netherx7

Does anyone have any experience with running a 7 on SU's. I'm planning on building a custom intake manifold for my 12A because the hurley kit is a bit on the expensive side for me. I've always had good results running SU's on my piston engined cars and I have a few spare HIF6's lying around the workshop.

MattG

iTrader: (2)

Thats a carb ay?



To be honest with you I had to look it up, before I knew what in the world you were talkign about. I have never seen one of those carbs before.

Like I always say, anything is possible!

ray green

iTrader: (14)

Had them on my Volvo and MGB, a bit much to keep tuned but nice gas deliverers, the main thing a rotary wants.

Ray

64mgb

iTrader: (1)

Dual SU's for my MGB...I knew Ray would be on top of this!



Rich

cosmicbang

Dual HIF6. Excellent combination of performance, fuel economy, and driveability. They are great carbs.

netherx7

Cosmicbang is that a Hurley setup? Do you have anymore pictures?
I think the HIF6 will flow penty, still need to find a needle to suit the 12A. If I remember correctly the Hurley setup uses a BAK needle for the 13B, so I think I'll take that as a starting point and change it as necessary.

DJAngelicon

What company makes those?

Are those the one the Mini Copper use?

netherx7

SU carburettors were originally made by the company 'Skinner Union' and are now still in production by Burlen Fuel Systems. The SU carbs have been used on a lot of british cars from the thirties til mid eighties and like cosmicbang mentioned: they provide a good combination of performance, fuel economy and driveability.

cosmicbang

The later SU carburettors such as the HIF6 look somewhat similar to the earlier models, but were much more advanced.

Yes that is a Hurley setup for 4-port 13B; a custom "one-off" he made for me about 20 years ago. I have a few in amongst the tons of old parts but I'm away this weekend. Remind me later, describe any specific shots and I'll get them for you. Will have a look for needle specs too.

netherx7

Any pic will do, I'm especially interested in how the throttle and choke linkages were fitted and how the oil injection system was hooked up.

cosmicbang

Bottom, showing oil lines. Throttle cable attachment is on left.

netherx7

So if I see this right you used some type of clamp to link the throttle spindles together, but how were the starter devices linked.
Just wondering about the fuel pump, were you usining a stock Rx-7 or an SU pump?? And Shouldn't the overflow pipes be directed away from the exhaust manifold yours seem to be aimed at the manifold.

turdbo

i have also though about that to..i have an old nissan Z car and it has SU carbs on it wich i just upgraded to EFI...now the carbs just sit..but i was thinking about messing with them...

netherx7

If I remember my figures correctly you can get about 240CFM per HIF6 carb, which roughly adds up to a maximum of 480CFM. Compared to somewhere around 300CFM for the stock Nikki carb, this should free up some extra horses.
Turdbo, I believe the Zs were running Hitachi SU carbs, I don't have any experience with those, but they should work. You might have an even bigger challenge finding a correct needle for those than I will for my HIF6s.

cosmicbang

Have fun, but those may be an older model, and your results will vary. The HIF6 represented the pinnacle of SU carburettors.

There are in fact two links or connections between the carbs; more detailed photos would show it better. I successfully used a stock Mazda fuel pump in conjunction with stock 12A and 13B engines, dual HIF6, and headers. The overflow pipes are directed up and out to the sides. IIRC they connected to the fuel return line.

netherx7

One more thing, spring selection. I believe yellow should do, but just to make sure...

netherx7

Damn, my engine has gone down just when I started work on the manifold... Need another engine to continue this little experiment...