998 Turbo
Turbo Mini Forums

Hi everyone,

Right, my plans to turbocharge my 998 mini are slowly getting off the ground (Don't ask why I want to have a 998 turbo). However, my plans are now at a crossroad, here goes...

I've managed to buy an unmolested 12G295 head from an ebayer which needs a bit of work and I am told that If I fit the head onto the car without a skim of 2mm, my chamber volume will be around 28.4cc's each. This in turn means the CR will be about 8.3:1 which I hope is low enough for turbo application - no faffing about taking the block out and replacing pistons!

From this stage, I obviously need to buy a few more bits for the conversion, can anyone confirm this list?

-Metro carb+inlet manifold (is the plenum part of the assembly?)
-R5 Turbocharger
-Mirage pipes
-assorted fuel return pipes+pump/regulator (nightmare)

I've seen a metro fueling system on ebay for about 30 quid, http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...&category=10414 but dont outbid me!!! and I recon I'll be safe with a r5 turbo unit from the same place, as I wont be running much boost it doesnt matter if its a bit on the smokey side.

If anyone can give me some advice on the next few stages It would be much appreciated..

BTW, my budget for this conversion is about 650 quid and counting down! (50 spent on the head already)

Psshhhtt

Hello and welcome...

I think you have hit the nail on the head there... I'd thought about that head with a turbo too :)

The only other thing you need for your list is a modified fuel tank to take the return...

The only problem I can see is the cost.. if you were going for std t3 then I'd say you were ok, but it might be tight with the mirage manifold (they are just far to much labour to ever be a cheap item).

Alex

AlexF

At least I know im on the right sort of track!

As far as I can see, I'm going to have to buy a MPi tank to replace the standard carb tank on the 998 as they have a return feed built in.

The reason I want to go for the T2 is I wont need to chop up the car, or even remove the engine (I think), its just a case of slapping it all on - I dont have the luxury of a garage or even a driveway!

350 for the mirage kit leaves another 300 for the turbo, tank, lines, pump/regulator and refacing the head+new valves (the old valves are all f*cked)

Any other advice would be appreciated

P.S. Just got that pun

Just seen this

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...tegory=633&rd=1

Might be able to extend my budget if thats the right kind of turbo - at least it will last..??

Only thing i can think, is that the Mirage kit is Very tight (about as low as you can get away with) regarding height at the oil return into the 'fuel pump' hole.

As i recall, the small bore blocks are around 3/4" ??? shorter than the large bore units, hence the turbo will sit even lower. This will mean the oil drain is sligthly restricted (like the u-bend in a toilet).

Unless, you do like Jimster and myself and TIG weld a 16mm pipe into the gearbox casing to act as the return, sufficiently low to not give problems...

Check with mirage on their thoughts, but the last thing u want to do is restrict the oil return on a turbo....

WOW ?300?

a rebuild is not often that much :S


As Dave says watch out for the turbo drain... its vital.

alex

AlexF

Correct me if im wrong, but surely feed for the turbo comes from 'infront' of the oil pump therefore under the same sort of pressure as the rest of the engine (can someone explain the plumbing to me) and the return will be at some sort of pressure - at least enough to feed back into the sump. The engine I have has a healthy 60kg/cm2 of oil pressure at 1000rpm, so surely this is enough to overcome a slight u-bend.

As i say, correct me if im wrong - but i cant visualise it

The oil return from the turbo is under no pressure, just like the oil that exits the bearings and returns to the sump.

I run a metro turbo return into the fuelpump hole on a 998 turbo and although it's not spot-on 90 deg I've never had any problems with oil return.

Wil

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

No theres not... you'll have to write one when you do yours!

The oil drain is definalty not under pressure, the return tends to be frothy hence the large dia pipe... if the oil can't drain freely and you get backing up in the drain, the engine will at best smoke like hell and worst destroy the turbo as the cooling effect of the lubricant isn't working properly.

Alex

AlexF

Just thought i'd add some pics just to keep this thread alive - and hopefully get some more responses/advice

the state of the 12g295 - http://flatbed.dyndns.org/dirty/images/seatclean.jpg

http://flatbed.dyndns.org/dirty/images/chamber2.jpg

(I know this next bit is in the wrong section, but my car isnt quite a turbo yet )

My car (a bit dirty)

http://flatbed.dyndns.org/dirty/images/front.jpg
http://flatbed.dyndns.org/dirty/images/back.jpg
http://flatbed.dyndns.org/dirty/images/dash.jpg

looks good....


alex

AlexF