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Carb needles...again.. https://www.ausmini.com/forums/viewtopic.php?f=2&t=101181 |
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Author: | ben73 [ Sat Jan 15, 2022 7:20 am ] |
Post subject: | Carb needles...again.. |
Hi All, Does anyone know of a needle with the top end somewhere between a 7/CP4 and a BG? I've been doing a lot of dyno and road testing. #6's were great at all cruise speeds/loads but went way lean above 5k. I skimmed them down to something close to a CP4 and 7 (and beyond) at the top end and it's getting better but those needles are a bit untidy now, so I'm looking to start again with fresh needles closer to what it wants. I'd love to try a BG, but it's a big jump from a 7 so it could turn out to be too rich and I'm getting sick of buying needles So something a bit thicker I can mod if required would be great starting point. Any ideas? Thanks! |
Author: | OGW1152 [ Sat Jan 15, 2022 7:41 am ] |
Post subject: | Re: Carb needles...again.. |
Have you had a look at the Mk1 performance- Conversions Website? There is a free to use Su needle selection tool in their Technical Section. It's a very well put together piece of software and easy to use after some practice. Regards Glen |
Author: | ben73 [ Sat Jan 15, 2022 8:06 am ] |
Post subject: | Re: Carb needles...again.. |
Hi Glen. Yes I've been using that spreadsheet to modify my needles from 6-CP4-7 etc using the 'Advanced' tab, it's a fantastic tool. But I haven't been able to make any sense of the 'Show Suggested' option on the 'Basic' tab. It only ever seems to suggest a AY needle, which is nothing like what I'm seeking. I'll play with it some more later and see if I can get it to make better suggestions. |
Author: | Steam [ Sat Jan 15, 2022 4:51 pm ] |
Post subject: | Re: Carb needles...again.. |
Have a look at an SS needle, or an MME. They seem to fall somewhere near your parameters. |
Author: | ben73 [ Sat Jan 15, 2022 5:20 pm ] |
Post subject: | Re: Carb needles...again.. |
Thanks Dave. The MME will be a swinging needle, but I'll look at the SS, I've never heard mention of it before. |
Author: | IndigoBlueCooperS [ Sat Jan 15, 2022 6:02 pm ] |
Post subject: | Re: Carb needles...again.. |
ben73 wrote: Thanks Dave. The MME will be a swinging needle, but I'll look at the SS, I've never heard mention of it before. The MME is fixed, used to run them on the rally car - 1293, 649 cam and twin 1 1/2's. From memory about as rich as you can go. |
Author: | Steam [ Sun Jan 16, 2022 7:49 am ] |
Post subject: | Re: Carb needles...again.. |
Both are fixed 090 needles. In fact the MME may be the better choice for you. |
Author: | FNQ [ Sun Jan 16, 2022 10:17 am ] |
Post subject: | Re: Carb needles...again.. |
Hi ben73. Just for clarification for me..... you are running twin HS4s? Have you tried pulling the bridge down a little to make it run richer throughout the range? I had a 1310 motor with twin HS4s that ran #6s BUT on the road they would slowly lean out if you kept WOT for more than 20 seconds or so. I did slight mods on the last couple of stations on the needles( similar to you again)- AND i pulled down the bridge to fudge a little more richness ( albeit throughout all revs) Result - had to up the idle - made it sound mean just sitting at lights and still had good drivable AFRs - on cruise and importantly on WOT - (NOTE this was a weekend warrior - fun drive car so not flat stick for extensive periods) I used an innovate wide band AFR meter plumbed in just after the merged pipes and had it hard wired in for a while . This was a relatively tame cam though and i didn't have to worry about traffic and being too rich for long periods at idle. How often are you planning on being above 5000rpm for extended periods of time? I would also suggest checking the curve on your dizzy - i had a CSI 16 different curve dizzy and found the engine liked early advance ( 22-24 degree at 2000ish - but 30 overall) Cheers Darryl |
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