pocketed 998 with 12G940 forced inductin thoughts..
Turbo Mini Forums

opinoins on how to go about this..
i recently bought the above,
Block
all i know is that its a pre A-plus (cam runs in the block?), it has a 2 bolt centre main strap, very well pocketed deck with generous radii. the block has been decked at some point, it has an ultra light flywheel and a very lumpy cam. The rods appear to have been stsress relieved, and the pistons are dished slightly and appear to be non standard and of minispares origin, can i post some serial numbers for anyone who might be able to identify them?
Head
it has a 12G940 that appears to have been skimmed to the max (looking thru coolant hole the deck is less than 5 mm) its had the guide bosses removed and new bronze guides holding (35.7x29.25mm In/Ex) valves they are stainless and have been stemmed and the heads the thinnest i have ever seen! the ports are as big as the casting allows and appear to follow Vizards rules, it has hardened inserts, double springs, titanium caps and very high quality chambers that seem to be geared towards high compression.
It used to run a webber 45 and as such would be a poor daily driver (my intention) so.. how is the best way to turbocharge? Work out C/R and buy some more dished dished pistons get me? sell the head for 200 (offers) to fund a virgin 12G940 because i want to make use of my ability to use a 1275 large valve head but almost standard because port size will be nowhere near as relevant with a turbo. Would have to skim to reach desired C/R but thats no problem.. I plan on using a flowed met.turbo ex. manifold mounted 180degrees giving a high turbo and an underslung inlet manifold with an intercooler of sorts. anybody tried anything similar??? or will i get more power going N/A using two chokes? bike carbs hmm..
complete engine with elec dizzy was 200.. its in very good condition and jsut needs de-dusting. dont talk to me about i need an elec fuel pump an stuff the only trouble im having is with the best cylinder head choice and associated variables..
ps pics soon ye.

Edited by hario on 19th Jun, 2008.

Post up the piston serial numbers for the pistons, some one will know what they are.

If you want to go turbo the head you have doesn't sound suitable. The standard chambers on the 940 are to small to get the compression down on a 998, even with dished pistons. You will need a new head with enlarged chambers.

You will not get more power N/A with bike carbs (if you do the turbo properly)

Have you seen the spec of our 998 turbo. http://www.twin-turbo.co.uk/The%20Spec.html

And Wil's build a 998 turbo in 20 hours?
http://www.turbo-mini.com/62147.html

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

hiigh piston reads

106 T16 20536
+.508

A

as in imperial of .508mm. A-series.
..just about to find the part number and its circliped little end with angled big end cap stamped 12G127 so its a standard 998 one just cant find the capacity. we think 1040 if its +20tho. so what sort of compression ratios do pocketed 998s with a skimmed 12G940 have? an example combustion chamber size please? guestimate, giving me something to go by..

anyone looked at a metrotrurbo manifold upside down saving a bulkhead mod?

thats some asian girl im seein''

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itsa 3-ring +20thou standard overbore piston (2.559"), 0i think the stroke is about 84mm which seems abit long?! thats from BDC to TDC and the pistons are proud by .2mm..the cam is slot drive with no markings of any kind, does that indicate a reprofiled item? timing is with a later duplex timing chain fitted to a gear kit that uses dowel adjustment. surfaces seem good throughout.
The head will go on fleabay soon, once i paint it red to it sells for more. £160 if anyoness interested, collection only from the south, its a bit too delicate for a road head for me, standardsintered rockers inclued if you want..
i have a syring in the post calibrated in CC's so ill know the dish soon.
Ps i love turbominis..

doesnt sit as high as we thought mate? perhaps we should get that bit of wood calibrated.........

still think you should man the fuck up and fit a bulkhead box...... got to be lot easier in the long run.........

And on the 7th day........... God created turbochargers!

Yes a bulk head box would be wise!

i would go along head wise with wil-h head,

not plugging me ................ BUT if you go along with wills spec he has done all the home work for you
And it works
there is always more train of thought from different people
to get there heads togeather and push the boundries

but thats oh so very done before!
i want to try something new like everyone else does, like the very reason behind this forum!
anybody have a turbo manifold theyd like to sell me? anything considered..

the other day me and nutterdriver fittedd a manifold and turbo upsidedown to an a-series and it will work so long as the rear of the bonnet is raised about an inch which i was planning on doing anyway to aid cooling. the inlet manifold would need to be inverted also with the carb offset to one side of the engine bay slightly..
offers? suggestions??

If you think of something new that will perhaps give a performance advantage, then all well and good. Doing something different because it is better (or at least arguably better). Doing something just to be different is silly and a waste of time.

What are the reasons for you inverting the manifold?

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Edited by BENROSS on 1st Jul, 2008.

look up DOZ on this forum he is in aus and has a flipped manifold

1152cc turboed mini clubman, most powerful 1.1L a-series?

http://boostmini.justboard.net/

because a raised turbo eliminates bulkhead mods and this means the inlet manifold will either need to be turned upside down or a plenum welded to the end of some standard manifold runners with the carb entering on either the right or lefthand side..
bought an engine stand from machinemart todaysies
best thing EVER..