Single to Twin SU Worth It?

General Chat with an emphasis on BMC Minis & Other iconic cars of the 1960's. Includes information on MK1 Action days.
Tornado99
Posts: 12
Joined: Thu Dec 24, 2020 9:03 pm

Re: Single to Twin SU Worth It?

Post by Tornado99 »

I'm in BC Canada and do not know of any rolling road facilities in the region. So not likely it will ever be possible to get that level of tuning done.
This twin idea came up bc I came across a complete twin SU setup for mini on a used parts lot for sale. With the input here and other forums, seems the wise option is to stick with what I have and avoid introducing more complexity than I can sort out.
mascher
Posts: 109
Joined: Thu Jun 24, 2010 5:12 pm
Location: Seattle Washington

Re: Single to Twin SU Worth It?

Post by mascher »

If you're still using the original intake and exhaust manifolds, I would say keep the HS4 and change to an alloy intake manifold and a Cooper free flow exhaust manifold. Cleaning up the HS4 throat should help a bit as well. This works well on an engine that you're not going to rev much above 5500 rpm.

Kelley
De-hira5729
Posts: 5
Joined: Fri Feb 17, 2023 3:59 pm

Re: Single to Twin SU Worth It?

Post by De-hira5729 »

I didn't feel like using HIF very often in Japan, so it's very fresh.
I would love to try it! !
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MiNiKiN
Posts: 617
Joined: Tue Oct 10, 2017 3:15 pm
Location: Graz/Austria // NN1 4ST previously

Re: Single to Twin SU Worth It?

Post by MiNiKiN »

Tornado99 wrote: Thu Mar 02, 2023 8:06 pm I'm in BC Canada and do not know of any rolling road facilities in the region. So not likely it will ever be possible to get that level of tuning done.
This twin idea came up bc I came across a complete twin SU setup for mini on a used parts lot for sale. With the input here and other forums, seems the wise option is to stick with what I have and avoid introducing more complexity than I can sort out.
Not having access to a rolling road is no excuse. Simply fit a broad-band O2-sensor (Lambda-sensor) to the LCB manifold connected to a black-box or A/F-Meter. Such you can set-up the carbs on the road - better than on many rolling roads.

I have a Zeitronix System that even records the AF-Signal along with other sensor signals (rpm, throttle pos, temperature, etc - many optional input signals ). You could define a certain test track and navigate it with defined throttle positions - so you see how the AF-ratio behaves over the revs and correct it en route with different needles to match. e.g. https://www.lambda-tuning.de/zeitronix_ ... sonde.html
If only I knew the power of the Dark Side...I wouldn't have made contact with an Innocenti :mrgreen:
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Rolandino
Posts: 534
Joined: Sat Oct 22, 2016 11:37 pm
Location: Wokingham, Berkshire

Re: Single to Twin SU Worth It?

Post by Rolandino »

I'm not sure if anyone has told you this on this thread but if you go from single carb to twins, you have to not only change the inlet manifold but you need a new exhaust manifold and all the rest of the exhaust system. It will give you more power, better torque and higher revs which can't be used with benefit unless you change the gears to S ratios. Good luck! R
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