We have detected you're not on the correct site for the car you have selected! Click the green button below to go to the correct site.
Select your car: 
BMW Mini Cooper
Select
   Forum Width:     Forum Type: 

 Posted: Nov 7, 2019 03:18PM
Total posts: 1684
Last post: Jul 3, 2020
Member since:Oct 18, 2011
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
"....HS2’s might struggle a little on this tuned engine..."

Depending on how well the mods originally mentioned were done, this is a distinct possibility.

But you have to remember that the determinant controlling how much you can get out of your engine is how air you can get through it rather than the amount of fuel.  

The needles are there to provide the "right" amount of fuel to whatever air flow the engine can achieve.  Vizard provides good explanations as to the need to determine where the choke point is that determines the airflow through the engine.  Only be opening up this choke point can you increase power .... and of course, as soon as you do this the choke point moves somewhere else.... and so on 

IMO people tend to concentrate on the 
needle when tuning SUs and tend to ignore the spring...  The 1.25" dimension is only nominal.. the actual bore is determined by the interaction of engine vacuum and spring strength.  With the correct spring the carb bore will be completely open at WOT under full load.... Too much spring = a reduced carb bore = restricted air flow..  Too little spring = wide open bore = all the fuel possible ..without sufficient air flow.. 

This load+carb opening is why you can't really tune an SU without a dyno ... or as they used to do it with "plug chops"  or more recently O2 meters (and a lot of unrestricted road

You can start with a recommended needle (and spring) and then go through as many variations on the dyno (that you choose to afford) until you get to the optimum.  BTDT .. it took 3 set of needles before we decided enough was enough..

Cheers, Ian

 Posted: Nov 7, 2019 09:27AM
Total posts: 9
Last post: Feb 24, 2020
Member since:Mar 14, 2019
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
Thanks for all of the replies! Been crazy busy at work lately. The carbs have AAA needles in them now. The carbs were new and have been ran very little since going on the car. I’ve been told the HS2’s might struggle a little on this tuned engine and that going to a HIF44 might be less of a headache. Hahaha

 Posted: Nov 3, 2019 01:55PM
Total posts: 313
Last post: Nov 3, 2019
Member since:Jul 3, 2003
Cars in Garage: 0
Photos: 6
WorkBench Posts: 0
US
My 1275 engine Inno Mini Export With HS2s has AAP needles and that is what is listed for it.  Joe Curto said the engine is more like a 1275 GT or AH Sprite and is why the needles are different from other Mini carbs.  

I have an oxygen sensor and gauge.


 Posted: Oct 26, 2019 01:30PM
Total posts: 3479
Last post: Jul 2, 2020
Member since:Feb 26, 1999
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
US
I checked this afternoon and find I am running V3 in mine.

 Posted: Oct 22, 2019 07:09AM
Total posts: 4075
Last post: Jul 8, 2020
Member since:Oct 8, 2011
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
US
If compression is in the 10 to 1 region 5 or 6 should get you close. I find my O2 gauge is the answer to all my questions. Steve (CTR)

 Posted: Oct 21, 2019 06:04PM
Total posts: 3479
Last post: Jul 2, 2020
Member since:Feb 26, 1999
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
US
Quote:
Originally Posted by Smithengineered
Anyone have recommendations on proper needles for hs2 carbs on a 1310, ported/polished head, cam, roller rockers, lightened flywheel, exhaust? Trying to dial in the fuel on my Innocenti with a colortune kit. Seems to be lean at idle and super rich under acceleration. I have yet to take the needles out to see what’s currently in there.
Start by finding out what you have - then you can look at some of the books on SU's
Look up what was used on the 1275 - they list a weak/standard/rich needle ( as noted above /M/AH2 )
Check the cam specs and see which needle they recommend for their cam.
Check the specs on the head - what do they recommend for their head.
Which rockers - standard or 1.5:1 ratio?  there again what do they recommend.
Look at Vizard, "How to modify your Mini" where he goes over the spring/needle to use ( Red/AH2 )
When was the last time the carbs were serviced/rebuilt

 Posted: Oct 21, 2019 04:45PM
 Edited:  Nov 4, 2019 09:23AM
Total posts: 8282
Last post: Jul 3, 2020
Member since:Feb 7, 2006
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
Check out mintylamb.co.uk there is a comprehensive list of needles there with a chart to compare them.
Joecurto.com in NY is a good source for harder to get needles.

If in doubt, flat out. Colin Mc Rae MBE 1968-2007.

Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.

 Posted: Oct 21, 2019 12:47PM
Total posts: 13844
Last post: Jul 3, 2020
Member since:Jan 22, 2003
Cars in Garage: 4
Photos: 381
WorkBench Posts: 1
CA
M is a standard 1275 needle and AH2 is the rich needle........so I'd use the AH2 as a starting point.

( or switch to twin HS4 or H4     )

 

"Everybody should own a MINI at some point, or you are incomplete as a human being" - James May

"WET COOPER", Partsguy1 (Terry Snell of Penticton BC ) - Could you send the money for the unpaid parts and court fees.
Ordered so by a Judge

 

 

 

 Posted: Oct 21, 2019 08:40AM
Total posts: 9
Last post: Feb 24, 2020
Member since:Mar 14, 2019
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
Anyone have recommendations on proper needles for hs2 carbs on a 1310, ported/polished head, cam, roller rockers, lightened flywheel, exhaust? Trying to dial in the fuel on my Innocenti with a colortune kit. Seems to be lean at idle and super rich under acceleration. I have yet to take the needles out to see what’s currently in there.