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Carb needle 12G295
Posted: Thu Feb 08, 2007 10:22 am
by donhailo
Hello,
I´ve just fitted a 12G295 c-head to my 1098er block. Inlet is alloy, exhaust standard, head has been skimmed to the proper compression rate. Does anyone has a needle-suggestion for a HS4 or a HIF38 carb?
Thank you very much,
donhailo
Posted: Thu Feb 08, 2007 11:18 am
by picky
its not an exact science. Idealy you would have it setup on a rolling road that is used to working on the A series engine. They would test a few needles and then fit the one that made the most power. An hour on a rolling road costs about £80 to £100 I think.
The car will run with any needle, but you might find that at certain engine speeds the car loses power, called a "flat spot".
If you have the budget then go for the rolling road, if not then get the winsu software
http://www.winsu.co.uk/ which is free for 10 uses, but the registered version is only cheap I think. Tell it what engine configuration you have and it will suggest what needle to use.
Good luck!
Posted: Thu Feb 08, 2007 11:59 am
by alex_holden
I don't think that's right. You can use the unregistered version as many times as you want but it won't show you the part numbers of the recommended needles. You have to pay £10 to activate that feature even if you only want to use it once.
Posted: Thu Feb 08, 2007 12:10 pm
by picky
alex, yes you are right I have checked the website and I have a much older version!!
the older version you could use 10 times for free. The current version is £10, which is still value for money in my opinion.
Posted: Thu Feb 08, 2007 7:19 pm
by plastic_orange
I used a Number 5 or 6 needle on a 1098 with that head and HS4 - worked fine (off the clock and hitting the stop needle on the way back), but can't recall exactly which of the 2 I used - 6 is slightly richer I think.
Hope this helps.
Pete
Posted: Thu Feb 08, 2007 7:55 pm
by bmcecosse
There are plenty of free sites that list ALL the SU needle profiles. The HIF 38 is by far a better carb than the old HS4 - and gives no splutters on cornering. I think you will find an AAA needle works well in that carb for your set-up..