After pondering over engine swaps and briefly toying with the idea of supercharging I've finally decided to build a turboed A series for the coupe.
I see there are at least a couple of turboed coupes on here and I would be interested in what engine specs people have gone for, what modifications you have made to increase reliability and if you've encountered any problems or issues.
I've read quite a lot over on the turbomini forum but I'm obviously more interested in peoples experiences with the coupe.

This will probably be a very long term thing as I intend to run the coupe as it is for a while but I already have some parts and ideas...

1293cc A+ dry decked purely for cooling
ARP fasteners throughout with mains studs rather than bolts.
3 layer Cometic headgasket (block + head surface-ground)
Undecided on 11 studs as I've never really been convinced.
Also undecided on centre main strap for a road engine that won't see past 6500rpm (spoke to Ken about this at Stoneleigh).
(Can do most of the block mods at work if they're needed.)
Undercrown piston cooling jets.
Standard 35.7/29mm valves.
Metro turbo exhaust manifold mated to Garrett GT17.
Straight-cut drops and gears with LSD or cross pin diff.
Undecided on compression and boost for now but will also be running Megajolt with the biggest/most efficient intercooler I can fit.

Re the mains strap, have a read here http://www.calverst.com/cc110f.htm cick on engine, scroll down on the left, should be there somewhere

Maybe bigger engine to gearbox bolts to help stop the shuffle.

The only problem with an lsd is the cwps are expensive!!

Does sound like a very sensible spec there.

Intercooler or Charge cooler?, Charge cooler may be easier to package and get air too than an intercooler.


Neil

Yeah Keith Calver has been round the block a few times (no pun intended) and is certainly respected. My aim will be to improve the clamping via studs instead of bolts, but the part about using ARP washers was interesting.
It certainly wouldn't be a problem grinding the cap and strap flat and flush as I have access to the machinery and wheels but again as Keith says, is there any proof that it's needed and which steel would be best for the job? I would imagine most of the steel straps for sale at mini tuners aren't anything special.

I'll definitely be going with bigger bolts engine to gearbox as it's an easy mod.

I think Swiftune sell an LSD made by Quaife that you can use standard cwp's with but will have to investigate. I believe it's exclusive to Swiftune, but the LSD ain't cheap that's for sure. I'm not sure how much torque a standard cwp will stand but it would be nice being able to use the taller 2.95 or 2.76 FD.
Maybe going crosspin would be easier on the gearbox and driveline? I remember reading somewhere that coupes break dropgears and/or gearboxes easier than a mini due to lack of wheelspin (that photo of West's coupe pulling a wheelie at Santa Pod strangely springs to mind lol)

Yeah this is something I'm still undecided on. I think maybe a chargecooler would be better suited to the coupe being mid-engined.
I was looking at the one fitted to Celicas and the MR2 - don't know how good they are but could probably pick one up cheap.
The barrel shaped ones are supposed to be excellent but they're expensive.

Am I right in thinking there's negative air pressure above the engine compartment/boot?
I had thought of mounting an air to air intercooler horizontally just beneath the boot cover or engine cover and ducting air up to it then out the otherside?

Subaru Legacy twin turbo also has a charge cooler

The highest ratio fd i can find to fit a tran-x lsd is 3.4, i have one here for another project with 10" wheels which i may swap out as the gearing will be too low (currently 3.9 )

As for mains strap i would have thought en16 or something along those lines, having said that Calvers advice seemed to make a lot of sense.

Thanks, I'll have to investigate that further.

This is the sales blurb from the Swiftune website on their LSD...

"Swiftune's new ATB -Automatic Torque Biasing- differential

The ATB diff delivers a cost saving of almost £500.00 because it fits directly into your standard transmission without the need for a new crown wheel and pinion or matching output shafts...just push in your standard pot joints!

The Automatic Torque Biasing Helical LSD Differential enables your Mini to accelerate quicker and corner faster. How? Simply by getting the power to the ground!

The Swiftune differential, manufactured by Quaife, powers both drive wheels under nearly all conditions. It senses which wheel has the better grip, and automatically biases the power to that wheel. It does this smoothly and constantly, and without ever completely removing power from the other wheel. Power is transferred automatically without the use of normal friction pads or plates seen in other limited-slip designs.

In cornering, while accelerating out of a turn, the ATB diff biases greater power to the outside wheel, reducing inside-wheel spin. This allows the driver to begin accelerating earlier, exiting the corner at a higher speed.

The ATB Helical LSD differential's unique design offers maximum traction, improves handling by reducing understeer, curbing steering 'fight' and puts the power where it is needed most. A definite advantage, whether you are on a Track Day, racing or driving a performance Mini on the road.

Swiftune has exclusive rights to the Quaife patented ATB diff for Minis. Quaife is so confident about the quality of its ATB the unit comes with a lifetime guarantee."