10 replies to this topic

[MiniCarJack]

I'm currently running a single HS4 1.5" SU carb on my 1293 engine, and am considering upgrading it either to a twin 1.5" carb setup, or a Weber 45 DCOE. However I'm just wondering what the benefits and drawbacks are of both of these potential setups, and which one would be the more effective upgrade.

 

The engine is from an Austin/Morris 1300 but has been fully rebuilt, bored out +20 to 1293, and fitted with a cam ground to ST948 specs. I've also recently had a Stage 1 kit fitted (but not the needle yet). It has a good power band and pulls the car along nicely, but I wouldn't mind getting a bit more out of the engine and making it more responsive. Basically I'm trying to decide which carb setup would be better to invest in; I already have some 1.5" SUs from an MGB, which with the right parts, a rebuild kit + a new manifold I could adapt to fit the mini. For a similar cost, I can also get a hold of a complete kit for fitting a Weber, including a short manifold which doesn't necessitate any bulkhead modifications. Of course I'd then have to source the carb itself, but I'm in no hurry to upgrade.

 

Any opinions and advice on which setup would be better is much appreciated

[Anthony30]

Twin HS4 carbs.

[1968andyf]

Use the su's with your mods and a short swan neck manifold the weber will be a lot worse

[The Matt]

Have you considered upgrading to a single HIF44? 

 

Upgrading the carbs may not necessarily increase your power that much if the head is fairly standard.  It's all about how well the head can flow really.

[timmy850]

Have you considered upgrading to a single HIF44? 
 
Upgrading the carbs may not necessarily increase your power that much if the head is fairly standard.  It's all about how well the head can flow really.

Yep, or an HS6 which are the same size. They are pretty easy to get hold of compared to HIF carbs on this side of the world..

[nicklouse]

a nice big single SU carb on a good manifold will be more than enough.

[ucchockey]

Twin su for me. That's what I'm running. They give a slightly better throttle response than a single carb in my opinion. And they look the business too. Mine is a 1293 with a stage 2 head.

[rally1380]

If you don't want to modify your bulkhead go with the SU's......I run Twin HS4's (ITG filter, MED trumpets, Maniflow steel manifold - not a cheap setup!!!) and find them very nice to drive with. I had a HIF44 and that was a superb carb too and only swapped as i do historic rallying and the HIF carbs ain't allowed.

 

So the choice is yours regarding twin or single SU - but seeing as you've already got 2 HS4's, seems the decision is easy???

[fwdracer]

Only use a weber if you can put a decent length (3.5"+) none swan necked manifold. It'll necessitate a bulkhead box by default to get manifold/carb/filter set-up.

If you don't want to cut your bodywork, either twin SU's, or as others have suggested an HIF44 (1.75) inch carb is the default answer.

[MiniCarJack]

Thanks for the feedback and opinions. I'm strongly leaning towards using the twin HS4s, as it sounds like they're more suitable for road use. Plus there's just something "cool" about them - they look awesome, and I love the stock setup on the MGB with its very responsive throttle, which I'd love to have on the mini as well :)

[Dusky]

Only use a weber if you can put a decent length (3.5"+) none swan necked manifold. It'll necessitate a bulkhead box by default to get manifold/carb/filter set-up.

If you don't want to cut your bodywork, either twin SU's, or as others have suggested an HIF44 (1.75) inch carb is the default answer.

You can fit à 3.5 inch cannon inlet without bulkhead modifications, it has the same chape of the alloy su manifold.