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| Drag Racing Discuss Drag Racing here be it dirt or tarmac. Sponsored by Sydney Dragway. |
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24-05-2009, 07:18 AM
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loving the turbo
Join Date: Dec 2007
Location: Far north queensland
Posts: 1,535
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g'day, I've got a bf turbo with 277kw at the wheels. Last night was my 2nd time down the townsville strip since it has been tuned, running 235/45/17 with some standard full street radials. I went in february and ran 13.10 @ 109.75, was spinning a little bit in 2nd with the tyres at 26psi. Last night was probably 14 degrees cooler and half the number of cars there. The tyres were at 25psi andi was spinning in 3rd which i can't even chirp on the road with 38psi. I let the tyres down to 22psi and had my spare and 2 more wheels and tyres in the boot to try and get traction. Ended up with 13.10 @ 111.38. Sooooo after all that long windedness
What is the lowest pressure i can safely run 235/45/17 on a 7.5 inch rim?
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BF mkII 6 speed ZF now with 500hp at the tyres best times so far on street tyres 12.48@113.92 with 277rwkw 12.27@119.1 with 320rwkw |
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24-05-2009, 08:19 AM
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FF.Com.Au Hardcore
Join Date: Sep 2006
Location: TAS
Posts: 2,551
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Lowest is about 16psi, but the best traction is at around 20 to 22 psi from my experience. A track that is not prepared can be slipprier than the street. Dust, old hard rubber, dried up traction compound etc. need to be removed for best traction. Have a look at your 60foot times to get idea how well you are getting off the line. 2.0 to 2.2 is about normal for the bfs on street rubber. On my 12.8 pass in my bf the 60 foot was 2.1 sec with street rubber and 24psi warm.
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XA coupe 8.8sec @ 150mph http://www.fordforums.com.au/showthr...coupe+drag+car BA GT-P for the shed Mustang GT for the other half E3 chubsport - fully fat (and slow), sitting there waiting for me to get sick of it and sell it. BA XR6T for a daily NT Pajero for the bush XB 4 door project- swallows a BF xr6 turbo My dad is a generous bloke. He gave away his dead car batteries free of charge.... |
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24-05-2009, 08:55 AM
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loving the turbo
Join Date: Dec 2007
Location: Far north queensland
Posts: 1,535
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thanks for that
2.314 best 60ft.
__________________
BF mkII 6 speed ZF now with 500hp at the tyres best times so far on street tyres 12.48@113.92 with 277rwkw 12.27@119.1 with 320rwkw |
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24-05-2009, 10:23 AM
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FF.Com.Au Hardcore
Join Date: Oct 2005
Posts: 727
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Townsville is slippery in winter after dark. I raced there years back and it's still the same.
I never tried this while drag racing (in an altered) but when I was kart racing later on we used to pump the tyres up in cold weather and it worked a treat. The idea being to reduce the contact patch on the ground and the tyre will gain more heat. It works. I'm certain that a couple of losses I had in winter drag racing would have been different had I pumped the tyres up instead of letting air out. Next race day try your existing pressure then next run pump them up a couple of pounds and try it. If it goes quicker add a little more (maybe 1-2). |
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24-05-2009, 02:24 PM
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#5 | ||
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loving the turbo
Join Date: Dec 2007
Location: Far north queensland
Posts: 1,535
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ok will try that too.
__________________
BF mkII 6 speed ZF now with 500hp at the tyres best times so far on street tyres 12.48@113.92 with 277rwkw 12.27@119.1 with 320rwkw |
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24-05-2009, 04:12 PM
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Cat be Still !!!
Join Date: Oct 2007
Location: Perth. WA
Posts: 1,672
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More contact patch = more friction = more heat, which would have to give you more traction.
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24-05-2009, 07:34 PM
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FF.Com.Au Hardcore
Join Date: Oct 2005
Posts: 727
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Quote:
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tyre pressure
Linear Mode
