
Which carb?
#1
Posted 15 October 2006 - 09:33 PM
How does a single HIF 44 compare to twin 1 1/4"s? Obviously twin carbs look the business, but I want the best performance.
Are there other carb alternatives that don't require modification to the bulk head?
I'm pretty sure my 998 engine is standard - apart from an LCB.
One last question: after fitting a better carb, what is the next logical step in squeezing out a bit more power?
Cheers
#2
Posted 15 October 2006 - 10:01 PM
This is around 38mm or 1.5" the design of the HIF carb is better than the HS4, that you I guess have?
you don't need a HIF44! IMHO, its too big!
#3
Posted 15 October 2006 - 10:08 PM
So you'd recommend the HIF 38 over twin 1.25 SUs? Or is that just if I chose the go the HIF route?
Now that you mention it - how does over-carburetion effect performance? Do you just sacrifice fuel economy? I always thought 'more petrol, more power'...
#4
Posted 16 October 2006 - 07:26 AM
#5
Posted 16 October 2006 - 08:15 AM
Dog is right in that you should get the HIF34 over the HIF44 though, if you don't go with twins.
After the carb, if you haven't already got it, get a decent exhaust system, the best for the 998 being the 1.5" RC40 (from MiniSpares or Maniflow), with the freeflow manifold. On from there you can either go for increased ratio rockers (1.3s or 1.5s), a new camshaft or modified head.
#6
Posted 16 October 2006 - 08:17 AM
On verrrry hard cornering you don't get fuel starvation with these, and since you want performance I would go for this, also carbs cannot add 'power' as such, they can only take it away. A nice set of twin carbs would increase throttle response and probably make power very smooth through the revs... But so would an HIF38. And it's cheaper and easier to maintain.
#7
Posted 16 October 2006 - 10:53 AM
Thanks for all your input - I really appreciate it.
My mini's been with a mechanic recently and he's informed me that my single HS4 is quite badly worn, so it seems a carb change is now more of a necessity than a luxury

I'm gonna have a think about which option to go for: HIF 38 vs twin HS2s.
Fuel economy isn't an issue, as I only really use my car on weekends. Obviously twin carbs will be more expensive to buy, service and setup; so if they don't offer a significant power advantage over the HIF38 then maybe I should go with the HIF. However, if twin HS2s are worth the extra money then I'd rather spend a bit more


How does the HIF38 compare with the standard HS4?
Thanks again for your input. After owning minis in south Africa it's such a pleasure to have the resources/parts/expertise that you do in the UK...
#8
Posted 16 October 2006 - 10:57 AM
Personally I'd go for the twins if this is an occasional use car you drive purely for fun. You can pick them up on Ebay for between £60-£140.
The HIF38 won't have much, if any performance advantage over the HS4. The main thing is that it has an internal float, which means it doesn't suffer from fuel starvation when going round right hand turns quickly.
If you find anything in the UK, and they won't send to SA, contact me and I'll act as a 3rd person if you want and send the stuff out to you.
Also, for future reference, could you fill out the 'Location' field of your personal information, it would help future advice given to you.

#9
Posted 16 October 2006 - 11:42 AM

He didn't acutally say, where the wear on the carb is. I figure, seeing as I was thinking about upgrading my carb anyway, I might as well just do it now...
Sorry, I thought I had filled in my location. I'm in London - used to live in SA. Thanks for the middle-man offer though

I think the twins are what I'll go for. I've been watching carbs on eBay for a while actually, so I'll probably strt bidding. How important is it to get a set of carbs that were intended for a mini compared with a set from an MG or other BMC car? Are there certain AUD-type numbers to avoid? (eg. AUD69L&R or AUD104L&R) I have no idea what differences these signify
Miniworld have an article on servicing twin HS2s. So maybe it would be a good idea to strip them down first
#10
Posted 16 October 2006 - 12:35 PM
#11
Posted 16 October 2006 - 01:17 PM
#12
Posted 16 October 2006 - 03:10 PM
I ask this because a mini mechanic in SA once told me that one 1 3/4" would produce similar power AND be a bit more economical that two 1 1/4"s
Thanks again for the previous advice...
Edited by iamweasel, 16 October 2006 - 03:13 PM.
#13
Posted 16 October 2006 - 03:49 PM
This isn't quite correct. A HIF38 will still work on a 998, quite well in fact, but as you can understand, the vacumm can be used more efficiently in the throat of a 1 1/4 carb.
#14
Posted 16 October 2006 - 04:18 PM
Quite the opposite, if I understand you correctly.
Cheers!
#15
Posted 16 October 2006 - 06:56 PM
i think the twin 1 1/4 carbs work better than a single big carb on a small cc engine(or even a big one) because the air speed thru the smaller diameter carb is much higher thus picking up the fuelling and putting it in the cylinders much nicer and in a better mix than a big wide carb taking the air slowly!!
1 of my minis had twin 1 1/4's and a cooper head and it made nearly 72bhp at the crank!! the twins sound nice but are really hard to setup properly!! really needed 2 rolling road setups per year!! 1 for winter and 1 for summer!! it never lost anyting but the sound when i changed it for a single 1 1/2" hs carb!!
Edited by fikus01, 16 October 2006 - 06:56 PM.
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