4722 replies to this topic

[DarrylB]

Exhaust #4 has been comissioned tonight: https://sites.google.../07---update-27

This will be the last one one hopefully !!

Glad to hear it

[Nev]

Have been falling out of love with the black menace recently. Getting tyres for it has been both bloody hard as usual and mentally expensive. Grrr, why can't these Jap companies ever keep their stock levels up. I must have spent 1/2 day on the phone non stop to get a pair of rears. I think I will seriously consider getting some normal road tyres next time. Also, my steering rack/column has been been developing too much play, so that is yet another expensive thing to do

Edited by Nev, 20 December 2012 - 10:10 AM.

[JG]

Given that you only use it on the road, wouldn't road tyres make more sense anyway? I mean you can't really be exploring the levels of grip of an 18in cut slick on the road can you?

[siztenboots]

what tyre are you after?

[CocoPops]

It's suprising that they dont really warm up, even after a long 70 MPH run on the motorway I have got out and felt them and they are only cool (in current 5 degrees ambient weather).

Why would they warm up when driving in a straight line?!
Surely they need lateral movement to create warmth...

A wheel rolling along wouldn't generate any heat I wouldn't have thought unless the tracking was out and it was scrubbing.

[ianrm]

I did 1000 miles on AO48s in a day on Motorways to Firenze in Italy earlier this year and the tyres were warm every time I checked at a fuel stop. I could do a few laps on track and they will be hot and sticky. Why do race cars weave on warm up laps ?

[siztenboots]

Drove to Brands at the weekend, it was pretty cold and stopped at Clacket services, tyres were warm and that was just cruising along, my setup does have a fair bit of rear scrub dialled in

[Nev]

The warming issue is due to the weight/surface area. In summer/spring/autumn they are fine, it just winter when temps < about 10 degrees that it is a problem. Contrary to the implied comments above (from people who as usual haven't even sat in the car for a ride, let alone driven it) the car does go round corners rather well. I am open minded about road tyres next time, will see whats on offer when the time comes. Ideally I'd like to go up 5% in profile on the rears as the ride is pretty harsh at 30% profile. Interestingly the fronts seem to be wearing out a lot faster than my old R888s, which presumably is mainly due to the change in geo, though the front axle is a fair bit heavier now (41% front to 59% rear with me in the seat). When my new machined uprights arrive in January, I will strip the front end apart and address the rack/steering column at the same time as fitting them and then re-geoing the whole car again.

Edited by Nev, 20 December 2012 - 12:44 PM.

[luke.]

Sorry if i have missed this Nev but how many miles have you done on those tyres? Must be an expensive game with those sizes too.

[GeorgeBC]

It's the v70's Nev. I've been changing all 4 at a time as the fronts wear almost as much as the rears. When I use to run 888's the fronts would last twice as long as the rears.

[Nev]

It's the v70's Nev. I've been changing all 4 at a time as the fronts wear almost as much as the rears. When I use to run 888's the fronts would last twice as long as the rears.

Thanks for corroborating that George - it is strange how the fronts wear so much faster than R888s. Like you, my R888s on the fronts used to last 2 or 3 times longer than the rears.

I tried getting hard compound V70a's this time, but no stock was available, so had to get medium ones again.

The crux problem is lack of stiffness in the carcass of the V70a I think. They are only "W" rated, perhaps switching to Y or Z rated tyres implies stronger carcass, so that they don't deflect in the centre with speed. I rang up Adams&Page as they really know a lot about tyres and though they wouldn't comit to commenting on the V70a (as they dont have experience of them) they thought the R888s wouldn't be much stronger. I can't really be arsed with thinking about it any more at the moment, I have enough things to be getting on with ATM - new exhaust, new uprights, new rack+UJs, Autosport, new wheel, new geo, new hub carrier bolts.

Edited by Nev, 20 December 2012 - 01:07 PM.

[Boombang]

Toyo R888s have soft sidewalls like standard road tyres. If you want a stiff sidewall, and you can get them in your sizes, Yoko A0XX and AD08s are far stiffer (and I prefer them in all circumstances I have tried - have heard however that LTS spec A048s have softer sidewalls but that might be internet bullshit).

Edited by Boombang, 20 December 2012 - 01:17 PM.

[Nev]

Toyo R888s have soft sidewalls like standard road tyres. If you want a stiff sidewall, and you can get them in your sizes, Yoko A0XX and AD08s are far stiffer (and I prefer them in all circumstances I have tried - have heard however that LTS spec A048s have softer sidewalls but that might be internet bullshit).

Thanks. I think I'd prefer a softer sidewall so that there is more flex/give in the floating assembly. However, the problem with the R888s is the side buldge is considerable, so I'd have to drop down in width to 275 and even then I might well get rubbing issues.

[Nev]

I got my 4" honeycomb (from the USA) a few days ago and installed it (with an interference fit) into the MAF to 'smooth' the airflow prior to the sensor. Good value for $4.95, there is a pic of it here (if you scroll down).

Am off to Slough tomorrow to leave the car with Dan at YapFab for a few days for the new 3.5" exhaust. Hopefully it will be ready for pick up prior to the Autosport show on the 11/12/13 Jan. He has had a bespoke backbox end caps and baffles made up to size and we will design the interior of the box to flow VERY well with lots of change of direction of flow to ensure noise abatement. The 3.5" mandel bends were made on special request and the flexijoint is a 'truck' part.

I am praying that this will silence the car nicely.

Edited by Nev, 04 January 2013 - 05:43 PM.

[siztenboots]

if i'd known , i would have met you there

[Nev]

The exhuast is coming along nicely apparently. There was a problem with the diameter of the bends, so the narrow part near the turbo mouth has had to be made from sections of stright pipe. The bespoke box with 2 baffle sections and 3.5" internal pipeing has been completed and I am awaiting some pics. Hopfeully should be able to pick the car up on Thurs evening in time for Autosport 2013. Exciting stuff, I don't think I know of a VX with a 3.5" jobbie.

Edited by Nev, 08 January 2013 - 07:14 PM.

[Nev]

Here is the 'tight' downpipe.

[MrSimba]

Nice bit of fabrication there Nev Be good to catch up this weekend

[Duncan VXR]

Here is the 'tight' downpipe.

Nev would it not have been easier to use a 1D or 1.5D mandral bend? The radius does not look that tight tbh, I have found a supplier of the bends at a good cost and quality is A1

You will lose 5bhp for not having a nice smooth bend

Looking forward to seeing a back to back test with the new exhaust on current setup

DG

[CocoPops]

Will there be any silencing effect? What noise level do you expect it to be?