MGB & GT Forum
SU improvments
Posted by andrew240
Topic Creator (OP)
Mar 23, 2005 01:58 PM
Joined 19 years ago
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Mar 23, 2005 02:27 PM
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Mar 23, 2005 02:27 PM
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Mar 23, 2005 02:52 PM
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Homewood, IL, USA
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Mar 23, 2005 04:41 PM
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There's also a book called "rebuilding and improving SUs" or something to that effect by Des Hammill that also does a good job of showing the things that can be done.
Be conservative when/if you round any edges work on the throttle-shafts, etc. If you do too much your carb will flow so well that it won't idle. Note that I said won't idle, not won't idle well, won't idle! Smoothing the bridge - the area where the needle meets the the carb body - is not recommended unless you're racing. Grinding down the throttle shaft at the butterfly is a good mod.
Be conservative when/if you round any edges work on the throttle-shafts, etc. If you do too much your carb will flow so well that it won't idle. Note that I said won't idle, not won't idle well, won't idle! Smoothing the bridge - the area where the needle meets the the carb body - is not recommended unless you're racing. Grinding down the throttle shaft at the butterfly is a good mod.
Mar 23, 2005 05:59 PM
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Mar 23, 2005 06:49 PM
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On HS2s and HS4s for racing we thru-bore them, meaning no bridge what so ever, on HS2 you will actually run out of room, meaning a hole in the bottom of the carb you have to epoxy up. However for street cars this would ruin driveabilty, but with race carb nothing but wide open throttle matters. On a street car I would not worry about bridge mods, if I made any mods to a stock carb for the street I would think about beveling the slide so the square leading and trailing edge is nicely radiused towards the opening front and rear. There are a good many books on SU carbs that was mentioned above, also consider getting on chassis dyno with a air/fuel ratio meter, you might be pleasantly surprised with the gains you can make with stock carbs with the proper needles and jet adjustments.
Hap Waldrop
Acme Speed Shop
Greenville, SC
www.acmespeedshop.com
Hap Waldrop
Acme Speed Shop
Greenville, SC
www.acmespeedshop.com
Mar 24, 2005 10:17 AM
Joined 11 years ago
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Mar 24, 2005 02:03 PM
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