468 replies to this topic

[techieboy]

That's crazy, suggests that tyre sizes are not accurate at all...

Correct.

Same manufacturer, same "sizes".



Should have stacked them up on top of each other with the tyres in their proper orientation to see what the difference was in that direction too.

[CHILL Gone DUTCH]

How did the ZZRs do Impressed ??

[Captain Vimes]

How did the ZZRs do
Impressed ??

 

Better than the RSR's:

• they don't squeal
• the shoulder seems to have held up well
• they didn't melt. Even when they were VERY hot at Rockingham they didn't go off
• they have more grip than the old RSR's

but.. not as grippy as I expected. Maybe that's me expecting too much from them. I'd guess the V70a's would set faster lap times but these are going to last pretty well (hopefully).

[CHILL Gone DUTCH]

Good stuff I read to aim for 29 psi hot

[Captain Vimes]

I just had a look back and I've now managed a heady 13 track days in the VX since getting it and 8 since supercharging it in 2014. I know some of you manage 10+ per year so I really must try harder!

 

 

So, thoughts on what next after the national...

 

- Cool it down on very hot days so I can run for longer stints. Not sure how but current thoughts are:

• Add a gearbox oil cooler
• Spal fan on engine cover
• Decat exhaust
• Nothing happening on this any time soon. Maybe next spring..

- Fuel Starvation

• Is an issue at anti-clockwise circuits. Simple solution is to change gear early or just stick to clockwise circuits. A pro-alloy tank will be fitted at some point in the future but not this year...

- Suspension/handling

• It's a bit oversteery at the moment (turn in and exit) so I've stiffened the front ARB and will play with damping and driving style.
• The outer shoulders on the front tyres have rounded off more than the inners. Maybe a bit more front camber would help.
• At some point I'll bite the bullet and pay to get it setup properly but I'm enjoying feeling the difference each change makes.

 

A couple of video's from the national..

 

Drive by sound of the soup'a'charger on the straight:

 

 

Final Session following SteveA.

 

It's fairly quiet at the start but there's some others in it from lap 3 and then loads of people coming out if the pits on lap 4 (including JimmyBoy) at around 5 mins 15s.

 

This one also highlights the fuel starvation despite starting the session with a tank completely brimmed, it starts causing issues from lap 7.

 

 

 

Edited by Captain Vimes, 22 August 2016 - 09:37 PM.

[fezzasus]

On cooling it,

 

1. Do you know the gear oil is getting hot enough to need to cool it?

 

2. Adding more NACA ducts is supposedly the most effective way to increase airflow in the engine bay. Turbo cars have three while NAs make do with two. Was the 3rd simply added for heat removal? It'll cost about £4 and a few dremel discs to find out.

 

 

[SteveA]

Final Session following SteveA.

 

That was a great little session, was gutted I forgot to put the memory card back in the vbox as we did a few 1:35's. Glad I got out for one more short session just to get the fast laps on camera.  

[sworks]

Good stuff I read to aim for 29 psi hot

According to here it's 30psi: https://www.lotrdc.com/tyres-avon-zzr

 

I ended up 30 rear and 29 front (this was from starting at 25 rear).

 

Tyres are brilliant and a big improvement for me over the RSR 

[sworks]

My car was also running hot at Snetterton and suffering from fuel starvation. I will also fit a PA tank, bit not this year. I'll take the simpler option of jerry cans and keeping half a tank of fuel in the car for now.

 

Will be interested to see what you do in terms of cooling.

[Zoobeef]

I started on 24f/26r they went up to 28f/32r so dropped the rears to 30 and left it at that. Seemed to be ok so will prob start 24 front and rear. I do wonder about the 30 recommended as surely the weight of the car comes into it too.

[Captain Vimes]

On cooling it,   1. Do you know the gear oil is getting hot enough to need to cool it?   2. Adding more NACA ducts is supposedly the most effective way to increase airflow in the engine bay. Turbo cars have three while NAs make do with two. Was the 3rd simply added for heat removal? It'll cost about £4 and a few dremel discs to find out.    

I have 4 NACA ducts already, one of the pro-alloy fans removed and blocked the gaps around the rad to force air through. The water temp was slowly creeping up through the session to around 105c but a slow lap would see it drop back to 100c quickly so it's not a big issue but I'd prefer to get it under control. My theory on the gearbox cooler is that the current oil/water cooler is adding heat to the water temp. If I can get some of that heat out via an inline air/oil cooler it'll help bring water temps down. In use, it does feel like the clutch is less grabby (technical term) at the end of a hot track session but I have no empirical evidence that it's too hot.

[Rosssco]

The Spitfire replacement fuel pump unit has a larger canister inside the fuel tank - might be all you need rather than a replacement tank.

[techieboy]

The Spitfire replacement fuel pump unit has a larger canister inside the fuel tank - might be all you need rather than a replacement tank.

It didn't seem to help a VX'er with one fitted at Zandvoort. He was still getting starvation issues. May or may not have further delayed the onset of the problem but I'm not sure what his fuel levels were at the time.

[Captain Vimes]

I ran the ZZR's at 30psi hot. Not sure what that was cold but around 22-24. They were more stable over multiple laps than the RSR's and they have a much stiffer sidewall so they survived a lot better but I'm not sure they were much grippier than a new set of RSR's. I was also more conscious of the cost of drifting and tried to avoid spinning them up... I'll do a few more days before reaching a conclusion.

Final Session following SteveA.

  That was a great little session, was gutted I forgot to put the memory card back in the vbox as we did a few 1:35's. Glad I got out for one more short session just to get the fast laps on camera.  

Yep, I really enjoyed that session. Shame I couldn't join you for your very last session!

[james_ly]

The thing with the VX220 is that it seems designed to make you worry about it. Giving a digital readout for water temp makes you worry much more than a normal gauge. And because it's so unrefined you hear every little noise and panic...

 

Having said that, 105C with full air flow through the rad would scare me a lot! Mine never really goes much above 90C on track.

[Zoobeef]

Has anyone tried to run an SC car on track for 40+minutes? Is it possible?

If I do want to go up a class then is the SC even an option.

[CHILL Gone DUTCH]

I've done 30 min run with no issues

[Captain Vimes]

I can run very long sessions on clockwise circuits where ambient temperature is consistent with UK weather (below 25c). WI might be another solution. Cooler intake will help keep everything cool. Acidpopstar is reporting low water temps on his hot euro trackday.

[Acidpopstar]

The Spitfire replacement fuel pump unit has a larger canister inside the fuel tank - might be all you need rather than a replacement tank.

It didn't seem to help a VX'er with one fitted at Zandvoort. He was still getting starvation issues. May or may not have further delayed the onset of the problem but I'm not sure what his fuel levels were at the time.

Twas I! Yep, desire Gaz's assurances that the spitfire fuel pump would eliminate fuel starvation I've had it on 3 different tracks since fitting. I've told him and he asked me to test how long it takes but can't do that on the road! Disappointed.

I can run very long sessions on clockwise circuits where ambient temperature is consistent with UK weather (below 25c). WI might be another solution. Cooler intake will help keep everything cool. Acidpopstar is reporting low water temps on his hot euro trackday.

I did Paul Ricard yesterday in crazy heat. Everything else overheated including me but my coolant temp didn't go above 91 on track. I don't have the big CC rad upfront so maybe that aids airflow to the main rad which is pro alloy. Sent from my iPhone using Tapatalk

[Exmantaa]

 

 

The Spitfire replacement fuel pump unit has a larger canister inside the fuel tank - might be all you need rather than a replacement tank.

It didn't seem to help a VX'er with one fitted at Zandvoort. He was still getting starvation issues. May or may not have further delayed the onset of the problem but I'm not sure what his fuel levels were at the time.

 

Twas I! Yep, desire Gaz's assurances that the spitfire fuel pump would eliminate fuel starvation I've had it on 3 different tracks since fitting. I've told him and he asked me to test how long it takes but can't do that on the road! Disappointed.

 

 

I have fitted the same new Spitfire pumpunit with bigger cannister, but still got fuel starvation after the long left hander @ zandvoort.    It is better than stock and I'm probably guzzling a bit more fuel (330-ish HP => 1:3.5 ) but it normally started after using ~20ltrs in the stock tank...