9 replies to this topic

[alsy]

What's the best carb to fit to a 998 mini with stage 1 kit?

[Dan]

Whatever one the kit came with a manifold and needle for.

[alsy]

it didn't come with a carb.. only a needle, but surely there's upgrades?

[AVV IT]

The HS4 carb that was supplied with most 998's as standard, or the HIF38 is more than sufficient for a stage1 kit. (The HIF38 is basically the metric and slightly more modern version of the HS4)

Edited by AVV IT, 06 February 2012 - 07:17 PM.

[alsy]

so changing the carb is almost pointless..

[AVV IT]

Pretty much yes.

Unless you are going to change your engines demand for fuel, then there is no point in upgrading the carb. Basically the carb just supplies the fuel that the engine draws in. If you don't increase the engines demand for fuel, then it won't draw any more fuel in, regardless of how big the carb is that it's drawing it through. If anything a carb that is too big, will probably reduce performance as opposed to improve it.

When you fit a stage one kit you improve gas flow, slightly increase the power and therefore the engines demand for fuel as well. You therefore fit a richer needle to the existing carb, to compensate for this slight increase in fuel demand. If you then went on to do further tuning mods, such as upgrading the head and fitting a warmer cam etc, (so that the engine out demands the fuelling capabilities of the existing carb), you would then need to fit a bigger carb, such as the HIF44 that was fitted to the 1275 cooper models.

Edited by AVV IT, 06 February 2012 - 08:11 PM.

[Dan]

Changing the carb is entirely pointless. Changing the needle in the carb is all the upgrade it needs. A stage 1 kit is a method of tuning an engine, it's a complete package and the needle is part of it. If you change anything else it's not a stage 1 engine any more. If you want to tune it further then eventually you might need a different carb but you would need to make a lot of changes before it can't cope.

[alsy]

Okay thanks guys, I know I've asked quite a few questions on here in the last few days.. but I'm learning! rather then making another topic as you seem pretty clued up, my car currently has drum
brakes all round without a servo.. will fitting a servo make a big difference because I feel a little scared about their current stopping power and a brake conversion is too costly at the moment, if so what servo should I be buying?

[AVV IT]

Not really my area of expertise this one, but as I understand it whilst a servo will improve the feel of the brakes, it won't really improve the efficiency. That said I've driven a mini with servo brakes and also one without and on balance I definitely preferred driving the one with the servo. Whilst I think there are after market servo kits available, I believe that the cheapest option is probably to fit a complete unit from a post 84 model that had them fitted as standard. I think it's a fair amount of work though and it's probably debatable as to whether or not the benefit you would get from a servo actually outweighs the amount of work involved in fitting one.

Some people seem to think that drums all round are just as good as discs so long as they are properly maintained. I'm not convinced though and If it were me I would probably opt to invest in a disc brake conversion first before bothering with a servo.

[Dan]

Fitting a servo does nothing to increase maximum braking effort, it has an effect on brake performance but only in so much as it makes it easier to apply more force to the brakes. It takes the effort out of the pedal is all. No problem with how many topics you start or questions you ask, that's what the forum is for.