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#1
07-02-2010
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Shocks: Drilling pistons for on-road TC?
Hi just wondering is it really worth doing this for indoor touring car racing, Ive looked on the off road section and a good few people seem to be increasing the diameter of the holes to 1.2mm or greater with drill bits to reduce 'pack'. I'm currently running kit 2 hole pistons on my xray. Will anyone think it will make a noticeable difference in grip on smooth carpet if i go about drilling them? / Anyone tried it?
Cheers 
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我听见 我忘记; 我看见 我记住; 我做 我了解 Chinese proverb: ''I hear and I forget; I see and I remember; I do and I understand'' Ken Block for the WRC title 2010
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#2
07-02-2010
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Touring cars dont land jumps so is there much need to worry about pack?
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#3
07-02-2010
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it makes a difference
 When I ran my xray 008 I had 1.1mm 3 hole pistons all round.
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#4
07-02-2010
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It will make a difference. Pack and rebound also apply to on-road cars. If you have enough choice of damping (different pistons) then there is no need for the changes to chassis flex featured on some cars. However, you'll need a lot of pistons, a range of 'letter' drills and not a little patience to work it all out. Good luck!
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#6
08-02-2010
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Cheers
Thanks all for your replies. Based on the replies its seems pretty worthwhile drilling the pistons as pack isnt really needed.
Makes sense with the three hole pistons my car currently seems too 'overdamped' using kit 2 hole pistons with 40 weight oil so will change and stick to using three hole pistons (preferably get a bunch drilled to 1.1mm and 1.2mm) and see how things go; fingers crossed it should give the car a better 'feel'. Which brings me to another question: what sort of oil are people using in general is it anywhere from 30wt to 40wt? Is there any difference in visocity using 40wt schumacher oil for example compared to 40wt much more, 40wt losi etc? Thanks again
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我听见 我忘记; 我看见 我记住; 我做 我了解 Chinese proverb: ''I hear and I forget; I see and I remember; I do and I understand'' Ken Block for the WRC title 2010
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#8
09-02-2010
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as above, depends on the car you're running, but if it's an xray 008/9 then try 500/550cst oil with hpi pink/silver springs
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#9
09-02-2010
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The general rule I use is 3 hole pistons everywhere because you get a much smoother damping action due to even triangular application of damping. Then just adjust the size of the holes. Bigger holes for lower grip tracks. The viscosity of the oil effects the whole action of the shock, whereas the hole sixe effects the initial action of the shock so how the shock reacts when it first hits the bump in track.
If your running 1500g then much more 450 all round or if at new 1350 id say 300, or 40W down to 35W
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#10
09-02-2010
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Hi, I'm running a old xray T2
 (but its in good nick) with 66mm long shocks. It has a 17.5 lb spring on the front and 14.5lb on the rear (which are the longer old x-ray springs). It hasnt been run for a year or so and have just got back into the hobby just recently and has just had its weight reduced to the new limit (1350g). I changed over the kit 3 hole pistons late last night and 35wt oil all round and just by feel it was SO much better -has a lot less bump stiffness and it also returns to its rest position a lot quicker than before. (forgot how much of a pain measuring shock lengths, droop and tweak afterwards was though  )Makes great sense about the arrangement of the 3 holes with them being equidistant from each other on the piston (never thought about it that way!). So it should be more efficient as the oils being forced to change its direction less, over less distance to where the holes are placed. Will head down to maplins later this week and see if they have some drill bits / have a gander on the net for those tamiya and hotbodies pistons which seem handy being ''predrilled''. Then get testing! Fingers crossed it all goes well this weekend! Thanks!!!
__________________
我听见 我忘记; 我看见 我记住; 我做 我了解 Chinese proverb: ''I hear and I forget; I see and I remember; I do and I understand'' Ken Block for the WRC title 2010
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#11
09-02-2010
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Maplins do a set from .6 to 2mm in .1 steps or something like that, that's what I use
Quote:
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#12
14-02-2010
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Hiya Just a quick follow up from my racing after the changes
Ran Friday at don valley and the car was unbelievable it made a huge difference 2nd fastest of the meeting in 13.5 . Also today the car was really strong in 13.5 and qualified 4th today in the A at stocksbridge unfortunately my front belt turned upside down which ruined my last qualifying round and both legs of finals  . But car was very strong overall and got some nice comments about how my car handled.still need to drill these pistons yet! That was just running the 3 holes!  Cheers for the help made me enjoy my racing a lot more- car was so much grippier and stable! Couldnt believe how much of a difference it made to the car. I did manage to get those drill bits from Maplins cheers
__________________
我听见 我忘记; 我看见 我记住; 我做 我了解 Chinese proverb: ''I hear and I forget; I see and I remember; I do and I understand'' Ken Block for the WRC title 2010
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