13 replies to this topic

[toms]

Has anyone changed the carburettor on thier 998 to something which may give a bit more punch?
Just trying to add things to my 'to do list'

[toms]

Infact guys, I know you can buy a stage one tuning kit but rather than just buy one of those I may eventually go down the route of buying parts seperately.
If I did this what list would you recommend for my 1982 998

Cheers

[irish.yobbo]

A stage 1 kit is your first step for more power, it's the cheapest, easiest and best way of getting more power. For a 998 I would recommend cooper freeflow extractors, RC40 exhaust and a heated manifold.

As carbies go, the best for a 998 is a 1 1/2" SU. Yes, you can put on a 1 3/4", and you may get a tad more power, but you will lose all your low down torque, which is one of the benefits of the A-series engine. Twin 1 1/4" look the part and again will give a bit more power, but they will use more fuel and be much harder to tune.

[jaydee]

Has anyone changed the carburettor on thier 998 to something which may give a bit more punch?
Just trying to add things to my 'to do list'

Whats the engine spec in the to do list?
Carbs have to be choosen on engine capability
You cant pretend to make a tiny girl eat two double whoppers
You cant pretend to feed an engine with 27x25 valves and 240° cam with an HIF44 or twin HS2s

[Big_Adam]

You cant pretend to make a tiny girl eat two double whoppers
You cant pretend to feed an engine with 27x25 valves and 240° cam with an HIF44 or twin HS2s

Well, you can try, but its going to put a lot to waste and make a mess ... yeah that covers both cases.

Anywho, if you want to make your carb setup rather perky, do the Vizard mods from the book How To tune the A-Series engine by David Vizard.

Its pretty much just halving the butterfly spindle, putting a bevel on part of the piston in the carb and a few little tweaks but it feels much nicer to drive even back when I had the pea shooter exhaust. Will require a new needled, but I changed the air filter when I did mine as well.

[jaydee]

You cant pretend to make a tiny girl eat two double whoppers
You cant pretend to feed an engine with 27x25 valves and 240° cam with an HIF44 or twin HS2s

Well, you can try, but its going to put a lot to waste and make a mess ... yeah that covers both cases.

obviouly better a girl that wont even touch BK and a car that wants the bigger carb

[toms]

Has anyone changed the carburettor on thier 998 to something which may give a bit more punch?
Just trying to add things to my 'to do list'

Whats the engine spec in the to do list?
Carbs have to be choosen on engine capability
You cant pretend to make a tiny girl eat two double whoppers
You cant pretend to feed an engine with 27x25 valves and 240° cam with an HIF44 or twin HS2s

Im not wanting to completly bore the engine out. I want to try and keep it as standard as I can.
Its all standard at the min, so was wondering what subtle changes I could make by simply swapping parts that want add much stress or damage to other parts,
things I was thinking of would be the carb, and as Irish Yobbo stated above 'cooper freeflow extractors, RC40 exhaust and a heated manifold'.

Only reason i ask is becuase you can buy stage 1 kits but thought it may be better to get the parts myself. Im new to the mini business so please excuse my Homer Simpson knowledge

[TA2DMAC]

You can always mod the carb for better flow and less drag.
trim bolts on butterfly.
Thin the rod out that the butterfly attaches too.
Square off the port for more air flow through the carb.
All easy mods which will improve performance and it's free.

Edited by TA2DMAC, 06 September 2012 - 04:21 PM.

[bmcecosse]

Larger carb is not the answer......and tiny twin SUs are certainly not the answer......... The main power gain comes from eliminating the 'hot spot' on the original manifold by using a separate alloy inlet manifold, and better exhaust manifold and system help too.

Edited by bmcecosse, 06 September 2012 - 05:14 PM.

[AVV IT]

A larger carb alone won''t give you any more "punch" unless your engine is under fuelled in the first place. (which if it's a standard 99 with a stock HS4 or HIF38 it won't be). The carb does not provide extra power in itself, in simple terms it merely allows the fuel/air to flow in that the engine demands, so unless you modify the engine in a way that requires more fuel (upgraded head, increases CC, warmer cam etc) then fitting a larger carb is pretty much pointless.

If you're planning on fitting a stage 1 kit, (high flow air filter, gas flowed inlet, exhaust system & manifold etc) then an upgraded/richer carb needle in your current carb is all that is required, not a larger carb. It's generally to cheaper to buy all the parts together in kit form, than it is to buy them all separately though. The other benefit with a complete kit is that you should get everything you need to fit it. including the correct gaskets, clamps and brackets etc.

Edited by AVV IT, 06 September 2012 - 05:39 PM.

[toms]

Cheers fellas! Been a big helps. New inlet and exhaust will be first on the list when the engine comes out!

[jaydee]

http://www.minispare...ts/C-STN17.aspx

Start with this.

[toms]

Give it 4 weeks and my next pay this should be ordered
Unless I find one cheaper but that seems about right with what ive been looking at

[Spitz]

Twin 1.25"

I fit a set to my bone stock 998. ( stock exhaust, I just cut off the intake part )
I used correct needles for the engine ( GY I think )
It made a very noticeable difference. I'm not saying it turned it into a monster, just that it was an easily noticeable increase in power.
I drove the car with this set-up for three years without having to adjust carbs at all
You only need to tune them once....contrary to popular belief.