4722 replies to this topic

[chris_uk]

i meant so your louvres worked better. 

 

i noticed a great improvement of downforce over the front end when i did the louvre cut outs.. steering gets noticeably stiffer above 100mph

[ChrisS1]

http://www.vx220.org...e/#entry1705267

[Nev]

Yep, my front louvres vent any positive air pressure from the font wheel arches, the front arch liners have huge holes to allow pressure out. Also, I have meshed rear facing vents from the front arches as well.

[VXT Tim]

Can you wrap the water pipe in 'cool' tape to help?

[turbotoaster]

i assume your talking 95mm from the chassis or 95mm from underneath the splitter?

 

if you cant run the car any lower you can fit a proper carbon splitter that extends forward to get larger surface area but also run a 12mm foam core so you end up with your splitter 80mm from the floor, that will help it interact with the ground more as it will be closer, just a thought

[smiley]

Can you wrap the water pipe in 'cool' tape to help?

 

There are removable sleeves for that:

http://www.heatshiel...shield-sleeving

[cnrandall]

I REALLY doubt you are experiencing and aerodynamic issue.

[Nev]

The car deffo lightens off at the front at mid to higher speeds. I suspect part of this is to do with the camber. However, I still remember my dropped suspension experiments (65mm under the splitter and 90mm under the rear chassis) where the front got pinned to the floor, if I could gain 1/2 of that frontal downforce and be able to get over speed bumps I would be a happy man.

Edited by Nev, 23 June 2014 - 08:30 PM.

[cnrandall]

Before making any assumptions about aerodynamic effects I would suggest getting your car into a sensible baseline mechanically. You have quite an unusual set of components on your car with big wheel sizes etc and you have never properly baselined it. On the road it's going to be very hard to make any sensible assertions about aero load from the drivers seats, there just isn't the opportunity to load the car in that sort of way. What you feel at road speeds (even very high road speeds) is going to be predominantly effected by the mechanical aspects of the car unless there is a fairly extreme aerodynamic imbalance. Ride height will effect the way the underfloor performs, not the splitter. The splitter simply gives the high pressure zone which is at the front of the car a surface to act on. The splitter shape/size does act to increase the area of the underfloor and that will slightly change the centre of pressure but, again, that's of little consequence on the road.

[Nev]

Fixed the hose with a section of pipe yesterday and went out for a test today, all seems fine once all the water soaked exhaust wrap had billowed off the water for 10 miles. Need to book his MOT next week.

[Nev]

MOT passed with flying colours, road tax paid up, insurance paid, the bills never stop

 

The next thing is finding some new rear tyres, I've just worked out my mileage and all the Khumo V70 tyres have done is 2400 miles, and half of those would just be pottering about/stuck in slow moving traffic. Am probably abandoning the V70 tyres for R888s this time, I know they will last longer even if they are hard/impossible to get up to temps in the winter. A case of longevity winning over grip !

Edited by Nev, 03 July 2014 - 04:55 PM.

[turbotoaster]

what about something more middle ground like federal rsr then, no point hardly getting many miles out of the tyres unless your using them for competition.

 

Any reason your burning through them so fast, running such wide rear rubber means you must be hitting them pretty hard to eat them

[leevx2.2]

What compound you running Nev I have the same problem they don't last long ,I have just gone for hard on the rear I will let you no how long they don't last lol

[Nev]

Yea, Federal 565RSR's were the other possibility, they are cheaper but I don't think they will last as long as the R888s.

 

I've had about 5 sets of R888's in the past and they used to last me about 6000 miles. With the extra grunt out of Nipper these days I'd be happy if they last 4500 to 5000 TBH. Also, if you do get the R888's fully upto temps (circa 50 degrees Centigrade) they really are very sticky indeed for a couple of runs, though I did notice that towards the end's of their life the R888s got noticeably worse, whereas my V70s seem just as sticky at the ends of their lives.

 

For summer driving I think putting the R888s on the rear and softer V70 on the front would be the best to help equalise the temp/warming up difference due to the VX220 front axel being so light.

 

Edited by Nev, 03 July 2014 - 08:51 PM.

[Nev]

What compound you running Nev I have the same problem they don't last long ,I have just gone for hard on the rear I will let you no how long they don't last lol

 

I had medium compound on both the front and rears of the V70s. They are great for traction, but I can't afford a new set of tyres every 4 months !

[Nev]

I've just come back from a 70 miles country road blast, you just can't beat it in the summer, particularly later on in the evening when the traffic thins out. The car is just amazing to drive, so brutal and raw, noisy, smelly, pin-sharp - I particularily love that special smell you get of partially burnt hydrocarbons - the same smell as from steam engines.

 

I've got to do something about the bump steer though, its worrying on uneven roads at high speed. Also, I'm gonna put some more spacers in the front to reduce the camber, only about 25% of the rolling radius of my front tyres is actually on the bloody tarmac. This should improve front tyre longevity and make it more "road" compatible.

Edited by Nev, 03 July 2014 - 09:00 PM.

[Bumblebee]

Sounds like it's all coming together now

[turbotoaster]

what camber are you running on the front and do you have EP bump steer kit to help?

 

Since you run such wide front tyres i would have thought on the road you would be running a bit less camber than normal.

 

I run 225 fronts with 2.2* and thats fairly aggressive

 

I bet I run a steeper upper wishbone than you and I dont suffer to much with bump steer which i can only put down to the kit

[Nev]

what camber are you running on the front and do you have EP bump steer kit to help?

 

Since you run such wide front tyres i would have thought on the road you would be running a bit less camber than normal.

 

I run 225 fronts with 2.2* and thats fairly aggressive

 

I bet I run a steeper upper wishbone than you and I dont suffer to much with bump steer which i can only put down to the kit

 

Hi Lee,

 

Front camber is supposed to be set at 0.5 degrees (and toe is virtually a straight line), but looking at the wheel angle visually and the scrub/uneven wear on the inside I don't think it is any more.

 

When it gets wet/cold I intend to strip the front suspension off and look at it from first principles. It might be possible to swap the OS/NS OEM steering arms from one side of the car to the other (thus inverting them) and then the tapered ball joint would point down, such that the arms would union underneath the steering arms rather than ontop of the steering arm. That way they will naturally become way more horizontal, but not necessarily correctly angled as there wouldn't be any adjustment possbilities I think. If this doesn't look feasilbe, I'll have to splash out on the EP kit.  

Edited by Nev, 04 July 2014 - 06:55 AM.

[Nev]

Bah, had the usual problem of finding R888 tyres (Camskill can't supply them any more), so had to buy a full set of Federal RSRs. Bought them from Pneus Online (who were remarkably cheap). Lets see if they delivery with 3-5 days as they promise...