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| Mikuni hsr Sc12 https://ausmini.com/forums/viewtopic.php?f=5&t=92110 |
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| Author: | MINI66 [ Mon Mar 14, 2016 8:45 pm ] |
| Post subject: | Mikuni hsr Sc12 |
Hi there Just finalised my mikuni setup. Massive increase in performance over the hif6 su. 20% (seat of pants est) Boost has increased by 2psi with carb change alone. 42mm hsr mikuni with the following specs: - vperformance upgraded accelerator pump -300 main jet . Custom drilled out as youcan only buy up to 240 -20 pilot jet -96 needle from 45mm custom filed -y8 needle jet Now pulling 10psi around town and 13 full noiseon the hwy. I have also made up a custom accelerator pedal with pivot moved up to change ratio. This has reduced the effect of leanout , stumble on fast depression of the pedal / vac sgnal loss. Stock pedal only had 44mm travel from idle to wot. 27mm at carb. New pedal sees 80mm at the pedal so less sensitive. Note that the accel pump upgrade alone does not cure the stumble on tip in. Only real downside is that air fuel ratio a bit rich at cruise , but this was required to combat the stumble on tip in/transition to boost. 11.2 at cruise, 11.8 wot, 12.5 mid, 12.2 idle Just thought this may interest some other sc12 owners. Note that you do needto drive a little differently. Ease on throttle a little at start and then mash it. 3rd gear wheel spin everwhere , limslip will be next . Stoked Rick |
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| Author: | FNQ [ Tue Mar 15, 2016 3:00 pm ] |
| Post subject: | Re: Mikuni hsr Sc12 |
thanks for the info..... just as an aside what were the specs you were running on the hs6. |
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| Author: | Kennomini [ Tue Mar 15, 2016 6:37 pm ] |
| Post subject: | Re: Mikuni hsr Sc12 |
Any pics please? |
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| Author: | drmini in aust [ Tue Mar 15, 2016 6:59 pm ] |
| Post subject: | Re: Mikuni hsr Sc12 |
Gafmo is running an HSR44 on his (was mine) 1412 stroker and is very happy with it. Good performance, sounds great, easy to tune, and no SU needles!!! |
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| Author: | MINI66 [ Tue Mar 15, 2016 7:44 pm ] |
| Post subject: | Re: Mikuni hsr Sc12 |
Was running a hif6 similar to hif44 not hs6. Bcg needle I think. Was the richest available. Twin dashpot springs 25w 60 dashpot oil. Was a dog of a thing , spent endless hours trying to get it right. Profiling needles, all types of oil and spring weights. Could never get a good compromise between lean out on tip in and wot piston at full height. |
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| Author: | MINI66 [ Tue Mar 15, 2016 8:15 pm ] |
| Post subject: | Re: Mikuni hsr Sc12 |
This is my Mini - The silver one with the twin sunroofs - back in the SU days viewtopic.php?t=46795 I have attached a few photos of the Mikuni Setup - as requested |
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| Author: | MINI66 [ Tue Mar 15, 2016 8:59 pm ] |
| Post subject: | Re: Mikuni hsr Sc12 |
Fyi - carb was from john at vintage performance. 3weeks wait from new york. Not a bad guy from my experience |
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| Author: | gtogreen1969 [ Tue Mar 15, 2016 9:55 pm ] |
| Post subject: | Re: Mikuni hsr Sc12 |
I like the position for the Brake Servo. Looks like a factory fit. |
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| Author: | MINI66 [ Wed Mar 16, 2016 7:42 am ] |
| Post subject: | Re: Mikuni hsr Sc12 |
Yeah thanks, I needed to fit the oil cooler in there so it was really the only place that I could put it. It is a VH44 and works well with my 8.4inch rotors. Just welded a little bracket onto the brace to mount it. Need to update the scabby looking oil catch can next to it. All of the chrome has come off and I would like to make one up the fits that space better. A fair bit of tidy up planned for the engine bay. Just need to find the time. |
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| Author: | FNQ [ Wed Mar 16, 2016 5:17 pm ] |
| Post subject: | Re: Mikuni hsr Sc12 |
thanks good fit up, glad you gave it running well |
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| Author: | MINI66 [ Tue May 03, 2016 2:41 pm ] |
| Post subject: | Re: Mikuni hsr Sc12 |
Update on a few things. - Changed pilot jet from 20 to 22.5. Has thickened up the mixture on transition to boost (low revs under load transition), feels a fair bit stronger but has left the idle very rich at about 11:1 when the blower is hot. - Went hotter on the plugs from BPR6 to BPR5 to avoid plug foul at idle with such rich mixture. May even go iridium if this is a good final heat choice. Running 0.8mm gap (Electronic pulsar dizzy). - Dialed in 20 Deg of static ignition timing (was 12) which has also helped off boost drivability. - New 600cca battery to assist starting with so much timing (bosch starter) - Skimmed some timing off the top with the MSD boost retard (now at 0.75deg retard per pound of boost > 5psi) Pretty happy with it where it is now. (50ltrs worth of fuel so far just in tuning time) Downsides: - Can't just dive into the throttle pedal like with an SU. Gradual at first, however this transition is much better now. Wife drove it yesterday and said that it drives fine (the wife test), (she also said that she shat herself with the horsepower increase over the SU) - Idle and cruise is rich which will effect fuel economy but you get that. (Not build for economy) (required compromise) Upsides: - So much more horsepower than the SU (I would say up to 25% now that I have fully finished tuning) - Mad induction noise - No SU oil or springs to mess with I might recalibrate my Tech edge wide band air fuel meter as it has never been done in the 10 yrs that it has been on the car. I suspect that it may be reading a bit rich. It says idle at the moment is around 11:1 (sometimes dipping to 10.5-10.8 if left idle long enough)but there is no black smoke evident. Cheers Rick |
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| Author: | zulu_warrior1976 [ Wed May 04, 2016 6:51 am ] |
| Post subject: | Re: Mikuni hsr Sc12 |
Maaaaaaad |
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