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Home > 998cc > Advice about supercharging a 998.

Tremayne

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Member #: 10441
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So having mostly lurked about here for a while and reading various build threads, I've pretty much settled on supercharging the existing 998 engine I have in my Mini, but I do have some questions:

Firstly and I suppose most importantly, the supercharger itself: The Eaton M45 seems to be the most popular unit to use, though people seem to have better things to say about the SC12. The question is: Are there any other superchargers I should be looking at as an alternative to these units?

Secondly: Blow-through or suck-through? I've done a fair bit of searching around the forum about this and I've not really been able to get a decent feel for the pros and cons of each. Suck-through seems to mean you can do what you like with the carb, but I'm unsure about putting fuel/air mix through the charger itself.

Thirdly: The carb. I'm assuming that even on a lowly 998 I'm going to need to move to a 1.75" unit of some kind?

Finally: Exhaust. I'm currently running a regular stage 1 kit, so the freeflow manifold and RC40 twin box unit. Is that going to be sufficient or am I going to need to move to an LCB, (or god-forbid three-into-one) setup?

As a note, I'll be doing this project in conjuntion with a complete strip and rebuild of the engine and some long needed bodywork repair. This is not going to be a rush job of any kind, (if only because there's no way I'm going to be able to afford to buy all the parts anything other than piecemeal) so if anyone has good suggestions that might otherwise seem inconveniently time/effort consuming then I'm all ears.

Thanks!


wil_h

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Betwix Harrogate and York

What is your objective?

Lots of power?
Good drievability?
Decent MPG?
Something to show off?

In generat the M45 is not an ideal SC for a 998, net even a 1275 either really. The SC12 is better, but there are no install kits available so you're on your own.

Suck-thru is easier and when considering everythin, probably the best solution for an SC.

The honest opinion you'll get on here is just turbo instead.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

On 2nd Jan, 2013 fastcarl said:

the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


John

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10020 Posts
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Mongo

Barnsley, South Flatcapshire

Save yourself the hassle of being branded the biggest gay in the village and go turbo! *hehe!*

You will most likely get more power, more fuel economy, better drivability (if you size your turbo appropriately) and a lovely wooshy noise if you fit a dump valve *wink*

Also mapped ignition would be a good idea :)

Welcome to TM BTW!

If something is worth doing, it's worth doing half of.


Tremayne

12 Posts
Member #: 10441
Member

On 5th Jul, 2013 wil_h said:
What is your objective?

Lots of power?
Good drievability?
Decent MPG?
Something to show off?


I'm not looking for *lots* of power, ideally I'd like to break 100bhp but I'm not wedded to that. A decent improvement on torque throughout the rev range is more important to me than top end power.

Good drivability is important, but this isn't going to be a daily driver, he's done his service as that and now it's time to perk him up a bit. :)

MPG would be nice, but really not critical.

Showing off is always nice! There is also just something about the *sound* of a supercharger. *happy*

On 5th Jul, 2013 wil_h said:

In generat the M45 is not an ideal SC for a 998, net even a 1275 either really. The SC12 is better, but there are no install kits available so you're on your own.


I don't mind the lack of an install kit. This is after all going to be a labour of love. I don't need it to be *easy*, I just need it to be *doable*. Hence why, if there is a better choice of SC out there, whether it has a kit or not, I'm interested in hearing about it.

On 5th Jul, 2013 wil_h said:

Suck-thru is easier and when considering everythin, probably the best solution for an SC.

The honest opinion you'll get on here is just turbo instead.


At most I'm considering 10-15psi boost, which seems to be the upper limit for an SC anyway and as mentioned, there's nothing quite like the sound of one. *tongue*


Tremayne

12 Posts
Member #: 10441
Member

On 5th Jul, 2013 John said:

Save yourself the hassle of being branded the biggest gay in the village and go turbo! *hehe!*


*tongue*

On 5th Jul, 2013 John said:

You will most likely get more power, more fuel economy, better drivability (if you size your turbo appropriately) and a lovely wooshy noise if you fit a dump valve *wink*

Also mapped ignition would be a good idea :)

Welcome to TM BTW!


Mapped ignition, (probably Megajolt) is indeed on the list of things to do during the engine rebuild.

I will admit I've been very interested in the fully sequential injection threads here on the forum, but I figured I should try to tackle one thing at a time and start with the forced induction side of things. :)

Thanks for the welcome!


apbellamy

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King Gaycharger, butt plug dealer, Sheldon Cooper and a BAC but generally a niceish fella if you dont mind a northerner

Rotherham, South Yorkshire

You can buy a kit for the sc12 from aus. I can put you in touch with the chap that makes them. They top out at 12psi. I doubt you would make 100bhp on a 998.

Have a look at my build thread to see the sc12 kit etc (search for 1275gts)

On 11th Feb, 2015 robert said:
i tried putting soap on it , and heating it to brown , then slathered my new lube on it

*hehe!*


WRLondon

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Surrey




On 5th Jul, 2013 Tremayne said:


Showing off is always nice! There is also just something about the *sound* of a supercharger. *happy*



*Sick*

turbo is what you want my man *happy*
and if you get the parts ordered you can do it in a weekend easy =
http://www.turbo-mini.com/62147.html

plus you wont get problems with carbs icing up, the power it takes to drive the supercharger,
to get the same horsepower as a mildy tuned 1275 :)

Reading up on RTS Clutches

On 21st Sep, 2006 Paul S said:

Go on, be brave, put it in the car and tell us how it works.
Pity your bollocks are in line with the flywheel!
On 27th May, 2013 robert said:

putting my testicles on the line for turbo mini owners everywhere ,and they still work !


Tremayne

12 Posts
Member #: 10441
Member

On 5th Jul, 2013 apbellamy said:

You can buy a kit for the sc12 from aus. I can put you in touch with the chap that makes them. They top out at 12psi. I doubt you would make 100bhp on a 998.

Have a look at my build thread to see the sc12 kit etc (search for 1275gts)


How easy is it to track down the actual SC12 charger in the UK, or would that need sourcing from aus as well? I'm not expecting this process to be cheap, but I would like to minimise costs where I can. *tongue*

Ah well, 100 would be nice, but it's not the end of the world. :) I plan to bore the engine out to +.060 and I'll open out the chambers in the existing 12G295 I've got to drop the compression ratio. Currently I'm thinking of an SW5 for the cam, but I'm open to advice on that front.

Edited by Tremayne on 5th Jul, 2013.


apbellamy

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16540 Posts
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King Gaycharger, butt plug dealer, Sheldon Cooper and a BAC but generally a niceish fella if you dont mind a northerner

Rotherham, South Yorkshire

There was on in the for sale section recently. I think mine came from new zealand. It cost me about £750 in total I think (kit and charger), so better value than eaton chargers and kits.

On 11th Feb, 2015 robert said:
i tried putting soap on it , and heating it to brown , then slathered my new lube on it

*hehe!*


Paul S

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8604 Posts
Member #: 573
Formerly Axel

Podland

I have an Eaton M24 for sale.

Perfect size for a 998.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


apbellamy

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16540 Posts
Member #: 4241
King Gaycharger, butt plug dealer, Sheldon Cooper and a BAC but generally a niceish fella if you dont mind a northerner

Rotherham, South Yorkshire

That might be a good option if you are comfortable with your fabrication.

On 11th Feb, 2015 robert said:
i tried putting soap on it , and heating it to brown , then slathered my new lube on it

*hehe!*


Tremayne

12 Posts
Member #: 10441
Member

On 5th Jul, 2013 Paul S said:
I have an Eaton M24 for sale.

Perfect size for a 998.


M24? Interesting. I'm assuming it's smaller than the M45?

Time to go looking for a map.


Tremayne

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Member #: 10441
Member

On 5th Jul, 2013 apbellamy said:

That might be a good option if you are comfortable with your fabrication.


I'm a bit out of practice, but I've got plenty of time to get it all planned out and several competent friends. *happy*


gr4h4m

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Chester

i recon at 77 bhp ATW my sc12 998 was about 100 at the fly.

Edited by gr4h4m on 5th Jul, 2013.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!


Tremayne

12 Posts
Member #: 10441
Member

Regarding the blow-through / suck-through choice, are there any problems associated with having the air/fuel mix going through the SC and intercooler rather than just air?

Suck-through seems to make life very easy, so I'm wondering what the downsides are.


Joe C

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Carlos Fandango

Burnham-on-Crouch, Essex

yeah, you dont want fuel and air going through the intercooler,

I saw a suck through turbo'd beetle at pod a few years ago that had a chargecooler after the turbo, it had a backfire or somthing and the charge cooler exploded....

On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



Tremayne

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Member #: 10441
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On 6th Jul, 2013 Joe C said:
yeah, you dont want fuel and air going through the intercooler,

I saw a suck through turbo'd beetle at pod a few years ago that had a chargecooler after the turbo, it had a backfire or somthing and the charge cooler exploded....


O_O

That's distinctly sub-optimal!

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