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Post by Zed on May 29, 2018 17:02:27 GMT
So that's why you now have a top speed of 35mph: " When I say fine I mean it doesn't object, cough or splutter, but it doesn't go very fast, 35mph tops." You would be surprised. Sometimes I look down at the gauge and on the flat or downhill around 65mph I see 15:1 to 16:1 and its running on the primary barrel judging by how far off the floor the accelerator pedal is. Up hill it hits 12:1 and lower if I can hit the bottom of the hill rolling above 60 mph as the power valve cuts in.. coming off the top of the hill it will still be doing 60mph. Same hill struggle to reach 50 mph if hit it below 55... I'm only at 1/4 throttle on the flat doing 70mph. I was describing driving with the main jets, airs amd emulsions in my pocket. 35mph is top speed on idle jets like that. 👍
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Post by chad on May 29, 2018 17:07:32 GMT
I was just being a smartarse when I posted that.
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Post by Zed on May 29, 2018 17:23:11 GMT
I was just being a smartarse when I posted that. I know, I was answering Mike but he'd fucked up quoting you. Or something. Oh well!
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Post by Zed on May 30, 2018 14:08:12 GMT
Believe it or not I'm still messing with this ---ing thing. It runs too well on the smallest idle jets. Just in case, despite it being capped off, I soldered up all the choke jets. No change but it's as if it was getting petrol from somewhere other than the idle jets so I soldered up a set of those too - it wouldn't run.
But now with the tiny idle jets back in it does show lean AFR -that's progress. But as soon as I fitted the main stacks it went richer from idle. So the mains have been coming in from idle which has caused me no end of confusion.
Next step is to make the mains come on stream later so I've refitted dickies 34 vents to reduce the suck on the mains. That's worked too well and the mains are now coming in too late but I do have lean cruise which was the whole point of this sorry tale.
According to theory, now I need even bigger air jets which should cause the mains to come on tap sooner. Then no doubt it'll be too lean and need even bigger main jets to compensate. One step at a time...
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Post by chad on May 30, 2018 14:27:59 GMT
From a layman's point of view I always thought that one of the reasons for the development of fuel injection was to optimise fuelling across the load/revs spectrum, being more 'tuneable' than carbs.. I'm more than happy to be corrected but if you're searching for the optimum, as opposed to 'good' or 'very good', settings aren't you likely to just carry on tweaking and tweaking and tweaking, which may be the object of course.
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Eoin
Full Member
Posts: 101
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Post by Eoin on May 30, 2018 14:52:46 GMT
From a layman's point of view I always thought that one of the reasons for the development of fuel injection was to optimise fuelling across the load/revs spectrum, being more 'tuneable' than carbs.. I'm more than happy to be corrected but if you're searching for the optimum, as opposed to 'good' or 'very good', settings aren't you likely to just carry on tweaking and tweaking and tweaking, which may be the object of course. I'm sure there are improvememts to be made, just takes time and experimentation. Zed's efforts are what I always expected a RR to do 'professionally' when I had carbs, but not what they actually do.
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Post by chad on May 30, 2018 15:05:43 GMT
I guess where I'm coming from is when do you decide to stop?
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Post by Zed on May 30, 2018 15:39:35 GMT
I guess where I'm coming from is when do you decide to stop? FI would be better but the carbs are sexy and they growl. There's no common sense involved or I'd have a £2k transit/Renault/whatever. So far I've gone round in circles so I could stop just about anywhere. But the aim is for it not to guzzle fuel at light throttle positions, to be slightly rich at fast speed and not implode at WOT. That's it! In terms of AFR, that's 15-16-17 very light throttle which I mean creeping up through the gears to 35mph full speed in 4th. Transitioning smoothly to about 13.5 with more throttle and up to 13.1 WOT I've finally got the first bit done even though theoretically it shouldn't run on 48 idles. Then again, over on samba someone flow tested a heap of aftermarket Dellorto idle jets and they were worryingly random both within each set and between marked sizes. Some smaller sizes flowed more than bigger ones. I suspect this hasn't been helping my quest. Now I've got to sort out for more than tiny throttle because it goes too lean in transition (18) and stays too lean (15) from then on. WOT also starts too lean and ends up too rich as the revs rise.
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Post by chad on May 30, 2018 15:54:21 GMT
Fair enough - I can understand your preference for carbs over FI as the latter seems to 'sanitise' the noise, if that makes sense.
If we had common sense we wouldn't be driving round in T2s.
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Eoin
Full Member
Posts: 101
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Post by Eoin on May 30, 2018 16:45:18 GMT
......Now I've got to sort out for more than tiny throttle because it goes too lean in transition (18) and stays too lean (15) from then on. WOT also starts too lean and ends up too rich as the revs rise. Can you adjust the acelerator pump action to get a bigger squirt?
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Eoin
Full Member
Posts: 101
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Post by Eoin on May 30, 2018 16:48:56 GMT
Fair enough - I can understand your preference for carbs over FI as the latter seems to 'sanitise' the noise, if that makes sense. If we had common sense we wouldn't be driving round in T2s. FI with IDF pattern throttle bodies gives the same basic acoustics as Dells / Webers. The noise then depends on the fiter construction and the cam / valvetrain.
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Post by Zed on May 30, 2018 17:04:25 GMT
......Now I've got to sort out for more than tiny throttle because it goes too lean in transition (18) and stays too lean (15) from then on. WOT also starts too lean and ends up too rich as the revs rise. Can you adjust the acelerator pump action to get a bigger squirt? That might mask it a bit while accelerating from slightly open throttle but it's not the answer.
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Post by popegregoryxi on May 30, 2018 21:13:41 GMT
Interesting stuff.
Does it not get hot running on 48 idles at all?
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Post by Zed on May 31, 2018 6:59:44 GMT
Interesting stuff. Does it not get hot running on 48 idles at all? No, because as soon as it's under any load the mains come in, or will when I've finished - hopefully.
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Post by pkrboo on May 31, 2018 8:21:29 GMT
Aaand I'm now lost, been trying to follow this and get my head round it but it's rather confusing.
Think I need to re-read it all
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