RE: Subaru Isle of Man TT car - new pictures
Discussion
AntiLagGC8 said:
I'm not sure why you quoted me in your previous post? 
Because the point is that as you pointed out, the car is making up the time in the very bits that some were insisting made the track unsuited to cars. It's losing time in the acceleration zones and the high speed sections, not because it can't "thread the needle", handle the bumps or traverse the bridge.
otolith said:
AntiLagGC8 said:
I'm not sure why you quoted me in your previous post?
Because the point is that as you pointed out, the car is making up the time in the very bits that some were insisting made the track unsuited to cars. It's losing time in the acceleration zones and the high speed sections, not because it can't "thread the needle", handle the bumps or traverse the bridge.paulwoof said:
Should have let the bikes chase him 
TX.
ZX10R NIN said:
What's that?
Have a readhttp://www.gfb.com.au/tech/tech-articles/11-the-tr...
http://youtu.be/fq2ekzptguo
Edited by Coatesy351 on Tuesday 7th June 01:23
daniel-5zjw7 said:
RobM77 said:
Absolutely nowhere near it. I've been on test days with loony tuned Imprezas and Evos and they were doing Caterham lap times. I suspect this factory job is faster, but it's still going to be nowhere near a proper racing car. I suspect it'd do about 7min30 at the ring? Group C were in the low 6s in the 80s and modern racing cars would be deep into the 5s. I'm not saying that Subaru's effort this week isn't a great thing to watch, made all the more impressive by Mark's superb driving, but a tuned road saloon is never going to be 'fast' in absolute terms.
Wouldn't say absolutely nowhere near it, a prodrive built car with 600bhp and many WRC parts including the gearbox is a pretty serious proposition and no doubt cost 100s of thousands to build, I expect it is close to the ideal for the Isle of Man course, I still feel most 'race' cars wouldn't work for this, and something along the lines of a pikes peak car would be needed to push the boundaries further. Lets see what speed Higgins ends the week on.1) CofG. As far as I know, the engine is wet sumped and located in the same position as the road car, which will make the CofG much higher than necessary. The need for the driver to see over the scuttle will also put him too high. The shell is also not the best thing for CofG, plus the addition of a heavy rollcage. Look at the layout of an LMP or single seater for comparison. This is all going to make a huge difference. You could actually keep the ride height the same as the Subaru for the bumps and still have a much lower CofG.
2) 4WD. In the dry, I suspect this is more of a burden than it is a benefit on the fast and flowing TT course. Given the constraints of a road car listed above, I suspect it's fine, but if you were to build a car from scratch for outright performance that weighed 600kg I doubt 4WD would improve performance
3) Weight. F1, LMP1 etc are all sub 700kg, so I see no reason why a purpose built TT car wouldn't be half this Subaru's weight, or less.
4) Power. 700bhp+ is easily available from a range of pre-existing off the shelf racing engines. They're also probably more driveable due to being normally aspirated.
5) Drag. The road car shell is a huge lump of frontal area compared with how big the car needs to be to carry a driver and an engine around the course.
6) Downforce. That tiny wing on the back picking up turbulent airflow isn't going to produce anywhere near the sort of downforce a pukka racing car would have. Big downforce is probably a burden on the fast TT course, but with a purpose built car you could undoubtedly obtain far more downforce with a lot less drag.
7) Wheels and tyres. Freed from the constraints of the road car shell, wider wheels and tyres would be possible.
8) Unsprung mass. The Subaru has huge brake discs and callipers to stop 1200kg; if the car was sub 700kg it would have to carry much less unsprung mass. A racing suspension system with push rods would further improve things. On that subject, even with harder bushes the Subaru is still running road car suspension, which is far from ideal from a geometry and unsprung mass point of view.
So in short, this car could be half the weight, with much less drag, a much lower CofG and more power. As I said earlier, look at Nuburgring times and I suspect such a car would be in the 5s without an issue, whereas I suspect this Subaru would be in the low 7s. Potentially then a purpose built car could shave about 3 or even 4 minutes off the TT time of the Subaru. Basically there's just a huge gulf of performance between road car based machines and racing machines at any course around the world, including hillclimbs on public roads, some of them at the IoM.
Edited by RobM77 on Tuesday 7th June 10:51
RobM77 said:
On that subject, even with harder bushes the Subaru is still running road car suspension, which is far from ideal from a geometry and unsprung mass point of view.
Not sure I agree with that Rob. My guess (and it is only a guess) is that's it's running a full WRC suspension set up.The picture Big Mowley posted and indeed the picture in the intro to the other thread running about "The Secrets of ...) shows the front inner flitches to have been tubbed and the car is running WRC front top mounts.
This is S11 (2005) front suspension :
this car is running the suspension from the last WRC cars Prodrive built the S14 (2008) :
by which time the suspension and its components had been further refined still.
In the images of the S11 front suspension it can be seen the front crossmember is a bespoke tubular item. It's strong, light and easy to replace, it also allows the front suspension geometry to be optimised. The car's bespoke wet sump can be seen, and the engine is mounted lower, you'll be aware that being a flat four it's CoG is better than most.
The biggest issue is that WRC cars run on relatively narrow wheels/tyres (8J X 18 for Tarmac), and accordingly their suspension geometry is optimised for this width of wheel.
Higgins car may be running wider wheels with it's Dunlop BTCC tyres, but judging by the width of the wheelarch extensions, I suspect they're little if any wider at all than the WRC width wheels.
This is to all intents and purposes an S14 WRC car built into a current STi shell. As a WRC car, it is massively compromised, after all those suspension components are designed for the yumps of Finland, the loose stages of Wales and the vineyards of Germany, to name but a few.
Where they will be of benefit will be the huge suspension travel and damping of which the quality is probably as good as it gets (they look to be running ExeTC dampers). The down side is, given the choice they'd most likely run wheels 10-11" wide with suitably stickier rubber.
This attempt is, whatever your standpoint, an incredible feat, Higgins is a massively talented driver, that he's coerced this car around the island at the speeds he has, says a lot for his talent and the quality of the car, irrespective of the massive compromises within it that you've so concisely highlighted.
Slippydiff said:
My guess (and it is only a guess) is that's it's running a full WRC suspension set up -snip-
You're right.It's got suspension from exe-tc. http://www.exe-tc.co.uk/
Coatesy351 said:
ZX10R NIN said:
What's that?
Have a readhttp://www.gfb.com.au/tech/tech-articles/11-the-tr...
http://youtu.be/fq2ekzptguo
ZX10R NIN said:
As for a MotoGP bike the main problem would be the stiffness of the chassis this is something the R1M in particular suffers with this. You need have a certain amount of flex in the chassis I reckon a Panigale would be a nightmare.
My R1-M is terrible on the road, its run in now so straight onto the track.
ZX10R NIN said:
You could hear the compressor surge on those clips Coatsey
Glad people now understand what the noise is, goes someway to people understanding that a dump valve/bov/all the other names, are not fitted to reduce turbo lag, but to keep sufficient flow to prevent the turbo crossing the surge line, and by keeping the turbo moving a mass of air, actually can reduce the speed of the compressor making lag slightly worse.Gassing Station | General Gassing | Top of Page | What's New | My Stuff