20 replies to this topic

[JoneseyBoy]

i built my 998 and the only mod i did was put in a piper BP270 in and it is kicking out 54.4 bhp and 55.4 lbft at the flywheel. i dont know if that is good or not but the man said standered is 42bhp and my mates 1275 is 53bhp so im over the moon with it. when i have the moneys is it worth putting another head on it but it drinks enough petrol as it is.

i dont know why but it dosent spin up unless i take the revs right up is that right ?

ive fitted it with double valve springs aswell so how high can i take the revs up.

what else could i do to it. ive got a standered su carb on it and a straight threw mini spares stage one kit ?

also what have you all done with your 998's

also the search tab is not 998 friendly so i made a new thread

[twrminisport]

I think ive copied and pasted this round different threads about 5 times in as many days *rolls eyes*
Seriously if your tuning a 998 im happy to help, heres a little guide i put together a while ago

For you specifically i would say cylinder head and rockers next. Help you get the best out of the cam. Also adjustable duplex timing chain will be benificial here

On a 998. First things first.
Make sure all your standard stuff is working properly. You cant tune a badly running engine.
New plugs HT leads points condenser dizzy cap oil filter change oil change and a new radiator cap will all be on this list.

Larger bore exhaust which you can have in a 'large bore single box' or 'small bore twin box' variant. Not much difference. Choice. better noise go for the single box. however an extra 1 bhp 2 bhp can be found from twin box system particulaly through accelleration. And a new manifold. Maniflow or similar.
Different air filter element. Not a shitty pancake things some people will try to sell you but a proper k and N cone filter or similar.
Different carb needle.
This is basially what a stage one kit is
After that ROLLING ROAD. Get it optimised by a MINI frienddly rolling road.

You can do that service for about £40 and the stage one kit for about £120-£150 if you know where to look. Then the rolling road prices vary per hour. usually about £40-60 per hour and they may take an hour and a half so you can see this listed above can be done definatley for under the £250 mark. This will have given your car a freshen up and a better breathing external system. Power gains for this maybe around 25% increase.

Next you will look at the head for options. a cooper head 12g295/12g206 is the eaisiest because unlike the 1275 heads you will not have to pocket the block or resess the valves. A new head can be found on ebay for about £150 then fitted but i would advise stongly having new seals fitted and having it checked over properly with the possibility of new valves/guides etc. REMEMBER YOU MIGHT HAVE TO DO AN UNLEADED CONVERSION. There are many companies who do these heads for you but expect to pay in the region of £500 for one already done for you 'as new' spec. This again you will need to have rolling roaded when finished so expect to pay about £300 for a second hand head or £700 for a new one (all in prices) but expect another 25% power increse at least.

Rockers. 998 need little more than standard. Extensive testing by Calver and Vizard etc have shown the standard units with an acclaimed 1.25.1 to produce little more than 1.22.1 on a good day therefore a 1:3:1 roller rocker is a good upgrade. 1.5.1 is too much for the 998 really. 1:3:1 is optimum until about 85bhp so unless you are running a 100bhp small bore 998 miglia spec then 1:3:1 is for you

Carburation. 2 main choices here. with an upgrade to a HIF44 carb or a twin HS2 set up or even a reese-fish or other set up. Expect to pay about £50-£150 for a decent HIF44 carb and buy a decent filter and needle for this.
HS2 carbs expect to pay more like £100-£200 for a carb setup to refurb and fit with new needles butterflies etc. but you will need a twin manifold, heatshield, etc, This is the more expensive way to go. The vast majoirty of people stick to HIF44 carbs for ease of use and price but the twins will give you a better power on a 998 but are possibly arguably not worth the extra over a hif 44
NOTE: with all carbs expect to have to fit new service parts within the carb.


^^ Pictures of my twin HS2 setup with custom made Pipercross airfilter.

Other considerations:
The mini cooling system is far too good so dont mess around with that. However if experiancing overheating then fit a lower thermostat and consider a 2 core ally radiator.
Electronic ignition, Aldon ignitor or something similar maybe a peronix system for about £80 can go a long way to sorting dizzy and timing problems if present aswell as eliminating the need for points.

After this:
Camshafts, 998 tuning you will not want a camshaft with a duration of more than 270 degrees. This is ultimate for a 998.
Kent 276 therefore is the max. Pulls from 1500-6000. Lumpy idle
Swiftune Sw5-07. Less cammy on idle. Pulls from 1200. Flies from 3500. Bit more tame than the 276. This one is the performance increase that you dont know is there. Great for motorway miles and sitting in traffic in town.
Make sure you fit an adjustable duplex timing gear. No point in shelling out on a new cam without timing it correctly. Off the mark a cam will give more of a bang for your buck than a head.
A brand new sw5-07 full duplex kit can be bought for £250. Again ROLLING ROAD.

Flywheel and clutch, next is to lighten the flywheel. A full featherlight flywheel and clutch assembly can be purchased from swiftune for £680

Further options
Lightened and balanced crank
Lightened rods

Sorry for the in depth awnser ask me if you want to know more ask me

Jesus

[JoneseyBoy]

Cheers mate you have never have enough info. So am I getting a good power out put on her then

Edited by JoneseyBoy, 01 March 2011 - 12:32 PM.

[micromontenegro]

TWR: that's a brilliant post.

[izzy]

Next you will look at the head for options. a cooper head 12g295/12g206 is the eaisiest because unlike the 1275 heads you will not have to pocket the block or resess the valves. A new head can be found on ebay for about £150 then fitted but i would advise stongly having new seals fitted and having it checked over properly with the possibility of new valves/guides etc. REMEMBER YOU MIGHT HAVE TO DO AN UNLEADED CONVERSION. There are many companies who do these heads for you but expect to pay in the region of £500 for one already done for you 'as new' spec. This again you will need to have rolling roaded when finished so expect to pay about £300 for a second hand head or £700 for a new one (all in prices) but expect another 25% power increse at least.

Hi, could you explain this bit again please?

what is an unleaded conversion and what does it consist of doing? And why do you need the rolling road (what is it exactly used for? To measure engine power?)

sorry if these are noobish or simple question's. Im only still learning ya see

[izzy]

its ok about the rolling road cause i just figured out it was a dyno tester.

[JoneseyBoy]

Better description bellow

Edited by JoneseyBoy, 01 March 2011 - 05:17 PM.

[twrminisport]

Next you will look at the head for options. a cooper head 12g295/12g206 is the eaisiest because unlike the 1275 heads you will not have to pocket the block or resess the valves. A new head can be found on ebay for about £150 then fitted but i would advise stongly having new seals fitted and having it checked over properly with the possibility of new valves/guides etc. REMEMBER YOU MIGHT HAVE TO DO AN UNLEADED CONVERSION. There are many companies who do these heads for you but expect to pay in the region of £500 for one already done for you 'as new' spec. This again you will need to have rolling roaded when finished so expect to pay about £300 for a second hand head or £700 for a new one (all in prices) but expect another 25% power increse at least.

Hi, could you explain this bit again please?

what is an unleaded conversion and what does it consist of doing? And why do you need the rolling road (what is it exactly used for? To measure engine power?)

sorry if these are noobish or simple question's. Im only still learning ya see

Of course i can

Ill start with the rolling road. Basically its a set of rollers that can turn your wheels at road speeds. By raising the speeds of the car then letting it 'run-down' it converts the mechanical drag into true wheel speed thereby giving you a power reading or BHP figure.
The key thing though is by doing this we can simulate driving on a real road at all different speeds and RPM levels. Even a gradient can be added.
An engine tuner can then look at the figures produced and by using diagnostic equipment can tune your car accordingly.
This means you will get the best out of your engine. Slarks, where i go to tune mine charge about £55p/h +VAT for a full rolling road tune. This involves power readouts and all the equipment he needs to test your car and then he will tune it for you.

Heads. The standard 998 head has small valves at 26.99mm inlet and 25.4mm inlet valves and a nominal chamber capacity of 25.5 this head is identified as CAM4180 and was fitted to all minis after 1980 and is able to run on lead free (unleaded) petrol. Minis before 1980 had the same head but it was not able to run on unleaded fuel. Casting no's are 12A1456 and, 2A628.
This head is very restrictive in terms of chamber size and the physical size of the inlet and exhaust valves. Also the port sizes are a big factor.

To get the best out of your engine after fitting a stage one kit then it is nesessary to have a better flowing cylinder head that is capable of bringing in more fuel/air mix to combust. The easiest way to do this is to get a cooper head. These had larger valves at 30.93 inlets and flow better than the standard item. Also has a larger chamber capacity at 28.3. You can pick one of these up on ebay for about £150. However it is wise to have the head checked over and possibly reconditioned. If it has not already it will need skimming by a head shop to the correct compression ratio of about 10:1. This is relativly cheap and easy for them to do. The slight bull in the china shop with these heads is that they were never designed to run on unleaded fuel. Now with there being very few garages around that sell 4 star or LRP fuel it will be necessary to do something about this.
1. Run an additive. You can buy an additive and put this in the fuel however its a pain in the bum and can end up very expensive
2. Get unleaded valve seats put into the head. Because of the higher temperatures required to combust unleaded fuel the exhaust valve particulaly can risk melting to the head so unleaded valve seats will need to be fitted. The good news is that they are about £50 fitted and most head shops can do this whilst they have the head for skimming.
The easy option is to buy a head already done for unleaded use. Calver does a small bore head with 30mm inlets and 26.5mm exhaust valves for £500 fully gas flowed, ported and polished. All skimmed down to correct CR and ready to bolt on. You pay more for someone to do all the different bits and peices for you.

Of course many people will tell you to "put a 1275 head on it" however this is not without its problems because it will be necessary to pocket the block to stop the valves hitting the engine (very loose analogy here) This can be done DIY but be careful. It involves drilling into the block to give more clearance to the head.

If you are having your own heads done it is wise to remember that you only need to get the exhause valve to flow at about 65-75% of the inlet valve.
But getting your own heads done is another story and i can write a guide on that if anyone wishes.

Hope this helps, one day i think i will become a fountain of knowledge for 998's everywhere *rolls eyes*

Jesus

Edited by twrminisport, 01 March 2011 - 05:23 PM.

[twrminisport]

Better description bellow

Sorry mate i dont do it to annoy people i promise :/

[izzy]

WOW! thanks a lot great bit of information.

Now if i do buy that 998 i know exactly where start modifying, and how to do it. (well sort of)

THANKS ALOT!!!

[twrminisport]

Good glad you know where your going with it.

I think i ought to start copying this all down somewhere :/

[tomgale]

also if you havent already, get a copy of 'david vizard's tuning the a series engine', its very usefull. (although at one point he does spend a page talking about this amazing inlet manifold which is better than anything, and ends with the sentance "this was too expensive to produce, so never made production" )

[JoneseyBoy]

No offense taken my friend . Also I have vizards book but being dislexic its boring and I lose consentration easy but if some one could note down the pages worth reading to do with things that would b needed for a 998 is happily give it ago again lol and if.you could post up links to do with 998s we could make a little guide type thing with it all

[JoneseyBoy]

No offense taken my friend . Also I have vizards book but being dislexic its boring and I lose consentration easy but if some one could note down the pages worth reading to do with things that would b needed for a 998 is happily give it ago again lol and if.you could post up links to do with 998s we could make a little guide type thing with it all

[twrminisport]

lol i think im most of the way to making a small bore guide anyway