but rather the "amount of travel / pressure" required to deliver it with the required force (pressure). .....

So am I right that: a smaller bore m/c (assuming the same travel) would provide slightly less fluid but under higher pressure than a larger bore m/c (assuming the same travel) but under less pressure.

If so my belief is:

small bore m/c same travel/same pedal pressure = less fluid higher pressure
large bore m/c same travel/same pedal pressure = more fluid lower pressure

The difference is probably so minimal that the main consideration is can the m/c provide enough fluid without resorting to a long travel to provide the extra (although small) amount of fluid to charge the larger area of all the calliper chambers under breaking?

I'll not get into expansion and fluid breakdown as it heats up or we will be here all day .....


Laurie.