dandan

Been after one for ages Rob, you've made my day.

Yes yes yes please

Thanks Luc - I see you are even more up against it as you are running 19" wheels....I am also looking at my options now to drop to a 17" x 11.5" at the rear with a 315/35 Trouble is the only tyres easily available in those sizes are Vredestein Sessantas and Kumho V70a - I'd probably need a set of each as the Kumho is apparently even worse than the R888 through any puddles. I'll have a nose around for the Michelins as well now, thanks. I guess the lag and torque stuff is all very personal because its effect depends what you use the car for. Mine is not a track car or anything like that so all the midrange torque (and more importantly the response when off boost and transitioning into boost down at 1500rpm ) makes it very easy to drive on the road and it can easily be trundled around under 2000rpm all the time without ever feeling sluggish or strained. If you are hammering a car to death all the time on a track then you're not likely to be left wanting more lower rpm torque or improved manners and response when off boost as you'll probably be north of 4000 or even 5000rpm for the majority of the time. Personally I love it...especially now it's got the top end power to match up the the midrange grunt - best of both worlds for my usage Thanks bud. On the car right now I have 285/35/18 P Zero Rossos on a 10" rim. The grip is better than my 275/35 Eagle F1's but I still need more and for some reason I had it in my head that i wanted to find this mysterious extra grip without switching to an R888 type tyre but perhaps that's my only real option. The suspension is Chris Wilson's modified Bilstein dampers with custom springs and height adjustable platforms....I already ditched my Tein coilovers in an effort to soften things up. Thanks very much

Great - thanks.

Imi - do you by any chance happen to have a photo of your 235 tyre on those front rims? If they were 235/40 (as opposed to 235/35) could you post up a pic please? I'm trying to figure out what a 235/40 will look like on an 8.5" rim. Looking closely at the pics with your Sessantas I think I see 245/40.

Nice work What wheel and tyre sizes are you running there on the track?

On the stock 323mm discs you'd be down by approx 13% on combined braking torque and the bias increases to the rear by 3%. On a pair of 330mm discs you'd be down by approx 11% on combined braking torque and the bias increases to the rear by 2.5%. In both cases I expect you'd be fine. On a track I assume you'll be running a race compound pad so you can easily make up for, and far surpass, the deficiencies in braking torque so they are irrelevant really. The main thing is the brake bias shifting to the rear slightly. I'm sure CW has his thoughts on how much extra rear bias a MKIV could take in track form (there's a whole heap of inputs and variables) but I suspect the 3% would be ok.

Did you wap in a new water temp sensor?

How long is the runner to the wastegate and over how much of that length does it stay divided?

Good advice The Sessantas are supposed to be good in the wet.

I think I am getting close to finding a wheel and tyre combo I am going to purchase and at the moment it looks like an 18x11 rear and 19x9 front is about my best option....so far. Without going with something custom made I'm struggling to find anything half decent with a wide rear wheel in useable offsets so ths mixed 18" and 19" combo is a bit of a compromise I am looking into. Nothing is final yet though and I'm still looking around Rear tyres will be either 315/30/18 R888 or 305/30/18 Kumho V70a for summer use or possibly a normal 295/35/18 street tyre that can stay on for occasional use in the winter when the roads are dry and free from salt. This will be on an 18x11 rim and the offset will be 45mm meaning I need a bit of arch rolling at the back for the 315 to fit. For the front I am thinking about a 19x9 wheel and I'm trying to figure out what sort of offset and tyre shape will be best. I am not looking to have the wheels sticking way outside the wing, nor do I want to stretch a 235 over it looking like a long lost drifter I'm thinking that a 255/35/19 would be ok on the 9" rim with a 45mm offset. I have pretty soft CW based suspension and the car is a little bit lower than standard. Is anyone running anything similar up front without any arch rubbing issues? Cheers Dan

Thanks Paul No problem at all mate, will get on it tomorrow.

Cheers JP - sounds like the whole fandango could be a little pricey for me at the mo mate so I'll have to pass. Cracking wheels though, damn shame

Noise reduction and protecting the underside of the body from the heat from the exhaust. (It sits fairly high with loads of ground clearance). Thanks Luc. What size and price are the tyres you run now? I had a set of R888's on the car a while back but not tried anything similar since this recent "upgrade". I am looking into trying some Kumho V70a's in a 305/30/18 or possibly R888 295/30/18 if Jamesy decides he wants to sell them I think this will be the only way forward from now on but that obviously won't be much use in the coming months. The joys of winter motoring in boring cars awaits! I reckon you'll still be ok for traction with a Greddy plenum and more boost, you might well get to the 700hp with that turbo and cams which will be great. Someone like Jay could give you a better idea of potential traction problems as he is much closer to those sorts of figures and spec. The problem I have (funny way to think of it though) is the amount of torque mine makes in the lower revs....that is what busts the tyres loose as it's always around 4000-4500rpm that I have issues and I don't think this will be the case for you running a tubular manifold. The only other setups I have seen kicking out the same low rpm grunt are Wez's and Mike B's and they're on cast manifolds too. I have attached a comparison of my setup to yours but mine is only on low boost (1.4bar) and making 556bhp and about the same torque as you. You can really see the difference in the midrange and get an idea of what I'm up against trying to put down ~500lbft compared to ~270lbft at less than 4500rpm. Our gearing means that transferring this sort of torque to the tarmac at low engine speeds is no mean feat for the tyres. When I run higher boost the situation only gets worse One thing is for certain...once I get the traction I want with somethng like the R888s or Sport Cups like you suggest - this thing is going to be very fast indeed Roll on summer 2011.

Nice work Daryl

So how much would I have to pay Noel to widen up the back end on my car to fit these under?

Here's a comparison of the "valve shut" to "valve open" setup. Ryan didn't get chance to do a second map to optimize things for when the valve is shut so those numbers may pick up a bit if he removed a little fuel. To be honest though I don't hammer it with the valve shut so it's probably not worth the effort, it's mainly for starting up in the mornings and driving around town/suburbia when I don't want to be too antisocial! It looks like it's only costing abut 35hp in the midrange and about 25hp at the top end which is a better result than I expected. This is how the exhaust turned out and some sound level numbers measured 45degrees up and away from the tailpipe. Exhaust bypass valve closed - quiet mode: 1000rpm - 83.5dB 4000rpm - 90dB 5000rpm - 96dB Exhaust bypass valve open - noisy mode: 1000rpm - 90dB 4000rpm - 91dB 5000rpm - 101dB And if you lean under the car and measure closer to the dump tube: Exhaust bypass valve open - noisy mode: 1000rpm - 89.3dB 4000rpm - 99dB 5000rpm - 103dB

OK I have a few updates to this thread The Alcon brake setup is now waiting on me to finish the caliper mounting brackets, the custom pads that Carbotech made for me are done and I have all the discs and braided lines. With any luck I'll get back onto the brackets in the next few weeks. As some of you may have seen I got back to SRR last week to see what my latest round of mods achieved. Since my last RR session I swapped the intercooler to a Greddy 3 row, modified my quiet 2 7/8" exhaust to have a 4" first silencer and an electric cutout straight after that, plumbed in the breather kit and surrounded my air filter with a shield that seals against the bonnet. I'm now on the lookout for some wider wheels and tyres as the midrange torque (and the rate that it builds) is causing me problems in 3rd gear on bone dry roads with hot 285/35 tyres....2nd gear is a no go at the moment. I need more rubber I also had a pressure transducer plumbed into the exhaust manifold but that obviously made no difference to the results. I'll take a look over the log data soon as I'm interested to see how much greater the exhaust manifold pressure is compared to my boost pressure. Anyway here's the latest plot: And this is a comparison to the old setup when it was last dyno'd:

In theory the boost should build more progressively and smoothly so that part of your bum dyno is not unbelievable. What's the A/R of both turbo housings? What is the bore diameter of the runners on your old XS manifold and the new Greddy manifold? I suspect the Greddy will be bigger. Also, are the runners a lot longer on the new Greddy manifold? I have seen some where they very very long.

My better half has just reminded me that I have a pair of these boxed in the garage. I didn't believe her but after popping out to check she is absolutely spot on - brand spanking and waiting to be fitted! Typical. At least I have a Supra job for tomorrow now Jay, I'm sorry mate but I'd be an idiot to buy these when I already have a set which I forgot about. Really sorry to faff you about! Friends again

Yes please Jay. PM me your payment details.

If you still have the blanket I would like it Rob. Will reply to your pm this afternoon, just heading out the door.

Damn - looks like mine is a little diff Am I right to think that I'd need more than just the casing to make this fit? Different prop and different drive(half)shafts?

Very interesting - thanks mate. Maybe a 295 R888 would see me through. Did you ever sell those 315 Yokos that you beat me to on Ebay?