Ross' TD Turbo Daily

[Ade 517]

1 minute ago, S18 RSG said:

Another consideration here. @Riceburner informed me that I should be ok with a 255/35 on an 8.5 (something I've noticed is commonplace on the BMW forums), and the Michelin PS4's are only £130 each at that size, £20 per corner cheaper than 245/35's!

Gotta be a good option right?

Yep i've cconsidered 255s. I can get 255/35 AD08Rs... I wonder fi they will rub though as its a bit tight. 

I get around 28MPG on mixed driving, but its very right foot dependent! 

[S18 RSG 429]

3 minutes ago, Ade said:

Yep i've cconsidered 255s. I can get 255/35 AD08Rs... I wonder fi they will rub though as its a bit tight. 

I get around 28MPG on mixed driving, but its very right foot dependent! 

Hmm, didn't think about the rubbing issue. I know plenty of US guys run 255's all around for Autocross and the like, and I can't find anything relating to rubbing at that size, but of course that doesn't mean it isn't an issue, perhaps just that I can't find it

[Ade 517]

5 minutes ago, S18 RSG said:

Hmm, didn't think about the rubbing issue. I know plenty of US guys run 255's all around for Autocross and the like, and I can't find anything relating to rubbing at that size, but of course that doesn't mean it isn't an issue, perhaps just that I can't find it

hmmm It might be okay. I had a bit of rubbing  under hard tight cornering at the track. I think it was rubbing somewhere on the inside plastic lining when the wheel was at a sharp angle.

Had to raise the front 5mm to stop it. The 235/40/18 have a diameter 20mm bigger than stock though, whereas a 255/35 is only 10mm more than stock so might be okay. 

[S18 RSG 429]

3 minutes ago, Ade said:

hmmm It might be okay. I had a bit of rubbing  under hard tight cornering at the track. I think it was rubbing somewhere on the inside plastic lining when the wheel was at a sharp angle.

Had to raise the front 5mm to stop it. The 235/40/18 have a diameter 20mm bigger than stock though, whereas a 255/35 is only 10mm more than stock so might be okay. 

I would guess I'm probably not running as low as you either, due to having the HTAutos lip kit. If I run anything more than a mild drop, I hit everything, so I kept it at a sensible height (no more than 20mm lower than stock almost certainly).

[Ade 517]

7 minutes ago, S18 RSG said:

I would guess I'm probably not running as low as you either, due to having the HTAutos lip kit. If I run anything more than a mild drop, I hit everything, so I kept it at a sensible height (no more than 20mm lower than stock almost certainly).

I think im only about 20mm at the front. My wheels are 35 offset though, so if it rubbed where I think it was rubbing (I couldnt see any signs) a larger offset closer to stock will help too. 

[S18 RSG 429]

Just now, Ade said:

I think im only about 20mm at the front. My wheels are 35 offset though, so if it rubbed where I think it was rubbing (I couldnt see any signs) a larger offset closer to stock will help too. 

Mine are 35 offset front, 30 rear, but obviously half an inch narrower, so we're probably in a similar situation.

[Ade 517]

 

Just now, Ade said: I think im only about 20mm at the front. My wheels are 35 offset though, so if it rubbed where I think it was rubbing (I couldnt see any signs) a larger offset closer to stock will help too. 

 

 

Mine are 35 offset front, 30 rear, but obviously half an inch narrower, so we're probably in a similar situation.

 

 

 

Well raising 5mm was all I needed to stop it so it might be enough well 6mm less poke.

 

 

You've got me thinking though as £130 for ps4 in 255/35 looks tempting. 4dB quieter too

 

 

[TTR 509]

7 minutes ago, Ade said:

 

You've got me thinking though as £130 for ps4 in 255/35 looks tempting. 4dB quieter too

Likewise, just worried it's too much grip. Can still get sideways on my Vredestein 255's. Don't think that'll be the case on PS4's 

Might shoot for some Hankooks. 

[S18 RSG 429]

11 minutes ago, TTR said:

Likewise, just worried it's too much grip. Can still get sideways on my Vredestein 255's. Don't think that'll be the case on PS4's 

Might shoot for some Hankooks. 

On stock(ish) power, I think you're probably right. A sticky 255 will probably take away some of your ability to steer the car with your right foot. With FI, I think a sticky 235-255 is probably about right to get back towards OEM levels of fun, without uncontrollable fear of death.

[S18 RSG 429]

17 minutes ago, Ade said:

Mine are 35 offset front, 30 rear, but obviously half an inch narrower, so we're probably in a similar situation.

Well raising 5mm was all I needed to stop it so it might be enough well 6mm less poke.

You've got me thinking though as £130 for ps4 in 255/35 looks tempting. 4dB quieter too

Malvern Tyres (not sure if they're Nationwide, or just Wales) can do them for £135 fitted. Gonna pop by on my way home and see if they can't knock that down to £500 for a set of 4 (£125 each). If so, I'll probably get a set on order.

[TTR 509]

2 minutes ago, S18 RSG said:

With FI, I think a sticky 235-255 is probably about right to get back towards OEM levels of fun, without uncontrollable fear of death.

May the spirit of Daigo guide you 🙏

[GT86-Ian 351]

Don't ask me how good they are but I have Avon ZZ5 £410 fitted 245/40/18

[Lauren 2259]

Isn't a 255 just a bit wide on a 8.5" rim? I'm sure you can fit it, but you're going to get some sidewall flex with that. 

I would have said 235 as a maximum ideally. 

I'm starting to feel relatively under tyred with a 215 on an 8" rim!

[Kodename47 446]

14 minutes ago, Lauren said:

I'm starting to feel relatively under tyred with a 215 on an 8" rim!

I still run 215s and will continue to do so.

[Lauren 2259]

6 minutes ago, knightryder said:

I still run 215s and will continue to do so.

Good, I'm glad it's not just me. I like handling over grip and you can still go fast enough, it's just more fun.  

[S18 RSG 429]

24 minutes ago, Lauren said:

Good, I'm glad it's not just me. I like handling over grip and you can still go fast enough, it's just more fun.  

You gotta remember though, tyre sizes aren't just about handling. Running a 225 with nearly 50% more power than stock means I can barely enjoy the power, as it's spinning up 1st through 3rd (sometimes even 4th in damper conditions) when I get on it.

Going to a 235, I would say, is hardly gonna make a difference. In fact, I know Mark is running 235's and I'm sure he said he had some traction issues at that size.

A 245 I feel would be ideal. The problem is, a set of PS4's in 255/35/18 are cheaper than a fair amount of tyres at 245 (only Yoko V105's and Vredestein Sessanta's are cheaper, of those I would run anyway), perhaps due to the more common size, so while it may be a little wider of a tyre than I had planned, I feel it's justified.

Also, 255/35/18 and 255/40/18 are what BMW, Mercedes and Audi all run on OEM 8.5J wheels. Now I'm not saying that's all the proof we need, but it shows that it's clearly a fine setup.

[Lauren 2259]

It's an interesting debate. I tried 225/45/17's on my 8" rims. I found there was some difference in grip, but it was the sidewalls moving around that I really didn't like. I've been in Kev's car with 235's on sticky Direzzas on track and well, it re-arranged my kidneys with the grip levels. It was hugely more grippy than mine, but I didn't like it at all as that's all it was. Whilst it was obviously quicker, Kev admitted that it wasn't as much fun. Rob was running 235's IIRC with his Sprintex. 

Manufacturers commonly seem to stick on the widest tyre on the narrowest rim it seems. 

[rob275 1817]

I've ran both 225's and 235's on my 9" wheels and I am currently making my way back to 225's as I prefer it. After my blowout on the rear I got 2 more tyres so I am running the new 225's on the front and 235's on the rear atm to wear them out.

[S18 RSG 429]

4 minutes ago, Lauren said:

It's an interesting debate. I tried 225/45/17's on my 8" rims. I found there was some difference in grip, but it was the sidewalls moving around that I really didn't like. I've been in Kev's car with 235's on sticky Direzzas on track and well, it re-arranged my kidneys with the grip levels. It was hugely more grippy than mine, but I didn't like it at all as that's all it was. Whilst it was obviously quicker, Kev admitted that it wasn't as much fun. Rob was running 235's IIRC with his Sprintex. 

Manufacturers commonly seem to stick on the widest tyre on the narrowest rim it seems. 

I think I conceded that the car was never going to be as fun to throw around when I went for the turbo. Part of the fun of the stock car is that it's fast enough to have serious fun, but "slow" enough to drive it almost flat out most of the time without getting in too much trouble (I know it's not slow, hence the " ").

Admittedly, since I picked up my car from TD, it's been Autumn or Winter, so I've not had chance to try it in decent weather, but I have no doubt it's going to require a lot more concentration and effort than it used to, to have even nearly as much fun. That's one downside I feel to increased power (not that I would change my decision).

1 minute ago, rob275 said:

I've ran both 225's and 235's on my 9" wheels and I am currently making my way back to 225's as I prefer it. After my blowout on the rear I got 2 more tyres so I am running the new 225's on the front and 235's on the rear atm to wear them out.

Interesting. In what way do you prefer it? 

Don't get me wrong, I find it entertaining how easy it is to spin the wheels, however, knowing how easy it is to overwhelm the tyres in a straight line has made me less confident in the corners. I feel like with an upgrade in grip (something in line with the upgrade in power), I'll have the confidence to start having fun in it again.

It's a bit of a fine balance really. Too far, and it becomes a sticky track car (which is fine if that's what you want), but not enough, and it becomes a little lairy. I feel like I'm closer to the latter than the former.

[Lauren 2259]

4 minutes ago, S18 RSG said:

 

Don't get me wrong, I find it entertaining how easy it is to spin the wheels, however, knowing how easy it is to overwhelm the tyres in a straight line has made me less confident in the corners. I feel like with an upgrade in grip (something in line with the upgrade in power), I'll have the confidence to start having fun in it again.

It's a bit of a fine balance really. Too far, and it becomes a sticky track car (which is fine if that's what you want), but not enough, and it becomes a little lairy. I feel like I'm closer to the latter than the former.

Grip in a straightline is not the same as grip in the corners. For example, I tried two tyres. Firstly the Contisport Contact 5's which had really good grip off the line and in a straight line when accelerating. They were better than the V105's in that respect. But when it came to lateral grip the situation was reversed. Spinning wheels in a straight line is easy to control, but I preferred the better lateral grip of the V105's. Also remember it's harder to get the heat into big wide tyres than it is skinnier ones. I'll bet Rob prefers the skinnier tyres because of the better feel you get and the better response of pulling the sidewall to the rim a bit as it sharpens things up noticably. 

[S18 RSG 429]

10 minutes ago, Lauren said:

Grip in a straightline is not the same as grip in the corners. For example, I tried two tyres. Firstly the Contisport Contact 5's which had really good grip off the line and in a straight line when accelerating. They were better than the V105's in that respect. But when it came to lateral grip the situation was reversed. Spinning wheels in a straight line is easy to control, but I preferred the better lateral grip of the V105's. Also remember it's harder to get the heat into big wide tyres than it is skinnier ones. I'll bet Rob prefers the skinnier tyres because of the better feel you get and the better response of pulling the sidewall to the rim a bit as it sharpens things up noticably. 

Sure, there's nothing wrong with what you're saying, and for the most part, I agree, but as much as the theory carries over, it's still a very different story comparing 200hp to 275hp.

Where I agree with what you've said, is that you're right saying a 235 tyre might be plenty, especially a stickier tyre like the PS4, however I still don't know whether it will be enough for what I want, given how small the difference is compared to my current setup. While it is, as you say, very easy to control straight line grip with the throttle, it's not something I want to have to do. If I can upgrade the levels of grip in such a way that makes the car as it was as stock, albeit significantly faster, then that's what I'll do (and certainly what I'm aiming for).

It would be a bigger disappointment for me to spend £400-500 on a new set of tyres, and find I'm still having the same drawbacks as currently, than if I were to find the car had too much grip.

If someone was to chime in and assure me that they have a setup that works in a way that it sounds like I would enjoy, I'd go for it, but so far the most relevant information I have to go off, is Mark's feedback, and experiencing Mike's demo car. Both cars with the same power as mine, both struggling to put down their power on 235 tyres.

[Lauren 2259]

See what Rob says, he runs much the same power as you. 

[rob275 1817]

@S18 RSG I prefer the lesser sidewall flex from a 225 on the 9" 235 gave too much for my liking and it felt over gripped. It'd take too long for it to step out. Maybe i could have got used to it i don't know.

[DanJ 374]

 

Mines supercharged with similar power to the TD turbo kit and 225s on 8" rims are absolutely fine for me. You have to be really aggressive with either steering, throttle or both to get the rear to break loose in the dry.

 

 

 

It's also worth bearing in mind that as tyres get wider the shape of the contact patch changes and while they may have more ultimate grip, they are much less progressive as they lose grip over the top of the traction vs slip curve.

 

 

 

[S18 RSG 429]

12 minutes ago, rob275 said:

@S18 RSG I prefer the lesser sidewall flex from a 225 on the 9" 235 gave too much for my liking and it felt over gripped. It'd take too long for it to step out. Maybe i could have got used to it i don't know.

10 minutes ago, DanJ said:

Mines supercharged with similar power to the TD turbo kit and 225s on 8" rims are absolutely fine for me. You have to be really aggressive with either steering, throttle or both to get the rear to break loose in the dry.

Hmm, ok. Seems like a similar situation to that of Lauren's, and why she's stuck with a narrower tyre.

What's worth mentioning though Dan, is that there is a difference in power delivery between yours/Rob's setups compared to mine. While the TD kit is, to my mind, a very smooth power delivery for a turbo, there's no getting away from the fact that there is a distinct "on" position for boost, whereas yours are both building boost from much lower in the rev range.

I think Mark agreed with me when I last spoke to him too, that the throttle on the TD map is very sensitive. Seems like 80% of the power comes on with the first 30-40% of the throttle, so even the slightest movement of your right toe can get the tyres spinning.

If I drive it like a sensible person, I absolutely agree that 225's are fine. It's only when I get on it and go for a spirited drive that I start to lose a bit of confidence, which I feel would have to be helped by a little more grip.