19 replies to this topic

[dedposh]

Hello All,

 

I have owned my VXT for 6 years however only recently started tracking it. I wish I had done this earlier as its bloody awesome and I have definitely got the bug now. I have a few questions/issues;

 

Out of the 5 days I have done so far I've ended up boiling the brakes on 2 of them. The first time I have no idea when the fluid was changed and the second time I was at Bedford and I had just changed the fluid. I was on the back straight doing 125mph when they went then came back slightly and I managed to turn into the left hander then slow the car. I'm going to change the fluid to RBF600 so hopefully this will fix the problem. I'm running Mintex 1144 pads but not sure if these are ok for track? Can it be the pads generating too much heat?

 

Most of the cars at the days seem to be running on semi slick tyres. If I want to go down that route and move to a 16/17 set up do I need to change the suspension set up? The 16s would leave a large arch gap, what have people done to sort this?

 

Finally on the last day I did my temps were going upwards of 100 on track and to be fair it was a really hot day. What should my temp be typically running at and what is the cut off where you would bring the car in for a cool down? 

 

Thanks

 

 

Edited by dedposh, 08 July 2021 - 09:51 AM.

[smiley]

The RBF600 is excellent, the 1144 not so much.

 

Once you start building speed you need to break harder.
With the 1144 not being all that, you start braking earlier and keep your foot on the brake longer in order to make the turn.
That causes your brake fluid to boil.

Decent pads will change that behavior, (ie brake late, hard and short)

Also a good practice to bring a spare bottle RBF600 and an easybleed in case you do get the issue again, as once it has boilt, you will loose brakes much easier, and the full day is fooked.

 

Would suggest to get a spare set of wheels with the semi's. That way you can run them to the ground, and use the normal set when MOT comes.

 

Once you have that setup you will notice that you will be to busy smiling all day on track to notice the gap on the front  wheels.
 

Here is a good vx trackday prepguide.

http://www.speedster...ages/1/prep.pdf

 

Edited by smiley, 08 July 2021 - 11:19 AM.

[dedposh]

Thanks for the comprehensive reply Smiley. Which pads do you recommend? Reading online the RS14 seems popular. I have tried to find a set of TD 1.2 16/17 however they seem like hens teeth at the moment!!!!!!

 

 

[smiley]

Pads are a complex discussion.

What works for one does not always work for another.

Me for example kept boiling my fluid with RS14, and CL6 works for me.( I only used these 2 in my VX life)
Others here reported the RS14 to be lovely and even use it for racing.

 

As you can see in the list, same friction rate but different behavior. (I love the CL6 cold bite)

For serious braking you need to be in the .50 and up area, but each pad has it's own characteristics that are difficult to explain.

 

Keep in mind that these are sold as motorsport pads.

That means squeeling, creating brake dust, and aggressive wear on the disks.

 

Bringing an extra set of pads (even worn) to a trackday is advised.

Either to get back home when you went to town, or miscalculated the wear for the day and they are done at lunchtime.

Edited by smiley, 08 July 2021 - 02:01 PM.

[PaulCP]

Smily has covered the brake situation well and fwiw, just to further highlight Smily’s point about finding out what suits an individual best, my preference on pads was always RS14’s

 

Also don’t  forget to upgrade the hub carrier bolts. If you haven’t done so already these should be done before thinking about semi slick tyres & changes to shocks etc

Edited by PaulCP, 08 July 2021 - 07:58 PM.

[Ivor]

Smily has covered the brake situation well and fwiw, just to further highlight Smily’s point about finding out what suits an individual best, my preference on pads was always RS14’s

Also don’t forget to upgrade the hub carrier bolts. If you haven’t done so already these should be done before thinking about semi slick tyres & changes to shocks etc

And toe links

[Ivor]

Pads:
Used pagid and CL, not a good enough driver to tell the difference, when I bought it it had mintex 1144, main braking problem I had was abs ice mode so generally run with abs disabled, went down a load of rabbit holes before I worked out ( was told) what the problem was .

[smiley]

As Ivor says; ice mode.

That is when our standard 2 channel abs get's confused. That can happen on agressive braking, or an unstable road. Car will just keep going.
Within that margin of the 2 channel it is mediocre at best.

If you switch to 16/17, you can worsen this problem if you choose a front tyre width outside the 5% margin from oem:

https://www.verboom....0422/index.html

 

Once that happens, it goes from mediocre to just trying to kill you at every chance it has.

People either fit a 4 channel, which is a bit of an expensive solution, or put in an abs switch which disables the abs. Mainly used on track.

 

Long story short; try to stay within 5% from oem, and fit an abs switch.

If the switch sounds to complicated, you can just unplug the left front sensor, and tape it to the hub carrier for the day. Same result.
 

[WrightStuff]

On my car, even with fresh dot 5.1 fluid and RC6 pads I can sometimes boil the fluid.

 

This seems to be down to a small amount of old fluid and/or air trapped in the caliper despite the flush. The solution is to go through a procedure of removing the caliper, turning it and pushing the piston back in a certain sequence to ensure there is definitely no air and old fluid left. According to my local specialist mine is the only car that needs this so go figure! You might be ok and not have to go through this hassle. Replace fluid once a year at least!

 

On the standard suspension, a 16/17 setup will leave a big gap at the front, you're right. Most people tracking regularly buy aftermarket coliover suspension; Nitron/Quantum/Gaz are all popular. These allow you to lower the ride height and close up the gap, and also the stiffness can be changed for ride comfort.

Proper sem slicks can take much more punishment that normal track tyres so you can have longer stints. Adding an uprated ARB for further handling improvement is also a popular mod.

 

Not sure what level of tune you are running but if your radiator/coolant is doing its job there should not be any need to finish a session on track early because the car is overheating. The engine protects itself by retarding the ignition if it detects intake temps getting too high so it may be possible to detect a slight drop in power on a really hot day.

[Zoobeef]

On my car, even with fresh dot 5.1 fluid and RC6 pads I can sometimes boil the fluid.

 

This seems to be down to a small amount of old fluid and/or air trapped in the caliper despite the flush. The solution is to go through a procedure of removing the caliper, turning it and pushing the piston back in a certain sequence to ensure there is definitely no air and old fluid left. According to my local specialist mine is the only car that needs this so go figure! You might be ok and not have to go through this hassle. Replace fluid once a year at least!

 

On the standard suspension, a 16/17 setup will leave a big gap at the front, you're right. Most people tracking regularly buy aftermarket coliover suspension; Nitron/Quantum/Gaz are all popular. These allow you to lower the ride height and close up the gap, and also the stiffness can be changed for ride comfort.

Proper sem slicks can take much more punishment that normal track tyres so you can have longer stints. Adding an uprated ARB for further handling improvement is also a popular mod.

 

Not sure what level of tune you are running but if your radiator/coolant is doing its job there should not be any need to finish a session on track early because the car is overheating. The engine protects itself by retarding the ignition if it detects intake temps getting too high so it may be possible to detect a slight drop in power on a really hot day.

 

 

Try RBF600 or 660. I use 660.

I've never had brake fade or boiled the fluid even with the RC6 pads running very hot. (I can use a set of pads on a test day and race, more heat increases pad wear, I also cook rear caliper seals as a yearly item).

 

Fluid is perfect though. I need more cooling front and rear and I've got some titanium to make shims to protect the seals.

[dedposh]

Thanks for the detailed replies. I've had the hub carrier bolts changed recently and spitfire toe links fitted a few years back.

I had the rad replaced in jan as the old one was starting to leak. The car has a stage 1 mmg map. I will keep my eyes peeled for 16/17 wheel set as you can't buy them new at the moment.

[Pidgeon]

Evening all.  I'm with Zoobeef in never boiling fluid on a TD.  I swear by 1144 for the road, but they will fade within a couple of laps on track.  I expect this is what you experienced.  My latest favoured track pad is the CL8, they're bloody awesome.

[dedposh]

Still deciding which pads to go for.. in the meantime I have changed brake fluid. I'm really not happy with the brake pedal travel though. Looks like I have air trapped somewhere. Going to follow advice on here and flip front calipers whilst bleeding. What travel if any is acceptable?

[coldel]

Next month I am tracking for the first time, I put some mintex 1155 along with RBF600 fluid - some mates and I hired the circuit and going out in groups of 4 so its all easy going can come back in whenever. So I might just do short stints to give everything a chance to cool down, I am not a fast driver anyway.

[Strugs]

Next month I am tracking for the first time, I put some mintex 1155 along with RBF600 fluid - some mates and I hired the circuit and going out in groups of 4 so its all easy going can come back in whenever. So I might just do short stints to give everything a chance to cool down, I am not a fast driver anyway.

You've hired a circuit, Colin?!

[Ivor]

Next month I am tracking for the first time, I put some mintex 1155 along with RBF600 fluid - some mates and I hired the circuit and going out in groups of 4 so its all easy going can come back in whenever. So I might just do short stints to give everything a chance to cool down, I am not a fast driver anyway.

You've hired a circuit, Colin?!

I've looked at hiring llandow before, it's not as bad as you might think, well llandow isn't anyway

[oblomov]

As Ivor says; ice mode.

That is when our standard 2 channel abs get's confused. That can happen on agressive braking, or an unstable road. Car will just keep going.
Within that margin of the 2 channel it is mediocre at best.

If you switch to 16/17, you can worsen this problem if you choose a front tyre width outside the 5% margin from oem:

https://www.verboom....0422/index.html

 

Once that happens, it goes from mediocre to just trying to kill you at every chance it has.

People either fit a 4 channel, which is a bit of an expensive solution, or put in an abs switch which disables the abs. Mainly used on track.

 

Long story short; try to stay within 5% from oem, and fit an abs switch.

If the switch sounds to complicated, you can just unplug the left front sensor, and tape it to the hub carrier for the day. Same result.
 

Smiley,

What's the % tolerance on the Lotus four channel?

[smiley]

Smiley,

What's the % tolerance on the Lotus four channel?

 

Dunno. I switched to 17"' DTC around the same time i put in the 4 channel.

Never had to turn it off, even on track. Some better drivers then me managed to upset it tough. 
 

[oblomov]

 

Smiley,

What's the % tolerance on the Lotus four channel?

 

Dunno. I switched to 17"' DTC around the same time i put in the 4 channel.

Never had to turn it off, even on track. Some better drivers then me managed to upset it tough. 
 

 

I have Racelogic TC so my concern has been tolerance of both tyre size and the TC settings. At the moment although I have a 16/17 combo for tyre choice convenience my tyre circumference front and rear I would prefer to go for a smaller front tyre without triggering either. 

[coldel]

 

Next month I am tracking for the first time, I put some mintex 1155 along with RBF600 fluid - some mates and I hired the circuit and going out in groups of 4 so its all easy going can come back in whenever. So I might just do short stints to give everything a chance to cool down, I am not a fast driver anyway.

You've hired a circuit, Colin?!

 

 

Yep! 16 of us clubbed together its actually quite reasonable we hired it on the Friday as that saves about 20% vs a Saturday. Worked out to about £130 each I think for the day which includes marshal's etc. We can go out and come in when we want, and its good that its a group of us that all know each other, so no egos or issues with stupid randoms going on. I'm on the list as Captain Slow lol